| 摘要 |
<p>PURPOSE:To accurately correct a noise level by finding the running mean value of noise level correcting values obtained in a noise level correction period. CONSTITUTION:A noise sampling circuit 1 calculates the running mean value of noises in the noise level correction period in synchronism with noise sampling timing. Thus, the noise level mean value in the noise level correction period is calculated. Then a dividing circuit 3 divides the noise level mean value by a noise level set value 2 to calculate one noise level correcting value sample. This correcting value is supplied to an averaging circuit 4 to calculate the running mean value, which is held by a holding circuit 5 and multiplied by a multiplying circuit 6 to correct the noise level. Thus, the noise level is accurately corrected.</p> |
