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Yes I know all about these issues - I used to design ADSL and then VDSL modems which have to adapt around moving interferers, including other modems of course. The 56kpbs 'analogue' modem speed was only on download so we could put more energy with pre-distortion
into the signal at well above 3.4kHz. This couldn't be done on upload so was limited to 33k.</div>
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Terrestrial TV depends on Trellis coded modulation and very long Reed-Solomon (RS) codes that you couldn't use in modems because of latency to get a useable signal out of the mush These could have been applied to a cassette if they had been invented back then
and you had some way of building the huge amount of logic required, but one didn't back then.</div>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> Roman Sowa <modular@go2.pl><br>
<b>Sent:</b> 08 August 2024 13:28<br>
<b>To:</b> Mike Bryant <mbryant@futurehorizons.com>; synth-diy@synth-diy.org <synth-diy@synth-diy.org><br>
<b>Subject:</b> Re: [sdiy] Sampler with tape dump?</font>
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<div class="PlainText">There's no more truly random medium than "the air" and still QAM64 is
<br>
doing perfectly fine there as in terrestial TV. 256 was maybe tiny <br>
exaggeration, althogh I'd be tempted to try it hoping for really good <br>
results if I cared anough.<br>
Don't forget, we (as in "we, humans) have reached theoretical limit of <br>
56kbs in lousy 3kHz bandwidth of a phone line.<br>
<br>
Roman<br>
<br>
W dniu 2024-08-08 o 14:13, Mike Bryant pisze:<br>
> QAM256 (or any other such technique) depends on a consistent, almost <br>
> predictable, level of noise. I suspect cassette noise is truly random <br>
> so it would drop back to lower levels, in the end a single binary bit <br>
> and just get the speed we used to get.<br>
> ------------------------------------------------------------------------<br>
> *From:* Synth-diy <synth-diy-bounces@synth-diy.org> on behalf of Roman <br>
> Sowa via Synth-diy <synth-diy@synth-diy.org><br>
> *Sent:* 08 August 2024 12:44<br>
> *To:* synth-diy@synth-diy.org <synth-diy@synth-diy.org><br>
> *Subject:* Re: [sdiy] Sampler with tape dump?<br>
> Using modern modulation techniques like QAM256 one could achieve much<br>
> higher throughput from a cassete. I wouldn't be surprised to see 200kbps<br>
> of clean data after all correction stuff, so that 128kB Commodore loads<br>
> in like 5 seconds.<br>
> <br>
> Roman<br>
> <br>
> W dniu 2024-08-08 o 01:19, Gordonjcp pisze:<br>
>> On Wed, Aug 07, 2024 at 02:41:38PM -0700, brianw wrote:<br>
>>> I seriously doubt it. The dump to tape would take so long that it would probably have a 100% chance of error. The size of a synth patch versus the size of a sample is quite a significant difference.<br>
>> <br>
>> It depends. Home computers with as much as 128kB of RAM used tape for storage, so you could easily store an entire Ensoniq Mirage's worth of sample and program RAM to tape. Using standard ZX tape routines it'd take about 15 minutes to load or save, considerably
slower than floppy disk. Even using something like Speedlock would <br>
> only take that down to about 10-11 minutes.<br>
>> <br>
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