Mechanical control system for digitally set studio attenuator - has endless belt moving to generate pulses that set attenuation

摘要

The mechanical control is for a digitally-set attenuator for sound studios. It consists of a belt moved by the operator and causing pulses to be generated according to the distance travelled by the belt. These pulses are used to set the attenuator. The belt (7) loops around two rollers (2, 4) at the front of the housing and around a third roller (9) at the rear. The third roller is attached to a disc with holes (10) around its circumference. As the disc rotates a light beam (13) impinges on a photodetector (12) each time a hole passes. The photodetector output pulses are used indirectly to control the attenuator -- also inside the housing.