| 摘要 |
A horizontal synchronizing apparatus includes a horizontal synch. signal source for providing a horizontal synch. signal, a horizontal deflection circuit for generating a deflection current which has scanning intervals and blanking intervals respectively successing in response to driving pulses and also retrace pulses which delay from the driving pulses as a function of a load on the horizontal deflection circuit, a phase locked loop having an input, an output and a first feedback path, for producing from the output a substantial bi-level signal synchronized to the horizontal synch. signal applied to the input, and a phase controlled loop having an input, an output and a second feedback path, for maintaining the retrace pulses in synchronous with the bi-level signals. In the horizontal synchronizing apparatus as constructed as above. the phase controlled loop is provided with a phase detection circuit having a first input connected to the output of the phase locked loop and a second input connected to the deflection circuit, for producing a first polarity current in response to the bi-level signal when the retrace pulses being a first state or a second polarity current in response to the bilevel signal when the retrace pulses being a second state, a filter connected to the phase detection circuit for producing a control signal by filtering out undesired components of the - ?? first and second polarity signals, and a phase controllable device having a control input coupled to the output of the filter for producing the driving pulse which maintains the retrace pulses in synchronous with the bi-level signals. - ?0
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