VC LFO 1

VC LFO w/ Inverted Outputs

This module is a very useful utilty module in a modular synthesizer. It provides low frequency signals with different waveshapes that can be used to modulate and control many other modules. Another interesting feature of such a module is that its oscillation rate can be controlled by a CV.
In this version, the frequency can be set with the RATE knob between 0.1Hz (10s repetition rate) and 100Hz (0.01s repetition rate) or between 0.01Hz (100s rate) and 10 Hz, depending on the rate switch.
The frequency can be modulated in an exponential manner using the FM socket, the FM level knob let us control the amount of modulation.

The signals that are available at their own direct output sockets : SAWTOOTH (rising ramp), TRIANGLE, SINE and SQUARE.
Furthermore, the INV OUT socket provides any of the above but inverted with reference to the direct outputs. The signal is selected through a 6 position rotary switch : OFF (no signal), SINE, TRIANGLE, SAWTOOTH (rising ramp), RAMP (falling ramp) and SQUARE.

The oscillating heart of the circuit is based on the "design idea" by J. Brice (1976) . The wavshaper part is based on very basic classical buiilding blocks such as summers, inverters, full-wave rectifier and non-linear waveshaper.

The oscillation rate is indicated by a yellow LED, the brightness of which being linked to the signal at the INV OUT socket.