Skip to content

Instantly share code, notes, and snippets.

@JerryWiltz

JerryWiltz/.block

Last active May 29, 2019 20:06
Show Gist options
  • Save JerryWiltz/6d9d877624c1270fe68405a906698501 to your computer and use it in GitHub Desktop.
Save JerryWiltz/6d9d877624c1270fe68405a906698501 to your computer and use it in GitHub Desktop.
Download ZIP
9 Section Low Pass Filter
Raw
.block
license: gpl-3.0
height: 600
scrolling: yes
border: yes
Raw
README.md

A design and analysis of a 9 section low pass filter is shown in the html. The output frequency response plot by nP.lineChart uses all the key-value pairs for the lineChartInputObject. nPort methods shown are:

  1. g.fList generates 101 frequencies
  2. nP.chebyLPNsec computes the number of sections in the filter, n = 9
  3. nP.chebyLPgk determines the gk values of the low pass prototype
  4. nP.chebyLPLCs finds the L's and C's of the filter
  5. nP.lpfGen finds overall s-paramters of the filter
  6. nP.lineChart plots the frequency response

Documentation for nPort is a README that can be found at https://github.com/JerryWiltz/nP/blob/master/README.md

Raw
index.html
<!DOCTYPE html>
<html>
<head>
<title>Low Pass Filter with LC</title>
</head>
<body>
<svg id="chart1" width="600" height="400"></svg>
<img src='LowPassFilter.png'></img>
<script src="https://cdn.jsdelivr.net/gh/JerryWiltz/nP@latest/dist/nP.js"></script>
<script>
// generate frequency list
g = nP.global;
g.fList = g.fGen(50e6, 6e9, 101);
// specify the filter requirements
var minRejFreq = 1.5e9;
var maxPassFreq = 1.0e9;
var passBandRipple = 0.01;
var rejLevel = 35;
// find the normalized frequency, w
var w = minRejFreq/maxPassFreq;
// find the number of sections, n, using nP
var n = nP.chebyLPNsec(maxPassFreq, minRejFreq, passBandRipple, rejLevel);
// determine the lowpass fitler prototype elements, gks, using nP
var gk = nP.chebyLPgk(n, passBandRipple);
// find the parallel C and series L components using nP
var LCcomponents = nP.chebyLPLCs(gk, maxPassFreq);
// compute the s-parameters per frequency point of the filter given the LC components
var myFilt = nP.lpfGen(LCcomponents);
// produce the output
var LPF = myFilt.out('s11dB', 's21dB');
// set up the lineChartInputObject
var fullInputObject = {
inputTable: [LPF],
chartID: 'chart1',
metricPrefix: 'giga',
titleTitle: 'Response of a 1 GHz 9 Section Lowpass LC filter',
xAxisTitle: 'Input Frequency, GHz',
yAxisTitle: 's11 and and s21, dB',
xRange: [0,6e9],
yRange: [0,-160],
showPoints: 'hide',
showLables: 'show'
};
// plot the filter response
nP.lineChart(fullInputObject);
// show the LC components
var LC = document.createElement('div');
LC.innerHTML = 'Starts with a parallel capacitor, then with a series inductor, and so on ...' + '<br>';
LCcomponents.forEach(function (element) {
LC.innerHTML = LC.innerHTML + element.toString() + '<br>';
});
document.body.appendChild(LC);
</script>
</body>
</html>
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment