JPS5787215A - Stabilizing device for output power of high frequency power amplifier - Google Patents

Abstract

PURPOSE:To prevent automatically the occurrence of a transitional excessive output power, by inputting an artificial high output power signal to an error amplifier through a changeover switch when the no-output power state is detected and comparing this signal with an output power command value to limit the comparison output. CONSTITUTION:When a switch 10 is closed and the current/stand-by switching is performed for an energizing part 1 and a power amplifier 3, an output power (a) becomes zero temporarily. This state is detected by an output power existence detector 16, and a relay 17 is energized to swich a contact 17a, and an output signal (i) of an artificial high output power signal generator 14 is connected to one input of an error amplifier 9. Since the signal (i) has a value higher than a signal (d) of an output power setter 8, the amplifier 9 generates a signal (e) of such polarity that the power (a) is lowered. The signal (e) is limited by an amplitude limiter 13 so that this signal does not become a regulated output power or more for restoration of the power (a) and does not lower excessively, and the signal (e) becomes a signal (h), and a variable attenuator 2 is controlled through a DC signal synthesizer 12 by a signal (g). Thus, the occurrence of a transitional excessive output power is prevented even for restoration of the power (a).