#1
|
||||
|
||||
Using an op-amp "rectifier" as an AM detector
Using a high speed op-amp, in this case a HA2525, I built a "rectifier" circuit as an AM detector. Idea is that it should be more linear than an ordinary diode.
This particular op-amp circuit outputs the negative going parts of the RF carrier and the amplitude modulation. Instead of a curved diode knee, this circuit would do a much sharper knee, thus better detection of weak signals and also strong signals (better audio fidelity on music). Like this (though the polarities are different) vs for a diode We also avoid the effects of the AGC cap backfeeding the detector. The RC circuits fed by the op-amp's output filters out the RF part of the rectified waveform to get audio, and AGC voltage.
__________________
|
Thread Tools | |
Display Modes | |
|
|