| 摘要 |
PURPOSE:To keep the vertical amplitude of a picture (raster) of a picture tube unchanged regardless of a vertical deflection frequency. CONSTITUTION:A sawtooth wave signal generating circuit 1 generates a sawtooth wave signal synchronously with a received vertical synchronizing signal, a vertical deflection output circuit 2 implements waveform shaping and amplification or the like, outputs the result to a vertical deflection coil 3 to implement vertical deflection of the picture tube. A peak value detection circuit 4 detects a peak value of an output signal of the sawtooth wave signal generating circuit 1, a comparator circuit 5 compares the peak value with a DC voltage set by a variable resistor 6, outputs a signal in response to a difference, the signal is amplified by an operational amplifier 7 and the amplified signal is inputted to a control terminal of the sawtooth wave signal generating circuit 1 via a control circuit 9 to keep the amplitude of the outputted sawtooth wave signal unchanged. |
