AF attenuator for sound mixing consoles - has switch pulsed at frequency twice upper cut=off frequency of passband

摘要

The AF attenuator, for sound mixing consoles, passes the audio signal over a switch (SCH) controlled by a pulse generator (Z1, TTa, LOG). The pulse generator produces pulses whose repetition frequency is at least equal to twice the upper cutoff frequency of the AF signal transmission band. The switch is followed by an LP filter (TP). The pulse generator contains a connector (Z1) counting clock pulses and producing an output pulse when its contents are less than or greater than a given representing the wanted attenuation.