AnsweredAssumed Answered

vrf Harmonics measurement

Question asked by VRFuser on Aug 15, 2003


Dear John,

I think your objective is to measure the "maximum average" power, as per FCC
part 15 specs. The "maximum" part involves getting a worst case duty cycle
for TDMA signals, presumably you're working on a continuous modulation, so
no problem there. The "average" part means your objective is to measure the
thermal heating effect of the harmonic component. You can check whether
you're achieving that by comparing the output of the signal generator
directly (i.e. no amplifier under test, modulation on), measured on a
thermal power meter, with your channel power measurement of the same thing
with the spectrum analyzer. I'm not sure whether your particular analyzer
has an RMS detector setting, you should use that or a sampling detector to
avoid the log-averaging effect of the video bandwidth filter. A large VBW
compared to RBW may help. Anyhow, getting agreement with a power meter at a
range of power levels is what you need to achieve to be able to proceed with
confidence. Hope this helps.


best regards,

Chris Potter
-----------------------------------------------
P&H Technology Consultants
10, Teversham Road, Fulbourn,
Cambridge, U.K. CB1 5EB
Tel +44 1223 882033   Fax +44 870 7061487
Mobile +44 7946 354276
http://www.ph-technology.com
http://www.softplot.com
-----------------------------------------------


-----Original Message-----
From: John jr [mailto:fsc729@yahoo.com]
Sent: 15 August 2003 05:26 PM
To: VEE vrf
Subject: [vrf] Harmonics measurment


Hello everyone, I have a 8536EC spectrum analyzer, I want to program it to
measure the harmonics of a CDMA2000 signal.

The test setup is as follows, we have a cell band and PCS band amplifier,
we test the amplifiers one at a time. We connect the output of the
amplifier to some attenuators and then connect the attenuators to the
spectrum analyzer, the input to the amplifier is provided by a vector
signal generator, generating a CDMA2000 waveform.

Since semiconductor amplifiers are nonlinear it produces harmonic signals,
the problem is that measuring the harmonics of non-CW signal on a pure
Spectrum analyzer is not trivial, as I have found out, the spectrum
analyzer has some features that maybe useful, I have been playing around
with the channel power over bandwidth feature, but I am yet to be
convinced this is the proper way to measure harmonics.

My question is how does one measure the harmonics of a CDMA2000 waveform
on a spectrum analyzer that has channel power over bandwidth feature??

Thank You
JOhn

__________________________________
Do you Yahoo!?
Yahoo! SiteBuilder - Free, easy-to-use web site design software
http://sitebuilder.yahoo.com

---
You are currently subscribed to vrf as: chris.potter@ph-technology.com
To subscribe send a blank email to "join-vrf@it.lists.it.agilent.com".
To unsubscribe send a blank email to "leave-vrf@it.lists.it.agilent.com".
To send messages to this mailing list,  email "vrf@it.lists.it.agilent.com".
If you need help with the mailing list send a message to
"owner-vrf@it.lists.it.agilent.com".


---
You are currently subscribed to vrf as: rsb@soco.agilent.com
To subscribe send a blank email to "join-vrf@it.lists.it.agilent.com".
To unsubscribe send a blank email to "leave-vrf@it.lists.it.agilent.com".
To send messages to this mailing list,  email "vrf@it.lists.it.agilent.com". 
If you need help with the mailing list send a message to "owner-vrf@it.lists.it.agilent.com".

Outcomes