| 摘要 |
In an analog multiplying-averaging circuit for detecting very small mean power in a wide band and a wattmeter using the circuit, a first voltage signal is inputted to a base and a second voltage signal is inputted to a collector of one transistor circuit of a first differential amplifier, to supply a power corresponding to the multiplying-averaging of the two input signals to the collector of the transistor circuit. A base and a collector of another transistor circuit of the first amplifier are grounded to extract a DC collector voltage corresponding to junction temperature differences produced between the two transistor circuits from the collector of the other transistor circuit. A second amplifier is provided, which also has two transistor circuits. A base of one transistor circuit of the second differential amplifier is grounded. The second voltage signal is inputted to a collector of the one transistor circuit, and a base and a collector of another transistor circuit of the second amplifier are grounded to also extract a DC collector voltage corresponding to junction temperature differences of the two transistor circuits from the collector of the other transistor circuit of the second amplifier. From the two DC collector voltages, a signal corresponding to the multiplying-averaging of two input signals is obtained. |
