| 摘要 |
PURPOSE:To measure easily a noise and vibration in comparatively large dark noise and dark vibration environment, by adopting the minimum value with respect to each transducer of a sampled noise level, smoothing the minimum value at a constant time interval for covering a sampling period, and deriving a level variation pattern. CONSTITUTION:Microphones M1-M5 are placed at each interval in the vicinity of a road, and a noise is received at each spot. Their electric outputs are amplified by an amplifier 11, and also the S/N ratio is improved by a filter 12 so that a signal of object sound region passes through easily, an output of this filter 12 is inputted to a level recorder 13 and the analogical processing is executed. In this case, a controller 20 is provided so as to operate the level recorder 13 only when an object noise source (aircraft) approaches. In case when the output of the filter 12 is processed digitally, data is held by a memory 14, and the data is read out and inputted by a command from a central arithmetic part 15. |
