STANDARDS

Digital television channels are transmitted at a lower power than the older analog channels however instead of just two frequencies (one for vision and one for sound) as used in analog transmission, 6817(8K) digital carriers are compressed into the same channel width (7Mhz).

The digital services use MPEG video and audio compression and SD(standard digital televion) and HD (high definition television) progams are transmitted. SD pictures have a 16:9 picture ratio with 576 x 720 pixels which means that the pixels are not square but rectangular. Typical data rates for SD are 4 - 6 Mbits per second and 12 - 14 Mbits per second for HD

The analog television system will be phased out of service by 2008, by then all television transmitters will have been replaced with a digital transmitter. The current tuners in VCRs and television sets will no longer be able to receive television as they will all television signals will be digital.

SCART is the the 21 pin connector now being introduced on Australian video equipment with the advent of digital television. Being used in Europe for many years it has the advantage that video can be connected between devices using the Red, Green and Blue components (RGB) of the picture. This is similar to the video connection between a computer and it's monitor, resulting in sharp clear pictures.

The SCART connectors can be used for both input and output of video and audio, configuration of the SCART socket function can be changed by hardware or software methods - the rewards in using SCART are worth the time in learning how to use it correctly.

The recording of digital television from a Set Top Box for play back on an analog television setup may cause the picture to look squeezed up depending on how the Set Top Box aspect ratio settings have been set. A test recording is advised to find the correct combination for the recording.

HOBART DIGITAL

Hobart digital television is transmitted on the following VHF channels, WIN channel 7, ABC channel 8, SBS channel 9A, Southern Cross (SCT) channel 10 and Tasmaninan Digital Television (TDT) channel 11.  The UEC DTT-720i set top box requires the following information to be entered to receive all Hobart channels. For UEC select Menu, Installation, PIN "1379", Antenna Instal, Signal Setup once set use Tune DTT and not Scan DTT (current as at Jan 2004)

HIGH DEFINITION

HD has a pixel ratio of up to 1080x1920. HD programs can also have five channels of audio providing for the transmission of surround sound, future SD Set Top Boxes may include a 5 channel audio decoder.

HD's increased cost of producing, storing and viewing when compared to widescreen SD means that SD is more able to suit the pockets of the average Australian viewer, film maker, professional and the broadcast industry.  One hour of recorded true HD transmission quality requires 23 Gigabytes or more of storage, with current storage technologies the creation of portable domestic HD recordings is limited.

The Melbourne Age - 2 May 2002 reports - The ABC has asked the Senate's media ownership enquiry, that the HD deadline be delayed by up to five years (all television broadcasters are required to provide 20 hours per week of HD programs from January 2003). Channel Seven's spokesman Simon Francis said networks had already spent $1 billion on digital televison, but consumer reaction indicated viewers were more interested in choice than better picture quality.

Properly designed home theatre, medicine and scientific applications are really the only place where the quality of HD can be appreciated. In the typical home viewing environment most experts would be hard pressed to pick the difference between an HD receiver and a line doubling CRT receiver showing the same program in SD.