| 摘要 |
PURPOSE:To realize a recording of a picture having a rich half tone, by controlling one of several semiconductor lasers by the number of pulses or the pulse duration and according to the size of the input signal and thus delivering several tens of modulation levels by making use of the high frequency modulation characteristics. CONSTITUTION:The input picture signal 9 is amplified up to a prescribed level by the waveform shaping amplifier 10 and then applied to the A/D converter 11. The high frequency pulse 19 supplied from the high frequency oscillator 15 is divided by the divider 12 to produce the sampling pulse 20. The pulse 20 is then applied to the converter 11, digital value collating circuit 22 and counter 14 each. Then the concentration is decided by the comparator 30 for the picture signal sampled by the converter 11, and then the picture signal is applied to the gate 16. Then the signal corresponding to the concentration of the picture signal sent from the coincidence circuit 13 that detectes the coincidence of the outputs between the circuit 22 and the counter 14 is applied to the gates 16 and 16'. The pulse 19 given from the oscillator 15 is applied to the gates 16 and 16', and the semiconductor lasers 1 and 1' are controlled by the outputs of the gates 16 and 16'. Then the lasers 1 and 1' are modulated by the high frequency pulse. |
