Re: [amsat-bb] 9600 baud test with .wav file?

[Roy Welch <rdwelch@xxxxxxxxxx>]

Ron,
I have used the Hi-FI, not the PCM digital, audio channel on my Sony Hi-8
VCR to record it off the air onto a Hi-8 Video tape.  I'm not sure the
sampling rate of the PCM track would do as good a job as the analog Hi-Fi
track.  Simultaneously, I copied it on WiSP to get the 100% bit (byte?)
count.  Then when I played the VCR tape back to WiSP through the same
modem, a PacComm TNC-200, I got 98% of what I got live.  A WAV file would
be way to big a file to have more than about 20 seconds of it for
transmission vie internet, etc.  You really need to copy it to a CDROM as
you suggest.

Maybe you should stripe the tape first with blank video for synchronization
and then record the audio in the audio dub mode for best results.  However,
I recorded the sound at the same time I was recording blank video and I
don't see why that wouldn't be just as good.  In either case the sync pulse
recording would have come from the VCR.

I do not have a write CDROM capability here.  Someone would have to find a
recording facility for it and find out what it would cost to make the
CDROMs.  First of all a test CD should be made to be sure the sampling rate
on the CD is good enough and determine what quality of sound card is
required to recover it adequately.  I don't know if my Sound Blaster 16
would be good enough.  Some of the digital Gurus perhaps can enlighten us
in this.

"Ronald K. Long" wrote:
> 
> Some questions:
> 
> 1. Is it possible to play a .wav file of 9600 bd satellite data for testing
> a new modem/tnc setup?
> 2. If so who has a file to share?
> 3. Are there limitations concerning the speed of the computer, sound card
> type etc.
> 4. If the above is possible could AMSAT prepare a CDROM for this purpose
> and collect donations for it? There could be files of various sizes - 1min,
> 5 minute etc. Could P3D telemetry be included?
> 
> thanks ron w8gus.
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-- 
73, Roy

Internet: w0sl@amsat.org
Home Page: http://home.swbell.net/rdwelch
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