| 摘要 |
PURPOSE:To meet omission of an index pulse with simple constitution by providing a pulse generating circuit, a gate circuit and a detector. CONSTITUTION:A voltage control type oscillator 6 oscillates in the prescribed frequency relation with index signal frequency. An output of a four divider 7, which divides an output pulse of the oscillator 6 into four parts, is supplied to a gate circuit 9 and a reset clock generator 11. An output of an LPF10, which smoothens an output of the gate circuit 9, is added to the oscillator 6. An output of a detector 12, which is installed on a funnel of a cathode-ray tube 1 and converts an index optical signal into an index electrical signal, is supplied to a pulse generating circuit 8, which generates a pulse with a certain width synchronizing with a fall or a rise of an index signal, through a pulsing circuit 13. An output of the oscillator 6 can pass through the gate circuit 9 only during this pulsing period. With such simple constitution, a beam index type-color television receiver, which can meet omission of an index pulse, can be obtained.
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