A. g. c. circuit including a constant impedance variable-attenuation network utilizing current-sensitive impedances

Claim 1

AN AUTOMATIC-GAIN-CONTROL CIRCUIT COMPRISING AN AMPLIFIER, A T-SECTION VARIABLE-LOSS NETWORK HAVING A SERIES CIRCUIT AND A SHUNT CIRCUIT, CONNECTIONS FOR APPLYING A SIGNAL THROUGH SAID VARIABLE-LOSS NETWORK TO THE INPUT OF SAID AMPLIFIER, EACH OF SAID CIRCUITS OF SAID VARIABLE-LOSS NETWORK INCLUDING AN IMPEDANCE CONTROL DEVICE WHOSE IMPEDANCE VARIES INVERSELY WITH THE FLOW OF DIRECT CURRENT THERETHROUGH, EACH OF SAID CIRCUITS OF SAID VARIABLE-LOSS NETWORK ALSO HAVING A DIRECT-CURRENT CONTROL PART FOR CONTROLLING THE IMPEDANCE OF SAID RESPECTIVE IMPEDANCE CONTROL DEVICE, EACH OF SAID DIRECT-CURRENT CONTROL PARTS INCLUDING A CONSTANT VOLTAGE ELEMENT CONNECTED IN SERIES WITH THE RESPECTIVE ONE OF SAID CONTROL DEVICES, A SOURCE OF DIRECT-CURRENT VOLTAGE, A VOLTAGE DIVIDER, SAID DIRECT-CURRENT CONTROL PART FOR SAID SERIES CIRCUIT, SAID VOLTAGE DIVIDER AND SAID DIRECT-CURRENT CONTROL PART FOR SAID SHUNT CIRCUIT BEING CONNECTED SUCCESSIVELY IN SERIES BETWEEN THE TERMINALS OF SAID DIRECT-CURRENT SOURCE, SAID VOLTAGE DIVIDER HAVING AN INTERMEDIATE TAP, SAID CONSTANT VOLTAGE ELEMENT DETERMINING THE LEVEL TO WHICH THE VOLTAGE THAT IS APPLIED TO A RESPECTIVE ONE OF SAID DIRECT-CURRENT CONTROL PARTS MUST RISE BEFORE SUBSTANTIAL CURRENT FLOWS THEREIN TO CONTROL THE IMPEDANCE OF THE RESPECTIVE ONE OF SAID IMPEDANCE CONTROL DEVICES, AND A DETECTOR AND VOLTAGE CONTROL CIRCUIT CONNECTED SUCCESSIVELY BETWEEN THE OUTPUT OF SAID AMPLIFIER AND SAID INTERMEDIATE TAP OF SAID VOLTAGE DIVIDER TO CONTROL THE DIRECT-CURRENT VOLTAGE AT SAID INTERMEDIATE TAP, THE IMPEDANCE OF SAID SERIES CIRCUIT AND SAID SHUNT CIRCUIT CHANGING INVERSELY IN RESPONSE TO CHANGE IN VOLTAGE AT SAID INTERMEDIATE TAP, THEREBY REGULATING THE OUTPUT OF SAID AMPLIFIER.