[R-390] Signal Generator Impedence Questions

Barry n4buq at aol.com
Thu Jun 2 18:17:57 EDT 2005


Dave,

Looks like I'll be finding a 40-ohm resistor post haste.

I didn't say the 1001A does not have a calibrated attenuator; I said it
doesn't have a microvolt meter.  Your instructions to get 150uV are exactly
what I did.

I am confused on one issue, though.  If a 40-ohm resistor is in series with
the output and then a 50-ohm resistor is in parallel with the output, the
10-ohm output sees 90-ohms, right?  I don't quite understand this.

Thanks and 73!

Barry - N4BUQ

----- Original Message ----- 
From: "David Wise" <David_Wise at Phoenix.com>
To: <R-390 at mailman.qth.net>
Sent: Thursday, June 02, 2005 4:43 PM
Subject: RE: [R-390] Signal Generator Impedence Questions


Roy Morgan beat me to the punch in saying that the GR1001A
"impedance matching adaptor" was nothing more than a 40 ohm
resistor.  The connector assembly it's embedded in costs
about 100x what the resistor did.

But I want to take issue with your statement that the
1001A does not have a calibrated attenuator.  It most
certainly does, unless early production omitted it.
To get 150uV (assuming it's terminated right), using
the CARRIER control you set the meter to the SET CARRIER
line, then set the step attenuator (MULTIPLIER) to 100uV,
and set the vernier (OUTPUT) to 1.5 .  Simple.

73,
Dave Wise



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