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phase_t

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Sébastien Bourdeauducq 2024-12-31 17:04:37 +08:00
parent 4306a234b9
commit 5991fa600d
1 changed files with 11 additions and 8 deletions
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19
dsp_lib.h
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@ -3,18 +3,21 @@
#include <cstdint> #include <cstdint>
#include <complex> #include <complex>
static uint32_t frequency_to_ftw(double f) { typedef uint32_t phase_t;
return f*(double)UINT32_MAX; #define PHASE_MAX UINT32_MAX
static phase_t frequency_to_ftw(double f) {
return f*(double)PHASE_MAX;
} }
class DDS { class DDS {
private: private:
uint32_t phase = 0; phase_t phase = 0;
public: public:
uint32_t ftw = 0; phase_t ftw = 0;
double get() { double get() {
phase += ftw; // wraps on overflow phase += ftw; // wraps on overflow
return sin(phase*2.0*M_PI/(double)UINT32_MAX); return sin(phase*2.0*M_PI/(double)PHASE_MAX);
} }
}; };
@ -41,10 +44,10 @@ template<unsigned int order>
class Lockin { class Lockin {
private: private:
double scale; double scale;
uint32_t phase = 0; phase_t phase = 0;
Lowpass<std::complex<double>, order> lpf; Lowpass<std::complex<double>, order> lpf;
public: public:
uint32_t ftw = 0; phase_t ftw = 0;
void set_scale(double s) { void set_scale(double s) {
scale = s; scale = s;
} }
@ -53,7 +56,7 @@ class Lockin {
} }
std::complex<double> update(double x) { std::complex<double> update(double x) {
std::complex<double> rotated; std::complex<double> rotated;
rotated = x*std::polar(scale, phase*2.0*M_PI/(double)UINT32_MAX); rotated = x*std::polar(scale, phase*2.0*M_PI/(double)PHASE_MAX);
phase -= ftw; // wraps on underflow phase -= ftw; // wraps on underflow
return lpf.update(rotated); return lpf.update(rotated);
} }