| 摘要 |
PURPOSE:To stably control an output signal level with simple configuration. CONSTITUTION:A high output amplifier 31a is used for TDMA and provided with a final stage amplifying part 31a and an excitation amplifying part 31b biased to a B class or a C class. Potential difference corresponding to the change of a drain current at the excitation amplifying part appears at a resistor 35 and corresponding to this potential difference, a control trigger pulse generating circuit 36 generates a rectangular pulse to be turned to a high level when transmission is turned on (when there is an input signal). While receiving the rectangular pulse, an integration circuit 37 applies a shaped pulse, which rise is smooth and fall is sharp, to a drain driving power source circuit 33. Based on the shaped pulse, the drain driving power source circuit controls the drain voltage at the terminal amplifying part. As a result, concerning the transmitting output (output signal), its fall is made sharp and overshoot is suppressed at the time of rising. |
