FREQUENCY CHANGER Russian patent published in 2001 - IPC

FIELD: radio engineering; panoramic receivers. SUBSTANCE: frequency changer has first, second, and third mixers, local oscillator, first, second, and third intermediate-frequency amplifiers, first and second adders, first, second, and third 90-deg phase shifters and 90 deg phase shifter, first and second multipliers, first, second, third, and fourth narrow-band filters, first, second, third, and fourth amplitude detectors, first, second, third, and fourth switches. EFFECT: enlarged signal frequency search range without extending local-oscillator frequency tuning range. 2 dwg