This blog is moving!

Lately, I ran to a little bit of problem with Adsense. The account I had with them, the result of which was the ads you might have seen every now and then on this blog, was suspended and my efforts to reinstate the account proved to be futile. This along with the fact that I am trying to collect my results and gather my thesis results in my long absent from this blog.

Therefore I decided to move this blog over to wordpress and as it happens this move has collided with my physical move to a new apartment. For the time being, please continue reading my posts at this address. If you have subscribed to my feedburner RSS you will be fine, as I have already redirected that to my new address. But if you are following through the traditional RSS or atom feed address then I am afraid you will have to change that to this. This will be my last post of this blog on blogspot.

Surround Sound Specifications

The description of surround sound specifications brought here is categorized using the number of discrete channels encoded in the original signal and the number of channels available for playback. Each channel may refer to a group of speakers. The graphics shown here denotes the number of channels, not the number of speakers.

3.0 Channel Surround (Dolby Surround)
Three audio channels are produced from a specially encoded two-channel source:

• Two channels for speakers at the front-left (L) and right (R).
• One channel for surround speaker or speakers at the rear-surround (S).
  

Placement: Three identical speakers placed equidistant around a central listening position. If two rear speakers are used they should also be placed above ear height, slightly behind the listening position, and should be of bi-polar construction.

4.0 Channel Surround (Quadraphonic)
Four audio channels are produced either from a specially encoded two-channel source or a four-channel source:

• Two channels for speakers at the front-left (L) and right (R).
  
• Two channels for surround speakers at the rear-surround left (LS) and surround right (RS). Some newer receivers support the LFE channel.
  

Placement: Quadraphonics is a system designed for music only. All speakers should be at an ±45˚. All speakers should be above ear height.

5.1 Channel Surround (3-2 Stereo) (Dolby Pro Logic II)
Five audio channels are produced either from a specially encoded two-channel or a stereo source:

• Two channels for speakers at the front-left (L) and right (R).
• One channel for speaker at the centre-centre (C).
• Two channels for surround speakers at the rear-surround left (LS) and surround right (RS).
• One low-frequency effects channel (LFE).
  

Placement: 5.1 speaker layouts should conform to the ITU-R BS.775 standard, despite the myth that music and video content require different placements. The ITU standard states that the left and right speakers are located at ±30˚, while the rear speakers should be positioned approximately ±110˚. There is speculation that rear loudspeakers at ±150˚ provide "more exciting surround effects".

(to be continued)

Surround Sound Systems

Surround sound systems use multichannel audio to enrich the sound reproduction quality of an audio source using additional audio channels reproduced by additional discrete speakers. the three-dimensional space of human hearing can be achieved using audio channels above and below the listener. Surround sound technology is used in cinema theatres, home theatre systems, video game consoles, personal computers, and so on.

Low Frequency Effects (LFE) Channel
The Frequency Effects channel (LFE) is originally developed to carry extremely low (sub-bass) sound effects such as thunder or explosions on a separate channel. This allows the theatres to control the volume of sound effects to suit the size of their sound system and the acoustic environment of their cinema. However, home system may not have a separate subwoofer that can handle such effects. Therefore, modern surround systems often incorporate a bass management system that allows bass on any channel to be fed only to speakers than can handle low-frequency signals.

Home Cinema

Home Cinema (a.k.a. Home Theatre) is basically an entertainment system that reproduces movie-theatre quality video and audio at homes. The first home cinema systems were 8mm film projector equipment which was replaced by laser discs. In mid 1990's, a typical home cinema would have been a laser disc or VHS videocassette player fed to a large rear-projection television. In late 1990's, DVD players with Dolby Digital (5.1 channel audio) were introduced along with high definition televisions. Nowadays the term home cinema includes a wide range of systems. The display might be a 60" HDTV and for audio, several thousand watts of power fed into a 12" (or more) subwoofer with five or seven surround sound speakers. The price on these equipments can go as high as $100,000.

Basically a home cinema is composed of the following components:

1. Input Device: Any audio/video source that can include high quality formats such as blu-ray. Others include VHS player or video game systems. Some of the newer models include a home theatre PC that acts as a library for video and music content.
2. Processing Device: Input devices must be processed for complex surround sound output.
3. Audio Output: Normally systems come with two speakers but can have up to 10 speakers and an additional subwoofer.
4. Video Output: A large High Definition display that can be LCD, plasma, video projector, rear-projection television or a traditional CRT television.
5. Atmosphere: High-end home theatres have sound insulation to prevent noise from escaping the room and a specialized wall treatment to balance the sound within the room.
   

Feed Burner

It has come to my attention that most of my feed subscribers have subscribed to old feeds (such as RSS and Atom) generated by BlogSpot itself. Promising as the large number of subscribers are, I should draw your attention to the new feed which is burned using FeedBurner at this address. This new feed enjoys a whole set of new features including but not limited to amazing compatibility to different feed readers, possibility of sending the post to your favourite sharing website, and of course more beautiful ads are featured!


So please change the old feed address to this. And happy St. Patrick day to everyone!

Television Buying Guide 8

Things to Consider

• Every floor model television is set its brightness to maximum. Try and ask the salesperson to reduce the brightness of the television you are comparing.
• Display floors are well-lit. Few living rooms are lit that much. See if you can ask them to reduce the light shedding on the picture.
  
• Blu-ray. If you have a disc that you are familiar with, see if you can use it instead of the TV signal that is normally shown. Blu-ray provides the best picture a television can display, so it makes for the best reference from which to judge. And if you are used to the look of a particular DVD, use it instead.
• Televisions come with many picture presets such as movie, sports, etc. Try all of them to see which is best.
  
• It is strongly recommended to protect your television with some sort of surge protection. Do not believe the hype that a better protector will somehow improve video quality, but do choose a model with coaxial inputs and outputs for your cable or antenna.

This concludes the series on television buying guide.

Television Buying Guide 7

Television Sound
Almost every new television has MTS (Multichannel Television Sound) stereo speakers, which is much better than a single mono speaker. MTS is a standard that allows the encoding of 3 channels of audio within a standard NTSC (analog) video signal to a television. A television that is able to receive MTS Stereo allows you to watch television with stereo sound. Usually 5 watts per channel or higher provides a decent audio system for a television. Some sets can simulate surround sound to provide semblance of rear speakers.

Of course no television can compete with a dedicated audio system. You can consider a home-theatre audio system for maximum impact.

Television Buying Guide 6

Inputs and Outputs
One of the most confusing items on a television spec sheet is the types of inputs and outputs the television can accommodate to get connected to other equipments. The following is a snapshot of different types of connections and their quality.



Name: RF (Radio Frequency)
Sources: Antennae, VCRs, cable and satellite boxes
Quality: Lowest, highest for HDTV tuners



Name: Composite Video
Sources: Cable and satellite boxes, VCRs, DVD players, game consoles
Quality: Low



Name: Component-video
Sources: HD cable and satellite boxes, DVD players, HDTV tuners, Blu-ray and HD DVD players, game consoles, other HD sources
Quality: High



Name: RGB
Sources: Computers, video processors
Quality: High



Name: FireWire
Sources: Some HDTV tuners, D-VHS VCRs
Quality: Highest (digital)



Name: DVI-D with HDCP
Sources: Computers; older HD cable and satellite boxes, HDTV tuners and DVD players
Quality: Highest (digital)



Name: HDMI
Quality: HD cable and satellite boxes, DVD players, HDTV tuners, Blu-ray and HD DVD players, game consoles, computers, other HD sources
Quality: Highest (digital)

Television Buying Guide 5

Almost all HDTVs sold nowadays are wide-screen televisions, which means the aspect ratio of the television is 16:9 compared to standard definition televisions which are 4:3.


Black Bars and Unused Screen
The problem with the aspect ratio is that most of the television shows are still broadcasted in 4:3 format. To view them on a wide-screen television without stretching or cropping the picture, you have to waste a portion of the screen by putting bars on either side of the image. Conversely, if you have an old 4:3 television, to watch a wide-screen show you will have to tolerate two bars above and below the picture.


Wide-screen Televisions and 4:3 programmes
If you do not want to waste your wide-screen space on empty bars, listen to a good piece of news. All wide-screen televisions can stretch, crop, or zoom 4:3 programmes to fit the screen. These methods distort the image to some extent, but it is a lot better than having two bars on either side of the screen.

Television Buying Guide 4

Regular Television Programmes on an HDTV
You may be disappointed in your HDTV the first time you see a programme on it. That may be because you are watching a standard definition channel. Regular television programmes can look very bad on an HDTV compared to high definition programmes. An HDTV is larger and sharper and shows more of the flaws of standard definition broadcasting.

DVD Programmes on an HDTV
Regular DVD programmes look very high-quality and spectacular on an HDTV and most people are quite satisfied with them. Many DVD players and all Blu-ray players have a built-in upconversion unit that converts DVD programmes to high-definition. However, in most cases the difference would be subtle.

HDTV is Tomorrow
Buying an HDTV is a smart move, as you can be fairly sure that they will not become obsolete at least for a few years. Of course, new technologies emerge every now and then but nothing on the scale of shift from SDTV to HDTV is likely to happen for a long time. Almost every HDTV is equipped with an HDMI input that can accept copy-protected signals.

Television Buying Guide 3

Air Antenna Receivers
The law requires most television sets sold after March 2007 to include a built-in tuner that can receive high-definition programmes broadcasted on air by a simple antenna. If the television is not equipped with such a tuner, an external tuner or box is required to watch these programmes. So most televisions (not monitors) sold after that date, must comply with the aforementioned law to accommodate DTV (Digital Television) transition.

Digital Television Transition
A bill has been passed by the congress that requires over-the-air stations to switch to digital broadcasting between 17 February and 12 June 2009. After the final date, televisions with old NTSC tuners will be unable to receive over-the-air programmes. So many people who use “rabbit ears” or rooftop antenna and their televisions do not have a tuner, will stop receiving broadcasts. As a result, a subsidy program has been created which provides $40 coupons (limit of 2 per household), that can be used toward a digital converter box.

Television Buying Guide 2

Television Types
Televisions can be categorized into four different groups according to what type of signal they can accept and what picture quality they can show:

1. Analog
2. SDTV (Standard Definition Television)
   
3. EDTV (Enhanced Definition Television)
4. HDTV (High Definition Television)

Analog
This type of television can not display HDTV programmes. It can only show standard definition programmes found on regular television, cable, or satellite channels.

SDTV
This type of television (standard-definition) is basically an analog television plus a built-in ATSC tuner. Therefore, it can receive digital television broadcasts. It will display a picture from these broadcasts, but HDTV shows will not look nearly as detailed as they would on a true HDTV.

EDTV
This type of television (enhanced-definition) is usually a type of television that can display HDTV signals but doesn't have enough resolution to really do them justice. Most often it applies to plasma televisions and denotes 852×480 resolution.

HDTV
High-definition televisions, or HDTV, can display standard television, progressive-scan DVD, and HDTV signals. They are by far the most common type of digital television. Nearly every plasma, LCD, and rear-projection television is an HDTV.

Television Buying Guide 1

Soon after posting the previous notes, I received feedback from several people to write in simpler and more practical terms and also shorter; this brings me to the following series of posts which are a short and simple guide to buying a new television.

Introduction
Televisions are expensive equipments, but price-wise they can be put into a few categories. Here comes a small chart that can match your funds with the types of television you can actually afford, which might be far from what you have pictured in your dreams.


Selecting the best size
Now that you have narrowed down your budget, you need to decide the proper size for your television. Obviously, larger screens cost more, but television should have the right size for the room in which you are intending to put it. Here is a small chart that gives the proper distance from your television.

Generally, 30" and smaller displays work great in bedrooms but they are too small for the living rooms. Larger displays are suitable for the whole family to enjoy but they would be too much for small bedrooms. If the television is put in an entertainment centre, make sure it has enough room for ventilation. Nowadays, many televisions come with dedicated stands that can even accommodate other components such as cable boxes and DVD players.

DLP (Digital Light Processing)

Digital Light Processing (DLP) is a technology patented by Texas Instruments, a technology used in projectors. This technology is used in front projection and rear projection televisions. It is also one of the leading technologies used in digital cinema projection.

Digital Micro-mirror Device
In DLP projectors, there is an array of small mirrors (microscopic) that are positioned on a semiconductor chip called Digital Micro-mirror Device (DMD). Each mirror produces one or more pixels in the image. The number of mirrors is the maximum resolution attainable by the display, e.g. 800×600, 1,204×768, 1,280×720, and 1,920×1,080. The mirrors can either pass the light through the lens (On) or completely block the light (Off) and they can switch positions quite rapidly. Controlling the on and off times can produce different shades of grey.

How colour is produced in DLP projectors?
There are three methods available to DLP projectors for colour production:

• Single-chip DLP projectors
• Three-chip DLP projectors
• Sequential illumination by three LEDs (light emitting diodes) (still in development, only in select Samsung models)
  

Single-Chip Projectors
In single-chip projectors, colours are either produced by a colour wheel between the lamp and the DLP chip or by using individual light sources to produce primary colours (e.g. LEDs).

Three-Chip Projectors

In three-chip projectors, a prism is used to split light from the lamp and each primary colour is projected to its own chip, then recombined and routed out through the lens. These are used in higher end projectors. They are capable of producing 35 trillion colours. It is suggested that the human eye can detect around 16 million colours


Digital Cinema
DLP is the current market-share leader in professional digital movie projection, largely because of its high contrast ratio and available resolution as compared to other digital front-projection technologies. As of December 2008, there are over 6,000 DLP-based Digital Cinema Systems installed worldwide.

Pros

• High resolution images (up to 1,080p)
• Perfect geometry and excellent greyscale linearity achievable
• High contrast
• No possibility of burn-in
• DLP rear projection televisions are considerably cheaper than LCD or plasma flat-panel displays and can still offer 1,080p resolution
• DLP Projectors can process up to 7 separate colours giving them strong colour performance
• DLP projectors do not suffer from “Colour Decay” often seen with LCD projectors in which the image on the screen turns yellow after extended periods of usage
  

Cons

• Not as thin as LCD or plasma flat-panel displays
• Dithering noise may be noticeable, especially in dark image areas. Newer (after 2004) chip generations have less noise than older ones
• Lower viewing angle than direct-view technologies such as CRT, plasma, and LCD

Plasma Televisions

The name plasma makes people think of it as a new technology and one would be surprised to hear that these screens have been around for more than 40 years now! Only recently, there has been much improvement in the making of these displays. Plasma televisions (a.k.a. plasma display panels) are emissive flat panel displays where light is created by phosphors excited by a plasma discharge between two flat panels of glass. This plasma/gas discharge uses an inert mixture of noble gases (such as Neon and Xenon). The plasma is sandwiched between two glass panes coated with phosphor material.

The television controller controls the plasma through electronic signals delivered with beams of electrons. Each pixel of a plasma display panel can turn red, green, or blue, and the controller combines them and varies their intensities to produce the entire color spectrum.


Nowadays, most plasma televisions support high definition resolutions such as 800×600 and 1,280×1,024 pixel resolutions. Plasma displays are also quite bright (1,000 lx or higher, with "lx" being the standard of measure for illuminance, lux). Plasma television manufacturers claim that their products can last about 60,000 hours (almost 7 years). However, unwise use of these displays can shorten their lifetime; these include, but are not limited to, setting the contrast to high levels or leaving still images on the display for too long as they can cause burn-ins.

How to calibrate your plasma television?
Plasma televisions are the showroom boast bright, flashy displays that draw you into buying them. However, once you install the television in your home, the same bright, flashy display will be excessive and even damaging to your new appliance. Here is why:

• Plasma televisions in the showroom have their settings configured to attract customers and "out-dazzle" the competing sets sharing the floor. For example, showroom televisions have their brightness levels set too high.
• Each home and television surroundings have different ambient light conditions, which means the optimal settings for one household might not work for the next.
• The default high contrast and brightness levels will prematurely age your plasma screen.
• The default brightness levels consume a tad more power than "normal" and toned down settings.
• Showroom settings might cause eyestrain in the long run.
  

Calibrating your plasma television gives you four things:

• More vivid images optimized for your environment and preferred lighting conditions.
• Longer lifespan for your beautiful television.
• A few more dollars off the monthly power bill.
• A comfortable experience for your eyes and senses.
  

Thus, you need to tone down the default settings of your plasma television, and adjust them to match the conditions of your living room/home theatre surroundings. The question is, how do you know which settings are right or wrong? And before that, what settings do you need to tweak? There are three ways to calibrate your plasma television:

1. Do it yourself (free)
2. Calibration disk (moderate)
3. Professional help (very expensive)

1. Do It Yourself
This method costs nothing but some mind and eye-work is necessary. Important things to note while doing the adjustments, in this order, are:

1. Room lighting
2. Viewing distance
3. Avoiding active modes such as Sports, Dynamics, and Vivid
4. Disabling factory settings and enhancements
5. Adjusting the colour temperature to 6,500K
6. Adjusting the brightness
7. Adjusting the contrast
8. Adjusting the sharpness
9. Adjusting the colour and tint

2. Calibration Disk
These disks provide step-by-step guides and also include test images and videos for adjusting. They also do audio calibration.

3. Professional Help
Have you ever heard of an ISF (Imaging Science Foundation) technician? These guys are the masters of plasma television calibration. ISF calibration, as it is called, will cost you seriously (check their website), but in the end, the expense will be worth it. ISF professionals can adjust settings that few laymen television owners can understand, and they have thousands of dollars worth of calibrating equipment to help them do the job. A plasma television calibrated by an ISF professional will give you stunning results.

LCD (Liquid Crystal Display) Televisions

An LCD television is sometimes called a "transmissive" display, as light is not created by the liquid crystals themselves; a light source behind the panel shines light through the display. A white diffusion panel behind the LCD redirects and scatters the light evenly to ensure a uniform image.

The display consists of two polarizing transparent panels and a liquid crystal solution sandwiched in between. The screen's front layer of glass is etched on the inside surface in a grid pattern to form a template for the layer of liquid crystals. Liquid crystals are rod-shaped molecules that bend light in response to an electric current; the crystals align so that light cannot pass through them. Each crystal acts like a shutter, either allowing light to pass through or blocking the light. The pattern of transparent and dark crystals forms the image.


LCD televisions use the most advanced type of LCD, known as an "active-matrix" LCD. This design is based on thin film transistors (TFT) which are, basically, tiny switching transistors and capacitors that are arranged in a matrix on a glass substrate. Their job is to rapidly switch the LCD's pixels on and off. In a colour LCD television, each color pixel is created by three sub-pixels with red, green and blue colour filters.

An important difference between plasma and LCD technology is that an LCD screen does not have a coating of phosphor dots (colours are created through the use of filters). That means you will never have to worry about image burn-in, which is great news, especially for anyone planning to connect a PC or video game system. LCD televisions are extremely energy-efficient, typically consuming 60% less power than comparably-sized tube-type direct-view televisions.

Older models of these televisions had a delay problem called "ghosting". As the pixels were not able to change colour instantly, fast moving objects left a trace on the screen. Newer models have decreased this delay to 8 milliseconds (recently 4ms), so unless you have a very large screen (more than 40"), the delay is not noticeable at all. Another problem of these screens is the black level. In order for the black colour to show on the screen, the back light must be completely blocked. This poses a problem as there is always a small amount of white light leaking from the narrow space between pixels. So most LCD televisions have difficulty going completely “black” and instead of showing black, a very dark grey is shown. Contrary to manufacturers’ claims, LCD televisions have a limited viewing angle. So at 170 degrees you will see “a picture” but it is not of high quality. Moreover, if you want to use your television as a computer monitor, it is advisable to buy an LCD television that has a computer input, not an LCD monitor that has a television tuner; as the latter acts as a very poor quality television whilst the former introduces good quality in both applications.

Nowadays almost all LCD televisions are high-definition televisions (HDTVs). This means that they are compliant with the recently-approved ATSC standard in North America. There are different resolutions available for LCD televisions. They include: 480p, 480i, 720p, 1080p, 1080i, and 2160p. These are the number of horizontal lines the television can display and the letter that follows shows the type of scan used to refresh the display (interlaced or progressive, for details see CRT televisions). In 480 models, the resolution is about the same as CRT televisions, although they are not called high definition anymore. In 720p models the resolutions that are supported include 1,024×768, 1,280×720, and 1,366×768. In 1080i models the resolution that is supported is 1280×1080 and in 1080p models resolution 1,920×1,080 is supported. In 2160p models, 3,840×2,160 is supported which is even higher than ATSC standard.

Technically speaking, all of these numbers are accurate and useful, but do not put too much stock in them. In the real world, it is difficult to tell the difference between native resolutions once you get into high definition. An important factor is the number of pixels the LCD can support which is dependent on its physical size. For example, a 37" LCD with "only" 1,366×768 pixels has to throw away a good deal of information to display a 1080i picture and there is really no way for you to see more details on a similar 37" LCD with 1080 resolution. This used to be the case when there was a huge price difference between 1080 and 720 versions of LCDs with the same size, but nowadays 1080p native resolution is so common among high definition televisions that you should not even consider it as a factor in your purchasing decision.

Projection Televisions

These televisions fall into two categories: front-projection and rear-projection.

Front-projection televisions: A front-projection television uses a projector and a separate screen to project images onto the front of that screen. This setup is very similar to what you would find in a movie theatre.

Rear-projection televisions: Rear-projection systems look more like traditional televisions. They display images on the back of a screen rather than the front, and the projector is completely contained within the television itself.

This type is specific to large-screen displays. Up until mid-2000s, most of the affordable large screen televisions (up to 100 inches) used this technology. They first appeared in 1970’s but they were outwitted by CRTs. The projection televisions are thicker than LCD and plasma displays; however, newer models are smaller than their predecessors. Earlier models were basically CRT and their picture was fuzzy at close range. Newer models incorporate DLP, LCD, and LCoS (Liquid Crystal on Silicon). LCoS is able to generate 1080p resolution (1080 horizontal lines progressive). In 2005 and 2006, these televisions were much cheaper than LCD and plasma panels. But as the prices on these competitors fell, sales of projection televisions declined dramatically. These televisions are able to display a variety of resolutions, and their blackness and contrast levels are excellent. They also offer better viewing angle than LCDs and have long lives. Older models had limited viewing angle with the optimum viewing position being one directly in front of and eye-level with the unit.

The main drawback for these televisions is their large footprint and glare if a light source is placed at complementary angle to your viewing angle; the problem gets worsened if the television is protected with a screen saver (a clear protective material that covers the fragile screen). Furthermore, price of changing the lamp (every 3-5 years) is substantial compared to the television price itself.

CRT Televisions

With this being said, I start the discussion with introducing different generations of television sets and the technology incorporated in each of them; at the end of this introduction, a post will be dedicated to comparing all of them and a small buyer's guide would be in order.

CRT (Cathode Ray Tube) Televisions
These televisions use an electron gun (a source of electrons) and a fluorescent screen, with internal or external means to accelerate and deflect the electron beam, used to create images in the form of light emitted from the fluorescent screen. Colour CRTs employ three separate electron guns that share some electrodes for all three beams (see picture).

The resolution on these televisions depends on the “dot pitch” (see picture). Health concerns include use of high-voltage (32 kilo volts for colour televisions), electromagnetic fields (Very Low Frequency), ionizing radiation (emitting a small amount of X-ray), toxicity (proper recycling is required), and flicker (relatively low refresh rate causes headaches).

The screen is scanned with the ray gun repeatedly and the image is refreshed 60 times per second. There are two types of scan available: progressive and interlaced. In progressive scanning, the whole picture is created in one scan (usually 480 lines); in interlaced scanning, the entire screen is refreshed in two phases. In phase one, half of the lines (even numbered) are refreshed and in phase two, the other half (odd numbered) are refreshed. Progressive scanning introduces less flicker compared to interlaced scanning.

The Beginning

It has been my intention to write about the "Wonders of the Digital Era" or "Our Digital Age" for quite some time now. Yet, somehow I could not or rather want not gather the courage or better say stamina to actually step forward and start doing it. Noteworthy is that I am not new to this field and that before coming to Canada I was already penning articles for a rather nice computer & communications magazine, which was interrupted with my migration to this beautiful and friendly country.

Busy as I am with my ongoing research and efforts toward a graduate degree, I will try to relate stories about stuff and experiences I find of use to other people. With this post, I shall begin working on this blog, in hope that stories within will shed light on someone else's problem or be interesting enough for others to read and follow.