| 摘要 |
PURPOSE:To realize a highly efficient power amplifier without switching distortion by generating a control signal switching an output transistor (TR) in response accurately to a level of a signal and using a digital delay device so as to compensate the processing time required to generate the control signal. CONSTITUTION:A signal fed to an input terminal 1 is converted into a digital signal from an analog signal by an A/D converter 2. The digital signal is retarded by a time (t) set by a digital delay device 3, converted into an analog signal by a D/A converter 4 and the result is fed to a power amplifier 5. On the other hand, part of the digital signal of the A/D converter 2 is fed to a control signal generator 8, from which a control signal is generated. Until the most significant bit MSB is detected, low level output TRs 54A, 54B are driven by a power supply 1/2Vcc, and when the MSB is detected, high level output TRs 55A, 55B are driven by a power supply + or -Vcc.
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