NOTCH FILTERS USING PIEZOELECTRIC CERAMICS.
ARMY ELECTRONICS COMMAND FORT MONMOUTH N J
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Several notch filter networks using ceramic benders are analyzed to determine bandpass characteristics. These include the bridged-R, with inductive terminations, and bridged R-C networks. Analyses and experiments show that the simple bridged-R has a rising attenuation with increasing frequency, caused by the shunting capacitance of the bender element. The inductively terminated network can have low attenuation at a single frequency in the passband, depending on coil Q. However, for optimally flat bandpass in very wideband applications e.g., audio bandpass, the attenuation at both extremes is equal to or larger than the attenuation of the bridged-R network at the high frequency end. The bridged R-C network provided the flattest bandpass at about 3.5 dB attenuation with a 23-dB notch. The notch bandwidth at 6dB is about 1 of the notch frequency. The practical frequency range of application of ceramic benders considering size limits, fragility and nodal point mounting problems is approximately 200 Hz to 20 kHz. Author
- Electrical and Electronic Equipment