Analog / Digital stations
OK you are not going to like this but here we go any way. First of all I need to explain how your channels are created.
When the RF signals come into the headend of the Down converters they are separated into pre channelized designations DC (Down Converter) 4 Stream 1 (DC 4-1, DC 4-2...) now once this is done the down converter signal is fed into a channel processor which takes the incoming signal from the Down Converter remodulates it and puts it on an assigned channel 4-1 could become channel 4, 4-2 could become channel 5 and so on. Once this is done you end up with your regular channel line up for analog channels, now for digital its a little different you have IRDs (Integrated Receiver Decoders) which take the off air or satellite Digital RF signals and convert them into MPEG Streams which is the fed into what is called a SEM (Motorola Architecture) Stream Encryption Module which assigns numeric designations to the MPEG streams and then converts the MPEG streams back into RF. Now at this point we have analog and digital signals what then has to happen is the the analog signals must be turned into MPEG streams to go through the system so what happens is from the channel processor the analog signal is put into a SE (Stream encryptor) Like the SE1010. This takes the analog stream and turns it into am MPEG stream and feeds it into the SEM also and the SEM assigns a numeric designation just like the digital signal and this can sometime follow the same numeric designations as was obtained from the Down Converter, So what you end up with is analog and digital signals having the 4-1, 4-2, 5-1, 5-2, ..... format. This is where other equipment comes into play These designations are then kept in a database and are matched to their proper channels by use of the DAC and RADD along with an IPG server. These allow the SEM to assign true channel designations to the converted channels, now the SEM DAC, and RADD talks to your STB, this is way the channels are correct because the SEM and the DAC/RADD are matching what is on the IPG (Interactive Program Guide). When you remove your cable box the tuner in your TV does not know how to deal with the DAC, RADD and IPG signals so it only displays the RF information which is the 4-1, 4-2, 5-1, 5-2 data.
I hope this helps,
Feb 27, 2009 |
RCA 20F424T 20" TV