Hi David,
I haven't considered it closely yet. A quick numerical average would be
obvious for doing just a few sweeps, while a more complex look at the data,
including for example showing some form of error bars, might be useful for
more in-depth analysis. I don't necessarily intend to break new ground
here, and I haven't yet looked at what's the industry norm for averaged
display.
Do you have suggestions?
--
Rune / 5Q5R
On Wed, 18 Sep 2019 at 22:15, Dr. David Kirkby from Kirkby Microwave Ltd <
drkirkby@...> wrote:
On Wed, 18 Sep 2019 at 20:30, Rune Broberg <mihtjel@...> wrote:
Hi Bruce,
good to hear that it works! Averaging is on the roadmap, probably for
0.0.11 (or 0.1.0 or 1.0.0, however I name it)
What sort of averaging do you intend doing?
The HP 8753/8720 VNAs use an Infinite impulse response (IIR) filter. It
means that one can take 1000 averages, without storing data for the last
1000 readings, so it is very memory efficient. However, I personally find
annoying as it always concerns me how long to wait before it's safe to take
a measurement, results from previous measurements are still in the output
data. I should sit down one day and read the documentation, or find out the
exact formula used, and work out a time for it to settle to 99% or
something. In practice, I rarely use averaging, but prefering to just
reduce the IF bandwidth.
But of course, averaging has its place - especially if doing an isolation
measurement during the calibration, but on the professional VNAs I never
feel the need to do that. On a profesional VNA, the only use of an
isolation measurement is if there is leakage *outside* the instrument, as
the isolation inside the instrument is good enough to make an isolation
measurement of no benefit. Of course the NanoVNA is different, and
isolation measurements and averaging probably play a greater role.
--
Dr David Kirkby Ph.D C.Eng MIET
Kirkby Microwave Ltd
Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, CHELMSFORD,
Essex, CM3 6DT, United Kingdom.
Registered in England and Wales as company number 08914892
Tel 01621-680100 / +44 1621-680100
