The CS-05 is a single oscillator monophonic synthesizer with a 3 octave, 37-note (C-C) keyboard. the voice architecture consists of a single VCO, a VCF, a LFO, and a simple envelope generator. The VCO (Voltage Controlled Oscillator) has sliders controlling the level of it's two waveforms, sawtooth, and pulse. The pulse width can be modulated by the LFO (Low Frequency Oscillator). The LFO features a sample-and-hold setting and can modulate up into the audio range for FM sounds. There is an input and a trigger circuit which allows you to trigger a sound via an external audio signal.