| 摘要 |
PURPOSE:To make it possible to seek an overall evaluation value similar to that by a man's auditory sense, by calculating three particular physical volumes of a noise, and then, by calculating the overall evaluation value by an overall evaluation function in which these three physical volumes are used as variables. CONSTITUTION:An input signal A, which is made by converting sound pressure of a noise into voltage and provided with the auditory sense compensation, is attenuated by an attenuator 10 and becomes a signal B. The signal B passes through a square averager 12 and a log converter 14 and indicated on an indication meter 16 as an average X1 of magnitude of the noise within a prescribed time. The signal B also passes through an LPF20, a square averager 22, a composite circuit 24, a log converter 26 and a composite circuit 28 and indicated on an indication meter 30 as X2 being a rate of high frequency component occupying in the noise. The signal B further passes through RMS converters 32 and 34, a composite circuit 36, a square averager 38, a log converter 40 and a composite circuit 42 and incidated on an indication meter 44 as X3 which is a time-wise variation of the noise magnitude within the prescribed time. An overall evaluation value E is sought by giving these physical volumes X1-X3 to a composite circuit 46 through attenuators 48, 50 and 52. |
