Electronically tunable microwave frequency FET discriminator

A microwave frequency discriminator comprising:

• signal limiting means responsive to an input RF signal of varying power level for generating an RF signal of substantially constant power level;
• a transistor amplifier including a field effect transistor having first, second and third electrodes, said transistor amplifier having an output port, and an input port for receiving said RF signal of substantially constant power level, said transistor being biased an amount for generating in response to said RF signal of substantially constant power level an output RF signal having a predetermined frequency vs. gain roll-off characteristic within a predetermined frequency bandwidth;
• electronically variable capacitive means connected to said limiting means and to said input port for providing a predetermined impedance condition at said transistor input port to augment said transistor frequency vs. gain roll-off characteristic;
• detector means responsive to said output RF signal for generating a dc signal;
• and
• biasing means responsive to a predetermined bias voltage for matching the output impedance of said transistor with the input impedance of said detector means,
• whereby at said conditions of matched impedances the voltage of said dc signal varies substantially linearly as a function of the frequency of said input RF signal.