| 摘要 |
PROBLEM TO BE SOLVED: To provide a beam scanning rate modulation circuit for a cathode ray tube. SOLUTION: The deflection system of this invention includes a variable gain amplifier 32 for a luminance component of a video signal. A first differentiation device 34 differentiates an amplified luminance component. An output amplifier 36 biases an auxiliary horizontal deflection yoke 20 in response to the differentiated luminance component to modulate the scanning rate of an electron beam. A second differentiation device 38 differentiates the differentiated luminance component and an integrator 40 integrates the luminance component differentiated twice to output a gain control signal. The gain of the variable gain amplifier 32 is changed with the gain control signal. This gain changes inversely with respect to a change in the frequency contents of the luminance component. The second differentiation device and the integrator form a feedback loop having a sufficient time constant with respect to transition of a level of the luminance component so that the deflection signal corresponds to the primary differentiation of the luminance component independently of the variable gain.
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