Doepfer 's A-149-4 module is a quadruple random control voltage source whose voltages move in note context. Each of the four CV outputs has its own trigger input, which are also normalized. So you can switch all four at once with a Gate or trigger the next voltage in pairs/groups. In concept the operation of the module is very similar to a Sample & Hold circuit, but here the voltage range can be set in a musical way. You can define for all four outputs, or the voltages octave, octave + fifth, chord, scale, semitone or stepless in the range of 0-5V. Additively you can choose between major/minor and sixth respectively seventh.