| 摘要 |
1515229 Measuring non-linear distortion POSTA KISERLETI INTEZET 3 Nov 1976 [5 Nov 1975] 45691/76 Heading G1U In measuring the non-linearity of a nominally linear system, the response to a test signal is analyzed to provide an output representing a distribution function of the response which is both independent of the level of the response and which indicates the non-linearity. The Specification describes circuits for producing signals representing the amplitude distribution function (i.e. the probability that the response signal is less than or equal to a given threshold), the amplitude density distribution function (i.e. the probability that the response lies within the range between a threshold value x and x+#x, where #x is very small), and the density-moment function (i.e. the product of the means of the response signal and the threshold exceeding function, this being the probability of the response signal exceeding a given threshold. All these functions remain constant so long as the response signal shows no sign of distortion. The test signal is preferably stochastic e.g. Gaussian noise, but may also be a stationary signal providing the distribution functions thereof can be determined. The threshold level is always taken as the mean level of the response signal, and the function signal is averaged and compared to a reference level representing the mean value of an undistorted response, Figs. 10-16 (not shown). |
