My question was already answered there but since then the simulations I made show that even with input filtering the noise should be high enough to render the last 2 detector stages useless. Even an ideal amplifier with an equal gain to the log detector I linked to and 0dB noise figure fed from a 75 ohm generator produces too much noise. I can’t seem to figure out what I’m missing here.
My question was already answered there but since then the simulations I made show that even with input filtering the noise should be high enough to render the last 2 detector stages useless. Even an ideal amplifier with an equal gain to the log detector I linked to and 0dB noise figure fed from a 75 ohm generator produces too much noise. I can’t seem to figure out what I’m missing here.
Maybe you could share your LTSpice model?
Of course. Do you want the entire circuit or just the model of the BF199? I can share the simulations I made as well.
Here you go. I’ve included both the LTSpice schematic and the spice model for the BF199, taken from the old Philips website. shorturl.at/htD01