js8::FrequencyTracker Class Reference

Lightweight PLL/Kalman-style tracker for residual frequency offset. More...

#include <FrequencyTracker.h>

Public Member Functions
void	reset (double initial_hz, double sample_rate_hz, double alpha=0.15, double max_step_hz=0.3, double max_error_hz=5.0)
	Initialize or reconfigure the tracker.
void	disable ()
	Disable the tracker (subsequent apply() calls become no-ops).
bool	enabled () const noexcept
	Whether the tracker is enabled.
double	currentHz () const noexcept
	Current estimated residual frequency.
double	averageStepHz () const noexcept
	Average step size applied by the tracker (Hz).
void	apply (std::complex< float > *data, int count) const
	Rotate an array of complex samples by the tracked frequency.
void	update (double residual_hz, double weight=1.0)
	Update the tracker estimate using a measured residual.

Detailed Description

Lightweight PLL/Kalman-style tracker for residual frequency offset.

Initialized with coarse estimates and sample rate; apply() rotates samples by the tracked offset, update() nudges the estimate using pilot residuals. Used inside the JS8 decode loop per candidate frame.

Member Function Documentation

apply()

void js8::FrequencyTracker::apply	(	std::complex< float > *	data,
		int	count ) const

Rotate an array of complex samples by the tracked frequency.

Apply frequency correction to the provided data.

Parameters

data	Pointer to complex input/output samples to be rotated in-place.
count	Number of complex samples.
data	Pointer to complex float data
count	Number of samples

averageStepHz()

double js8::FrequencyTracker::averageStepHz ( ) const

nodiscardnoexcept

Average step size applied by the tracker (Hz).

Get the average step size in Hz.

Returns

Average per-update frequency step in Hz.

double

currentHz()

double js8::FrequencyTracker::currentHz ( ) const

nodiscardnoexcept

Current estimated residual frequency.

Get the current frequency estimate in Hz.

Returns

Frequency estimate in Hz.

double

disable()

void js8::FrequencyTracker::disable

(

)

Disable the tracker (subsequent apply() calls become no-ops).

Disable the FrequencyTracker.

enabled()

bool js8::FrequencyTracker::enabled ( ) const

nodiscardnoexcept

Whether the tracker is enabled.

Check if the FrequencyTracker is enabled.

Returns

true when enabled, false when disabled.

true

false

reset()

void js8::FrequencyTracker::reset	(	double	initial_hz,
		double	sample_rate_hz,
		double	alpha = 0.15,
		double	max_step_hz = 0.3,
		double	max_error_hz = 5.0 )

Initialize or reconfigure the tracker.

Reset the FrequencyTracker with initial parameters.

Parameters

initial_hz	Initial frequency estimate in Hz.
sample_rate_hz	Sample rate in Hz for the input data.
alpha	Smoothing coefficient for the estimator (default 0.15).
max_step_hz	Maximum allowed step change per update (Hz).
max_error_hz	Maximum tolerated error before aggressive limiting.
initial_hz	Initial frequency estimate in Hz
sample_rate_hz	Sample rate in Hz
alpha	Smoothing factor
max_step_hz	Maximum step size in Hz
max_error_hz	Maximum allowable error in Hz

update()

void js8::FrequencyTracker::update	(	double	residual_hz,
		double	weight = 1.0 )

Update the tracker estimate using a measured residual.

Update the FrequencyTracker with a new residual frequency measurement.

Parameters

residual_hz	Measured residual frequency (Hz) to incorporate.
weight	Weighting applied to this update (default 1.0).
residual_hz	Residual frequency in Hz
weight	Weighting factor

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The documentation for this class was generated from the following files:

• JS8_Mode/FrequencyTracker.h
• JS8_Mode/FrequencyTracker.cpp