| 摘要 |
PURPOSE:To compensate the wave distortion produced when the pulse width is narrow, by taking the phase of audible frequency signal as opposite phase and feeding this signal to the demodulated output signal with B or C class amplification. CONSTITUTION:The pulse width modulation is made for the audible frequency signal inputted at the pulse width modulator 10 and this signal is amplified at the transistor Tr11. The amplified signal is demodulated at the demodulator a. On the other hand, the audio frequency signal is fed to the coupling inverter 20 to constitute the phase into opposite phase and this opposite phase signal is fed to the amplifier 21, which is an amplifier of class B or C and amplifies almost positive half wave of the opposite phase output signal and picks up the peak. This peak is fed to the output signal of the demodulator a. With this constitution, if the pulse width of the output of Tr11 is narrow, although the low level part of demodulated output signal is distorted, the wave distortion can be compensated by adding the output of the amplifier 21 to the peak level of the output of the demodulator a. |
