| 摘要 |
<p>PROBLEM TO BE SOLVED: To allow use of an effective value measuring means of relatively narrow dynamic range. SOLUTION: An attenuation amount of variable attenuators 13, 16 is made zero, an average value of signals is detected by a detection means 31 and multiplied by a constant to find an effective value VRS. An average value of noises is detected by the detection means 31, and multiplied by a constant to find an effective value VRN, and gains of an amplifier 15 are controlled to make the VRN equal to the VRS. At least, one of the attenuators 13, 16 is regulated in response to a desirable S/N ratio, and outputs of the attenuators 13, 16 are totalized to be output from a terminal 21.</p> |
