Einrichtung zur digitalen Regelung des Gleichstromwertes eines Signals.

摘要

A digital D.C. control system includes a multiplexer (22), a digital-to-analog converter (24), a capacitor (30), offset generating circuitry (26,27,28) and clamping circuitry (33,34 or 42,44,46). A digital signal (from 20) to be D.C. controlled and a digital brightness control signal (from 16) are alternatively coupled by the multiplexer to the input of the digital-to-analog converter. The output from the digital-to-analog converter is coupled to a system output terminal via the capacitor. When the signal is applied to the digital-to-analog converter a fixed D.C. offset is applied to the interconnection of the converter and capacitor. During preselected intervals the D.C. control value is coupled to the digital-to-analog converter concurrently with the system output terminal being clamped (through 33 or 44) to a fixed reference and the D.C. offset circuitry being disabled (at 27). This combination of apparatus permits controlling the D.C. level of a digitally processed signal without affecting the dynamic range of the digital signal.