[R-390] Signal Generator Impedence Questions

[Barry]

Bob,

That'd be great.  I've not been too handicapped with the 10-ohm output for
the most part, but I'd like to get 50-ohm output just so I can eliminate
that from the overall equations.

I'm guessing I'd still need details for the other test adapter as apparently
it is matching the 50-ohm output from the URM-25 to whatever is the input
impedance of the IF deck.

Thanks again,

Barry - N4BUQ

----- Original Message ----- 
From: <rbethman at comcast.net>
To: "Barry" <n4buq at aol.com>
Cc: <r-390 at mailman.qth.net>
Sent: Thursday, June 02, 2005 11:44 AM
Subject: Re: [R-390] Signal Generator Impedence Questions


> Barry,
>      The GR-1001A originally came with a 50 ohm adapter.  It, however, was
limited to certain outputs to "maintain" its 50 ohm output.
>
> I'll take a GOOD look at min and see if I can look inside and get a
schematic drawn of its insides.  May take a week!  I'm just starting a
string of 12 hour shifts.
>
> Bob - N0DGN
>
>
> > Gents,
> >
> > The IF alignment procedures for the R390A state to connect the URM-25*
to
> > the input connector using an impedance matching adapter  (either Test
> > MX-1487/URM-25D or CU-206/URM-25F depending on which generator you
have).
> > Assuming the URM-25* is 50-ohm output, what does this converter do?  I
find
> > it odd that the adapter is mentioned for the IF GAIN ADJUSTMENT
procedure,
> > but not for the IF alignment procedures even though the generator is
> > connected to the IF module the same way for both procedures.
> >
> > I assume the input impedance of the IF module is something other than
> > 50-ohms and the adapter is being used to match the two impedances, but I
> > don't know what the input impedance of the IF module is.
> >
> > I have a GR1001A signal generator which, for most attenuation settings,
has
> > an output impedance of 10 ohms.  The reason I'm asking about the above
> > adapters is I'd like to construct a proper matching network for my
10-ohm
> > generator to work the same way as the 50-ohm generators do for the IF
> > alignment procedures.
> >
> > Another question:  The instructions state to set the output at 150uV for
the
> > IF GAIN ADJUSTMENT procedure.  If I'm using a different adapter for
10-ohms
> > versus 50-ohms, will I need to change the output setting to something
other
> > than 150uV to account for the different adapter impedances?
> >
> > Thanks!
> >
> > Barry - N4BUQ
> >
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