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Transmission Tracking Specification
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on Apr 10, 2013
on Apr 10, 2013 by Dr_joel
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What is meant by the Transmission Tracking Specification for network analyzers and how would this relate to the Transmission Coefficient uncertainty?
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Apr 10, 2013 7:43 AM
This is one of five main elements in the transmission measurement uncertainty (S21 uncertainty)
The main elements are:
1) Transmission tracking error: best case around 0.025 dB, depends upon the quality of the calibration kit; typical is on the order of 0.06 to 0.1 dB.
2) Dynamic accuracy: how well the analyzer measures changes in power. It is a curve with zero error at the same power as at calibration, and the error increase as the power changes. Most older VNAs and many modern ones have an error of about 0.01 dB per 10 dB change, so for a 50 dB attenuator, the error would be 0.05 dB. PNA has an error on the order of 0.02 over 80 dB of range.
3) Input mismatch error: depends on S11 of the DUT, and goes as a function of 20Log(1-S11*ResidualSourceMatch). Residual Source Match is set by the calibration kit, and is typically 30-45 dB. For a DUT with S11=-14 dB, and RSM at -40 dB, the error would be 20log(1+(0.2)*(0.01)) = 0.02 dB. Note for the error formula, S11 and RSM are expressed in linear terms not dB.
4) Output mismatch error: same as above but S22 and Residule Load Match
5) Noise floor: at high attenuation measurements, noise floor can have substantial effects, but normally it can be reduced to arbitrarily small levels through averaging.
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vrf Slow 4419
vrf convert string into ADCII