GNU Radio Manual and C++ API Reference  3.7.9.2
The Free & Open Software Radio Ecosystem
 All Classes Namespaces Files Functions Variables Typedefs Enumerations Enumerator Friends Macros Modules Pages
atsci_equalizer_nop Class Reference

#include <gnuradio/atsc/equalizer_nop_impl.h>

Public Member Functions

 atsci_equalizer_nop ()
 
virtual ~atsci_equalizer_nop ()
 
virtual void reset ()
 reset state (e.g., on channel change) More...
 
virtual int ntaps () const
 how much history the input data stream requires. More...
 
virtual int npretaps () const
 how many taps are "in the future". More...
 
- Public Member Functions inherited from atsci_equalizer
 atsci_equalizer ()
 
virtual ~atsci_equalizer ()
 
virtual std::vector< double > taps ()
 
virtual void filter (const float *input_samples, const atsc::syminfo *input_tags, float *output_samples, int nsamples)
 produce nsamples of output from given inputs and tags More...
 

Protected Member Functions

virtual void filter_normal (const float *input_samples, float *output_samples, int nsamples)
 
virtual void filter_data_seg_sync (const float *input_samples, float *output_samples, int nsamples, int offset)
 
virtual void filter_field_sync (const float *input_samples, float *output_samples, int nsamples, int offset, int which_field)
 

Constructor & Destructor Documentation

atsci_equalizer_nop::atsci_equalizer_nop ( )
virtual atsci_equalizer_nop::~atsci_equalizer_nop ( )
virtual

Member Function Documentation

virtual void atsci_equalizer_nop::filter_data_seg_sync ( const float *  input_samples,
float *  output_samples,
int  nsamples,
int  offset 
)
protectedvirtual

Input range is known to consist of only a data segment sync or a portion of a data segment sync. nsamples will be in [1,4]. offset will be in [0,3]. offset is the offset of the input from the beginning of the data segment sync pattern.

input_samples has (nsamples + ntaps() - 1) valid entries. input_samples[0] .. input_samples[nsamples - 1 + ntaps() - 1] may be referenced to compute the output values.

Implements atsci_equalizer.

virtual void atsci_equalizer_nop::filter_field_sync ( const float *  input_samples,
float *  output_samples,
int  nsamples,
int  offset,
int  which_field 
)
protectedvirtual

Input range is known to consist of only a field sync segment or a portion of a field sync segment. nsamples will be in [1,832]. offset will be in [0,831]. offset is the offset of the input from the beginning of the data segment sync pattern. We consider the 4 symbols of the immediately preceding data segment sync to be the first symbols of the field sync segment. which_field is in [0,1] and specifies which field (duh).

input_samples has (nsamples + ntaps() - 1) valid entries. input_samples[0] .. input_samples[nsamples - 1 + ntaps() - 1] may be referenced to compute the output values.

Implements atsci_equalizer.

virtual void atsci_equalizer_nop::filter_normal ( const float *  input_samples,
float *  output_samples,
int  nsamples 
)
protectedvirtual

Input range is known NOT TO CONTAIN data segment syncs or field syncs. This should be the fast path. In the non decicion directed case, this just runs the input through the filter without adapting it.

input_samples has (nsamples + ntaps() - 1) valid entries. input_samples[0] .. input_samples[nsamples - 1 + ntaps() - 1] may be referenced to compute the output values.

Implements atsci_equalizer.

virtual int atsci_equalizer_nop::npretaps ( ) const
virtual

how many taps are "in the future".

This allows us to handle what the ATSC folks call "pre-ghosts". What it really does is allow the caller to jack with the offset between the tags and the data so that everything magically works out.

npretaps () must return a value between 0 and ntaps() - 1.

If npretaps () returns 0, this means that the equalizer will only handle multipath "in the past." I suspect that a good value would be something like 15% - 20% of ntaps ().

Implements atsci_equalizer.

virtual int atsci_equalizer_nop::ntaps ( ) const
virtual

how much history the input data stream requires.

This must return a value >= 1. Think of this as the number of samples you need to look at to compute a single output sample.

Implements atsci_equalizer.

virtual void atsci_equalizer_nop::reset ( )
virtual

reset state (e.g., on channel change)

Note, subclasses must invoke the superclass's method too!

Reimplemented from atsci_equalizer.


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