Multisim - AGC (JACK-AL version)

Ravi Miranda


Continuing my curiosity on how an AGC works in practise, I tried to
simulate the mentioned AGC circuit using Multisim.

The simulation runs for a few seconds and then comes up with an error message.

The S-Meter output shows the output signal in nV/dbm but it is very
low even if I increase the signal level. What would be the signal
level in uV after 2 stages of amplification, should I be trying to
simulate a complete section before trying to simulate the AGC on its

What I am doing wrong/not reading correctly?

I've also added the first stage of the uBITx as a test, this works
correctly. Both files are in the same folder.

Thank you for your time.

Best 73,
I'm here to add more value to the world than I'm using up.



I am not prepared to repair your simulation fault - but I can provide a clue on the AGC.  it is similar to the hybrid cascode (hycas) introduced by W7ZOI.  see what info you can find online - the article or related into may be there.  if not email me and I will dig for it. 

also the Jackal developers will gladly answer your questions also. 

if you did your own circuit - I would carefully check the front end matching on the input of the IF AGC amplifier.  if it is similar to the hycas, it requires a trimmer capacitor to peak the response. 

73 Curt wb8yyy