FILTER CRYSTAL PARAMETER MEASUREMENTS WITH FREQUENCY MODULATED SIGNALS (SWEEP FREQUENCY METHODS): FREQUENCY RANGE 1 MHZ TO 350 MHZ.
ARMY ELECTRONICS COMMAND FORT MONMOUTH N J
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It is shown that it is possible to extract from the crystal mode spectrum a large amount of information with an accuracy of 2-5. The use of the mode spectrum constitutes a great savings of time compared with other point-by-point methods. This is particularly true if a signal source of adequately high precision is used, so that the characteristics of the frequency response can be determined with sufficient precision relative to each other. Typical mode spectra are considered, covering a frequency range from less than 1.0 MHz to at least 350 MHz. A wide variety of component instruments were used for the measurement arrangements. The parameters were studied not only as a function of the frequency mode response, but also as function of the phase-frequency and phase-amplitude response. Immittance bridges were used exclusively for the response determination. The effects of the tuning conditions of the bridge on the mode spectrum response are illustrated. Methods for determining the magnitude of the individual parameter values from the response spectrum are discussed. The minimum conductance that could be detected was of the order of 0.1 millisiemens. The investigation was not restricted to filter crystals alone high Q, high precision crystals are also covered. Most emphasis was placed on studying a wide variety of instruments but it is by no means claimed that this study is exhaustive. It is certain that there exist many other commercial instruments which perform as good as, or better than, the ones studied, but the general nature of the techniques given are applicable in any event. Author
- Electrical and Electronic Equipment
- Test Facilities, Equipment and Methods