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8970B INSTALLATION

Question asked by mhtplsh on Jul 19, 2007
Latest reply on Oct 21, 2014 by karl

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I hv 8970B noise figure meter. It is mentioned that it should not be used near computer. Can i use it near 8712C HP network analyser?
Is there any power level adjustment in 8970B noise generator?

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Adrian Jul 19, 2007 6:31 AM
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Generally, you can use it near other instruments. However, especially when the DUT isn't mounted in a housing that keeps RF interference out, you'll likely get erroneous test results. So, in case of having unscreened DUT's, a RFI chamber might be very helpful. Keep in mind that any RF signal that meets the measurement frequency will affect the accuracy of your reading, even if -10 dB below the noise floor. That's why you should keep it away from any computer.
You'll need a calibrated solid state noise source like the 346A/B with your 8970B.
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iandoubleyou Jul 19, 2007 3:30 PM
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There's a good application note to learn more on Noise figure Measurements at:

http://cp.literature.agilent.com/litweb ... -8255E.pdf
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RayH Jul 19, 2007 3:30 PM
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The actual power levels involved in a noise figure measurement are VERY small. This makes the measurement susceptible to interference.

Most instruments are very well shielded, but a 8712C does have a built-in RF source that could cause a problem.

You might look in AN 57-2:
http://cp.literature.agilent.com/litweb ... -3706E.pdf
See pages 12 -13 for advice on interference.

The 346A/B/C noise source has a fixed noise level. You can not adjust it, they are either ON or OFF
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karl Oct 18, 2014 12:47 PM
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Hi, I am new to this forum and have not yet found how to open a new thread - so I pose my question here:

Trying to learn HPIB commands I have send *IDN? via a HPIB Interface to my 8970B/8971C
8970B serial 3043U02047, Software version 99.9SF: 02844

The 8970B responds with an Error 40.
Since I have checked all HPIB cables, HPIB I/O lines inside the 8970B, tried another interface but no change.

Some users suggested that *IDN? is not a command a 8970B would understand -

I ask this question as the user manual for the 8971 inidicates the 8971 should reply as mentioned in the manual.

Are there any later hard- or software changes in the noise figure test set which do not correspond to the 8970B/8971C I have in use
or
is this a beginners misunderstanding that only the 8971B/C will respond correctly if the c*IDN? ommand is sent directly to its GPIB interface.

Thanks for reading

Karl
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- HP8971C_IDN.jpg846.1 KB
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- RayH @ karl on Oct 20, 2014 10:09 AM
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  You are correct. The 8970B does not repond to the *IDN? command. The 8971B and 8971C do understand the *IDN? query.
  
  There is no update that will add this capbility to the 8970B. The 8970B is based on the older 8970A, and this command was never added when the "B" was introduced.
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  - karl @ RayH on Oct 21, 2014 3:19 AM
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    Hi Ray,
    
    thanks for your reply.
    Apparently I should have read the user manual more carefully to learn that IDN works only with the 8971B/C.
    
    Thank you
    Karl .
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8970B INSTALLATION

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