DESIGN TECHNIQUES FOR VHF WIDE-BAND CRYSTAL FILTERS.
ARMY ELECTRONICS COMMAND FORT MONMOUTH N J
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Modern network synthesis techniques have given the design engineer the necessary tools to design filters with optimum performance characteristics. The realization of such designs depends primarily on the availability of components to satisfy the optimum requirements necessary. Wide-band filter designs for VHF operation have been available for some years, however, the realization of these designs became contingent on the improvement of quartz crystal fabrication techniques. The advent of the trapped energy concept has made possible the fabrication of crystal units with enhanced characteristics. Suppression of spurious responses and reduction of crystal resistance now permit the design of wide-band filters in the VHF range. Utilizing a stretching coil technique in half lattice circuit structures, design equations, circuit considerations and parameter values are presented. Filters operating at 68 MHz, required for the RADA program, are analyzed and described in detail to illustrate the theory of design. The report is presented in sufficient detail concerning the design and alignment procedure so that engineering personnel not directly involved with filter design can follow the design theory. Author
- Electrical and Electronic Equipment