Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site nicmad.UUCP Path: utzoo!watmath!clyde!burl!ulysses!gamma!epsilon!zeta!sabre!bellcore!decvax!genrad!panda!talcott!harvard!seismo!uwvax!astroatc!nicmad!brown From: brown@nicmad.UUCP Newsgroups: net.video Subject: Re: Stereo Sound for Cable? Message-ID: <188@nicmad.UUCP> Date: Tue, 28-May-85 01:31:36 EDT Article-I.D.: nicmad.188 Posted: Tue May 28 01:31:36 1985 Date-Received: Thu, 30-May-85 07:58:56 EDT References: <331@pertec.UUCP> Reply-To: brown@nicmad.UUCP (Mr. Video) Distribution: net Organization: Nicolet Instrument Corp. Madison WI Lines: 60 In article <331@pertec.UUCP> bytebug@pertec.UUCP (roger long) writes: >I recently contacted my cable company, and wonder if what they told me is >correct. > >Are HBO, Cinemax, and/or any of the other movie channels broadcasting in >stereo? Do they plan to in the near future? Will there be any problems >with the stereo co-existing with their scrambling schemes? HBO and The Movie Channel I know are broadcasting in stereo. I understand that the Disney Channel is as well. But, the stereo information is NOT in the MTS format. It is meant to be placed onto the FM band of your local cable system. If you didn't know it, MTV can only be carried on a cable system if the stereo audio is also carried on the FM band. >Also, will the stereo signal be compatable with the current broadcast >TV stereo scheme? Does this work over the cable? I've been told not. Well, here is where the controversy gets started. Some specialists say that the MTS audio will work on cable systems and other specialists say not. I am just talking about normal channels, not the scrambled pay channels. Some say that the extra FM bandwidth of the MTS signal will cause intermod problems with adjacent channels. It depends on the type of equipment used at the head end (the cable transmitting end). If your cable company can get MTS to work on their system, it will be compatable with broadcast MTS. Some cable companies will strip off the broadcast MTS signal if their system can't handle it. At this point in time, the FCC has NOT declared a MUST CARRY RULE for MTS audio. My cable system doesn't know what they are going to do yet. We are in the enviable position of having two things in our favor; 1) all of the local stations, and most of the satellite signals have the audio portion on the FM band. 2) all of the local stations have a direct feed to our cable company. This means if the transmitter fails, the cable viewers will still get the picture and sound. Because of number 1, our cable company can go stereo on the FM band by installing the MPX circuit to the FM transmitter. Now, for scrambled pay channels. The problem here is caused by the fact that most scrambling techniques place a syncronizing signal on the audio sub-carrier. That signal is AM, so the TV FM circuit will throw it away and the pay service decoder will throw away the FM signal. Also, because the AM signal is normally the same frequency as the horizontal frequency, 15734 KHz, (or double it) it is outside the FM frequency bandwidth of 50 to 15KHz. But, it is not outside the maximum FM deviation, which is +/- 25KHz. Now, as I understand it, the MTS maximum deviation is now +/- 75KHz. This causes the AM signal to always be caught up in the FM deviation. There is also a FM modulated AM signal (the SAP signal?). My information on the MTS is at work. It is the FCC document on MTS. The scrambled AM signal could now do more damage to the FM MTS signal. Cable companies are not about the throw away their investment in the pay channel scrambling method that they chose. Our cable company won't, as they recently changed over to a new method. I hope all of this helps a little bit. -- |------------| | |-------| o| JVC HRD725U Mr. Video | | | o| |--------------| | | | | | |----| o o o | | |-------| O| |--------------| |------------| VHS Hi-Fi (the only way to go) ({!seismo,!ihnp4}!uwvax!astroatc!nicmad!brown)