Narrow‐band variance noise

摘要

The variance of the variance of current noise of a type 741 operational amplifier is examined in the frequency region where the 1/f noise is predominant. By using a Fourier analyzer the variance is measured for the relatively small bandwidths, 0.155 and 0.31 Hz, in the frequency region 0.31–10 Hz. The variance of the variance of 1/f noise in a constant narrow band is found to be greater than that predicted for white noise, and increases at lower frequencies. The probability distribution of the variance is found to change from an almost Gaussian shape at frequencies higher than 4 Hz to a positive skewed shape at lower frequencies. The difference of the variance of the variance for 1/f noise from that of white noise, the frequency dependence of the variance of the variance, and the skewness of the probability distribution of the variance are explained with a computer model.