johna@m wrote:
Hello All,

I am trying to simulate a simpe AM receiver circuit with diode
detector. I am assuming that the signal received from the antenna
(simulated with a voltage source) has a weak amplitude (around 100 uV)
and a high frequency (around 600 Khz). The issue is that the current
after the diode does not get rectified. The output current is very weak
(less than 250pA) and still contains the full sin signal (both halves
of signals).

When I try the simulation with smaller frequencies (around 5kHz) and
higher amplitude (around 0.2 v), the signal gets correctly
half-rectified, but not anymore when I work with higher frequencies and
smaller signals.

In real shematic for AM simple receiver, there is no ampification
bewteen the antenna (and the tuning LC circuit) and the diode. So how
the diode manage to half-rectifies correctly in real operating mode
when the signal is weak and high frequencies, which is the case of real
radio signals.

I use Ansoft Simplorer mainly. Any other simulators recommended ?
Thanks in advance and best regards,

What makes you sure the simulation and the reality agree ?
There is capacive coupling over the PN structure of the
diode to start with. And then at one point a diode has
an exponential characterization instead of binary on/off.

Rene
--
Ing.Buero R.Tschaggelar - http://www.ibrtses.com
& commercial newsgroups - http://www.talkto.net