| 摘要 |
PURPOSE:To obtain the instruction value of the real value of a transmitter/ receiver signal strength monitor voltage even if the length of the line of a signal changes by providing a comparison circuit detecting the line drop voltage of the signal line of a DC voltage supplied to a high frequency part in a modulation/demodulation part and a compensation circuit. CONSTITUTION:The DC voltage Vs is supplied from the modulation/ demodulation part 5 to the high frequency part 1 by using the signal line 11 between two lines and the DC voltage Vs supplied to the high frequency part 1 by a monitor signal line 12 is returned to the modulation/demodulation part 5. Then, a voltage Vs' lower by a line drop by the monitor signal line 12 is outputted. The voltage Vr of a reference voltage source 8 and the DC voltage Vs' are compared in the comparison circuit 9, the change of the amplitude value of a carrier wave owing to the change of the length of the line is compensated through the compensation circuit 10 by using the output signal showing the output of the comparison circuit 9, namely, the line drop voltage, and the transmitter/receiver signal strength monitor voltage V2 of the real value is outputted. Thus, it comes to be unnecessary to correct the monitor voltage whenever the signal line is exchanged. |
