| 摘要 |
A brushless tachometer is disclosed which provides a DC output voltage which is a direct function of an instrumented shaft's rotational velocity. The DC voltage is bi-directional, changing sign when the shafts direction of rotation is reversed. The disclosed tachometer preferably utilizes a brushless printed circuit resolver having a large number of poles. The sine and cosine outputs from the resolver are fed to a phase shifting circuit which provides two output signals whose frequencies are related to the speed of rotation of the shaft being instrumented. The frequency of one of the signals increases as the shaft speed increases while the frequency of the other signal decreases as the shaft speed increases. These two signals having frequencies related to shaft speed are fed to frequency to voltage converters. The outputs from the frequency to voltage converters are fed to a differential amplifier whose output is the DC signal which is indicative of the direction and the speed of rotation of the shaft.
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