An input into part of the synthesizer that allows that bit to be modulated by another part of the synth. For example there is a control input in the amplifier which controls the level of amplification. If a very slow sine wave (an LFO) is patched into this input then the sound will slowly get louder and quieter. If an LFO was patched into the control input of the oscillator instead, then the sound would go higher and lower in pitch....
CS-40M
The CS-40M is a duophonic (2-voice) analog synthesizer with a 44-note 3 1/2 octave (F-C)
keyboard and 2 banks of 10 patches that are backed up via a tape interface. It is housed in a
wood-finished cabinet with a metal faceplate. All in all, it has 36 knobs, 16 switches, 16 buttons,
12 sliders and 2 wheels. The CS-40M's voice architecture consists of two VCOs, a noise
generator, one LFO, two envelope generators (one for the VCA and one for the VCF), and a
VCA. Each VCO (Voltage Controlled Oscillator) has a knob to switch between a 6 octave range
and another knob for fine tuning. A mixer section adjusts the levels of VCO1 and VCO2.
Waveforms are switchable between triangle, sawtooth, and square (pulse). The LFO (Low
Frequency Oscillator) is switchable between sine, up-ramp, down-ramp, square, and sample-
and-hold. It can easily modulate up into the audio frequencies. The EG-VCO (the envelope
generator for the VCO) is a simple AR (Attack Release) envelope. the EG-VCF (the envelope
used for the VCF and VCA) is an ADSR (Attack Decay Sustain Release) envelope. The VCF
(Voltage Controlled Filter) is a multimode filter, switchable between LP, BP, and HP, with a
control for cutoff frequency and resonance (none oscillating). A switch enables and disables the
keyboard tracking. The Pitch Wheel is switchable between intervals of a 3rd and a 5th, and the
Modulation Wheel has switches to select the VCO and the VCF. There are separate CV(control
voltage)/Trigger outputs for each voice and CV inputs for portamento, sustain, brilliance, volume
and filter. The CS-40M has high, low, and balanced outputs.