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Can someone please help me with the demodulator part of the circuit, O/P is not coming i.e message signal is not being recovered. https://www.circuitlab.com/circuit/9kbn47/amplitude-modulator-and-demodulator/

Try running it with:

Start Time = 0

Stop Time = 10m

Time Step = 1u

If you do that, I'm not sure if the results are what you expect (i.e. I don't know if your circuit is correct) but the basic problem is that you are running the sim with far too large a time step and so you are effectively seeing a lot of aliasing which confuses both you and the simulator.

See:

https://www.circuitlab.com/docs/the-basics/#time_domain_simulation

and:

https://www.circuitlab.com/circuit/d4qjc5/relaxation-osc-fixed-01/

:)

Hello, I would recommend adding a couple of resistors, one in series with V2 to limit the diode currents, and one in series with L1 to give your tuned circuit less than infinite Q. At present the diode switch circuit is connected from signal to ground, I would recommend trying it in series with the signal line from R2 to L1. Hope this is helpful, mike