SYNCHRONOUS DETECTOR INCORPORATING NOISE REJECTION PROVISION Russian patent published in 1999 - IPC

FIELD: radio communications, phase telegraphy receivers, phase-locked systems, etc. SUBSTANCE: detector has series-connected intermediate-frequency filter, first multiplier, first low-frequency filter, and first subtracter whose output functions as detector output. Low-frequency filter output is also connected to inputs of second and third multipliers. Outputs of subtracters are connected through respective low-frequency filters to inputs of second subtracter whose output is connected through 90- deg. phase shifter to second input of first subtracter. Output of reference-signal shaper is connected to second input of first multiplier, through (+ϕ) phase shifter, to second input of second multiplier, and through (-ϕ) phase shifter, to second input of third multiplier. EFFECT: improved narrow-band noise immunity. 2 cl, 2 dwg