| 摘要 |
PROBLEM TO BE SOLVED: To execute calibration by simple circuit constitution and a simple procedure by providing a passive 3 port circuit supplying a digital modulation RF signal for a first port and connecting a power sensor to a second port and a means switch-selecting a prescribed signal to input to the third port of the passive 3 port circuit. SOLUTION: In the first 1/3 period of a modulating-state continuing period, a control circuit 18 puts an RF switch 7 at a switching position #1 and a passive linear 3 port circuit 1 sends a DC signal obtained by multiplying a prescribed coefficient to a power level and outputting it to a power sensor 4 to a DC interface. In the second 1/3 period, an RF switch 11 is put at a switching position #1 to input the RF signal of a local oscillator 6 to the second port 5 of the circuit 1 to mix the RF signal and the digital modulation RF signal. In the third 1/3 period, the circuit 1 mixes an RF signal, etc., whose phase is not shifted and the digital modulation RF signal received through a first port 2 to send to the sensor 4. |
