| 摘要 |
PURPOSE:To compare the noise signal level in a plurality of channels at a high speed, by imparting a reference signal a rising characteristic with the time constant almost the same as the smoothing time constant of a signal to be measured. CONSTITUTION:Noise signals N1-N4 are changed over with a switch 1 to obtain a signal to be measured through a rectifying circuit 2 and a smoothing circuit 3. On the other hand, a DC voltage source E provides a reference signal through an integration circuit 5. In this case, the time constants of the circuits 5 and 3 are set to be almost the same. Each time the switch 1 is changed sequentially, the signal being measured and the reference signal are grounded simultaneously through the switches S1 and S2 immediately after the changeover of the switch. At the moment t1 of the grounding, the charge of capacitors C1 and C2 in the circuits 3 and 5 is all discharged, eventually giving an earth potential. Then, when the switches S1 and S2 are opened simultaneously, the signal being measured is integrated by the smoothing time constant while the reference signal is integrated by the integration time constant, a transient rising characteristic which permits the discrimination of the level thereof with a comparator circuit 4 in the early period thereof. Thus, the comparative discrimination signal of the circuit 4 can be read in a short time t2 after the opening of the switches S1 and S2 thereby reducing the comparing response times of noise signals N1-N4 to t1+t2 very much.
|
