Re: Trying to simulate a 27Mhz receiver. Couple of questions
|
Another thing comes to mind:
It could be useful to do an .AC analysis rather than (or in addition to) .TRAN analysis.? .AC analysis involves sweeping the frequency, so it is helpful for looking at tuned circuits.? To do an .AC analysis, you should remove the Modulate component and substitute an ordinary voltage source (keeping the series resistor), with its "AC" value set to 1V.? In SPICE .AC analysis is a linear analysis, so you get the same results whether signals are microvolts or megavolts; therefore it is often convenient to set the signal source's amplitude to 1V.
I might start with .AC analysis until I get the tuned circuits where I want them, then change to .TRAN analysis with the modulated signal source.
An .AC analysis doesn't tell you anything about circuits that are nonlinear.? Therefore, it would be meaningless for the detector portion of your receiver.? Likewise, RF mixers in a heterodyne receiver would not simulate correctly in .AC analysis.? But it's useful for checking the linear RF circuits.
Regards, Andy
|
