| 摘要 |
The velocity of a moving mirror in a Fourier-transform infrared spectrometer is controlled by a circuit which utilizes a preset counter to generate pulses with a preset duration which are initiated at the zero-crossings of the signal from a detector of a laser light beam passed through the interferometer. This pulse signal is averaged and summed with a bias voltage and integrated and amplified to produce a drive current which is supplied to a drive coil which drives the moving mirror. When the mirror is moving too slowly, such that the preset duration pulses become a smaller fraction of the total time between zero crossings, the integrator provides an increased driving current and hence an increase in the speed of the mirror. If the mirror is moving too rapdily, the preset duration of the counter pulses will become a larger fraction of the time between zero crossings with a resultant reduction in the driving current and hence the velocity of the moving mirror.
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