| 摘要 |
PROBLEM TO BE SOLVED: To provide a gain controller which prevents a high-frequency amplifier from malfunctioning and has a wide dynamic range and is stable against variance depending upon devices and temperature and secular changes and actualized by space-saving design, energy-saving design, and low-price design. SOLUTION: The gain monitor device which monitors the gain of the high-frequency amplifier according to a 1st level-corrected signal branching off from the input terminal of the high-frequency amplifier and a 2nd level-corrected signal branching off from the output terminal of the high-frequency amplifier is equipped with a high-frequency changeover switch which selects the 1st and 2nd signals alternately at fixed intervals, a detector 112 which detects the output of the high-frequency changeover switch 111, a delay unit 202 which delays the 1st signal in timing to the delay time of the 2nd signal behind the 1st signal, and a comparison part which compares the 1st and 2nd signals in the same timing. |
