[sdiy] How to use an analog time-domain multiplexer?

[cheater cheater]

I'm not completely discounting having something like an impedance
matched transmission line for the signalling. One thing that I wonder
about is, though: what happens if you take the output of a normal euro
rack synth - either audio or CV - and feed it into such a
low-impedance input? Say the input is 50 Ohm, 300 Ohm, or 600 Ohm. I
don't really know what typical output impedances are in Eurorack. And
it would be nice to be able to patch a mono Eurorack module into the
polyphonic input of this thing.

On Fri, Jun 4, 2021 at 4:34 PM cheater cheater
<cheater00social at gmail.com> wrote:
>
> Interesting!
>
> I did some calculations earlier today and at 5m (which is the longest
> patch cord I'd consider practical), the first reflection would arrive
> at the receiving end after 33ns. That's way less than one on-period of
> the switching. I don't really know how to figure out how many
> reflections I'd be getting, though.
>
> On Fri, Jun 4, 2021 at 4:23 PM Mike Bryant <mbryant at futurehorizons.com> wrote:
> >
> > Those have all had digital filters since the mid 90s.  I doubt you have one older than that.  But before that they used SAW filters which were a sort of analogue primitive version of a digital FIR filter.
> >
> > Either way you need to terminate the links OR pre-distort the transmit signal OR put a compensation filter on the receiver to do what you want to do.
> >
> >
> > -----Original Message-----
> > From: cheater cheater [mailto:cheater00social at gmail.com]
> > Sent: 04 June 2021 15:18
> > To: Mike Bryant
> > Cc: Richard Wentk; synth-diy at synth-diy.org
> > Subject: Re: [sdiy] How to use an analog time-domain multiplexer?
> >
> > Nope! It works even with the cheapest analog TVs. Like the portable, 12", color kind.
> >
> > On Fri, Jun 4, 2021 at 4:14 PM Mike Bryant <mbryant at futurehorizons.com> wrote:
> > >
> > >
> > > > Explain one thing to me... how come I can send NTSC over minijack?
> > > > That's not RF designed, 50-ohm terminated, or even shielded. It's just a minijack. And the ground is shared with two audio channels, none the less!
> > >
> > > Probably because the final generation NTSC decoder in your TV is actually an advanced digital matching filter that works like mad cancelling out reflections and other noise.
> > >
> > >
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