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NF and Gain Measurement using SA & Noise Source - RF Cafe Forums
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arool
Post subject: NF and Gain Measurement using SA & Noise
Source
Unread postPosted: Sun Jul 11, 2004 5:38 pm
Please
help me to Measure LNA NF & Gain using Spectrum Analyzer & Noise
Source
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Kirt Blattenberger
Post subject:
Unread postPosted: Tue Jul 13, 2004 12:51 pm
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Joined: Sun Aug 03, 2003 2:02 pm
Posts: 308
Location: Erie, PA
Greetings arool:
Agilent has an application
note for that here:
Spectrum Analyzer Measurements and Noise
Application Note 1303
http://cp.literature.agilent.com/litweb
... -4008E.pdf
- Kirt Blattenberger :smt024
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Dr.W.
Post subject: Using Noise generator for
NF measurement
Unread postPosted: Tue Dec 14, 2004 9:30 pm
Sorry the Agilent app note referenced in the other reply will not
help you .
see instead /5952-3706E.pdf.
You need to set your
spec. an. to work as a RF power meter.
1. Set IF bandwidth high
as you dare.
2. Set Video filter as low as you have time to wait
for trace.
3. Set to 1 dB/ div or if youre lucky use a maker at the
centre of your noise.
4. You will need a low noise preamp if the
gain of your device or system (DUT) is gain is less than about 20dB.
5. Check for this - the noise level should drop by at least 10dB when
you disconnect or power down your DUT.
6. If not use minicircuits
or other gain block amplifier to get result 5.
super low noise not
required about 4dB is OK.
7. Connect noise generator to DUT. switch
on, your spec an noise should jump at least 3dB.
8. Apply Y factor
formula to calculate result from generator ENR, ambient temp (ussually
assumed), and change in spec. an. dB reading noise generator off to
on. Y is this dB reading converted to a straight power ratio
9. Y
factor method formulas are on the net see /5952-3706E.pdf
Posted 11/12/2012
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