Focus on Technology: Analog-to-Digital: The New Y2K? Part II

As you may know, February 17, 2009 is the date on which, in the US, any TV stations still operating analog (NTSC) transmitters must shut them down. Without a converter box or a television, DVD/VCR, DVD Recorder with a digital (ATSC) tuner all you will get is static.

The transition process started in earnest in 1996 when the FCC allocated additional channels to TV stations so they could bring up their digital transmission equipment and antennas while still operating their analog transmitters/antennas. Between now and February 2009 these stations will be shutting down their old analog systems so the federal government can auction off part of this spectrum for other uses.

While this has some obvious issues for home viewers the issues for professional AV systems have not been that clear. In this pervious blog post(insert link to part 1 feb 08) , we discussed situations in which systems with over-the-air tuners and antennas might be affected.

Another area that may receive some impact is in relation to wireless systems, such as wireless microphones, in-ear monitors, intercom systems, etc. All wireless systems that use radio frequencies above 700MHz will no longer be allowed to operate after the deadline. This frequency band is being auctioned off for other uses and some parts of it are being assigned to public safety use.

Most wireless systems in place today use frequency agile transmitter/receivers that allow the user to change the channel within a wide range of frequencies to find free spectrum in the area. It has become more and more difficult over the last few years as DTV stations have come on line and taken more and more channel space that previously was used by wireless systems. With the addition of the second TV channel in most areas (i.e. the digital channel that was brought up while the station kept its analog channel running until the 2/17/09 deadline) the available spectrum has gotten more and more crowded, particularly in large metro areas. The digital upgrade has also brought about the use of sub channels (additional channels that DTV stations can now transmit to broadcast multiple channels of content at the same time, i.e. channel 5, 5-1, 5-2, 5-3, etc.). All of this has made it harder for professional AV systems with lots of wireless systems to find clean channels to operate.

However, unless you have some specialty wireless equipment operating in 700MHz or higher region you should be able to work out any interference the same way it has been done for years: Adjust your equipment to use an open channel. There will be more interference than in the past, in most areas, but the equipment will still work.

The last area in which we will see change as we move to digital TV is video conferencing systems. Video conferencing systems are separate systems that transmit their encoded signals over telephone or data cabling, so they don’t necessarily have to convert to digital or HD at the same time as the over-the-air broadcasters. Over the past year or so, both HDTV signals from cameras and computer-generated content have moved forward, with all of the major video conferencing manufacturers providing CODECs (i.e. coder/decoder that translates AV signals to digital signals for transport over phone lines) that support the transmission of HD content at native rates (assuming the CODEC on the other end supports HD as well). These units come at a premium price and require more bandwidth to achieve true HD signals, but since everything else in the pro AV chain is moving to digital, it is to be expected that video conferencing will follow. Keep in mind that the change to HD conferencing won’t make your existing system obsolete. But the next time you upgrade your system, in a few years, HD conferencing will likely be the standard instead of the premium.

Overall, the analog to digital TV conversion will have a bigger impact on the home consumer environment than the professional AV system. But note that there will be a considerable impact on screen format. The switch will act as a catalyst to convert the traditional 4 x 3 format image to a 16 x 9 (or similar) widescreen format. Stay tuned in the coming months and we will begin to discuss the widescreen conversion and how it impacts AV systems.

Click here to read Part I.