| 摘要 |
The video recorder has a modulator modulating the write laser beam's intensity depending on the amplitude of the signals being recorded. The write beam produces a permanent non-reflecting zone on the recording medium when the beam intensity is below a given level and produces a reflecting intermediate zone when above this level. A stabilising circuit is provided for the opto-electronic modulator and produces a d.c. voltage characterising the amount of distortion in the write beam due to the second harmonic. This d.c. voltage is used to adjust the modulator to minimise this distortion. |
