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FM Homelab
@FMHomelab
FM Radios, Mathematics, Python, Nature and more
Joined June 2022
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Most simple code to collect one waveform from channel 1:
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Import waveforms from #siglent #oscilloscope using #python #matplotlib #SCPI commands over ethernet. Eliminates to export them as .csv file and import into python. Live capture even runs in #Jupyter. Code for live capture in github.com/kvdijken/SDS12.
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Extracting the 19kHz pilot tone from an FM station and doubling it to 38kHz with only discrete components was not easy. The resulting 38kHz is 40dB above its (local) noise floor and 36dB above the 19kHz residue.
#FM #pilot #stereo #radio #electronics
Sometimes you want to create an image file which is a 1:1 presentation of your 2-D data. We do not want scaling. We want one pixel per array element.
How to do this in #python #matplotlib is not so obvious. This is the easiest way I can come up with: 🔽
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Meracalculator shorturl.at/eklVZ calculated the inverse Laplace transform for (as^2+bs+c) / (xs^2+ys+z) in a few seconds while took several hours for this. Also, the (different) result from sympy may not be right (imaginary stuff from negative values within roots).
Waar zijn de #fitis-en gebleven? Normaal geproken hoor je ieder jaar honderden fitissen zingen. Dit jaar nauwelijks. Is er iets gebeurd met de fitissen in de overwinteringsgebieden? , enig idee?
Where are the #willowwarbler's? Hardly any willowwarblers this year.
Calculating L, ESR, EPR and EPC values for a variable A5552 inductor as described by (EPR is not mentioned there but easy to also get). Put the calculated values into a lumped elements model and compare it to the measured data. More mechanisms seem to be at play.
A rather difficult plot, with a secondary x-axis which is inversely proportional to the first x-axis (x2 ∝ 1/x1). With help of a post on (shorturl.at/ADG56) I was able to create a nice plot.
source code in follow up
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Be carefull when declaring symbols in . Sympy does not raise an error when wrong/unknown arguments are given. I'd expect error messages in 4, 6, 7 and 8.
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Ofcourse there was an error in the y ticks. The correct version of the plot is shown here.
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To give your high resolution #matplotlib plots the looks of an oldschool spectrum analyzer use a narrow linewidth and low alpha. Some tweaking needed with figsize, linewidth and alpha. In this plot the local FM radio band between 90 and 100MHz.
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Nice agreement between theory and measurements on a 19kHz bandpass filter. Solving a linear system of KCL equations in leads to a transfer function. Waveforms imported from oscilloscope and fft'ed with . Both plotted with .
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#bug in #sds1202xe firmware 1.3.26 . When saving a waveform file to a .csv file, probe attenuation is not taken into account. On the same signal, changing the probe attenuation setting on the scope without having changed probes give the same results in the csv file.
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STM32 generates all freqs from 1-50kHz at the same time lets me generate bode plots easily on oscilloscope which only has basic FFT options. No need to slowly scan the frequency range and max-hold the FFT. Here testing a 19kHz bandpass filter. #bodeplot #oscilloscope #fft #stm32
Measured V2 and phase shift φ with varying V1, then calculated C=-tan(φ) / (2𝛑fR), with R=99.
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Ceramic capacitors' capacitance depend on applied AC voltage.
See tinyurl.com/8pesycdt: "... multilayer ceramic capacitors have AC voltage dependence characteristics, and ... a tendency for the capacitance to decrease together with the AC voltage."
#electronics #matplotlib
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Import waveform data from Siglent SDS1202X-E oscilloscope into Jupyter. #carnets #matplotlib #jupyter #siglent #sds1202x-e
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