Quote:
Originally Posted by Radio Wrangler
The oscillator and the meter have to remain in tune or else the meter result will fall from the peak and this will affect calibration of the Gm ranges
The tuned nature of the Gm meter, I suspect is a ploy to reduce its sensitivity to mains harmonics. It might be best if it were tuned to a frequency which is not an integer multiple of the local mains frequency, and that the oscillator is tuned to match.
David
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Could I seek clarification of a couple of points you make; it's the oscillator and the meter
amplifier that need to be on the same frequency of thereabouts, though the meter itself plays no role in achieving that?
My recollection is that the system works up at a little over 14kHz (and may perhaps vary a little from one instrument to the next?). Are harmonics from 50Hz really likely to interfere with the ~14kHz signal?
I wonder if the day may be coming when someone may finally say, "Let's ditch those two boards and build something with modern components and incorporate a dedicated DC supply". Trading originality for reliability might be a temptation?
B