| 摘要 |
Apparatus for generating horizontal and vertical synchronization signals in synchronism with synchronization signals generated from an on-going television program received by a user is provided by employing a capacitive or inductive coupling to extract the electric or magnetic field surrounding the horizontal output transformer and deflection yoke of a television receiver and shaping the output of the coupler to provide pulses at the horizontal synchronization rate of the received program. These pulses are further multiplied, divided and shaped to provide vertical synchronization pulses. The dividing circuits include means for temporarily changing the divisor to accomplish proper framing. Auxiliary presentations can be displayed in conjunction with programs normally received by synchronizing the auxiliary presentations with the received programs by employing the generated synchronization signals.
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