Digital Glossary

[Gregg Lengling]

I know it can be hard to remember or even recognize all the acroynms used today, but DTV an HDTV have a set all their own...so here's a little primer..print it out and past it up and soon you too will legally be able to buy a pocket protector.

As you gather information about Digital-HDTV, you will likely come across some terminology that is alien. Here's a brief Digital-HDTV Glossary to help you with some common "tech-speak" terms...
AC-3
The 5.1-channel sound system specified in the Standard for Digital-HDTV. Also known as "Dolby Digital," AC-3 delivers CD-quality digital audio and provides five full-bandwidth channels for front left, front right, center, surround left and surround right speakers, plus an LFE (low frequency effect) subwoofer, for a total of 5.1 channels.

Advanced Television Systems Committee (ATSC)
The ATSC is the committee responsible for developing and establishing Digital-HDTV Standards; as well as all (18) formats of Digital TV.

A/D
Analog to digital conversion (or converter). Used at transmission end of broadcast.

Addressable Resolution
The highest resolution signal that a display device (TV or monitor) can accept.
Caution: Consumers should be aware however, that although a particular device (Digital-HDTV) is able to receive the resolution, it may not be capable of displaying it.

Analog TV
Analog TV is the NTSC Standard for traditional television broadcasts. Analog signals vary continuously, representing fluctuations in color and brightness.

Artifacts
Unwanted visible effects in the picture created by disturbances in the transmission or image processing, such as 'edge crawl' or 'hanging dots' in analog pictures, or 'pixelation' in digital pictures.

Aspect Ratio
Refers to the width of a picture relative to its height. If an NTSC picture is 4 feet wide, it will be 3 feet high; thus it has a 4:3 aspect ratio. HDTV has a 16:9 aspect ratio.

ATSC
See Advanced Television Systems Committee.

ATV
"Advanced Television" is an earlier term used to describe the development and advance applications of digital television, now simply referred to as DTV.

Bandwidth
A range of frequencies used to transmit information such as picture and sound. For TV broadcasters, the FCC has allocated 6Mhz for each channel. For DTV, the maximum bit rate possible within the bandwidth is 19.4 Mbps, which is one HDTV channel. SDTV has a lower bit rate, therefore the bandwidth can accommodate more than one channel.

Bit Rate
Measured as "bits per second," and used to express the rate at which data is transmitted or processed. The higher the bit rate, the more data that is processed and, typically, the higher the picture resolution.

Channel
A 6 Mhz (bandwidth) section of broadcasting spectrum allocated for one analog NTSC transmission.

Component Video Connection
The output of a video device (such as a DTV set-top box), or the input of a DTV receiver or monitor consisting of 3 primary color signals: red, green, and blue that together convey all necessary picture information. With current consumer video products, the 3 component signals have been translated into luminance (Y) and two color difference signals (PP, PR), each on a separate wire.

Composite Video
An analog, encoded video signal (such as NTSC) that includes vertical and horizontal synchronizing information. Since both luminance (brightness) and chrominance (color) signals are encoded together, only a single connection wire is needed (i.e. RCA cables).

Compression
A method of electronically reducing the number of bits required to store or transmit data within a specified time or space. The video industry uses several types of compression methods but the method adopted for DTV is called "MPEG2." Four full-range channels of programming and data can be compressd into the same space required by a single analog channel.

D/A
Conversion of digital to analog signals. The device is also referred to as DAC (D/A converter). In order for conventional television technology to display digitally transmitted TV data, the data must be decoded first and then converted back to an analog signal.


DBS
Abbreviation of "Digital Broadcast Satellite" - refers to digital TV transmissions via satllite. Digital Television (DTV)
Refers to all formats of digital television, including high definition television (HDTV), and standard definition television (SDTV). Also referred to as ATV (Advanced TV).

DTS
Digital Theater Systems sound. Discrete 5.1 channel surround system similar but not the same as Dolby Digital. Dolby Digital is the DTV standard, but DTS competes with it on DVD and in the movie theaters.

Downconvert
A term used to describe the format conversion from a higher resolution input signal number to a lower display number, such as 1080i input to 480i display.

EPG
Electronic program guide. An on-screen display of channels and program data.

Frequency
The number of times per second that a signal fluctuates. The international unit for frequency is the hertz (Hz). One thousand hertz equals 1 KHz (kilohertz). One million hertz equals 1 MHz (megahertz). One billion hertz equals 1 GHz (gigahertz). Television is broadcast in frequencies ranging from 54 MHz to 216 MHz (VHF) and 470 MHz to 806 MHz (UHF).

High Definition Television (HDTV)
The generally agreed upon definition of HDTV is approximately twice the vertical and horizontal picture resolution of today's NTSC TV, which essentially makes the picture twice as sharp. HDTV also has a screen ratio of 16:9 as compared with most of today's TV screens, which have a screen ratio of 4:3. HDTV offers reduced motion artifacts (i.e. ghosting, dot crawl), and offers 5.1 independent channels of CD-quality stereo surround sound, (also referred to as AC-3).

Interlaced Scanning
In a television display, interlaced scanning refers to the process of re-assembling a picture from a series of electrical (video) signals. The "standard" NTSC system uses 525 scanning lines to create a picture (frame). The frame/picture is made up of two fields: The first field has 262.5 odd lines (1,3,5...) and the second field has 262.5 even lines (2,4,6...). The odd lines are scanned (or painted on the screen) in 1/60th of a second and the even lines follow in the next 1/60th of a second. This presents an entire frame/picture of 525 lines in 1/30th of a second.

Letterbox
The term used to describe the way a 16:9 aspect ratio image is displayed on a 4:3 screen, where black areas are visible above and below the image.

Line Doubling
A method, through special circuitry, to modify an NTSC interlaced picture to create an effect similar to a progressively scanned picture. The first field of 262.5 odd-numbered lines is stored in digital memory and combined with the even-numbered lines. Then all 525 lines are scanned in 1/30th of a second. The result is improved detail enhancement from an NTSC source.


NTSC
National Television Standards Committee responsible for developing Standards for "traditional" Analog TV, prior to Digital-HDTV.


PAL
"Phase Alternation Line" - A signal format used in video equipment in Europe and parts of Asia. PAL signals give you 25 frames per second, and so are incompatible with NTSC, the American video signal format.

Pixel Term used for "picture element;" the smallest element in a television picture. The total number of pixels limits the detail that can be seen on a television. A typical television set has less than half a million pixels. The pixel count for HDTV is nearly two million.

Progressive Scanning
In progressive scanning, typically used by VGA computer monitors, all the horizontal scan lines are 'painted' on the screen at one time. Adopted DTV formats include both interlaced and progressive broadcast and display methods.

Resolution
The density of lines and dots per line which make up a visual image. Usually, the higher the numbers, the sharper and more detailed the picture will be. In terms of DTV, maximum resolution refers to the number of horizontal scanning lines multiplied by the total number of pixels per line, called pixel density.


SECAM
SECAM (Système Electronique Couleur Avec Mémoire) is a signal format used in video equipment in France and the former Soviet Union. It is incompatible with PAL and NTSC formats.

Set-top Box STB)(also: Decoder, Receiver, Tuner)
A unit similar to today's cable boxes, which is capable of receiving and decoding DTV broadcasts. A DTV 'Certified' STB can receive all (18) ATSC DTV formats, (including HDTV) and provide a displayable picture.

Spectrum
A range of frequencies available for over-the-air transmission.

Standard Definition Television (SDTV)
SDTV refers to DIGITAL transmissions with 480-line resolution, either interlaced or progressive scanned formats. SDTV offers significant improvement over today's conventional NTSC picture resolution, similar to comparing DVD quality to VHS, primarily because the digital transmission eliminates snow and ghosts, common with the current NTSC analog format. However, SDTV does not come close to HDTV in both visual and audio quality.

S-Video
Separated video. An encoded video signal which separates the brightness from color data. S-video can greatly improve the picture when connecting TVs to any high quality video source such as digital broadcast satellite (DBS) and DVDs.

UHF
Ultra high frequency, the range used by TV channels 14 through 69.

Upconvert
The term used to describe the conversion of a lower apparent resolution to a higher number, such as "upconverting" 720p to 1080i. This is a misnomer, though, since to accomplish this, the horizontal scanning frequency is actually lowered from 45kHz to 33.75kHz. Resolution quality is not improved by this method.

VHF
Very high frequency, the range used by TV channels 2 through 13.

Y, PB, PR
The most advanced method for interconnecting decoded video data. Generally used where a digital TV signal source is used. Preferred connection for High Definition TV signals; enables superior quality in transmitted picture. The video signal is separated into its component parts of brightness and color differentials.


Y, U, V
Also sometimes referred to as Y, Cr, Cb, where a video signal is separated into components of brightness and color, arguably to a degree more advanced than S-video.

[Matt Heebner]

Great job!
I vote to have this moved to the FAQ area where it will be permanent. Also that way it can be added to or adjusted as needed.
Maybe also we can have an area in the FAQ explaining all the different monitors capable of displaying an HD signal (ie. RPTV, Plasma, LCD, DLP, etc.)

Matt

[ReesR]

I second the motion.  All in favor say aye!

[Ron Pollitt]

This is a big help to a novice like me.  Thanks!
Ron

[StarvingForHDTV]

Aye

We could add RGB as a connection.  Sometimes people get confused with that.

Notice how the definition of HDTV includes  5.1 channels of sound...  I wonder if NBC and CBS realize that???

According to the definition given of SDTV, Faux does not meet that definition in my opinion.  There is supposed to be "a significant improvement over today's conventional NTSC picture resolution, similar to comparing DVD quality to VHS"  I don't see that personally with Faux 6-DT

Good job,

Starving

[Tom Snyder]

Your wish is my command!
 http://www.milwaukeehdtv.org/glossary.html  

Linked from the links page...

[P a u l]

Hey Starving where did you read that "the definition of HDTV includes 5.1 channels" I'm just curious because if it says anywhere in the sentence preceeding that statement something like "Dolby Digital sound" don't confuse that with 5.1.

Hey Tom I just dug out my books from school and could post a whole bunch of pages like this. It might be easier if ya drop me an e-mail then I could e-mail them to you and you could post them.

[StarvingForHDTV]

 

Originally posted by P a u l:
Hey Starving where did you read that "the definition of HDTV includes 5.1 channels" I'm just curious because if it says anywhere in the sentence preceeding that statement something like "Dolby Digital sound" don't confuse that with 5.1.

Hi Paul,

Welcome aboard.  I found the information I was talking about in the first post of this thread.  The 23rd paragraph:

"High Definition Television (HDTV)
The generally agreed upon definition of HDTV is approximately twice the vertical and horizontal picture resolution of today's NTSC TV, which essentially makes the picture twice as sharp. HDTV also has a screen ratio of 16:9 as compared with most of today's TV screens, which have a screen ratio of 4:3. HDTV offers reduced motion artifacts (i.e. ghosting, dot crawl), and offers 5.1 independent channels of CD-quality stereo surround sound , (also referred to as AC-3)."

By that definition (which I did not write) NBC and CBS still have some work to do.

Starving

[Pat]

There are probably others, but one missing is PSIP.  I know what it is, but not as a definition, and don't know what the letters satnd for.

[Gregg Lengling]

Program and System Information Protocol (PSIP)

The ATSC PSIP standard (A/65) for Digital Television allows broadcasters to identify themselves and convey up to 16 days of programming information. Consumer electronic manufacturers can use PSIP data to construct interactive electronic program guides to aid navigation of channels in DTV receivers. The standard is comprehensive, but can be difficult to understand and implement correctly, especially under the short time-to-market constraints for broadcast and consumer equipment.

------------------
Gregg R. Lengling
RCA P61310 61" 16x9
HiDTV Pro 2 computer reciever card
glengling@ameritech.net

[This message has been edited by lummox (edited 10-30-2002).]

[Joseph S]

OAR - Original Aspect Ratio

IEEE 1394a (Firewire)
With a maximum capacity of 400 Mb/s, Firewire can't handle uncompressed HDTV content over 480p. Firewire does have the advantage that the protocols it uses were designed to be two way, to allow control in both directions, and carry digital audio. You will soon see consumer goods using a common control format for the home theater. No longer will you need 10+ remotes. Connectivity is guarded with the DTCP encryption protocol.

DVI

DVI was developed by the Digital Display Working Group (DDWG) and has been chosen by the industry as the digital video connectivity solution. With a maximum capacity of 1.65 Gb/s per TMDS link (3 data channels  per link, 2 links possible per connector), DVI is just right for high resolution video. The new(er) standard affords digital audio as well. The DVI connector also allows for an analog connection. There are DVI display devices on the market now, with more on the horizon. Dish network and DirecTV both have products that incorporate DVI. Connectivity is guarded with the HDCP encryption protocol. DVI also allows manufacturers to place images over the content, such as menus and directories.

Source: http://www.hometheaterhifi.com

Then of course there is Firewire B with twice the fun. Great job, lummox on this lengthy list.