yes i think so
John Miles <jmiles@...> wrote: Isn't that what the 86222 sweeper plugin with the marker option does? Those
are pretty common.
-- john, KE5FX
this is another way but i havent seen anyone using this in
centuries, the last time i saw it was on a old jerrold sweeper,
everything i had ever since was using the approach i described,
problem with the RF method is that its quite expensive to
realize, a directional coupler, sampling mixer and the oscillator
and frequency counter costs money and space and also takes away
from the RF power, another factor is that whenever you use a comb
generator you run the risk of finding your peaks "everywhere"
even in places you dont want them :)
DC or LF stuff is cheap and doesnt take up much space so i
think thats why most companies opted for this approach
J Forster <jfor@...> wrote:
lothar baier wrote:
ok there are two basic ways to create a marker in a swept
system, one is called RF blanking the other one is called
intensity modulation, ok usually you have a control voltage thats
proportional to your RF frequency, if the analyzer sweeps its
basically a ramp, each point of the ramp corresponds to a certain
frequency, you feed this signal to a comparator and compare it to
a DC voltage thats adjustable (coming from your marker pot)
anytime the ramp "hits" this threshold you get a pulse on your
comparator output, you route this pulse back into your display
and use it to crank up the intensity just a bit at this point and
there you have a marker blip on your screen :)
There is another way. You sample the RF, mix it with a (frequency
settable) oscillator, run the output through a LPF, detector, and
comparator and use this output for intensity markers.
This system has the advantage that you can count the oscillator
and have accurate digital markers, and, if you replace the
oscillator w/ a comb generator, you get nice, calibrated pips.
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