Broadcasting video with sound

LewisD

Hi All,

I am setting up TV broadcasting with the prop to send telemetry back from a robot and
I was wondering if anyone has also sent Mono or Stereo sound as well as Video?
(I NEED R2D2 SOUNDS!!!!!)

Would it take another cog?
How would it be mixed with the video?

I am planing on doing something like this ...

www.technotoad.com/how-to-build-your-own-rf-modulator-for-your-tv.php
(I would put my antenna on the Modulators TV out.)

But I was hopping for a more elegant solution.

Thanks

LewisD

Post Edited (LewisD) : 7/11/2007 9:48:19 AM GMT

ciphernet

Since audio has it´s own carrier frq. in a Pal/NTSC television RF transmission, I can´t see how you can mix·video and audio·unless you use an external modulator circuit or generate an extra audio carrier frq. for the modulation of the sound and then mix the two outputs.

Jan

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·Give me some slack, please.. I have programmed SX controllers for five years but the prop just blows my mind :-)

Mike Green

If you look at the documentation for the video generator, limited as it may be, you'll see that the PLLA of one of the other cogs is used as the subcarrier frequency source for the audio subcarrier. This subcarrier can be modulated by that cog to provide the audio for the TV signal.

Kaio

LewisD,

I don't have seen an example for this in the forum. But I know from the documentation of the TV driver that you have to use a separate Cog to provide the modulated audio signal. In the TV driver you have to set the parameter tv_auralcog appropriate to the Cogid. You don't need extra hardware, the Propeller will do the mix.

Thomas

deSilva

Alas, also Andre LaMothe is very tacid about this feature in his elsewhere instructive and comprehensive book...