In several places we have a real valued signal x(t) that needs to be converted to an analytic signal g(t) such that real(g(t)) == x(t) and imag(g(t)) = shift_by_90degrees(x(t));. More...

#include <HilbertTransformer.hxx>

Inheritance diagram for SoDa::HilbertTransformer:

Public Member Functions
unsigned int	applyIQ (std::vector< std::complex< float > > &inbuf, std::vector< std::complex< float > > &outbuf, float gain=1.0)
	Perform a hilbert transform on the QUADRATURE signal in the input buffer.
unsigned int	apply (std::vector< std::complex< float > > &inbuf, std::vector< std::complex< float > > &outbuf, bool pos_sided=true, float gain=1.0)
	Perform a hilbert transform on the INPHASE signal in the input buffer.
unsigned int	apply (std::vector< float > &inbuf, std::vector< std::complex< float > > &outbuf, bool pos_sided=true, float gain=1.0)
	Perform a hilbert transform on the signal in the floating point input buffer.
std::ostream &	dump (std::ostream &os)
Public Member Functions inherited from SoDa::Base
	Base (const std::string &oname)
	The constructor – pass a name for the object.
void	registerSelf (BasePtr ptr)
std::string &	getObjName ()
	get the name of this object
BasePtr	findSoDaObject (const std::string &oname)
	find a SoDa Object by name.
double	getTime ()
	Get a time stamp in nS resolution that monotonically increases and that is very inexpensive (typically < 100nS).
BasePtr	getSelfPtr ()
	get a pointer to myself.

Static Public Member Functions
static HilbertTransformerPtr	make (unsigned int inout_buffer_length, unsigned int filter_length=256)

Protected Member Functions
	HilbertTransformer (unsigned int inout_buffer_length, unsigned int filter_length=256)
	constructor – build a Hilbert Transformer

Private Attributes
unsigned int	M
	these are the salient dimensions for this Overlap/Save widget (for terminology, see Lyons pages 719ff
unsigned int	Q
	the filter length
unsigned int	N
	the total length of the transform N > (M + Q-1)
std::complex< float > *	fft_I_input
std::complex< float > *	fft_Q_input
std::complex< float > *	fft_I_output
std::complex< float > *	fft_Q_output
std::complex< float > *	ifft_I_input
std::complex< float > *	ifft_Q_input
std::complex< float > *	ifft_I_output
std::complex< float > *	ifft_Q_output
fftwf_plan	forward_I_plan
fftwf_plan	forward_Q_plan
fftwf_plan	backward_I_plan
fftwf_plan	backward_Q_plan
std::complex< float > *	HTu_filter
	The DFT image of the hilbert transform – upper sideband.
std::complex< float > *	HTl_filter
	The DFT image of the hilbert transform – lower sideband.
std::complex< float > *	Pass_U_filter
	The DFT image of a Q/2 delay transform – used in USB.
std::complex< float > *	Pass_L_filter
	The DFT image of a Q/2 delay transform – used in LSB.
float	passthrough_gain
	the gain of the direct passthrough path.
float	H_transform_gain
	the gain of the Hilbert Transform path

Detailed Description

In several places we have a real valued signal x(t) that needs to be converted to an analytic signal g(t) such that real(g(t)) == x(t) and imag(g(t)) = shift_by_90degrees(x(t));.

HilbertTransformer provides the apply functions to convert x(t) as a float or complex<float>. Hilbert Transformer also provides a function (applyIQ) to convert a complex x(t) into g(t) such that real(g(t)) = real(x(t + tau)) and imag(g(t)) = shift_by_90deg(imag(x(t + tau)))

Definition at line 56 of file HilbertTransformer.hxx.

Constructor & Destructor Documentation

◆ HilbertTransformer()

SoDa::HilbertTransformer::HilbertTransformer	(	unsigned int	inout_buffer_length,
		unsigned int	filter_length = 256 )

protected

constructor – build a Hilbert Transformer

Parameters

inout_buffer_length	the length of the input and output buffers
filter_length	the minimum length of the hilbert transform impulse response

Referenced by make().

Member Function Documentation

◆ apply() [1/2]

unsigned int SoDa::HilbertTransformer::apply	(	std::vector< float > &	inbuf,
		std::vector< std::complex< float > > &	outbuf,
		bool	pos_sided = true,
		float	gain = 1.0 )

Perform a hilbert transform on the signal in the floating point input buffer.

Parameters

inbuf	input buffer of real (float) samples
outbuf	complex output buffer real is input delayed, and imag is Hilbert(input)
pos_sided	if true, swap I and Q outputs
gain	factor to apply to output buffer.

Returns: M – length of input buffer.

◆ apply() [2/2]

unsigned int SoDa::HilbertTransformer::apply	(	std::vector< std::complex< float > > &	inbuf,
		std::vector< std::complex< float > > &	outbuf,
		bool	pos_sided = true,
		float	gain = 1.0 )

Perform a hilbert transform on the INPHASE signal in the input buffer.

It is assumed that the QUADRATURE signal is zero, if not, the result is broken.

Parameters

inbuf	complex input buffer of I (real) and Q (imag) samples
outbuf	complex output buffer real is input.real delayed, and imag is Hilbert(input.real)
pos_sided	if true, swap I and Q outputs
gain	factor to apply to output buffer.

Returns: M – length of input buffer.

◆ applyIQ()

unsigned int SoDa::HilbertTransformer::applyIQ	(	std::vector< std::complex< float > > &	inbuf,
		std::vector< std::complex< float > > &	outbuf,
		float	gain = 1.0 )

Perform a hilbert transform on the QUADRATURE signal in the input buffer.

Pass the Inphase signal through a delay filter that matches the hilbert transform

Parameters

inbuf	complex input buffer of I (real) and Q (imag) samples
outbuf	complex output buffer real is input.real delayed, and imag is Hilbert(input.imag)
gain	factor to apply to output buffer.

Returns: M – length of input buffer.

◆ dump()

std::ostream & SoDa::HilbertTransformer::dump ( std::ostream & os )

◆ make()

HilbertTransformerPtr SoDa::HilbertTransformer::make	(	unsigned int	inout_buffer_length,
		unsigned int	filter_length = 256 )

inlinestatic

Definition at line 66 of file HilbertTransformer.hxx.

References HilbertTransformer().

Member Data Documentation

◆ backward_I_plan

fftwf_plan SoDa::HilbertTransformer::backward_I_plan

private

Definition at line 131 of file HilbertTransformer.hxx.

◆ backward_Q_plan

fftwf_plan SoDa::HilbertTransformer::backward_Q_plan

private

Definition at line 131 of file HilbertTransformer.hxx.

◆ fft_I_input

std::complex<float>* SoDa::HilbertTransformer::fft_I_input

private

Definition at line 124 of file HilbertTransformer.hxx.

◆ fft_I_output

std::complex<float>* SoDa::HilbertTransformer::fft_I_output

private

Definition at line 125 of file HilbertTransformer.hxx.

◆ fft_Q_input

std::complex<float> * SoDa::HilbertTransformer::fft_Q_input

private

Definition at line 124 of file HilbertTransformer.hxx.

◆ fft_Q_output

std::complex<float> * SoDa::HilbertTransformer::fft_Q_output

private

Definition at line 125 of file HilbertTransformer.hxx.

◆ forward_I_plan

fftwf_plan SoDa::HilbertTransformer::forward_I_plan

private

Definition at line 131 of file HilbertTransformer.hxx.

◆ forward_Q_plan

fftwf_plan SoDa::HilbertTransformer::forward_Q_plan

private

Definition at line 131 of file HilbertTransformer.hxx.

◆ H_transform_gain

float SoDa::HilbertTransformer::H_transform_gain

private

the gain of the Hilbert Transform path

Definition at line 139 of file HilbertTransformer.hxx.

◆ HTl_filter

std::complex<float>* SoDa::HilbertTransformer::HTl_filter

private

The DFT image of the hilbert transform – lower sideband.

Definition at line 134 of file HilbertTransformer.hxx.

◆ HTu_filter

std::complex<float>* SoDa::HilbertTransformer::HTu_filter

private

The DFT image of the hilbert transform – upper sideband.

Definition at line 133 of file HilbertTransformer.hxx.

◆ ifft_I_input

std::complex<float>* SoDa::HilbertTransformer::ifft_I_input

private

Definition at line 126 of file HilbertTransformer.hxx.

◆ ifft_I_output

std::complex<float>* SoDa::HilbertTransformer::ifft_I_output

private

Definition at line 127 of file HilbertTransformer.hxx.

◆ ifft_Q_input

std::complex<float> * SoDa::HilbertTransformer::ifft_Q_input

private

Definition at line 126 of file HilbertTransformer.hxx.

◆ ifft_Q_output

std::complex<float> * SoDa::HilbertTransformer::ifft_Q_output

private

Definition at line 127 of file HilbertTransformer.hxx.

◆ M

unsigned int SoDa::HilbertTransformer::M

private

these are the salient dimensions for this Overlap/Save widget (for terminology, see Lyons pages 719ff

the input buffer length;

Definition at line 119 of file HilbertTransformer.hxx.

◆ N

unsigned int SoDa::HilbertTransformer::N

private

the total length of the transform N > (M + Q-1)

Definition at line 121 of file HilbertTransformer.hxx.

◆ Pass_L_filter

std::complex<float>* SoDa::HilbertTransformer::Pass_L_filter

private

The DFT image of a Q/2 delay transform – used in LSB.

Definition at line 136 of file HilbertTransformer.hxx.

◆ Pass_U_filter

std::complex<float>* SoDa::HilbertTransformer::Pass_U_filter

private

The DFT image of a Q/2 delay transform – used in USB.

Definition at line 135 of file HilbertTransformer.hxx.

◆ passthrough_gain

float SoDa::HilbertTransformer::passthrough_gain

private

the gain of the direct passthrough path.

Definition at line 138 of file HilbertTransformer.hxx.

◆ Q

unsigned int SoDa::HilbertTransformer::Q

private

the filter length

Definition at line 120 of file HilbertTransformer.hxx.

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

src/HilbertTransformer.hxx

Public Member Functions

Static Public Member Functions

Protected Member Functions

Private Attributes

Detailed Description

Constructor & Destructor Documentation

◆ HilbertTransformer()

Member Function Documentation

◆ apply() [1/2]

◆ apply() [2/2]

◆ applyIQ()

◆ dump()

◆ make()

Member Data Documentation

◆ backward_I_plan

◆ backward_Q_plan

◆ fft_I_input

◆ fft_I_output

◆ fft_Q_input

◆ fft_Q_output

◆ forward_I_plan

◆ forward_Q_plan

◆ H_transform_gain

◆ HTl_filter

◆ HTu_filter

◆ ifft_I_input

◆ ifft_I_output

◆ ifft_Q_input

◆ ifft_Q_output

◆ M

◆ N

◆ Pass_L_filter

◆ Pass_U_filter

◆ passthrough_gain

◆ Q