I once tried using a VCR to record async serial data but found that playback
mangled because it tried to adjust tracking looking for sync.

I am sure there have been others doing this. (I remember a z80 board set up
as a tape archiver for a VCR)

If anyone cares to point out some links or even better, some PIC code (how
hard could it be?), I'd much appreciate it.

alternatively what about encoding digital audio into the video frames?  an
MP3 VCR?

        cya,    Andrew...

        Original message below left un-snipped for those that filter out
[OT], I think this deserves some list attention.

> -----Original Message-----
> From: andy howard [SMTP:musica@UKONLINE.CO.UK]
> Sent: Tuesday, February 08, 2000 10:49 AM
> To:   PICLIST@MITVMA.MIT.EDU
> Subject:      [OT]  Recording radio on a video recorder.
>
> Someone has mailed me offlist to ask about something I should've
> mentioned in my previous post.
>
> Some video machines do seem to need syncs in order to record audio
> properly. Most that I've tried over the years don't, luckily.
>
> A friend of mine solved the problem by buying a cheapo video
> test-pattern generator. About 15UKP (approx 25 USD) as I recall.  You
> can get these from several mail order suppliers (check the ads in a
> video hobbyist magazine) and possibly from Radio Shack or local
> equivalent (e.g. Tandy in the UK).
>
> Alternatively, with very little effort you could make a sync pulse
> generator with a PIC to achieve the same effect.
>
> I don't what system they use where you are but in the UK the TV system
> uses  625 lines at 50Hz, interlaced. This corresponds to a  625*25 =
> 15.625kHz line frequency = 64uS horizontal sync pulse repetition rate.
>
> I think the US uses 60 Hz * 525 lines but I could be wrong here. That
> would be 15.750kHz = 63.492uS.
>
>
> Sync pulses are normally 0.3V negative going and any video (picture)
> signal goes up to 1V peak which represents white.  0V = black.  You
> won't need any picture to sync the recorder for audio.
>
>
> Here's a (poor) illustration of what it'd look like.
>
>
>
>
> -------------------------------------------   1V. Typical peak level
>                                               of picture information.
>
>
>
>
>
> ______  ______  ______  ______  ______  0v
>       ||      ||      ||      ||
>       ||      ||      ||      ||
>       --      --      --      --        -300mV
>
>
>
>
>
> I also found this in an old file:
>
>
> "DigiKey lists 74ACT715PC-ND as "Video Synchronous Generator NEW!" It is
> a 20 pin DIP and costs $17.50 each for small quantities. The
> surface-mount version is SC instead of the PC in the above number. You
> have to pay an extra $1 for the datasheet if you want one."
>
>
>
> I'm lucky, my Panasonic recorder works quite happily with no video syncs
> connected.
>
>
>
> Cheers.
>
>
> Andy.
>
>
>
>
>
>
>
>
>
>
>
>     .-.
>    /   \           .-.                                 .-.
>   /     \         /   \       .-.     _     .-.       /   \
> -/-------\-------/-----\-----/---\---/-\---/---\-----/-----\-------/
>           \     /       \   /     `-'   `-'     \   /       \     /
>            \   /         `-'                     `-'         \   /
>             `-'                                               `-'
>
>
>
> ------------------------------------------------------------------------