| 摘要 |
PROBLEM TO BE SOLVED: To provide the output power detecting circuit of a transmitter that a detection voltage and a transmit signal are in linear relation and a control part has a wide dynamic range for gain control without using any dedicated large-size integrated circuit. SOLUTION: This circuit has a signal detection wave part 1 which is connected between a transmitter output terminal and a transmitter control part 12 and detects the output signal of the transmitter, a reference voltage generation part 2, an uninverted input terminal, an inverted input terminal, and an output terminal and is equipped with a differential amplifier 31 which supplies a detection voltage from the output terminal to the control part 12 and a voltage limiting element 32 which is connected between the inverted input terminal and a reference potential point. Then the output wave detection voltage of the signal wave detection part 1 is supplied to the uninverted input terminal, the addition reference voltage of the output reference voltage of the reference voltage generation part 2 and the output transmission level indication voltage of the control part 12 is supplied to the inverted input terminal, and the voltage limiting element 32 limits the addition reference voltage supplied to the inverted input terminal to put the detection voltage which increases as the wave detection voltage increases, within the gain control dynamic range of the control part 12.
|
