| 摘要 |
PURPOSE:To execute the detection without causing a distortion and a noise even if an input level of carrier wave is varied, by rectifying an AM modulated wave and a carrier, whose band has been restricted, and after that, applying them to two integration circuits whose time constants are different, and outputting a difference of the outputs. CONSTITUTION:A carrier which has been AM-modulated is applied to the terminal 1, is made to pass through the narrow-band filter 3, and is amplified. This output is rectified by the diode (D) 6 through the transformer 5. The output of D6 is inputted to two integration circuits consisting of a resistance (R) 7, a capacitor (C) 8 and R12, C13. The wave form of this output is shaped by the transistor 11, and a detection signal is outputted from the terminal 2. When a receiving level of the terminal 1 is varied, the integral output of R7, C8 and R12, C13 outputs the voltages e1, e2, following the variation of the receiving level, as shown in (b). When the time constant of R12, C13 is set enough larger than that of R8, C9, a detection output having no distortion nor noise is obtained at the terminal 2, as shown in (d). |
