4
frequency
shifting
The functions of these two pairs effectively
swap when the shift knob is turned to the left
of 0Hz, or a negative control voltage is applied.
Two ±5V range CV inputs are available for
modulating the amount of frequency shift:
exp fm 7for exponential control and lin
tz fm 8for linear control. The sensitivity
of the exponential input is switched together
with the range switch, while the sensitivity
of the linear input is controlled by the atten-
uator 9
Koszalin provides several internal feedback
options. The regen switch 10 determines
internal feedback routing: from downshifted
signals, upshifted signals, or both combined
feedback amount is controlled with the re-
gen knob 11 , and CV plugged into the corre-
sponding jack 12 . The temporal character of
the feedback effect depends on the density
parameter, controlled by knob 13 and/or CV
via the corresponding input below 14 .
WhAt IS freQueNcY ShIftING?
Frequency shifting is a process that affects all
spectral components of a signal by changing
their frequencies by an equal number of Hz.
For example: if the input is a periodic wave-
form with a 1kHz frequency, it usually con-
tains the 1kHz component plus the harmonic
overtones: 2kHz, 3kHz, 4kHz, etc. When this
signal is shifted by 200Hz the result contains
That means the new components are no lon-
signal is inharmonic and non-periodic.
-
fect to pitch shifting, which results in scaling
the frequencies by the same factor. So, for
example, applying a factor of 1.2 would re-
sult in a signal that contains 1.2kHz, 2.4kHz,
3.6kHz, 4.8kHz, etc.—still a harmonic signal,
just with a different pitch.
Technically, shifting of the spectrum is achieved
that is much more complex than a simple mul-
tiplication, which is sometimes inappropriately
called ring modulation.
A common fallacy says modulation is the same
as adding and subtracting signals, which is
nonsense since multiplying is not adding and
subtracting. Instead, this type of modulation
-
-
nents in such a way that their frequencies are
added and subtracted.
and offers two new signals: one with frequen-
cies shifted up and one with frequencies shift-
phase rotation, and quadrature modulations,
note:
summing both down- and upshifted signals
reduces the effect to a mere multiplication
