In ‘Radio Net’, the mixing was done with what could be seen as a special case of time-division multiplexing. Although heard as a conventional mix of input signals, the output was actually being switched very quickly from input to input. The perceived level of an input in the mix depended on how long the output lingered on it. The technique allowed automatic mixing according to an analysis of each signal; the criterion I used here was that the highest pitched signal at any given instant won the output for that particular fraction of a second.