There is a bug in the export of data from the impedance analyzer from Waveforms (specifically from Waveforms 3.8.2 using the Analog Discovery 2, but I have seen it with earlier releases of Waveforms 3 also).
The problem is that the frequencies are reported as if they were from a linear sweep, even though a logarithmic frequency sweep was done:
#Date Time: 2018-07-01 16:50:47.258
#Trace: Trace
#Start: 100 Hz
#Stop: 1e+06 Hz
#Steps: 101
#Resistor: 10000 Ω
#Average: 10
#ProbeCapacitance: 1.04e+06 Ω
#ProbeResistance: 4.3e-11 F
#Compensation: Open Short
#Wavegen: Wavegen1
#Amplification: 1 X
#Settle: 20 ms
#MinPeriods: 32
#Channel: Channel 1
#Range: 5.49577 V
#Offset: -0.000318847 V
#Attenuation: 1 X
#Channel: Channel 2
#Range: 5.51181 V
#Offset: -0.000280998 V
#Attenuation: 1 X
Frequency (Hz) Trace θ (°) Trace |Z| (Ω) Trace Ls (H) Trace Cs (F)
100 0.00067832392258167652 9971.9407134030535 0.00018789460945304077 -0.013481119008321029
10099 0.0018260127183053441 9972.4554790954317 0.00046132118972998595 -0.0045670615004842902
20098 0.0026165423173400044 9972.2098918719494 0.00060286028271848858 -0.0029068564833067186
Many of my students had problems with this bug last quarter, and we had to create a work-around in our gnuplot plotting scripts:
#if the frequencies in your data file don't follow log increments use the code below
#Written by AliFallahi#example: use plot 'data' u (correct($1)):3 instead of plot 'data' u 1:3
freq_u=1e6#last frequency
freq_l=10#first frequency
NoOfSamples=101#number of samples
indexno(f)=(NoOfSamples-1)*(f-freq_l)/(freq_u-freq_l)
correct(f)=10**(log10(freq_l)+indexno(f)/(NoOfSamples-1)*log10(freq_u/freq_l))##
plot 'measuring-10kohm-buggy-freq.txt' u (correct($1)):3 title '10k{/Symbol W}±0.1%'
It would be nice not to need to correct the data files.
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gasstationwithoutpumps
There is a bug in the export of data from the impedance analyzer from Waveforms (specifically from Waveforms 3.8.2 using the Analog Discovery 2, but I have seen it with earlier releases of Waveforms 3 also).
The problem is that the frequencies are reported as if they were from a linear sweep, even though a logarithmic frequency sweep was done:
Many of my students had problems with this bug last quarter, and we had to create a work-around in our gnuplot plotting scripts:
It would be nice not to need to correct the data files.
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