Patent ID: 7130433
Filing Date: 2006-10-31
Classification: G11B

Abstract:
1. A noise reduction apparatus which reduces a noise level of noise contained in an input signal, comprising: a high pass filter which extracts a high filter frequency component of the input signal from the input signal; a detecting device which detects the noise level of the noise from the input signal by use of the high frequency component of the input signal; a gain controlling device which generates a first control signal and a second control signal on the basis of the detected noise level, the first control signal being used for adjusting a level of the input signal so as to make the detected noise level equal to a predetermined threshold level, and the second control signal being used for adjusting a level of a reduced adjusted signal so as to restore the level of the reduced adjusted signal to an original level of the input signal; an adjusting device which adjusts the level of the input signal that does not pass the high pass filter on the basis of the first control signal; a reducing device which reduces a level of the adjusted input signal in accordance with a predetermined reducing characteristic and generates the reduced adjusted signal; and, a restoring device which restores the level of the reduced adjusted signal to the original level of the input signal on the basis of the second control signal.