| 摘要 |
<p>An analog geometric-mean calculating circuit suitable for detecting very small mean power in a wide band and a wattmeter circuit using the circuit. A first voltage signal is applied to the base of a first transistor of a collector multiplier, and a second voltage signal is inputted to the collector thereof, thereby to supply to the collector the power corresponding to the geometric mean of the two input signals. The base and collector of a second transistor are signally grounded, thereby to take the DC collector voltage corresponding to the difference of junction temperatures of the two transistors from the collector of the second transistor. Of an offset voltage generator, the base of a first transistor is signally grounded, and the second voltage signal is inputted to the collector thereof. The base and collector of a second transistor of the generator are signally grounded, similarly to take the DC collector voltage corresponding to the difference of the junction temperatures from the collector of the second transistor. From the two DC collector voltages, a signal corresponding to the multiplication-average of the input signals is obtained.</p> |
