| 摘要 |
PURPOSE:To improve the distortion characteristics by adding a phase shift circuit between an amplitude limiting circuit and a modulator for compensation of the phase characteristics obtained by an LPF. CONSTITUTION:When a high level is supplied to a signal input terminal C, an input signal receives the limitation of amplitude through an amplitude limiting circuit 4. Thus many higher harmonic waves are produced. The frequency components outside the band of a transmitter are removed out of the higher harmonic waves through an LPF5. While the frequency components within the band of the transmitter are delivered through the LPF5 with the phase different from the input signal component owing to the phase characteristics of the LPF5. A phase shift circuit 6 compensates the different phase relations to approximate the input signal component to the higher harmonic wave component within the band. Therefore it is avoided that the voltage of a signal supplied to a modulator 7 is increased unnecessarily. |
