Ultra linear frequency discriminator circuitry

Claim 1

Ultra linear frequency discriminator circuitry comprising: controllable attenuation means having a signal input, with varying frequency and amplitude a control input and an output, for providing different amounts of attenuation to signals applied to the signal input thereof in response to control signals applied to the control input thereof; first and second discriminator circuits each having a linear response over a predetermined band of frequencies and with response slopes which are equal and of opposite sign; a power splitter coupling each of said first and second discriminator circuits to the output of said controllable attenuation means; signal combining means connected to receive output signals from said first and second discriminator circuits for combining the output signals to provide a discriminator circuitry output signal which is a linear function of the frequency of signals applied to the signal input of said controllable attenuation means; and control signal generating means connected to receive the output signals from said first and second discriminator circuits and having an output connected to the control input of said controllable attenuation means for generating a control signal that maintains amplitudes of signals supplied to said power splitter from said controllable attenuation means constant whereby the discriminator circuitry output signal from said signal combining means is independent of the amplitude of signals applied to the signal input of said controllable attenuation means.

Claim 11

A method of frequency discrimination substantially independent of the amplitude of input signals comprising the steps of: splitting an input signal into two signals equal in power; high pass filtering and amplitude detecting one of the two signals to produce an output signal defined by V.sub.1 =m(ω-ω.sub.o)+b.sub.1 where m=filter sensitivity ω o =center frequency of interest b=offset amplitude ω=input frequency low pass filtering and amplitude detecting the other of the two signals to produce an output signal defined by V.sub.2 =-m(ω-ω.sub.o)+b.sub.2 subtracting the two output signals to obtain a frequency discriminated output signal defined by V.sub.out =2m(ω-ω.sub.o)+b.sub.1 -b.sub.2 combining the two output signals with a reference voltage, V ref , to produce a control signal defined by V.sub.s =b.sub.1 +b.sub.2 -V.sub.ref controlling the amplitude of the input signal prior to splitting so that V s is zero.

Claim 12

A method of frequency discrimination substantially independent of the amplitude of input signals comprising the steps of: splitting an input signal into two signals equal in power; high pass filtering and amplitude detecting one of the two signals to produce an output signal defined by V.sub.1 =m(ω-ω.sub.o)+b.sub.1 where m=filter sensitivity ω o =center frequency of interest b=offset amplitude ω=input frequency low pass filtering and amplitude detecting the other of the two signals to produce an output signal defined by V.sub.2 =-m(ω-ω.sub.o)+b.sub.2 subtracting the two output signals to obtain a frequency discriminated output signal defined by V.sub.out =2m(ω-ω.sub.o)+b.sub.1 -b.sub.2 combining the two output signals with a reference voltage, V ref , to produce a control signal defined by V.sub.s =b.sub.1 +b.sub.2 -V.sub.ref controlling the amplitude of the input signal prior to splitting so that V s is zero.