Rev. 5 – Jun 2020 Page 30 of 91
If the yellow generator too is brought to audio rate,
FALISTRI starts to perform amplitude modulation
(AM), also called unbalanced modulation because one of
the two signals is positive-only and only two of the four
quadrants of our hypothetical Cartesian plane are in use.
The result of the amplitude modulation is a signal
which retains the carrier frequency with additional fre-
quencies called ‘sidebands’: in case both signals are pure
sine waves, these sidebands will be two, that is the sum
and the difference of the Carrier and Modulator’s fre-
quencies, whose amplitude depends on the amount of
modulation, but in any case will not exceed half of the
Carrier’s amplitude. In case the Modulator’s frequency
is higher than the Carrier’s, and their difference results in
“negative” frequency, they will be heard with inverted
phase.
Figure 31: Amplitude modulation (AM).
In case both signals are bipolar, FALISTRI starts to
perform the so-called Ring Modulation (RM), or ‘bal-
anced modulation’ because it uses all of the four quad-
rants (i.e. the combinations of positive and negative po-
larities).
The result of RM is quite similar to the one of AM, with
the major distinction that in RM the carrier frequency is
suppressed, being the sidebands the only audible output.
Their amplitude, in this case, is equal to the Carrier’s one.
Figure 32: Ring modulation (RM).
3.2.2 Trimming
The front panel features a trimmer in the 4QM area.
This may be useful to set the zero level when used with a
unipolar envelope that falls at zero, reducing possible DC
offset that would cause a lower attenuation. By default, it
is trimmed with the yellow unipolar signal.
3.2.3 Linear Slew Limiter
Also known as portamento or glide when using a quantized
CV, this processor comes into play when any voltage
smoothing is needed. This section smoothens any kind of
voltage transition with independent controls over the ris-
ing and falling edges of the incoming signal.
The pot on the left (C.2) sets the slew of the rising volt-
ages patched to its input (C.1), while the pot on the right
(C.3) of the falling ones. The result is routed to the Output
(C.4) The two LEDs are also helpful to display what is
happening under the hood.
Figure 33: Linear slew limiting.
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