Digital Filter Design

Classes
class	gr::filter::firdes
	Finite Impulse Response (FIR) filter design functions. More...

Functions
FILTER_API std::vector< double >	gr::filter::pm_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 using Remez algorithm. More...

Detailed Description

Function Documentation

FILTER_API std::vector<double> gr::filter::pm_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 using Remez algorithm.

Calculates the optimal (in the Chebyshev/minimax sense) FIR filter inpulse response given a set of band edges, the desired response 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.