[R-390] Okay, don't laugh at me but...

[Curt Nixon]

I was reading an article in the HSN archive that described just what you 
are suggesting..  I think it should work.  Can't hurt anything to try 
it.  It talked about keeping the sweep freq low and the deviation 
controls the span of the display.

Curt

Barry wrote:
> I am aligning an old FM radio and I want to sweep the IF transformers but I don't have a sweep generator.  I know that my function generators with VCO input can function as a sweep generator, but they don't cover the 10.7MHz range.
>
> Here's the dumb question:  Can I use my HP-8640B (in FM mode) and feed the modulation input with a triangle waveform from a function generator to essentially cause the 8640 to sweep the center frequency?
>
> BTW, the reason I want to use the scope and sweep it is something doesn't seem quite right using the VTVM method.  It's adjusting the secondary of the last IF transformer is supposed to cause the measured point to go through a zero point (e.g. +V on one side, through zero, and then -V on the other).  The procedure is to set it zero volts but I'm only able to get a non-zero null point so I suspect something else is not right and a picture might help me confirm what I'm seeing on the VTVM.
>
> Again, please don't laugh at me.  FM is just weird to me...
>
> Thanks,
> Barry - N4BUQ
>
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