Hey folks, I’m just looking at the GD-1190 schematic (available online/google it) and I’d like someone to help me understand what type of detector this is. It seems a little strange. It appears to be a mono coil and the only mono coils I readily understand are BFO’s. But this does not look like a BFO. I believe I read somewhere that it was a VLF but not sure. Certainly doesn’t look like a PI. It appears to have a second oscillator for Audio Tone but I don’t fully understand the way it’s working along with the coil oscillator to generate output. The coil oscillator is driving (actually pinging not oscillating) the coil at 58khz (which oddly is the tank circuits tuned frequency but this is not a TR machine nor a PI I don’t think) and the audio tone is around 200 hz.
Also noticed that the signal going into the amp from the coil is only .6 volts peak to peak. That seems like not much drive on the search coil but maybe those voltages on the shematic are just for some test mode.
And even the discrimination control circuit near the coil has me a little puzzled.
I must admit to being a little confused by this circuit. Maybe it’s late and my brain isn’t working but i’d Like to discuss this with someone a bit.
Thanks.
Also noticed that the signal going into the amp from the coil is only .6 volts peak to peak. That seems like not much drive on the search coil but maybe those voltages on the shematic are just for some test mode.
And even the discrimination control circuit near the coil has me a little puzzled.
I must admit to being a little confused by this circuit. Maybe it’s late and my brain isn’t working but i’d Like to discuss this with someone a bit.
Thanks.