FREQUENCY DISCRIMINATOR OF RADIO ELECTRONIC EQUIPMENT Russian patent published in 2008 - IPC H03D3/02 

FIELD: radio engineering.

SUBSTANCE: the device has a self-excited oscillator, input and output power dividers, interference-type frequency discriminator, phase shifter, amplitude modulator, crystal shifting oscillator, amplifier, two mixers, two intermediate-frequency amplifiers and a phase discriminator. The device functions as follows. Oscillations of the self- excited oscillator via two output of the input power divider are fed to the signal and reference channels, to the signal channel-via the frequency discriminator and the phase shifter to the input of the first mixer. Via the reference channel the signal is fed to the input of the second mixer. Via the third output of the input power divider the signal is fed the amplitude detector and amplifier to the input of the output power divider. From the two outputs of the output power divider the signal is fed to the heterodyne inputs of two mixers. The shifting oscillator is connected to the modulating inputs of the amplitude modulator. From the outputs of both mixers the converted voltages of the signal and reference channels are fed the signal and reference inputs of the phase detector, whose output voltage is proportional to the measured frequency fluctuations. The output of the phase detector has its own tap for delivery of the respective voltage outside of the circuit. Operation of the frequency discriminator can be accomplished both with a single-band amplitude modulator, and a balanced amplitude modulator.

EFFECT: enhanced sensitivity of the two-channel frequency discriminator, and enhanced range of re-tuning of intermediate frequency.

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