FIELD: radio-electronics; transceiving equipment for measurement technology.
SUBSTANCE: proposed circuit designed for generating two high-stability waves by applying reference signal across PLL input functions as follows. Applying voltage of output signal arriving from reference oscillator of high-frequency-stability generator and converted voltage of generator being adjusted to mixer inputs sets up voltage across this mixer which is amplified in intermediate-frequency amplifier and supplied to signal input of phase detector whose reference input is supplied with voltage from shift generator. In the process periodic voltage is built up across phase detector output, constant component of this voltage passed through dc amplifier acts upon frequency control of generator being adjusted through low-pass filter thereby bringing its frequency closer to input signal frequency. With frequencies of reference oscillator and generator under adjustment being equal, intermediate frequency becomes equal to shift generator frequency and beat frequency equals zero, that is, circuit functions in lock-on mode. High-power wave at frequency equal to that of reference signal is built up across output of generator under adjustment and low-power waves of upper side band appear at output of single-band amplitude modulator. With phase-modulated signal applied to mixer signal input PPL functions as phase-modulated detector and respective signal is picked off dc amplifier output.
EFFECT: enhanced sensitivity in receiving weak phase- or frequency-modulated signal.
1 cl, 1 dwg
