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increase frequency calculation for log sweep

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This commit is contained in:
Jan Käberich 2022-01-05 21:40:51 +01:00
parent da5614f756
commit 48d00ec172
1 changed files with 16 additions and 4 deletions
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20
Software/VNA_embedded/Application/VNA.cpp
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@ -21,7 +21,7 @@
static Protocol::SweepSettings settings; static Protocol::SweepSettings settings;
static uint16_t pointCnt; static uint16_t pointCnt;
static float span_log10; static double logMultiplier, logFrequency;
static bool excitingPort1; static bool excitingPort1;
static Protocol::Datapoint data; static Protocol::Datapoint data;
static bool active = false; static bool active = false;
@ -57,7 +57,18 @@ static uint64_t getPointFrequency(uint16_t pointNum) {
if(!settings.logSweep) { if(!settings.logSweep) {
return settings.f_start + (settings.f_stop - settings.f_start) * pointNum / (settings.points - 1); return settings.f_start + (settings.f_stop - settings.f_start) * pointNum / (settings.points - 1);
} else { } else {
return settings.f_start * powf(10.0, pointNum * span_log10 / (settings.points - 1)); static uint16_t lastPointNum = 0;
if (pointNum == 0) {
logFrequency = settings.f_start;
} else if(pointNum == lastPointNum) {
// nothing to do
} else if(pointNum == lastPointNum + 1) {
logFrequency *= logMultiplier;
} else {
logFrequency = settings.f_start * pow(10.0, pointNum * log10((double)settings.f_stop / settings.f_start) / (settings.points - 1));
}
lastPointNum = pointNum;
return logFrequency;
} }
} }
@ -71,13 +82,14 @@ bool VNA::Setup(Protocol::SweepSettings s) {
active = false; active = false;
return false; return false;
} }
settings = s;
span_log10 = log10((double) settings.f_stop / settings.f_start);
// Abort possible active sweep first // Abort possible active sweep first
FPGA::SetMode(FPGA::Mode::FPGA); FPGA::SetMode(FPGA::Mode::FPGA);
if(settings.points > FPGA::MaxPoints) { if(settings.points > FPGA::MaxPoints) {
settings.points = FPGA::MaxPoints; settings.points = FPGA::MaxPoints;
} }
settings = s;
// calculate factor between adjacent points for log sweep for faster calculation when sweeping
logMultiplier = pow((double) settings.f_stop / settings.f_start, 1.0 / (settings.points-1));
// Configure sweep // Configure sweep
FPGA::SetNumberOfPoints(settings.points); FPGA::SetNumberOfPoints(settings.points);
uint32_t samplesPerPoint = (HW::ADCSamplerate / s.if_bandwidth); uint32_t samplesPerPoint = (HW::ADCSamplerate / s.if_bandwidth);