Pulse Modulation and Signal Processing Circuits to Perform Precise Control and Monitoring Functions with High-Voltage Isolation

Pulse-position modulators are used for remote sensing of analog signals in a high-voltage constant-current dc power supply for a wideband submarine cable system. The pulse-position modulators translate the sensed analog signals into the time domain in the form of time delayed pulses. The transfer characteristics of the modulators are linearized and made insensitive to clock frequency and other sources of timing errors by use of a demodulator feedback circuit. The modulators are operated synchronously by a common clock. The clock also establishes a precisely quantized time frame which is useful in processing the modulator output signals. A variety of closed- and open-loop control functions, level monitoring functions, and both analog and digital metering functions are realized. Pulse transformers are used for dc isolation and common mode noise rejection.