B-7 VCO with linear FM
X is V/Oct pitch input
Y is linear FM input
Z is tune ±0.5 octaves
A & B are selectable output waveforms
Receives MIDI
Parameter Min Max Default
Description
0
-16 8
0
Octave shift.
1
0
32
32
Sets an attenuation for output A.
2
0
32
32
Sets an attenuation for output B.
3
0
5
1
Type A.
4
0
5
3
Type B.
5
-51 50
-51
Fine tune/enable sync.
This algorithm is a VCO with a 1V/octave pitch CV input (X), and a linear FM input (Y), scaled at
100Hz/V. Note that, if the FM input goes sufficiently negative, it will take the frequency through
and below zero, resulting in a phase inversion ("thru-zero FM").
The 0V point for the pitch input is C3 (approximately 130.81Hz).
The Z knob/CV provides a tuning control, with a range of approximately ±0.5 octaves (but see also
parameter 5, below).
The A and B outputs provide waveforms according to the following table:
Parameter value
Waveform
0
Triangle.
1
Sine.
2
Square.
3
Saw.
4
Sub-octave square.
5
MIDI gate.
Parameters 3 & 4 control the waveform of outputs A & B respectively. The output signals are ±8V
(16V peak-to-peak) by default, but can be attenuated via parameters 1 & 2.
Parameter 5 controls the function of Z. At the default value of -51, Z is the tune control as already
mentioned. When the parameter is set to a value from -50 to 50, Z no longer affects the tuning, and
the parameter value is used as a fine tune control, in cents. Z then becomes a sync input: when Z
goes over approximately 1V, the VCO phase is reset to zero, which can produce 'oscillator sync'
sounds
MIDI Input
: MIDI note messages received on the MIDI channel set in the Settings are converted to
a CV which is added to that on input X. The 0V note is 48 (C3). MIDI notes also drive the 'MIDI
gate' output option.
9
https://en.wikipedia.org/wiki/Oscillator_sync
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