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Improve graph divisions and markers

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- Added group delay option to markers
- Additional configuration for calculation of group delay in the preferences
- Specify divisions as amount of divisions instead of spacing
- Add option for auto divisions on graph with manual min/max limits
This commit is contained in:
Jan Käberich 2024-06-02 19:37:14 +02:00
parent fe08937bb7
commit b2d07d532d
24 changed files with 462 additions and 243 deletions
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42
Software/PC_Application/LibreVNA-GUI/Traces/trace.cpp
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@ -1572,6 +1572,48 @@ double Trace::getNoise(double frequency)
return dbm;
}
double Trace::getGroupDelay(double frequency)
{
if(!isVNAParameter(liveParam) || lastMath->getDataType() != DataType::Frequency) {
// data not suitable for group delay calculation
return std::numeric_limits<double>::quiet_NaN();
}
// get index that matches frequency best
unsigned int sample = index(frequency);
auto &p = Preferences::getInstance();
const unsigned int requiredSamples = p.Acquisition.groupDelaySamples;
if(size() < requiredSamples) {
// unable to calculate
return std::numeric_limits<double>::quiet_NaN();
}
// needs at least some samples before/after current sample for calculating the derivative.
// For samples too far at either end of the trace, return group delay of "inner" trace sample instead
if(sample < requiredSamples / 2) {
sample = requiredSamples / 2;
} else if(sample >= size() - requiredSamples / 2) {
sample = size() - requiredSamples / 2 - 1;
}
// got enough samples at either end to calculate derivative.
// acquire phases of the required samples
std::vector<double> phases;
phases.reserve(requiredSamples);
for(unsigned int index = sample - requiredSamples / 2;index <= sample + requiredSamples / 2;index++) {
phases.push_back(arg(this->sample(index).y));
}
// make sure there are no phase jumps
Util::unwrapPhase(phases);
// calculate linearRegression to get derivative
double B_0, B_1;
Util::linearRegression(phases, B_0, B_1);
// B_1 now contains the derived phase vs. the sample. Scale by frequency to get group delay
double freq_step = this->sample(sample).x - this->sample(sample - 1).x;
return -B_1 / (2.0*M_PI * freq_step);
}
int Trace::index(double x)
{
auto lower = lower_bound(lastMath->rData().begin(), lastMath->rData().end(), x, [](const Data &lhs, const double x) -> bool {