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fix: calc group delay by average of 2

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TT 2019-10-16 23:22:47 +09:00
parent 7e3805f36c
commit 7ad51be1e4
1 changed files with 26 additions and 15 deletions
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41
plot.c
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@ -442,12 +442,9 @@ float phase(float *v)
/*
* calculate groupdelay
*/
float groupdelay(float *v, float deltaf)
float groupdelay(float *w, float *v, float deltaf)
{
float *w = &v[2]; // point to next coeff
#if 1
// w = w[0]/w[1]
// v = v[0]/v[1]
// atan(w)-atan(v) = atan((w-v)/(1+wv))
float r = w[0]*v[1] - w[1]*v[0];
float i = w[0]*v[0] + w[1]*v[1];
@ -507,10 +504,11 @@ cartesian_scale(float re, float im, int *xp, int *yp, float scale)
uint32_t
trace_into_index(int x, int t, int i, float coeff[2])
trace_into_index(int x, int t, int i, float array[101][2])
{
int y = 0;
float v = 0;
float *coeff = array[i];
float refpos = 8 - get_trace_refpos(t);
float scale = 1 / get_trace_scale(t);
switch (trace[t].type) {
@ -521,9 +519,15 @@ trace_into_index(int x, int t, int i, float coeff[2])
v = refpos - phase(coeff) * scale;
break;
case TRC_DELAY:
if (i != 100) {
float deltaf = frequencies[i+1] - frequencies[i];
v = refpos - groupdelay(coeff, deltaf) * scale;
if (i == 0) {
float deltaf = frequencies[1] - frequencies[0];
v = refpos - groupdelay(array[0], array[1], deltaf) * scale;
} else if (i == 100) {
float deltaf = frequencies[i] - frequencies[i-1];
v = refpos - groupdelay(array[i-1], array[i], deltaf) * scale;
} else {
float deltaf = frequencies[i+1] - frequencies[i-1];
v = refpos - groupdelay(array[i-1], array[i+1], deltaf) * scale;
}
break;
case TRC_LINEAR:
@ -655,8 +659,9 @@ gamma2reactance(char *buf, int len, const float coeff[2])
}
static void
trace_get_value_string(int t, char *buf, int len, float coeff[2], int i)
trace_get_value_string(int t, char *buf, int len, float array[101][2], int i)
{
float *coeff = array[i];
float v;
switch (trace[t].type) {
case TRC_LOGMAG:
@ -671,11 +676,17 @@ trace_get_value_string(int t, char *buf, int len, float coeff[2], int i)
chsnprintf(buf, len, "%.2f" S_DEGREE, v);
break;
case TRC_DELAY:
{
float deltaf = frequencies[i+1] - frequencies[i];
v = groupdelay(coeff, deltaf);
string_value_with_prefix(buf, len, v, 's');
if (i == 0) {
float deltaf = frequencies[1] - frequencies[0];
v = groupdelay(array[0], array[1], deltaf);
} else if (i == 100) {
float deltaf = frequencies[i] - frequencies[i-1];
v = groupdelay(array[i-1], array[i], deltaf);
} else {
float deltaf = frequencies[i+1] - frequencies[i-1];
v = groupdelay(array[i-1], array[i+1], deltaf);
}
string_value_with_prefix(buf, len, v, 's');
break;
case TRC_LINEAR:
v = linear(coeff);
@ -835,7 +846,7 @@ void plot_into_index(float measured[2][101][2])
if (!trace[t].enabled)
continue;
int n = trace[t].channel;
trace_index[t][i] = trace_into_index(x, t, i, measured[n][i]);
trace_index[t][i] = trace_into_index(x, t, i, measured[n]);
}
}
#if 0
@ -1410,7 +1421,7 @@ cell_draw_marker_info(int m, int n, int w, int h)
trace_get_info(t, buf, sizeof buf);
cell_drawstring_5x7(w, h, buf, xpos, ypos, config.trace_color[t]);
xpos += 64;
trace_get_value_string(t, buf, sizeof buf, measured[trace[t].channel][idx], idx);
trace_get_value_string(t, buf, sizeof buf, measured[trace[t].channel], idx);
cell_drawstring_5x7(w, h, buf, xpos, ypos, config.trace_color[t]);
j++;
}