Gain controlled amplifier using field effect type transistor as the active element thereof

Claim 1

A CIRCUIT FOR CONTROLLING THE GAIN OF AN AMPLIFIER COMPRISING: A FIRST SEMICONDUCTOR DEVICE HAVING INPUT, OUTPUT AND COMMON ELECTRODES; SIGNAL INPUT CIRCUIT MEANS COUPLED BETWEEN THE INPUT AND COMMON ELECTRODES OF SAID FIRST DEVICE; SIGNAL OUTPUT CIRCUIT MEANS COUPLED BETWEEN THE OUTPUT AND COMMON ELECTRODES OF SAID FIRST DEVICE; A SECOND SEMICONDUCTOR DEVICE COMPRISING A JUNCTION TRANSISTOR HAVING BASE, EMITTER AND COLLECTOR ELECTRODES; MEANS PROVIDING A DIRECT CURRENT CONNECTION BETWEEN SAID BASE ELECTRODE AND ONE OF SAID INPUT AND COMMON ELECTRODES; MEANS PROVIDING A DIRECT CURRENT CONNECTION BETWEEN SAID EMITTER ELECTRODE AND THE OTHER OF SAID INPUT AND COMMON ELECTRODES; MEANS PROVIDING A DIRECT CURRENT CONNECTION BETWEEN SAID COLLECTOR ELECTRODE AND SAID OUTPUT ELECTRODE; MEANS PROVIDING A SOURCE OF GAIN CONTROLLING POTENTIAL WHICH INCREASES IN A PRE-DETERMINING POLARITY DIRECTION TO REDUCE THE GAIN OF SAID AMPLIFIER; MEANS INCLUDING SAID SOURCE OF GAIN CONTROLLING POTENTIAL CONNECTED BETWEEN SAID BASE AND EMITTER ELECTRODES SO THAT SAID BASE AND EMITTER ELECTRODES ARE INITIALLY REVERSE BIASED, BUT INCREASES IN SAID GAIN CONTROLLING POTENTIAL IN SAID POLARITY DIRECTION REDUCES SAID REVERSE BIAS OVER A FIRST RANGE OF SAID GAIN CONTROLLING POTENTIAL AND FORWARD BIASES SAID BASE AND EMITTER ELECTRODES OVER A SECOND RANGE OF SAID GAIN CONTROLLING POTENTIAL.