Video disc player with RFI reduction circuit including signal subtraction
Noise suppressing circuit with gain control
Noise reduction apparatus for video signal
Noise reduction circuit for video signal having suitable nonlinear processing character Patent #: 4833537
ApplicationNo. 306382 filed on 02/06/1989
US Classes:348/622Noise component generator, limiter, subtractor type
ExaminersPrimary: Chin, Tommy P.
Assistant: Juo, James
Attorney, Agent or Firm
Foreign Patent References
International ClassH04N 005/21
Foreign Application Priority Data1988-02-10 JP
AbstractA noise reduction circuit comprises a high pass filter for extracting a signal component containing noise from an input signal, a variable level limiter for limiting the level of the signal component extracted by the filter to produce a noise suppressing signal, and a level adjustor for adjusting the level of the noise suppressing signal. A level detector detects the level of the input signal, and a control signal generator generates first and second control signals based on the detected output of the level detector, supplies the first control signal to the level limiter so as to control the limit level thereof, and supplies the second control signal to the level adjustor so as to control the gain thereof. In a signal subtracter, the noise suppressing signal from the level adjustor is added with reversed polarity to the input signal to suppress the noise contained in the input signal and thereby produce a low-noise output signal.