Sujet : Re: "Sampler??"
De : alien (at) *nospam* comet.invalid (Jan Panteltje)
Groupes : sci.electronics.designDate : 30. Jul 2024, 06:16:24
Autres entêtes
Message-ID : <v89sv9$hq1q$1@solani.org>
References : 1 2 3 4
User-Agent : NewsFleX-1.5.7.5 (Linux-5.15.32-v7l+)
On a sunny day (Mon, 29 Jul 2024 09:29:04 -0700) it happened john larkin
<jlarkin_highland_tech> wrote in <
72gfajl8ke966lsu54bpajpang9dvgmt63@4ax.com>:
On Mon, 29 Jul 2024 05:19:06 GMT, Jan Panteltje <alien@comet.invalid>
wrote:
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On a sunny day (Sun, 28 Jul 2024 21:40:41 -0000 (UTC)) it happened Cursitor
Doom <cd999666@notformail.com> wrote in <v86dsp$3n74$1@dont-email.me>:
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I still can't see where the 'sampling' bit comes into it.
AFAICT, there's are two signals into this thing and one signal out. The
signal from the LHS is passed through a very fast diode which generates
harmonics from that fundamental. The signal from the RHS is unmodified and
mixed with the desired harmonic to give the necessary output signal which
is then filtered to get rid of the unwanted mixing products. If that's all
correct, as I believe it is, where does any *sampling* come into it?
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A 'sampler' is fact a non-linear mixer.
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In the audio world, a "mixer" is a linear summer.
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In RF, a mixer is usually a multiplier, typically a 4-quadrant diode
thing or a Gilbert cell type circuit. Or a 2-quadrant thing like a
pentode. Or even a single diode. All do some flavor of multiplying.
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Some mixers inherently multiply a signal by a square wave, which
resembles other multiplier-type things once you lowpass filter the
output. That's a "synchronous detector", which we usually do in an
FPGA.
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A sampler is a signal multiplier too.
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These are all variations on the basic idea of multiplying two signals.
A the word 'mixer' in RF is not the same as a multiplier,
Multipliers are like harmonic generating stages
say you have a 1 MHz distorted sine wave
and then a second stage tuned at 3 MHz,.. turned to third harmonic.
mamamatical speaking RF mixing is indeed multiplication.
Like Shakepierce once said:
"What's in a name..." CocaCola wihout coke