Noise figure measurements
Noise figure measurements
(OP)
Hi,
I am doing amplifier noise figure measurements in the lab. I bought an Agilent PSU to power the amplifier. I realized the PSU, N6700B, introduced a lot of switching noise.
Could anybody recomend me an agilent PSU for noise figure measurements?
Thanks.
I am doing amplifier noise figure measurements in the lab. I bought an Agilent PSU to power the amplifier. I realized the PSU, N6700B, introduced a lot of switching noise.
Could anybody recomend me an agilent PSU for noise figure measurements?
Thanks.
RE: Noise figure measurements
supply more than enough current , add more electrolytic
and ceramic caps with short leads
AND FINALLY:
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RE: Noise figure measurements
RE: Noise figure measurements
Well, I apologize for the lack of information. I´m testing a LNA up to 1.5GHz.
Thanks for your answers.
RE: Noise figure measurements
The fact that your existing PSU is too noisy suggest the PSRR of the amplifier is not very good anyway. Are you sure the noise is coming from the wires and not coming from the power supply as say spurious magnetic fields?
Make sure you put 10nF to 100nF across the feedthru into the amp package to minimise HF noise.
RE: Noise figure measurements
Obvioulsy these are not "recommendations" because you still haven't given enough details and frankly other local situational requirements may be relevant (do you need the power supply for other applications as well, how much current does it need to supply, what power rail(s) does the amp have, and so forth).
RE: Noise figure measurements
Thanks for your comments, I found them quite useful.
Well I´m testing LNA amplifiers, AM, FM and DAB bands. I test them inside a Farady chamber. The amplifiers are for mass production but are still in the development phase. They have a regulator, using a zener.
I have also found in the Agilent website that the E3631 PSU has very good noise parameters.
Could you please explain me what is a feedthru?
PSRR issues, well that´s a good point and I´ll check that too.
Thanks!
RE: Noise figure measurements
Peter
RE: Noise figure measurements
The FT is a tubular capacitor; the inner electrode has
one lead which is coaxial with both electrodes and
protrudes at both ends . The outer electrode
of the C is a solder plated ring to be soldered
around to the perimeter of the hole in the shield.
Its effect is equivalent to a perpendicular wire going
through the hole. On each side of the shield all around
the wire there are a bunch of capacitors connecting
the wire to the rim of the hole in the shield with
infinitesimally short leads. ( i.e. with L=0 )
----------------------------
Please read FAQ240-1032: How to ask a meaningful question
My WEB: <http://geocities.com/nbucska/>
RE: Noise figure measurements
If all else fails, try that.
kch