Hi everyone,
I'm working on simulating an AM modem using circuit maker. My ultimate goal is to create several AM modulators working on different carriers and then sum them up with a summing amplifier in order to be fed into an optical transmitter ( IR LED for instance).
On the receiving side the signals are separated by active BPF and each demodulated by a proper envelope detector. Currently I'm facing these problems:
- The envelope detector is simply a diode with an RC circuit where
Carrier Period < ζ = RC < Message Period. I've tried several values for R and C but the result is unsatisfactory (Figures "Fig_1" and "Demod").
- After I added the summing amplifier I couldn't get a good result at the demod - perhaps impedance issues?
I've attached all the circuits and I really need help in determining the R and C value for both envelope detectors.
Note: first AM modulator has a carrier of 23.2 KHz and the second of 10.7 KHz, message for both is a sine of 25 Hz.
thx for all future help.
BR