HORIZONTAL DEFLECTING DEVICE

摘要

PURPOSE:To obtain a proper drive pulse width while aligning the center of a video signal to the center of a raster automatically even when a signal of different horizontal frequency is inputted selectively by controlling the delay amount of a horizontal synchronizing signal supplied to a horizontal AFC circuit and the drive pulse width according to the output of a frequency-voltage converting circuit which generates a voltage corresponding to the horizontal frequency. CONSTITUTION:The horizontal synchronizing signal applied to an input terminal 1 is supplied to a synchronizing pulse width setting circuit 7 through a delay circuit 6. The horizontal AFC (automatic frequency control) circuit 2 is supplied with horizontal pulses as the output of a synchronizing pulse width setting circuit 7 and the output of an output circuit 5. The output of the horizontal AFC circuit 2 is supplied to an oscillation circuit 3, whose output is set to a proper pulse width by a pulse width setting circuit 8 and applied to a driving circuit 4. The horizontal synchronizing signal (b) is delayed by T1 through the delay circuit 6 to obtain a signal shown by (c). This signal (c) is supplied to the synchronizing pulse width setting circuit 7 to obtain a signal with pulse width T2 as shown by a figure (d). Therefore, the waveform of a current flowing through a deflecting coil is as shown by a figure (e) and the center F of the raster is aligned to the center A of the video signal.