| 摘要 |
PURPOSE:To perform mode switching in a stable state by attaching a hysteresis characteristic on a reference voltage to be compared with the input signal of a voltage corresponding to the frequency of a horizontal synchronizing signal. CONSTITUTION:A horizontal mode switching circuit is constituted of a reference voltage generation circuit 18 as a reference voltage generating means, a comparator 20 as a comparison means, a reference voltage correction circuit 22 as a reference voltage correction means, and a mode designation circuit 24 as a mode designation means. When a signal with the voltage corresponding to the frequency of the horizontal synchronizing signal is inputted, the input signal is compared with each reference voltage at the comparator 20, and the reference voltage is corrected compulsorily at the reference voltage correction circuit 22 based on the output of the comparator. Thereby, the hysteresis characteristic can be attached on the reference voltage. A mode designation signal is outputted from the mode designation circuit 24 based on the output of the comparator 20. |
