AmpliTube

Turn your iPad into a fully featured electric guitarist's studio with one simple app!

AmpliTube mimics a typical guitarist's setup, providing you with an amplifier, effects pedals and a little recording studio, all on your iPad. All you have to bring to the party is your electric guitar, some talent and a pair of headphones. Oh, and a cable to connect your guitar to your iPad (or iPhone - there's a separate version available). There are two main types of cable on the market - the AmpliTube-branded iRig. Both work equally well with the AmpliTube app, but we prefer the iRig for build quality.

The level of detail in the photorealistic amps and effects pedals is superb - it's just like using the real thing. The downside of this is that the casual guitarist could well be put off by the level of complexity involved in setting an amp up, but thankfully there are presets available for each amp with names like 'Smooth lead' or 'Seattle'.

In the free version of this app, you get just three pedals (Noise Filter, Delay and Distortion) and one amp - with more available as in-app purchases. You can also purchase a version of the app with five amps and 11 pedals and make a significant saving compared to buying every item individually. But even with this version of AmpliTube, you still need to make in-app purchases to get all the extras, such as the upgrade to an eight-track recorder.

Other features of note include the ability to import songs from your iPod app (or over your Wi-Fi network), so you can play along with them. The lengthy importing process is a real hassle, but once it's done you can slow down the track and loop individual sections. Results are mixed, however - slowing down songs seems to result in a lot of audio crackle.

The app did crash a few times on us too, but these are relatively small niggles compared to the fun that's to be had here. Its nearest competitor is Griffin's iShred, but AmpliTube beats it hands down for sheer versatility, even if iShred works better with the iPod app.

Private spacecraft orbits Earth

The commercial space industry celebrated a landmark achievement on 8 December 2010, when California-based company SpaceX launched a spacecraft into orbit and successfully brought it back to Earth. It's the first time a commercial company has ever recovered a spacecraft from orbit, and it paves the way for private spacecraft missions to ferry supplies to the International Space Station. NASA Administrator Charles Bolden called the feat a 'dramatic step forward'. "We're witnessing the dawn of a new era, whose ultimate result could be routine, safe access to space with industry, academia and governments regularly sending payloads and people to low Earth orbit. That's the goal," he said. SpaceX used its own Falcon 9 vehicle to launch the Dragon spacecraft, which is capable of carrying a payload of six tonnes and could eventually be crewed by up to seven astronauts. Both the Dragon spacecraft and the first stage of the Falcon 9 are designed to be reusable, which is a key part of long-term plans to reduce the costs of spaceflight a factor of 10.

After lifting off from Cape Canaveral Air Force Station in Florida, the Dragon spacecraft orbited the Earth twice before re-entering the atmosphere. An advanced heat shield protected it from temperatures of up to 2,200"C. It then deployed parachutes before gently splashing into the Pacific Ocean off the coast of California.

"This has really been better than I expected there's so much that can go wrong and it all went right," said the company's CEO Elon Musk following the mission, which took less than four hours from lift-off to landing.

Later this year, Space X plans to carry out a five-day mission in which the Dragon will approach within 10 km (6.2 miles) of the International Space Station and communicate with its crew before returning to Earth. After that, a full cargo mission that docks with the station and delivers supplies should take place.

SpaceX has a $1.6 billion contract to make at least 12 flights to the International Space Station, following the retirement of NASA's Shuttle fleet later this year after nearly 30 years of service.

Japan's Energy Options in an Non-nuclear Future

Few months after the explosions and radiation leaks at the Fukushima Daiichi nuclear power plant in japan, the prime minister, Naoto Kan, has announced that the country will not build any new reactors.

If Kan really means it the government will have to abandon the plans for expanding nuclear power it adopted only last year. To make up the energy shortfall, Kan has set the ambitious goal of using renewables.

That is most likely to mean wind, according to a report released last month by the Ministry of the Environment There is "an extremely large introduction potential of wind power generation", it says, especially in the tsunami-hit north-east of the country.

'The potential of wind is huge because of the contribution from offshore generation with japan's long coastline," agrees Tetsunari Lida, founder of the Institute for Sustainable Energy Policies in Tokyo, who advocates a 100 per cent switch to renewable energy by 2050.

At present japan produces just 3 per cent of its electricity from renewables: solar; wind and geothermal. Nuclear contributes 30 per cent.

Taking into account wind strength, available land and the potential for offshore farms, the report estimates that japan could install wind turbines with a capacity of up to 1500 gigawatts. More realistic estimates in the report suggest that with appropriate financial incentives, turbines with a capacity of 24 to 140 GW could be installed. Assuming the turbines operate a quarter of the time, this would provide up to 35 GW of electricity on average, matching the combined output of about 40 of japan's existing 54 nuclear reactors.

Next in line is solar energy, which the report estimates could provide between 69 and 100 GW without taking up any productive agricultural land.

Perhaps surprisingly, given japan's 120 active volcanoes and the 28,000 hot springs associated with them, geothermal energy scarcely figures in the ministry's report. At best it says, only 14 GW is available, but much of that is inaccessible because of restrictions on development in national parks. At other sites, exploiting geothermal energy would disrupt springs currently used as spas.

A switch to renewables will require huge amounts of new infrastructure. This will need to be paid for by offering special tariffs as incentives for providers to feed energy from renewable sources into the grid. By coincidence, on the morning of 11 March - the day of the earthquake the japanese cabinet approved proposals that would achieve this. "It's under review by the parliament and could provide a really big push for renewables if it's passed" says Lida.

The contribution from renewables to japan's electricity supply is currently almost static, having increased from 3.1 to 3.3 per cent between 2008 and 2009. Lida blames "poor policy support'' for this lack of growth. So it is possible that as the shock of Fukushima fades, support for renewables will go the same way. However, polls reported this week suggest that two-thirds of japanese back a shift away from nuclear power.

Making the upgrade

This time, sensation-seekers, I'm going to talk about the three different bits of hardware in my office that I considered upgrading, and how I walked myself through each decision.

Device 1: Compact digital camera.

Reason for upgrading: A maturing technology. My three-year-old, but highly-beloved, Nikon P6000 pocket camera is exactly the sort of camera I like: small enough to slip into a pocket, but big enough to operate comfortably, and with a sprinkling of advanced features that allowed me to use it as my sole travel camera.

Last year, I did some work for a pal and he generously gave me his Olympus PEN E-P1 camera as a thank-you gift. I soon fell in love with the Micro Four Thir-ds system. It filled a gap for me: I travel a lot and take a lot of photos. and I am hellaciously fussy about the results. As great as my Nikon is, there's no ignoring the facts: it has a tiny image sensor and you can't swap out its fixed zoom for a more appropriate lens ... like Panasonic's magnificent 20 mm f1.7.

With that lens on the Olympus' body, I had nearly the optimum travel camera. It had most of the important features of my Nikon and it wasn't that much larger.

One problem: the Olympus doesn't have a built-in flash. What a pain in the butt! Also, the E-P1 was one of the first Micro FourThirds cameras made and I was eager to see how far the cameras have come after two years.

February seemed like the perfect time to upgrade. Olympus and Panasonic released new Micro Four Thirds cameras. The new Olympus was much like the E-P1, but it had a flash; the new Panasonic was barely larger than the Nikon. After a temporary dalliance with Nikon's fairly awesome P7000 (with its heroic assemblage of mechanical controls), I knew it'd be one or the other.

What I did: I bought an external flash for my Olympus.

Why: After poring through technical specs and advance reviews, I couldn't get excited about either new camera. I was hoping for a major advancement in Micro Four Thirds that would materially improve the Olympus, but I sure didn't see it in the reviews.

The clincher came when I found a couple of intense hardware teardowns and learned that both cameras were using two-year-old image sensors. I want the next-generation component: the one that'll allow next year's Micro Four Thirds cameras to shoot gorgeous photos in low light. And honestly, my big problem with the E-P1 was no flash. Fine: buy a flash. Sometimes you're so enamoured with having The New Version that you forget that the point of the expensive exercise is to solve problems.

Device 2: iPad.

Reason for upgrading: Er ... it's the iPad 2! I love iPad! That's, like, one whole iPad better than my iPad 1!

What I did: I stuck with my original iPad.

It's not that the iPad 2 isn't a huge improvement. Its CPU is a monster. When I ran it through its paces for a review, I didn't test its speed with an engineering benchmark suite. I used real-world apps. One task that took my old iPad more than three and a half minutes to process was chewed up and spat out by the iPad 2 in just 52 seconds. Whoosh!

Oh, yes, and the cameras and the Smart Cover and the gyroscope. I duly tested and wrote about it all. After I filed my review and I started thinking about the iPad like a consumer instead. I recognised all of those features as Nice Things that nonetheless I didn't really need.

But the speed!

Yeah. Well, Apple does a great job maintaining iOS as One Platform, With liberty And Time-Wasting Apps For All. Any app written in 2011 and probably even 2012 will work on my iPad 1. In the end, the speed of the iPad 1 isn't a handicap; the speed of the iPad 2 is a bonus.

Given that I wouldn't do anything with an iPad 2 that I can't already do, I'll wait until next year to upgrade.

Device 3: MacBook Pro.

Reason for upgrading: My current MacBook Pro is three years old. That's like having 125,000 miles on a car. You don't drive it to the scrapyard, but you know that it's entered its zone of Obsolescence.

There's always a faster CPU on the horizon. Tastes change, too. My 2008 MacBook has an ExpressCard slot. In theory, it'd open up a world of hardware enhancements. In practice, I wish it were an SD card reader.

Plus, my MacBook is my daily-use computer. I pound on it for hours a day, seven days a week and I've carried it around the world. Wear and tear is starting to show. The trackpad button hasn't worked since I splashed some coffee on it, and I'm lucky if the battery lasts 15 minutes.

What I did: I bought a new MacBook Pro.

If I'd upgraded last year, I would've had a slightly faster Mac, an SD slot, a working trackpad, and a nine-hour battery. Nice ... but this year, I got a CPU whose architecture is a whole generation ahead. It's clear that Apple's investing heavily in this new ultra-high-speed. multi-channel Thunderbolt I/O port. too. If the standard takes off, my new Mac Book will work with all of the great new high-performance hardware that's going to be released in the coming years. And if Thunderbolt fizzles ... who cares? It's still a functioning Mini DisplayPort.

This is a Mac that will get me through the next three years. That's a big deal given the scale of Mac OS X 10.7 and the OS to follow. I just need to not spill a drink on it.

The past month served as a reminder that hardware should only be replaced if it's about to stop working (whether it's worn-out or just not up to challenges that didn't exist when you first bought it) or if the new one can transform the way you work. Otherwise, you're just being a big, dopey consumer.

I did the smart thing. I thought my way through three potential upgrades, and only made one purchase. lucky me: it was the $2,000 item.

Use your iOS device as a MIDI control surface

If you don't want to wait for a commercial iOS-device control surface for your favorite DAW or virtual instrument, and you're willing to forgo some advanced features (two-way communication, for example), designing your own is much easier than you might think. You'll want to use OpenSound Control (OSC) because it is designed for network communication, and if you're not targeting an application that supports OSC, you'll need to convert the OSC messages to MIDI.

Hexler TouchOSC ($4.99 from the iTunes store) is an iOS application that hosts OSC control surfaces and handles WiFi communication with your computer. The free downloadable companion program TouchOSC Editor lets you design the control-surface GUI on your computer (Mac, Win, or Linux) and upload it to your iOS device. OSCulator ($39, Mac, osculator. net) lets you easily map OSC messages to MIDI messages and provides a MIDI port for routing these messages to your MIDI applications. The process for Windows is a bit more involved; it is documented on the Hexler website (hexler.net). Here are the details for a control panel that I use frequently with Propellerhead Reason.

Combinators Ready

TouchOSC Editor offers graphic elements for use as buttons, faders, knobs, labels, and LEDs. You can get as device specific as you like in your design, but you'll save lots of time and probably build a more useful control surface if you keep it generic. One way to do that with Reason is to target the Combinator module. That lets you control any Reason device by wrapping it in a Combinator and mapping its controls to the Combinator's.

Figure above shows the layout I use on my iPad. It controls as many as four Combinators along with four mixer channels into which the Combinators are routed. I've avoided labeling any of the iPad elements for the Combinators, relying instead on the labels on the Combinator to remind me of their function. I can use this iPad control surface with any Reason song that has a Combinator in it, ignoring any unused Combinator and mixer controls.

Once you design a control surface and upload it to your iOS device, launch OSCulator and ensure the iOS device's TouchOSC outgoing port matches OSCulator's input port (8000 by default). Touch the iOS device graphic controls one at a time and each will appear as a separate message line in the OSCulator window. These lines are ordered alphabetically by control name, so if you rename the controls in a logical fashion as you create them in TouchOSC Editor, you'll be able to easily identify the line corresponding to each control. (Edit only the part of the name after the last slash and limit yourself to lowercase letters and numerals.)

The next step is to set the MIDI event type, number, and channel for each line. Then lock the OSCulator document (Command + L) and save it. You'll need to open this document each time you use the TouchOSC control surface.

You can use your target's MIDI-learn function to map OSCulator's MIDI output to the desired controls, but in Reason, it's easier to set up OSCulator as an Advanced MIDI input and use Reason's built-in MIDI routings. Use a different MIDI channel for the mixer and each set of Combinator controls, and use Reason's Hardware Interface panel to route the controls by channel to the corresponding Reason devices.

Mobile Networks and Digital Dividend

Mobile networks, also called cellular networks, are based on different kinds of multiple access schemes in their radio interface (communication between mobile station and base station). Traditional multiple access schemes, such as Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), and Code Division Multiple Access (CDMA) are utilized in first-generation (1G) and second-generation (2G) systems.

Mobile Technology

Analog FDMA-based networks, such as Advanced Mobile Phone Service (AMPS), Nordic Mobile Telephone (NMT), and Personal Handy phone System (PHS), are called first-generation systems. The first digital mobile networks, such as North American TDMA (also known as D-AMPS because of the same frequency band used), and cdmaOne, European Global System for Mobile communications (GSM), and Japanese Personal Digital Cellular telecommunication system (PDC) are called second-generation (2G) systems. Enhancements of 2G systems, such as packet transmission - General Packet Radio System (GPRS) and Enhanced Data calls for GSM Evolution (EDGE) - are usually referred to as 2.5G.

In specification work, the International Telecommunication Union (ITU) defines the common name IMT-2000 for 3G systems, and the third generation partnership project, 3GPP, takes care of standardization work for the entire mobile network family - GSM (2G), GPRS (2.5G), EDGE (2.5G) and UMTS (3G).

Universal Mobile Telecommunication System

UMTS as a system is an evolutionary step for voice and data calls of different transmission rates measured in kbps or Mbps. The key idea of UMTS is to be as dynamic as possible and to use system resources for different purposes (for example FACH or RACH channels for both signaling and low data traffic needs). Voice calls range from low quality to high quality (6-12 kbps, for example), depending on the user profile. Data services also vary (from 0 kbps to 2 Mbps), depending on the application needs. Various data applications like video streaming and games are aggressively marketed, even though the applications most expected today are email and Multimedia Messaging Service (MMS) solutions, and the major goal of UMTS is the reduction of response time in these data transmission applications.

The UMTS network contains Radio Access Network (RAN), Core Network (CN), and Network Management System (NMS). Radio access network is also called UMTS Terrestrial RAN (UTRAN), and radio access (radio interface) is also called UMTS Terrestrial Radio Access (UTRA). GSM is also part of the UMTS network; thus the UMTS system has similar types of interfaces and network elements as in GSM. Due to similar architecture, the UMTS part of the specification is similar to the GSM part of the specification (for example, in the names and use of signaling channels or radio interface parameters); therefore, a good knowledge of the GSM is very helpful in understanding the UMTS system.

Digital Dividend

The latest development in mobile technologies is LTE (Long Term Evolution) technology which will be mainly used in frequency bands which were released after the transition to digital TV broadcasting - digital dividend. 3GPP Long Term Evolution is the latest standard in the mobile network technology tree that produced the GSM/EDGE and UMTS/HSPA network technologies. It is a project of the 3rd Generation Partnership Project (3GPP), operating under a name trademarked by one of the associations within the partnership, the European Telecommunications Standards Institute. The LTE specification provides downlink peak rates of at least 100 Mbps, an uplink of at least 50 Mbps and RAN round-trip times of less than 10 ms. LTE supports scalable carrier bandwidths, from 1.4 MHz to 20 MHz and supports both frequency division duplexing (FDD) and time division duplexing (TDD).

The mobile industry is seeking an allocation of at least 100 MHz of Digital Dividend spectrum in all regions, awarded on a harmonized basis. With such an allocation, the vision of mobile broadband everywhere can be transformed into a reality. Spectrum (or frequency) harmonization, where countries across a region use the same spectrum frequency, is vital. It is critical for the successful, cost-effective deployment of any wireless service as it provides the economies of scale which drive down handset and network equipment costs and encourage innovation. Without such harmonization, handset costs could be prohibitively high, which would reduce uptake. This would harm not only consumers and the mobile industry, but also reduce the benefits that mobile technologies bring to national economies. If spectrum allocation is not coordinated internationally, then many smaller markets may be neglected by device manufacturers, who would naturally concentrate on larger markets, with greater potential for volume sales and a higher return on investment.

Apple, iPad and Fashion

Anyone who dismisses the iPad as simply a big iPod touch is missing the point. Because of its size and the fact that it's based on an OS designed solely for touchscreen devices, the iPad could be called the first truly usable tablet. It's a great way to read, watch TV shows and movies, surf the Web (sans Flash, yes), take notes and even write longer-form items (with or without an add-on keyboard), and do a hundred other things. Businesses are finding ways to use them, as well.

With every new tablet released, pundits proclaim the arrival of an "iPad killer"- claims that echo the many false predictions regarding the fate of the iPhone. The fact is that the iPad has a big head start, and Apple and the huge community of developers will continue to make it better. There's no such thing as an iPad killer-get used to it.

iPad 2

The iPad 2 is here. All of you people who refuse to buy the first version of any product can now emerge from hiding and buy an Apple tablet device safely and securely.

As with all new Apple products, the iPad 2 is fascinating because of the choices the company made about which features to add (cameras and a magnetic case), which ones to change (thickness and weight), and which ones to leave out (an iPhone 4 - class Retina display).

But for me, perhaps the most interesting thing about the iPad 2's release was the pair of Apple-created apps that appeared alongside it: Garage Band (which also runs on the original iPad) and iMovie (which ran on other iOS devices, but has now been expanded to run on the iPad 2).

Tapping Out Rhythms

Let's get this clear: I'm no musician. I can play a bit of piano and I can sort of sightread music. But my musical education ended when I was in my early teens. Over the years, I've noodled around a bit in the musical corners of Garage Band on the Mac. But I never had as much fun as I did in the first few hours I spent playing with GarageBand on the iPad 2. The introduction of "smart'' instruments and the tactile nature of the iPad make the difference, I think GarageBand's Smart Instruments eliminate the learning curve usually required to make pleasant sounds: Once I set my song in D major, the smart guitar transformed into eight complementary chords, which I could play it' by touching the chord name, strumming in the strings, or choosing one of four auto- g play styles. Within 15 minutes I had created f2 a multilayered track with guitar, bass, organ, and drum parts. (My apologies to Fountains of Wayne: I butchered "Hey Julie." But I had fun doing it.)

Now, the tactile thing: To use GarageBand on the Mac, you have to use a mouse or (if you're really cool) a USB keyboard or a guitar with a fancy input. Playing music with a standard keyboard isn't fulfilling. But tapping out chords on an iPad screen, and running your fingers over virtual guitar strings? Fun. It's that simple. Not that Garage Band on the iPad is frivolous or dumbed down.

Unless you just don't like music, you will never get more for your $5 than by buying GarageBand for your iPad.

Making Movies

iMovie on the iPhone showed that a simplified video-editing app could work on an iOS device. iMovie on the iPad 2 shows that it doesn't even have to be that simplified. The app actually makes the radical redesign of the Mac version of iMovie make sense. iMovie on the iPad isn't the same as iMovie on the Mac, but you can tell how the two are related, and I'd imagine that they'll become even more so in the future.

iMovie on the iPad has room for an editing timeline, a preview window, and a view into the iPad's video library, making it easy to pick clips and add them to your project. I was able to piece together a video, trim clips, set transitions, and even record a voice-over in no time at all.

Unfortunately, iMovie can't use video files that aren't in the specific format shot by iOS devices. That will limit its appeal until more cameras start to support the ability to shoot video in formats iOS devices can understand. As a result, I won't be using iMovie on the iPad to edit my home movies just yet. Unless, that is, I ditch my camcorder and just start shooting everything with my iPhone 4.

But that quibble aside, let's step back to appreciate what iMovie on the iPad represents. This is a tiny, thin tablet that can edit high-definition video files without breaking a sweat, and then package them up and shoot them off to YouTube or Vimeo. A few years ago my iMac struggled to edit SD video.It's amazing the strides Apple has made, and it's no wonder the company chose to release this new version of iMovie to show off the increased power of the iPad 2. It's impressive.

The App Story

These days, so many stories about Apple focus on the success of the App Store, especially the sheer number of apps that are available. With the release of iMovie and GarageBand, Apple is sending a slightly different message: It's not just the number of apps; it's the quality of those apps-and of the devices that run them.

Conclusion

Finally, let 's send all the best wishes we can to Steve Jobs and his family. He's on a medical leave of absence again and I'm sure we'll find out sooner or later what the reason is this time but let's hope he recovers quickly. I'm not saying that for Apple's sake as I think the company will be just fine without him. Hopefully he'll return fully recovered to the helm of Apple during the year.

FM Radio - Free Music on Every Corner

Radio is probably one of the most popular free services. We can listen to it just everywhere. At home, at work, in the bus, in the car, while we walk, etc. With the term "radio" we usually mean a sound service that we can receive and is usually free, without any subscription or expensive equipment. With radio you also get free music. You can listen to it while working or you can relax and enjoy listening to your favorite band. There are many ways to get such free sound service. Each has some advantages and disadvantages but the fact is that the old FM radio as we know it is far the most widely used broadcasting service.

You can listen to radio stations that are broadcasting over internet. This service is still free, but you need access to the internet and a computer. There are also some devices (network players) that support internet broadcasting, but you still need access to the internet, either wireless (WiFi) or over local network. The advantage of internet broadcasting is that there are thousands of stations so it easy, at least in theory, to find a station that plays music according to your taste. Cable and IPTV systems also offer radio stations but this is limited to the place where you have the connection.

Satellites also offer a lot of radio stations. But to receive satellite stations you need a satellite receiver, so this type of reception is only suitable for home listening. There are also mobile satellite radio services, but in general they are not free. You have to pay a subscription. Despite the fact that satellite services are cheap and you get large coverage areas, this type of broadcasting is not suitable for general reception. Satellites do offer a huge choice of stations, but the receiving equipment is pretty complex.

Therefore, terrestrial broadcasting is the most popular platform for radio. While AM broadcasting is still used in some countries, mainly for international broadcasting, it is the FM radio that we can find it on every corner. There are many reasons for its popularity. It is free, you only need a simple and cheap receiver. Receivers are now integrated also into mobile phones, MP3 players and many other devices. The quality of FM (frequency modulation) is very high. With quality stereo reception and some high-end receiver you get superb sound quality comparable to vinyl records.

Because of many advantages of terrestrial broadcasting there are many stations interested in using this media. Of course, the radio-frequency spectrum is a limited resource and only a small fraction of the whole spectrum is allocated to broadcasting. Therefore, we can fit only a limited number of stations into this band. In addition to this, to prevent harmful interferences there are many strict rules on frequency planning which further limit the number of possible radio stations that we can receive.

But despite all the disadvantages and limitations the FM radio will be used for many years to come. Interestingly, there is still no comparable digital broadcasting system that could replace the old analog radio.

Radio Frequencies - What Do They Mean and Why Are They Important?

Radio frequency spectrum is a natural and limited resource. Radio waves are a mean to transfer information from one point to another without using any media. One of the most important properties of any waves is their wavelength or frequency. Radio frequency determines the position in Radio frequency spectrum and hence all the properties of radio wave propagation and potential use.

Because radio waves travel across country borders and may interfere with other radio waves there are many rules, frequency plans and procedures that define how to use radio frequency spectrum to avoid interferences. Because different frequencies have different properties there are some general harmonized frequency bands that define main purpose of the band and basic technical parameters of transmitters using these frequencies. The so called allocations are accepted on international levels and provide basic rules for frequency usage. Each allocation is then further refined and countries may have special agreements on how to use specific frequencies.

One of the most popular services using radio frequencies is terrestrial or satellite broadcasting. Radio and television are a well know and established way to send picture and sound with radio waves. Because we usually want large coverage areas with few transmitters we are using high power transmitters on high transmitting sites. Large coverage areas also mean coverage across the border.

This is a very important fact because in the same area there can be only one transmitter that can operate on a particular frequency without causing interference. Of course, there are special cases like digital broadcasting and single frequency networks where nearby transmitters operate on the same frequency without causing interference, but for analog broadcasting careful frequency planning is a must.

For broadcasting frequency bands there are many special regional agreements that very precisely define particular frequencies allocated to each country, procedures to be used to modify the plan and also many rules that have to be respected to avoid interference.

When we would like to listen to a particular radio we need to know the frequency on which this radio broadcasts. A frequency is like a street address where each house has its own number. For television the same applies. However, for practical reasons we usually do not operate with frequencies directly but we use channels where each channels number represents one (central) frequency with some channel bandwidth.

In general, most consumers are not aware of all the technical details that regulate frequency usage and are used to provide many wireless services. They only expect good music, quality movies and mobile phones that work anywhere.

Home Web Hosting - Access Your Home Server From the Internet

If you are a webmaster developing or maintaining websites then you probably have a home web server for development or testing purposes. An old computer can easily be transformed into a Linux server. If you install also Apache, MySQL and PHP applications you will be able to host websites at your home. Of course, this is not the same hosting as offered by commercial providers, it is only a place where you can install, develop and test web applications. With some additional settings you can access your home computers from any place that has internet access. This is very convenient for getting files you forgot at home.

Assuming that you already have a local area network (LAN) including the router, which is a bridge between your computers and the internet, you need no additional equipment. In order to enable web access from the internet, you have to configure your router to forward outside web requests to the your server. The default port for web is 80, but you can choose any other port number to increase security.

The first prerequisite for remote access is a domain. This is the name of your home server on the internet. There are many services that offer free domains and free updating of IP addresses. This is especially important if you don't have a static IP address. Most internet providers dynamically assign IP addresses which change once a day or with every connection. Since knowing your external IP address is crucial to access your computers from the internet, you need a way to update the domain DNS records.

Many routers support popular dynamic DNS services like DynDns. If your router has no such function you can still install simple software utility on your computer which will update address every time it will be changed. You should create an account, select preferred domain name and choose your name which you will use as a sub-domain. This account data you should enter into the router settings or external software for IP address update.

Now you have access to your router. Each time you will enter your name followed by the chosen domain, you will reach you router. If you have enabled access to its user interface from the external port, you will be able to configure it as you do it from your home computer. To reach your server you need to configure port redirection. If you would like to use the standard port 80 for web access, then simply create a rule to forward external (public) port 80 to the local port 80 at IP address of your web server. This is everything that is needed to access your web server from anywhere.

For hosting of real websites especially if they are commercial in nature you need a reliable hosting like Hostgator. Simply because the website needs to be available 24 hours a day and downtime in the case of hardware failure should be as short as possible. Commercial hosting companies usually provide professional service for few dollars per month. This includes unlimited number of domains, unlimited disk space and many other goodies.

Having a possibility to access home computers from any location is very useful when you need some files or data from home. Even if you have a dynamic IP address you can access your development websites and show them to your friends or clients.

What to Look For in a LCD Computer Monitor?

In general, it is difficult to say which computer component is most important. Probably there is no such component. Every part is needed to perform some task otherwise we wouldn't need it. But there is one difference. With some computer components we have direct contact. One of such components is monitor. Computer monitor communicates with us in a very special way. It displays all the information about the status of the computer as well as windows of currently active applications. Therefore, it is essential that this computer component is carefully selected and that it displays stable and clear picture.

Currently LCD is the predominant technology for computer monitors. There is no big difference between computer LCD monitors and LCD TV sets. The only major difference is the additional interface electronics that makes a LCD TV set look like a television and LCD monitor to look as computer monitor.

Usually, when buying computers we look at the price tag. This is normal since price ranges can vary significantly. But the price should not be the only parameter upon which we will make a decision. When buying computer monitors we should consider the following:

Main Purpose of Our Computer
We can use the computer as office tool, gaming machine, designer's drawing board, or a combination of listed and also other purposes. Each purpose needs emphasis on a different parameter. For example, designers working in desktop publishing need large desktops and realistic color reproductions, games need monitors with fast response, etc. The first step in choosing monitor is to define the main purpose of the computer.

Size
The bigger the better. This simple rule is valid for all computer purposes. With larger working area you will easily work with many applications at the same time. Application windows will not be squeezed to small cluttered rectangles, the taskbar will look as a nice informative bar and not like a bar with many small buttons, on the desktop you will be able to put more icons for frequently used programs, etc. Because all LCD monitors are flat there will be no problem with the space on the table. So the only disadvantage with large monitors is maybe higher price.

Resolution
Again, the bigger the better. The display resolution tells us how many pixels or points the monitor can display. More pixels means larger monitor or smaller image dots. A typical resolution for multipurpose computer is 1920x1200 pixels. It allows comfortable work with office programs, web browsing and also good experience with CAD programs.

Interfaces
Almost all computer LCD monitors have DVI input. This is standard for computer graphics cards. If we intend to connect multimedia devices we also need a HDMI input. Many monitors have also integrated USB hubs. This is very handy to connect keyboard, mouse and external disks. Some computer monitors have also a TV tuner which converts them into a real TV set.

Choosing computer monitor is not an easy task even if you know what to look for. For more tips and hints you can visit the http://computerlcdmonitors.org/ website which provides few basic facts about computer LCD monitors.

Perhaps the most important fact you should remember is that you will be staring for hours into this flat panel. Make sure it will look pretty.

Universal JTAG Cable

Every electronic device around has some microcontroller or other programmable device in it. Even kitchen appliances or toy has some kind of electronics which controls important functions. In some cases this electronic device has predefined functionality which can not be changed. But in most cases this electronics contains a processor that uses flash memory to store code. And if a device is programmable then you can change the program it runs at any time.

Of course, in many cases this programming is not needed since the electronics performs what is supposed to. But in some cases it makes sense to allow end users to update the device with the latest firmware. Therefore, it makes sense to have a universal interface that can be used in factory and at home to program electronic devices with simple additional hardware. This universal interface is JTAG. This is a standard that defines a serial interface to transfer data between a device and computer (or between devices). The JTAG interface needs only four basic signals. This makes it easy to use PC parallel port as JTAG interface. While this works many modern JTAG programmers use USB port to connect to the PC.

Another beauty of the JTAG interface is the possibility to connect many devices in chain. This way you can program all the JTAG enables devices on the board with only one interface. In any case you need a JTAG cable to connect to the device. Each device may have own JTAG pinout but this is not a problem since JTAG cables can be made (almost) universal--at least for few device types. Unfortunately, JTAG cable is not enough. You need also a suitable software that will program the target device.

JTAG is not used only for commercial electronics. It is also a standard interface for all embedded systems including FPGAs, microcontrolelrs and various memories. Each manufacturer has some kind of JTAG cable to program their devices. Unfortunately, these cables use dedicated software and can not be used for other purposes.

One of the very popular uses of the JTAG interface in consumer electronics is to reprogram some router models with new firmware. There are many cheap JTAG cables that can be used to bring a new life for an old router. Changing original firmware is very popular not just for routers but also for other highly popular electronic devices. The Xbox is such example where a simple JTAG hack can change some built-in functions.

There are many JTAG cable supplies around. Before you decide for specific cable you need to check the JTAG pinout and software support. Usually, cheap cables are made only for specific devices and use the parallel port signals to program the device. More advanced JTAG cables use USB interface or at least a buffer to boost signals from parallel port.

Digital Television and Computers - Watch TV on Your Computer Monitor

Digital television broadcasting uses satellite and terrestrial platforms to deliver content to the viewers. Digital television is available also via cable and IPTV networks. Most people use TV sets to watch their favorite channels, but there is an alternative way of watching television. If you have a computer you can receive and decode all available channels including premium services if you have a suitable subscription card.

There are at least two methods to upgrade your computer for television reception. You can either use an internal radio/TV card or a small USB stick. Both hardware solutions work well and are not expensive. USB stick is more suitable for use with laptops but you can also use it with a desktop computer as a permanent solution. There are many different models that support different technologies. For terrestrial broadcasting in Europe and many other countries your device should support DVB-T. DVB-S in needed for satellite television and DVB-C for cable reception. Many cards and sticks also support analog FM radio and analog TV. Before you purchase such card or stick you should check which standards are used in your country.

Many internal cards have on-board audio/video decoding support. This hardware decoder does the work which is otherwise very time consuming and processor intensive. USB sticks have no hardware decoder, there is only a demodulator that supplies the DVB transport stream. While the main computer processor will have to decode the sound and picture, this is also an advantage. It is much easier and cheaper to update decoding software than to replace decoding hardware.

Most TV cards and sticks are provided with a remote control. It is very similar to the real TV remote control and enables you to turn your computer monitor into an advanced TV set. Every television decoding software allows you to display the TV picture over entire screen so you can enjoy as in front of standard TV set. The only disadvantage of this way of watching TV is that while you watch full-screen TV you can not use the computer for other work.

Receiving television channels with computer has also one big advantage. You can easily record any channel. You can also record one channel and watch a different one. This is all possible because the software is able to decode many different services simultaneously. Of course, this also depends on the speed of your processor, but in general recording of particular channel or entire stream is not a problem.

Digital television is much closer to computers than it was in the old analog days. Digital broadcasting uses codecs which have roots in computers. Watching television on the computer is nothing new. In fact, digital broadcasting is only a network of many dedicated computers and peripheral devices.

Computer Forensics - How Volatile Data is Analyzed

Computer forensics plays an important role in fighting terrorism and criminal activity. The fact is that bad guys use computers, internet and other modern communication tools to communicate and to store their plans. We would be naive if we would think that they can barely open Word or Excel. They are aware of all the risks and they protect themselves with modern encryption algorithms and general protective measures. Fighting criminal activities is very different from discovering occasional violations on company computers.

Many traces can be hidden if the software used for criminal activity or otherwise unwanted is not present on the computer disk and runs in the memory of the computer. It is very easy to start some process and then successfully cover all traces that were left behind. In such case analyzing disk data makes no sense because nothing suspicious could be discovered. The only solution to this problem are tools that can protect volatile data like live memory.

The static analysis of computer data (i.e. the analysis of a hard disk removed from the computer) is usually not enough because many advanced techniques can be used to erase all traces from file systems and the only relevant data remains only in memory. Theoretically, it would be possible to freeze computer memory by liquid nitrogen and this would significantly increase chances to recover the data but this approach is not practical. Analysis of live volatile data in a computer is essential for any serious forensic analysis.

There are many open source and professional commercial forensic tools that can make a snapshot of crucial volatile data for later analysis. Such tools can discover open ports, virtual disk drives, VPN connections and other resources not visible to the normal user. In some cases also the whole disk drive or individual partition can be encrypted so it is important to make an image of it before the system is shut down. Once all the data is safely stored it can be analyzed regardless of the state of the computer.

A logical question would be, for example, what can be done to successful hide some processes running in the computer memory? Theoretically, it would be possible to eliminate traces from the memory when the process is not active or when it waits for some input. But even for such approaches there are some solutions. It is possible to create memory snapshots at periodic intervals and sooner or later the secret process will show itself.

For many computer users the most requested computer forensic service is recovering lost files. Check the http://digitaldatarecovery.org/ website for some practical tips on digital data recovery and practical advices to recover important files from broken hard disks or flash memories.

Computer forensics is becoming increasingly important part of the efforts to detect and prevent terrorist activities. But the game will never end. More advanced hiding techniques will lead to more advanced discovery techniques which will lead to even more advanced hiding techniques, etc.

Popular Microcontrollers

Embedded systems are not just complex projects in electronic laboratories--they are present in everyday devices. Every mobile device, electric toy or kitchen appliance has some electronic board which usually includes a programmable device--microcontroller. This is a special microprocessor with peripheral devices and I/O ports. Depending on the volume of the device the manufacturer can decide whether to develop an ASIC--a dedicated integrated circuit which performs all functions for this device or to make a standard board with discrete components. In both cases some microcontroller is used, either as a soft core in ASIC or a standard integrated circuit.

Popular microcontrollers are popular mainly because of availability of affordable development tools and low prices of devices. When hobby engineers start using one family they get used to it and it is very likely that they will use it later in a professional project. While PIC and AVR microcontrollers are heavily used in hobby projects, ARM has prevailed in the professional embedded world. However, 8051 microcontrollers are still used in many hobby and professional projects.

There is a plethora of choices from open-source projects to various IP cores with significant royalties for each device. Despite this choice there are few microcontroller families that are popular because of their flexibility, powerful development tools or because of historical reasons.

ARM

This is currently the hottest RISC core used in almost all mobile phones, portable devices and many other applications. It has powerful instruction set, low consumption, offers easy integration and there are many good development tools for easy development and debugging. The ARM core is also used in many popular microcontroller families from Atmel, Luminary Micro (now Texas Instruments), NXP and many other manufacturers. These microcontrollers are very popular among embedded engineers and are used in various applications from automotive industry to hobby projects.

AVR

This is one of the most popular microcontroller families from Atmel. It is also very popular among hobby engineers and it is used in many projects from simple LED controllers to complex communication devices. The RISC architecture offers fast execution and low power consumption. Development tools are available for free which is a great bonus for electronics enthusiasts. AVR is a direct competitor to Microchip's PIC. Some favor AVR, others like AVR. There is no clear winner. Both families work well. It is up to the developer/programmer what he like or prefers.

PIC

This is a leading microcontroller family from Microchip. PICs are available in very small packages with only few pins and also as powerful 32-bit microcontrollers with many peripheral modules and I/O pins. They are very popular among hobby engineers--in hobby projects you will find either AVR or PIC.

8051

This is a very old 8-bit microcontroller architecture that has managed to survive for more than 30 years. Many excellent compilers, a lot of code examples and simple development has contributed to the popularity of this family. This core is still used in many modern microcontrollers from Silabs, NXP, Atmel and many other microcontroller manufacturers. It is very likely that the 8051 is the most widely used core in embedded applications. Of course, many new designs will probably use ARM or some other advanced architecture, but because of popularity of the 8051 family in the past and availability of development tools (C, Assembler and Pascal),  it is still used in many applications.

Internet Service - Wireless Vs Wired

It is amazing that roughly 20 years after first commercial use of the internet we are now totally dependent of it. This dependence in many cases evolves into addiction. There are many popular services that we are using on a daily basis. Facebook, Gmail, and Twitter are only few popular names that wouldn't exist without internet.

First home access to the internet was via modems and telephone infrastructure. At that time speeds were adequate for websites and services that were available. The next step was replacement of modems with xDSL technology which significantly increased the range of available bandwidths. The latest approach is using fiber cables to get the fastest internet speeds in individual homes. 1 GBit/s is now reality for anybody having the possibility to connect to the optical network.

Another technology that evolved in parallel with wired access was, of course, wireless access to the internet. The most common technology today in use is Wi-Fi which allows speeds over 100 Mbit/s. All you need for a wireless access is an access point (usually a wireless router) and WiFi enabled laptop or any computer with wireless network card.

For average user there is probably no big difference between these two ways to access the internet. However, there are some very important aspects that need to be taken into account when deciding which technology to use.

Wired access provides constant bandwidth between individual user and internet service provider. It is mainly the bandwidth of the ISP's backbone which determines actual speed that we will be able to achieve. Wired access enables permanent connection. This is important when you need reliable connection which should be also available from the outside. Static IP address is usually used for such purposes and if the connection is important it is also powered by an UPS.

The main difference of wireless internet access is that it uses a radio channel to transfer data. This channel has limited capacity which is usually shared among many users. Even if there are many channels available the total bandwidth that we can get depends also on the number of users and their transfers. In general, this is an additional bottleneck for our access to the internet. Another significant difference is that the connection is not permanent. When it is established there is no guarantee that is will stay as it is. The situation in the radio frequency spectrum can change, other users may start using the same access point, slight change of antenna position may significantly decrease connection speed, etc.

One typical example of a device that can successfully use wireless connection is a wireless credit card reader. It enables credit card processing away from the office or counter. Wireless credit card terminals significantly simplify making business and allow buyers to keep their credit cards in their hands.

In many cases you can use either wired or wireless access. But there are also cases which imply reliable wired connection or wireless access at any cost.

Life With Internet

Internet was born long before we have noticed it. Today we can not imagine life without it. There are many people who believe that internet is world wide web (WWW) and vice versa. Of course, web is only one of the services that are available over the internet. The fact is that our lives depend on the internet services even if we don't have a computer. It it difficult to imagine life without internet as it was difficult to imagine life without electricity thirty years ago. Internet is a worldwide network. And only a network. Services are what helps us to send a message or to do something.

Internet Service Providers
In order to connect to the internet you need a contract with some internet service provider (ISP). Access to the internet can be made available over analog phone line, ISDN, various xDSL technologies, fiber to the home (FTTH), wireless networks, cable network, etc. The speeds vary but it is not uncommon to have 100 Mbit/s or even 1 Gbit/s via FTTH. Regardless of the connection speed, internet access is a must.

Email
Sending electronic messages is one of the very popular internet services. In order to send and receive a message you need at least two mail servers, one for sending and one for receiving the message. Since email address is a prerequisite for any business, not just online, each company has at least one mail server. Fortunately there are many free email service providers. One of the most popular and famous is Gmail, free email from Google. If you don't have a Gmail account you are missing a lot.

World Wide Web
WWW is probably the most widely used internet service. This is probably the reason that www means the same as internet to many people. Having a homepage is a must. Not just for companies but also for communities, clubs, organizations and also individuals. Writing a blog is very popular these days. Because of this popularity there is a huge competition among web hosting providers. The prices are low, setting up a website is pretty simple and just anybody can have his own website.

Spam
Spam is not an internet service but it is a direct consequence of cheap or even free internet services. It is so easy to create an email and send it to any address. And sending the message to millions of worldwide email addresses is no different. Email spam is a big problem. There are many companies that are offering anti-spam products or services. One excellent anti-spam filter is used by Gmail. You will rarely receive a spam email. But there is also spam on the web. There are millions of pages that offer no useful content. When you are searching for something it is very likely that you will land on such page.

Of course, there are also other services on the internet. Sending IP packets is simple and every modern appliance or consumer electronic equipment has an ethernet connector. We can expect a huge expansion of communication over internet.

Convert Your Old Computer to a Linux Server

Linux is a very popular platform. Not just because it is free but also because it is reliable and supports anything you can imagine. A popular setup is a Linux server without any graphical user interface. It can be used for web hosting, as a file server, as a database server, or for anything you need. Most people comfortable with Windows operating system are afraid to start thinking in a different way. In fact, installing and using Linux is pretty simple.

Once you decide to go for it you have already made the first step. The next step is to get some basic information about installing Linux. There are many Linux distributions. One that is very popular is Ubuntu. Simply Google for "ubuntu server" and learn about what do you need to install Linux. In general, things are pretty simple. You can install Linux on almost any machine. Your old computer that was replaced some time ago is a perfect choice for Linux. You only need some space on the hard drive, a CD or DVD drive, a network card and a lot of patience.

The first step is to make a bootable CD with the latest Ubuntu server image. Download the image file and burn it on a CD. Then you boot your computer with this CD and start installing Linux. It is a good idea to do this installation next to your main computer with internet accesses. This way you will be able to browse for any problem you may encounter. The most important thing you should know is that for every question you may have, there is an answer on some web page waiting for you. You only have to find it.

The installation process is pretty straight-forward. If you don't understand what the installer is asking you then simply select the default option. Of course, you can also ask Google for it and then choose appropriate option. You should understand that the Linux principle is very different from the Windows one. But once you become familiar with Linux shell and basic commands it will be very easy to work with Linux and to install and configure new software. In most cases the server will be located at some remote place and will not need a monitor. You will access it via network.

Having a Linux server is a great upgrade to your home network. This server will be your reliable storage for large peer-to-peer files, web server for website development or a computer to play with. And remember, sooner or later you will encounter a problem. Something will not work or you will not know how to change some setting. All you have to do is to search for the answer on the web. Web pages offer a giant encyclopedia on Linux.

Advantages of Joomla Content Management System

Most bloggers, internet marketers and individuals use the web to publish content. They usually don't care about HTML, CSS, JavaScript or PHP. Web content management system (CMS) is a complete platform to create a website from scratch. It provides the framework needed to communicate with the database, to store and retrieve data, to dynamically create pages, to deal with authentication and to do other tasks needed for any website. The main advantage of using CMS is that you can focus on content. You install the system, select template and few plugins and you are ready to go. One of the very popular web systems is Joomla.

Joomla is a universal free open-source content management system. Universality means that you can adapt it for almost any purpose. Bloggers usually choose Wordpress for the blogging platform. This is a natural choice, but you can also make blog with Joomla. The basic installation provides the backbone for a working website. The page layout can be set by installing appropriate template. You can choose among thousands of free templates or pay small fee for a professional customizable design. Additional features and functionality can be added with various extensions. Depending on the extension function they are available as components, modules or plugins. Extensions make Joomla extremely universal.

The beauty of extensions is that there is one for every imaginable function or feature. Whenever you need some functionality for the website you can go to the Joomla extensions page and search for the right module. Some extensions are available free of charge, for some you will have to pay. And if for some reason you can not find a suitable extension you can modify an existing one or you can create a new one from scratch according to your needs. For this you will need to know a little about HTML and PHP but this is not a problem since both languages can easily be learned from the existing code examples.

Another nice feature of Joomla is customization of the core system. With code overrides you can change default layout of most page types. If this is not enough you can modify any Joomla file to achieve the desired functionality. For this kind of customization you need to take into account that any upgrade may overwrite modified files. But if you are a skilled web programmer this will not be a problem. Since Joomla is an open-source platform you can modify it any way you like. Most customizations can be done without knowing any of the web languages, but if you know them you will have a very easy and pleasant task.

A simple example of Joomla CMS in practice is the http://fullspectrumbulbs.org/ website. This is a small site about full spectrum bulbs which uses basic Joomla system with a lightweight template. One of the benefits of such simple layout is fast page loading. Of course, there are few extensions installed but they don't provide any crucial functionality for visitors.

Joomla is a fantastic content management system. With few extensions you can make a website for any purpose. But if your goal is a blog you will probably use Wordpress. Not because it is better than Joomla but because it is easier to create a blog with it.

Details About Typical Television Resolutions

Television resolution is information about the number of picture elements (points or pixels) that make up TV picture. The higher the number the better and more sharper is the picture. In general there are two groups of television resolutions. The standard definition television (SDTV) as we know it for the last 50 years has few different standards that didn't change since they were defined. The only "upgrade" was the addition of colors which did not modify anything related to the picture resolution. The high definition television (HDTV) means picture with more lines and picture elements. There are even higher resolutions (beyond HDTV) but the technology is still in infancy. Currently we are mainly talking about SD and HD television.

Standard Definition Television - SDTV

There are few different standards that were defined in the age of black and white television even before the World War II. Those standards define parameters like the number of lines, the number of pictures per second, and some other technical details. In general, the number of picture lines together with frequency bandwidth reserved for picture defines the television resolution. NTSC (the color television standard used in USA and Japan for SDTV) has resolution of 480 lines each with 720 pixels. In Europe and many other countries where PAL was used the resolution was 576 lines with 768 pixels in each line. Because this resolution was quite satisfactory and there was no easy way to enhance it, the old analog technology survived until recently when we started a transition to digital broadcasting.

High Definition Television - SDTV

Digital broadcasting allows us to use many advanced services and one of them is television picture with higher resolution--high definition television. HDTV means any TV resolution higher than SDTV. There are few standard resolutions that are supported by professional and commercial equipment. Each resolution has two modes: interlaced and progressive. Interlaced means alternatively displaying odd lines in one frame (still picture) and even lines in the next one, while progressive mode displays all lines in each frame. The basic HD resolution is 1280x720 which means displaying 720 lines with 1280 pixels in each and the highest HD resolution is 1920x1080. There are also few intermediate resolutions which are mainly used by smaller display devices. This means that the highest HD resolution is 1920x1080p which is supported by larger LCD and plasma displays but currently there is no terrestrial television that broadcasts this way. Most HD televisions use either 720p or 1080i mode.

Of course, HDTV is not the last step in television resolution. As the technology will evolve there will come higher resolutions that will need higher bandwidths, new transmission equipment and new displays (TV sets). This is called development.

Digital terrestrial television in Europe uses DVB-T as transmission standard. Some countries use MPEG-2 coding standard while other use even more efficient MPEG-4 standard. An additional improvement can be achieved by using statistical multiplexing which dynamically allocated bandwidth to each service according to current needs.