Noise reduction circuit
US5227732A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 16, 1992 |
| Grant date | Jul 13, 1993 |
| Priority date | — |
| Expiry date | Apr 16, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N5/21
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A circuit for reducing noise from a luminance signal which controls the brightness of the screen in a video apparatus such as a color TV, VCR or VDP is disclosed. The circuit comprises a gate circuit for time-chopping a noisy luminance signal by a predetermined interval, a level detector for integrating the chopped luminance signal to detect an average DC level, a clipping circuit for clipping the chopped luminance signal based on the average DC level, a subtracter for subtracting the clipped signal from the chopped luminance signal, a level shift circuit for shifting the level of the subtracted luminance signal according to the average DC level and compensating the clipped luminance level, and a low-pass filter for low-pass-filtering the level-shifted signal, to thereby restore it to an original-waveform luminance signal. Accordingly, the circuit can prevent the edge of the luminance signal from being collapsed due to noise, resulting in the output of a noiseless luminance signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.