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hugo.coolens@kuleuven.be

measurement uncertainty for network analyser (bode plot)

Question

What is the measurement uncertainty in dB when using the network analyser  (bode-plot) function on a circuit which can be considered to approach quasi perfect linearity (not producing significant harmonics)? I suppose this figure will be dependent on the upper frequency for which the trace is produced. Same question for the phase uncertainty (absolute or procentual)?

kind regards and thanks in advance

Hugo

 

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The Network Analyzer uses the Wavegen to generate stimulus signal and the Scope to acquire data. The magnitude and phase information is stored for each frequency step as the stimulus frequency is changed. The Scope channel 1 is by default used as reference for the other channel(s).
The magnitude resolution depends on amplitude relative to scope input full scale, for Analog Discovery 5/50V pk2pk with 14bit ADC 0.3/3mV.
The phase depends on FFT bin resolution, how many periods are in 8k acquired samples. This can vary between 16 and 100.

See some other posts in this topic:

https://forum.digilentinc.com/search/?&q=bode%20or%20network&type=forums_topic&nodes=8

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7 hours ago, attila said:

The Network Analyzer uses the Wavegen to generate stimulus signal and the Scope to acquire data. The magnitude and phase information is stored for each frequency step as the stimulus frequency is changed. The Scope channel 1 is by default used as reference for the other channel(s).
The magnitude resolution depends on amplitude relative to scope input full scale, for Analog Discovery 5/50V pk2pk with 14bit ADC 0.3/3mV.
The phase depends on FFT bin resolution, how many periods are in 8k acquired samples. This can vary between 16 and 100.

Thanks for taking the time to answer my question. From the first part of your answer I conclude that the frequency as such is of no importance  for the magnitude (dB) measurement uncertainty.

Would it be possible to provide a numerical example of the amplitude- and  phase measurement uncertainty using the above data?

thanks in advance

Hugo

 

 

 

 

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