| 摘要 |
A digital path length control for ring laser gyros comprises a square wave generator, a dither counter (driven by the generator with a quarter cycle delay, a dither DAC, a control counter, a control DAC, and a PZT driven by the two DACs. The PZT controls the path length of the ring laser gyro, and thus controls the intensity of the light in the gyro. A photodetector samples this light and produces an ac signal, which a voltage comparator compares with ground. The output of the comparator is XORed with the square wave, and the output of the XOR gate drives the control counter, strobed with a frequency at least twice that of the square wave. All signal processing is digital, and analog conversion is made only when interfacing the gyro.
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