| 摘要 |
Apparatus for detecting an error condition in a deflection circuit of a cathode ray tube, the deflection circuit being of the type wherein a periodic retrace signal is generated, including a filter coupled to the retrace signal generator and normally non-responsive to the retrace signal. In the event of an error condition, the retrace signal is provided with higher frequency components which are transmitted by the filter. An output signal generator is coupled to the filter to produce an output signal in response to the signal components transmitted by the filter. In one embodiment, the deflection circuit is the horizontal deflection circuit of a CRT wherein the retrace signal is used to produce the high voltage for the CRT. In this embodiment, the output signal is used to vary the repetition frequency of the horizontal oscillating signal applied to the deflection circuit so as to correspondingly change the amplitude of the retrace signal and, thus, to reduce the magnitude of the high voltage.
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