AM base circuit
AM base for small-signal amplitude modulation, the circuit as shown C is a high frequency bypass capacitor.
Tl, T2 is a high frequency transformer, LC resonant circuit at the carrier frequency , passband is 2Fr. . Change, and then implement the detector through a low-pass filter, this detection method called square-diode detector. Due to the small high-frequency input signal amplitude, fork called small signal square-detector.