| 摘要 |
THE POWER VOLTAGE SUPPLY FOR A POWER AMPLIFIER IS SWITCHED BETWEEN AN OPERATIONAL FULL POWER MODE AND A REDUCED POWER MODE BY THE SWITCHING OF A DUAL STATE IMPEDANCE DEVICE CONNECTED IN SERIES BETWEEN THE POWER AMPLIFIER AND THE POWER SUPPLY(10). A CONTROL CIRCUIT(52) DETECTS THE LEVEL OF A SIGNAL TO BE AMPLIFIED BY THAT AMPLIFIER AND SWITCHES THE IMPEDANCE STATES THUS REDUCING THE POWER OUTPUT CAPABILITY OF THE POWER AMPLIFIER AND PLACING THE POWER AMPLIFIER INTO A REDUCED POWER MODE. IN ONE EMBODIMENT, THE SIGNAL IS PRODUCED BY SPECTRALLY FILTERING WITH A LOW PASS FILTER, WITH THE CROSS-OVER FREQUENCY BEING ADJUSTABLE. ADDITIONALLY, THE GAIN OF THE AMPLIFIER CAN BE REDUCED FOR HIGH LEVEL SIGNALS.FIG. 1 |
