PURPOSE: To eliminate noise securely while preventing lockout, by making noise elminating operation inactive during a vertical fly-back period by a vertical oscillation pulse with regard to at least the AGC circuit of the noise eliminating circuit of a TV receiver.
CONSTITUTION: For example, the output of the video amplifying circuit 5 of a TV receiver is inputted to circuits 7 and 8. The noise eliminating circuit 7 detects a noise by a fixed noise detection level and inverts and transfers it to an output buffer circuit 6 to cancel it with noise in an output video signal, thus performing noise eliminating operation. As for an AGC detecting circuit 8, a noise detection output is added to a synchronizing pulse detection output inverted by the AGC detecting circuit to cancel a noise contained in it. On the other hand, the oscillation pulse of a vertical oscillating circuit 15 stops the noise eliminating operation of the noise eliminating circuit 7 during a vertical fly-back period. Consequently, while lockout is prevented by an IC circuit having a high degree of integration, noise eliminating operation is performed securely.
KADOKAWA SHIGERU
OOSAWA MICHINAO
HITACHI MICROCUMPUTER ENG
| JPS53118925A | 1978-10-17 | |||
| JPS54101246A | 1979-08-09 |