Digital Filter Design

Classes
class	gr_firdes
	Finite Impulse Response (FIR) filter design functions. More...
Functions
GR_CORE_API std::vector< double >	gr_remez (int order, const std::vector< double > &bands, const std::vector< double > &ampl, const std::vector< double > &error_weight, const std::string filter_type="bandpass", int grid_density=16) throw (std::runtime_error)
	Parks-McClellan FIR filter design.

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Function Documentation

GR_CORE_API std::vector<double> gr_remez	(	int	order,
		const std::vector< double > &	bands,
		const std::vector< double > &	ampl,
		const std::vector< double > &	error_weight,
		const std::string	filter_type = "bandpass",
		int	grid_density = 16
	)		throw (std::runtime_error)

Parks-McClellan FIR filter design.

Calculates the optimal (in the Chebyshev/minimax sense) FIR filter inpulse reponse given a set of band edges, the desired reponse on those bands, and the weight given to the error in those bands.

Parameters:

order	filter order (number of taps in the returned filter - 1)
bands	frequency at the band edges [ b1 e1 b2 e2 b3 e3 ...]
ampl	desired amplitude at the band edges [ a(b1) a(e1) a(b2) a(e2) ...]
error_weight	weighting applied to each band (usually 1)
filter_type	one of "bandpass", "hilbert" or "differentiator"
grid_density	determines how accurately the filter will be constructed. \ The minimum value is 16; higher values are slower to compute.

Frequency is in the range [0, 1], with 1 being the Nyquist frequency (Fs/2)

Returns:

vector of computed taps

Exceptions:

std::runtime_error

if args are invalid or calculation fails to converge.