Hi,
I'll try to have a shot at it,
In a one-input frequency-shifter [FRS], the built-in signal is supplied by a built-in
sine-wave oscillator which outputs two sine waves of identical frequencies, but one of
this sine waves is 90 degrees out of phase compared to the other. Serge has such a
quadrature oscillator [QUO] as a separate module - also, the [VCFX] can be patch-
programmed to be used as such.
The free input of the [FRS] has to pass thru a phase shifting network that allows for a
phase shift of 90 degrees. This phase shifting has to constant throughout the whole
frequency range. To build such a phase shifter is AFAIK what makes a frequency
shifter (from any brand) so costly.
The [FRSX] needs two of those phase shifting networks, one for each input. It drops
the [QUO], but this seems not to make up for the money needed for the second phase
shifting network.
I don't know if the [FRSX] also needs doubling the level compensation curcuits (it
might, if this treats the input signal and not the output signal on the [FRS]).
Two questions from me to all owners and users of the [FRS] on SMOG: I could not find
any note on how low the shift frequency from the internal oscillator can go on the
[FRS] by (a) manual control and (b) voltage control.
Second one. From trying out different frequency shifters on Musikmesse and NAMM, I
found out that there two different frequency shifter designs out there -- thru-zero-
ones and not-thru-zero-ones. On a thru-zero (e.g. Modcan, Bode, Analogue
Solutions or Systems, I always confuse these two) one you can turn the shifting
frequency not only very low, to say like 0.1 Hz, but you can also make it negative. If
negative, the upshift output becomes the downshift output and vice versa. As you can
voltage control the shifting frequencies, you can voltage control if downshift and
upshift outputs exchange places. This should be useful for very interesting stereo
effects (connect upshift to left and downshift to right).
How does the Serge [FRS] fit in here? Thru--zero or not?
Thanks,
Jan-Hinnerk
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--- In
SergeModular@yahoogroups.com, John Papiewski
<johnp299792@a...> wrote:
> Yo,
>
> If you think of the FS as a souped-up ring modulator you might get
a
> clearer idea. Now, some ring modulators have one signal input and
they
> use a built-in oscillator to modulate your incoming signal. That's
like
> the first frequency shifter. Built-in oscillator.
>
> But some ring modulators have two open inputs so you can modulate
> anything against anything. The Serge ring modulator has two inputs.
> The FRSX is like that two. It drops the internal oscillator and
accepts
> anything.
>
> Frequency shifting by a sine wave is 'simple' - the output is A + B
> (upshift) and A - B (downshift). If your shifting a sine wave by a
sine
> wave, that's simplest. 100 hz in A and 200 in b gives you 300
upshift
> and 100 downshift.
>
> Frequency shift a square wave by a sine wave, things get a little
> trickier. All the harmonics get shifted by the same absolute
> difference. So the more you shift the more inharmonic the
overtones
> become. It sounds weird. Also, downshift by enough and you get
> 'harmonic inversion' - the fundamental is at the high frequency,
and the
> overtones are fractions (not multiples) of the fundamental.
>
> NOW - shift a square by a square. You get lots of things going on.
I'm
> not familiar enough with it to go into it, but there must be a lot
of
> frequencies flying around in there.
>
> I don't know why it would be so much more money - it might have
> something to do with level compensation.
>
> Anybody else care to comment?
>
> vtl5c3 wrote:
> > Last night I was perusing my Serge catalog and noticed that
> > there were two versions of the Frequency Shifter. The second
> > version (FRSX) caught my attention.
> >
> > Here's what it says about the FRSX:
> >
> > "The basic unit features a built-in oscillator .... Available at
a
> > higher cost and on special request is a version which accepts
> > any external shifting signal. This version may be of interest to
> > musicians wanting to shift the sound of one instrument by
> > another, say the flute by a tuba....."
> >
> > Does anyone know how the Carrier input is designed? Is there
> > a pitch to voltage converter that is used to convert an audio
> > signal to drive the FS? The catalog is a bit vague as to how the
> > module works.
> >
> > Romeo
> >
> >
> >
> > To unsubscribe from this group, send an email to:
> > SergeModular-unsubscribe@yahoogroups.com
> >
> > Keep on Patchin'!
> >
> >
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/docs.yahoo.com/info/terms/
> >
> >