SYNCHRONOUS COMB FILTER Russian patent published in 2002 - IPC

FIELD: radio engineering and electronics; signal processing systems such as those for machine diagnostics. SUBSTANCE: comb filter has adder 7, low-frequency filter 8, and potentiometer 6 built in feedback circuit of operational amplifier 5. Common point of connection of resistor 4 and switched capacitors 3 of RC filter 1, 2, 3, 4 is connected to noninverting input of operational amplifier 5. Potentiometer wiper 6 is connected to noninverting input of operational amplifier 5 and to adder 7 whose noninverting input is connected to input of comb filter and to input of resistor 4, and its output is connected to input of low-frequency filter 8; output of the latter functions as output of comb-filter band-elimination section and that of operational amplifier 5, as output of comb-filter band-pass section. Low- frequency filter 8 incorporates provision for cutoff frequency control and its input is connected to clock pulse input of distributor 1. EFFECT: enlarged functional capabilities, improved selectivity of synchronous rejection filter, eliminated pulse noise across operational amplifier output. 2 cl, 2 dwg