HLSI/powerSpectrumPlot.js at master · vtwireless/HLSI · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
"use strict"; // A must for debugging code.

// TODO:
//
//   1. We need to find the axis vertical scale based on all the signals
//      gn_min and gn_max (and etc).
//
//   2. Optional HTML element to place the plot on, like in Slider() and
//      Label().  Now it just appends the plot at the end of the <body>.
//      This may be okay for all 15 starting exercises.
//

// This function does not expose/return any object or other functions.
// Yes, it's magic.
//
// Generates a Power Spectrum Plot with one or more signals that are in
// the environment Signal.env
//
//
// opts:  options object
//
//    yMax:  maximum y plot values in dB
//    yMin:  manimum y plot values in dB
///
//
function PowerSpectrumPlot(opts = {}) {
  if (typeof opts.yMax === "undefined") opts.yMax = 20;
  if (typeof opts.yMin === "undefined") opts.yMin = -60;

  var sigs = [];
  var noises = []; // We can only have one noise.

  var freq_plot_min = 1.0e32; // large number that we change
  var freq_plot_max = -1.0; // small number that we change

  // We'll display spectrum from all signals in Signal.env;
  //
  Object.keys(Signal.env).forEach(function (key) {
    let sig = Signal.env[key];

    // Setup the plot to be updated when sig parameters change.

    if (sig.is_noise) {
      noises.push(sig);
      return;
    }

    // sig is not noise, so we add it to the list of signals.
    sigs.push(sig);

    // Get the limits freq_plot_min and freq_plot_max
    if (freq_plot_min > sig.freq_plot_min) freq_plot_min = sig.freq_plot_min;
    if (freq_plot_max < sig.freq_plot_max) freq_plot_max = sig.freq_plot_max;
  });

  // filter semi-length(m), over-sampling rate(k), total length
  const m = 80, // ! increasing this value squares off the signal
    k = 20,
    n = 2 * k * m + 1;
  var bw = 0.2, // bw
    gn = 0.0; // gain
  var nfft = 2048;

  var generator = new siggen(nfft);
  generator.m = m;

  // determine time and frequency scale/units
  var [scale_freq, units_freq] = scale_units(
    sigs[0].freq_init + sigs[0].bw_max * 0.5,
    0.1
  ); // freq scale

  // 5. X scale will use the index of our data
  var fScale = d3
    .scaleLinear()
    .domain([freq_plot_min * scale_freq, freq_plot_max * scale_freq])
    .range([0, plot.width]);

  // 6. Y scale will use the randomly generate number
  var pScale = d3
    .scaleLinear()
    .domain([opts.yMin, opts.yMax])
    .range([plot.height, 0]);

  const df = (freq_plot_max - freq_plot_min) / (nfft - 1);

  // 7. d3's line generator
  var linef = d3
    .line()
    .x(function (d, i) {
      return fScale((freq_plot_min + i * df) * scale_freq);
    }) // map frequency
    .y(function (d) {
      return pScale(d.y);
    }); // map PSD

  // 8. An array of objects of length N. Each object has key -> value
  // pair, the key being "y" and the value is a random number
  var dataf = d3.range(0, nfft - 1).map(function (f) {
    return { y: 0 };
  });

  // create SVG objects
  var svgf = svg_create(fScale, pScale, null); // ! null was formerly parentElement

  var labelPrefix = "";
  // TODO: This prefix label needs fixing so it works well for all the
  // signals in "sigs'
  //if(sigs[0].name.length > 0)
  //    labelPrefix = sigs[0].name + " ";

  // add labels
  svg_add_labels(
    svgf,
    labelPrefix + "Frequency (" + units_freq + "Hz)",
    labelPrefix + "Power Spectral Density (dB)"
  );

  // clip paths
  svgf
    .append("clipPath")
    .attr("id", "clipf")
    .append("rect")
    .attr("width", plot.width)
    .attr("height", plot.height);

  // 9. Append the path, bind the data, and call the line generator
  var pathf = svgf
    .append("path")
    .attr("clip-path", "url(#clipf)")
    .datum(dataf)
    .attr("class", "stroke-med no-fill stroke-yellow")
    .attr("d", linef);

  function update_plot() {
    generator.clear();
    // Iterate through signal array, calc values and pass to generator
    sigs.forEach(function (sig) {
      let df = sig.freq_plot_max - sig.freq_plot_min;
      let fc = -0.5 + (sig.freq - sig.freq_plot_min) / df;
      let bw = sig.bw / df;
      let gn = sig.gn;

      console.log("fc=" + fc + " bw=" + bw + " gn=" + gn);
      // ! bw (slider %) is limited to 90% range, as log(0) == inf
      generator.add_signal(fc, bw, gn + 10 * Math.log10(bw));
      //generator.add_signal(fc, bw, gn);
    });

    // use custom noise floor if given

    if (noises.length > 0) {
      let n_gn = 0.0; // total noise gain will be summed to n_gn.
      //
      // Having more than one noise is odd, but nothing says we can't.
      // We sum the noise gains this way:
      noises.forEach(function (noise) {
        // Sum the power.
        n_gn += Math.pow(10, noise.gn / 10.0);
      });
      // Now make it be in dB.
      n_gn = 10 * Math.log10(n_gn);
      //
      // Note: if there was just one noise than n_gn is just that
      // one (noise.gn).
      generator.generate(n_gn);
    }
    // else default noise floor is used (-120db, see generator src)
    else generator.generate();

    dataf = d3.range(0, nfft - 1).map(function (i) {
      return { y: generator.psd[i] };
    });

    pathf.datum(dataf).attr("d", linef);
  }

  // Add the update_plot callback to all the signals callbacks.

  noises.forEach(function (noise) {
    noise.onChange("gn", update_plot);
  });


    sigs.forEach(function(sig) {
        // Setup the plot to be updated when sig parameters change.
        sig.onChange("freq", update_plot);
        sig.onChange("bw", update_plot);
        sig.onChange("gn", update_plot);
        // sig.onChange("mcs", update_plot);
    });

  // update_plot() will be called by the callbacks that are set just
  // above.
}