BAND-PASS PIEZOELECTRIC FILTER Russian patent published in 2002 - IPC

FIELD: radio electronics. SUBSTANCE: invention can be used in the capacity of filter of main selection of professional radio receiving devices. Filter has N pairs of piezoresonators, first and second transformers 2, 3 of which first transformer 2 has one winding with N+1 leads and second transformer 3 has two windings. First winding of second transformer 3 has 2N+1 leads, second winding has two leads. First leads of each i-th pair of piezoresonators are tied up together and are connected correspondingly to i-th (i= 1, 2, . . .N) tap of first transformer 2. Second leads of each i-th pair of piezoresonators are connected to taps of first winding of second transformer 3. In this case second lead of first piezoresonator of i-th pair is connected to i-th tap and second lead of second piezoresonator of i-th pair is connected to (2N+2-i) tap correspondingly. (N+1)-th lead of first transformer 2 is connected to inlet potential terminal of filter, (N+1)-th tap of first winding of second transformer 3 is connected to common bus, leads of second winding of transformer 3 are connected to output terminals of filter. EFFECT: diminished level of intermodulation distortions of third order. 1 dwg