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Groups > comp.lang.forth > #12704
| From | Paul Rubin <no.email@nospam.invalid> |
|---|---|
| Newsgroups | comp.lang.forth |
| Subject | Re: DSP question (software modem) |
| References | (3 earlier) <StSdnc7tfoLjpFHSnZ2dnUVZ_okAAAAA@supernews.com> <7x4nqrodlk.fsf_-_@ruckus.brouhaha.com> <GYidnThRG4kkHVHSnZ2dnUVZ_r6dnZ2d@supernews.com> <7xehpvqt6n.fsf@ruckus.brouhaha.com> <t--dnQcLHf2CD1HSnZ2dnUVZ_sqdnZ2d@supernews.com> |
| Date | 2012-06-04 12:16 -0700 |
| Message-ID | <7xaa0iriot.fsf@ruckus.brouhaha.com> (permalink) |
| Organization | Nightsong/Fort GNOX |
Andrew Haley <andrew29@littlepinkcloud.invalid> writes: >> I don't understand about group codes--they are ECC codes, right? > No. http://en.wikipedia.org/wiki/Group_code_recording Oh, this makes much more sense. > All you have to do is poll the line at a regular frequency and look > for transitions. A software DPLL locks onto the stream. I will have to think about this to figure out how to do it, but the hint is very helpful, thanks. > The old phone modems used FSK because it's easy to do with tuned > analog filters. It occurs to me, they could have used PLL's rather than filters? Maybe the same thing can be done in software using on-chip timers as "VCO"'s. I.e. rather than sample at a regular rate, adjust the sample rate using a "phase detector". That may get rid of all the multiplication. > If you're going to use that much computer power you could use QAM or > even a trellis code, but AFAICS you really don't need that much speed. Of course there will always be uses for more speed, but slow is fine for getting started ;-). Per Richard Owlett's suggestion I just looked at some articles about microcomputer audio cassette formats (e.g. Kansas City Standard). They seemed to rely on external hardware (analog electronics I guess).
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post your solution to this problem quiet_lad <gavcomedy@gmail.com> - 2012-06-03 14:33 -0700
Re: post your solution to this problem "Rod Pemberton" <do_not_have@notemailntt.cmm> - 2012-06-03 20:59 -0400
Re: post your solution to this problem quiet_lad <gavcomedy@gmail.com> - 2012-06-03 19:06 -0700
Re: post your solution to this problem "Elizabeth D. Rather" <erather@forth.com> - 2012-06-03 18:27 -1000
Re: post your solution to this problem quiet_lad <gavcomedy@gmail.com> - 2012-06-03 19:49 -0700
Re: post your solution to this problem "Elizabeth D. Rather" <erather@forth.com> - 2012-06-03 18:28 -1000
DSP question (software modem) Paul Rubin <no.email@nospam.invalid> - 2012-06-03 22:22 -0700
Re: DSP question (software modem) Mark Wills <markrobertwills@yahoo.co.uk> - 2012-06-04 02:19 -0700
Re: DSP question (software modem) Paul Rubin <no.email@nospam.invalid> - 2012-06-04 03:07 -0700
Re: DSP question (software modem) Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-06-04 04:32 -0500
Re: DSP question (software modem) Paul Rubin <no.email@nospam.invalid> - 2012-06-04 03:15 -0700
Re: DSP question (software modem) Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-06-04 05:46 -0500
Re: DSP question (software modem) Paul Rubin <no.email@nospam.invalid> - 2012-06-04 12:16 -0700
Re: DSP question (software modem) Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-06-04 14:55 -0500
Re: DSP question (software modem) Paul Rubin <no.email@nospam.invalid> - 2012-06-04 13:32 -0700
Re: DSP question (software modem) Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-06-07 05:20 -0500
Re: DSP question (software modem) Paul Rubin <no.email@nospam.invalid> - 2012-06-07 10:01 -0700
Re: DSP question (software modem) quiet_lad <gavcomedy@gmail.com> - 2012-06-07 11:04 -0700
Re: DSP question (software modem) Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-06-07 17:21 -0500
Re: DSP question (software modem) Paul Rubin <no.email@nospam.invalid> - 2012-06-07 20:36 -0700
Re: DSP question (software modem) "Rod Pemberton" <do_not_have@notemailntt.cmm> - 2012-06-08 02:36 -0400
Re: post your solution, and don't over write my thread, or I'll do something to Paul Rubbin quiet_lad <gavcomedy@gmail.com> - 2012-06-07 23:55 -0700
Re: post your solution, and don't over write my thread ... BruceMcF <agila61@netscape.net> - 2012-06-08 09:56 -0700
Re: DSP question (software modem) Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-06-08 07:52 -0500
Re: DSP question (software modem) Paul Rubin <no.email@nospam.invalid> - 2012-06-08 11:14 -0700
Re: DSP question (software modem) "Rod Pemberton" <do_not_have@notemailntt.cmm> - 2012-06-08 16:29 -0400
Re: DSP question (software modem) Paul Rubin <no.email@nospam.invalid> - 2012-06-08 19:59 -0700
Re: DSP question (software modem) Richard Owlett <rowlett@pcnetinc.com> - 2012-06-08 22:37 -0500
Re: DSP question (software modem) Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-06-09 04:36 -0500
Re: DSP question (software modem) Paul Rubin <no.email@nospam.invalid> - 2012-06-09 09:41 -0700
Re: post your solution and Paul rubin is a stinker for changing it, you bugger paul!! quiet_lad <gavcomedy@gmail.com> - 2012-06-06 15:52 -0700
Re: post your solution and Paul rubin is a stinker for changing it, you bugger paul!! BruceMcF <agila61@netscape.net> - 2012-06-06 16:09 -0700
Re: post your solution, please no one change subject, start new thread of your own instead quiet_lad <gavcomedy@gmail.com> - 2012-06-07 11:02 -0700
Re: post your solution, please no one change subject, start new thread of your own instead "Elizabeth D. Rather" <erather@forth.com> - 2012-06-07 08:28 -1000
Re: post your solution, please no one change subject, start new thread of your own instead quiet_lad <gavcomedy@gmail.com> - 2012-06-07 23:58 -0700
Re: post your solution, please no one change subject, start new thread of your own instead Paul Rubin <no.email@nospam.invalid> - 2012-06-07 11:53 -0700
Re: post your solution, please no one change subject, start new thread of your own instead quiet_lad <gavcomedy@gmail.com> - 2012-06-07 23:54 -0700
Re: post your solution, please no one change subject, start new thread of your own instead quiet_lad <gavcomedy@gmail.com> - 2012-06-08 00:00 -0700
Re: post your solution, please no one change subject, start new thread of your own instead BruceMcF <agila61@netscape.net> - 2012-06-08 10:08 -0700
[OT] About cancellation of quiet_lad's messages, was Re: post your .... of your own instead Albert van der Horst <albert@spenarnc.xs4all.nl> - 2012-06-08 11:34 +0000
Re: post your solution, please no one change subject, start new thread of your own instead BruceMcF <agila61@netscape.net> - 2012-06-08 10:03 -0700
Re: post your solution and Paul rubin is a stinker for changing it, you bugger paul!! "Rod Pemberton" <do_not_have@notemailntt.cmm> - 2012-06-06 19:28 -0400
This thread is a load of s**t Mark Wills <markrobertwills@yahoo.co.uk> - 2012-06-07 00:54 -0700
Re: post your solution and Paul rubin is a stinker for changing it, you bugger paul!! quiet_lad <gavcomedy@gmail.com> - 2012-06-07 11:03 -0700
Re: post your solution quiet_lad <gavcomedy@gmail.com> - 2012-06-07 11:10 -0700
Re: DSP question (software modem) Richard Owlett <rowlett@pcnetinc.com> - 2012-06-04 07:08 -0500
Re: post your solution to this problem John Passaniti <john.passaniti@gmail.com> - 2012-06-04 09:06 -0700
Re: post your solution to this problem quiet_lad <gavcomedy@gmail.com> - 2012-06-06 15:51 -0700
Re: post your solution to this problem "WJ" <w_a_x_man@yahoo.com> - 2012-06-08 16:12 +0000
Re: post your solution to this problem "WJ" <w_a_x_man@yahoo.com> - 2012-06-09 16:15 +0000
Re: post your solution to this problem BruceMcF <agila61@netscape.net> - 2012-06-08 10:15 -0700
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