Sending video and data on same RF channel

[InSchool4Ever]

I have a video signal(NTSC or RS-170) and a low bit-rate data stream(like 9600 baud). I want to "add" these two signals and transmit them over a single channel RF link (S, C band). What hardware would I need to be able to do this? Can you buy a transmitter with two channel input? What about the decomm, on the receiver side, to split out the signal?
Thanks...Tom

 

[nbucska]

The video is about 6 MHz but for a B/W 16 levels of gray
it would be 24 Mbits/sec. The audio is a negligeable plus.

So it would take about many hours to xmit 1 second video.

<nbucska@pcperipherals.com>

 

[nbucska]

The prior posting assumes that you want to send the video
and audio on the RS-232.

Adding the RS-232 to the video is trivial: AM or FM a carrier with it and add it to the video. Modulate
the FR with the sum.


<nbucska@pcperipherals.com>

 

[twey]

You should not add the data by just modulate on the same carrier. The NTSC RF has two carriers: Video and Audio. The Video is AM and Audio uses FM. The video has bandwidth little more than 3 MHz and audio about 4.5 MHz +/- 250 KHz. Therefore, any straight modulation on the same RF frequency will interfere with your video and audio signals.

The TV companies mix data stream into their video signal in vertical retrace time. That is where caption and teletext are. However, they are fairly low bit rate.

twey