Preparation of 10.7 MHz medium band crystal filter

This paper using a relatively simple but very practical design method,with four sections eight crystal differential bridge type circuit,design and develop a miniaturized low-loss medium bandwidth quartz crystal filter.The product’s center frequency is 10.7 MHz,passband bandwidth is medium,resistance band suppressed the demand is higher,insertion loss is small,rectangular coefficient is small,the crystal filter physical size too small.The key to solve the technical problem is: crystal filter circuit design,the design of the crystal resonator filter,filter insertion loss IL≦3dB,3dB bandwidth Bw3dB≥± 19kHz,passband fluctuation ≦ 1dB,stop-band attenuation ≥60dB(off center frequency than 50kHz) and other technical indicators realization.