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gr_block Class Reference
[Signal Processing Blocks]

#include <gr_block.h>

Inheritance diagram for gr_block:

gr_keep_one_in_n gr_nop gr_simple_correlator gr_simple_framer gr_sync_block gr_add_cc gr_add_const_cc gr_add_const_ff gr_add_const_ii gr_add_const_sf gr_add_const_ss gr_add_ff gr_add_ii gr_add_ss gr_check_counting_s gr_check_lfsr_32k_s gr_complex_to_arg gr_complex_to_float gr_complex_to_imag gr_complex_to_mag gr_complex_to_real gr_divide_cc gr_divide_ff gr_divide_ii gr_divide_ss gr_fft_vcc gr_fft_vfc gr_file_descriptor_sink gr_file_descriptor_source gr_file_sink gr_file_source gr_float_to_complex gr_float_to_short gr_frequency_modulator_fc gr_head gr_hilbert_fc gr_iir_filter_ffd gr_lfsr_32k_source_s gr_multiply_cc gr_multiply_const_cc gr_multiply_const_ff gr_multiply_const_ii gr_multiply_const_ss gr_multiply_ff gr_multiply_ii gr_multiply_ss gr_noise_source_c gr_noise_source_f gr_noise_source_i gr_noise_source_s gr_null_sink gr_null_source gr_oscope_sink_x gr_quadrature_demod_cf gr_short_to_float gr_sig_source_c gr_sig_source_f gr_sig_source_i gr_sig_source_s gr_sub_cc gr_sub_ff gr_sub_ii gr_sub_ss gr_sync_decimator gr_sync_interpolator gr_vector_sink_b gr_vector_sink_c gr_vector_sink_f gr_vector_sink_i gr_vector_sink_s gr_vector_source_b gr_vector_source_c gr_vector_source_f gr_vector_source_i gr_vector_source_s List of all members.

Detailed Description

The abstract base class for all signal processing blocks.

Blocks have a set of input streams and output streams. The input_signature and output_signature define the number of input streams and output streams respectively, and the type of the data items in each stream.

Although blocks may consume data on each input stream at a different rate, all outputs streams must produce data at the same rate. That rate may be different from any of the input rates.

User derived blocks override two methods, forecast and general_work, to implement their signal processing behavior. forecast is called by the system scheduler to determine how many items are required on each input stream in order to produce a given number of output items.

general_work is called to perform the signal processing in the block. It reads the input items and writes the output items.


Public Member Functions

virtual ~gr_block ()
std::string name () const
gr_io_signature_sptr input_signature () const
gr_io_signature_sptr output_signature () const
long unique_id () const
virtual void forecast (int noutput_items, gr_vector_int &ninput_items_required)
 Estimate input requirements given output request.
virtual int general_work (int noutput_items, gr_vector_int &ninput_items, gr_vector_const_void_star &input_items, gr_vector_void_star &output_items)=0
 compute output items from input items
virtual bool check_topology (int ninputs, int noutputs)
 Confirm that ninputs and noutputs is an acceptable combination.
void set_output_multiple (int multiple)
 Constrain the noutput_items argument passed to forecast and general_work.
int output_multiple () const
void consume (int which_input, int how_many_items)
 Tell the scheduler how_many_items of input stream which_input were consumed.
void consume_each (int how_many_items)
 Tell the scheduler how_many_items were consumed on each input stream.
void set_relative_rate (double relative_rate)
 Set the approximate output rate / input rate.
double relative_rate () const
 return the approximate output rate / input rate
gr_block_detail_sptr detail () const
void set_detail (gr_block_detail_sptr detail)

Protected Member Functions

 gr_block (const std::string &name, gr_io_signature_sptr input_signature, gr_io_signature_sptr output_signature)
void set_input_signature (gr_io_signature_sptr iosig)
 may only be called during constructor
void set_output_signature (gr_io_signature_sptr iosig)
 may only be called during constructor


Constructor & Destructor Documentation

gr_block::~gr_block  )  [virtual]
 

gr_block::gr_block const std::string &  name,
gr_io_signature_sptr  input_signature,
gr_io_signature_sptr  output_signature
[protected]
 


Member Function Documentation

bool gr_block::check_topology int  ninputs,
int  noutputs
[virtual]
 

Confirm that ninputs and noutputs is an acceptable combination.

Parameters:
ninputs number of input streams connected
noutputs number of output streams connected
Returns:
true if this is a valid configuration for this block.
This function is called by the runtime system whenever the topology changes. Most classes do not need to override this. This check is in addition to the constraints specified by the input and output gr_io_signatures.

Reimplemented in gr_deinterleave, gr_interleave, and gr_oscope_sink_f.

void gr_block::consume int  which_input,
int  how_many_items
 

Tell the scheduler how_many_items of input stream which_input were consumed.

void gr_block::consume_each int  how_many_items  ) 
 

Tell the scheduler how_many_items were consumed on each input stream.

gr_block_detail_sptr gr_block::detail  )  const [inline]
 

void gr_block::forecast int  noutput_items,
gr_vector_int ninput_items_required
[virtual]
 

Estimate input requirements given output request.

Parameters:
noutput_items number of output items to produce
ninput_items_required number of input items required on each input stream
Given a request to product noutput_items, estimate the number of data items required on each input stream. The estimate doesn't have to be exact, but should be close.

Reimplemented in gr_sync_block, gr_sync_decimator, and gr_sync_interpolator.

virtual int gr_block::general_work int  noutput_items,
gr_vector_int ninput_items,
gr_vector_const_void_star input_items,
gr_vector_void_star output_items
[pure virtual]
 

compute output items from input items

Parameters:
noutput_items number of output items to write on each output stream
ninput_items number of input items available on each input stream
input_items vector of pointers to the input items, one entry per input stream
output_items vector of pointers to the output items, one entry per output stream
Returns:
number of items actually written to each output stream, or -1 on EOF. It is OK to return a value less than noutput_items. -1 <= return value <= noutput_items
general_work must call consume or consume_each to indicate how many items were consumed on each input stream.

Implemented in gr_keep_one_in_n, gr_nop, gr_simple_correlator, gr_simple_framer, gr_sync_block, gr_sync_decimator, and gr_sync_interpolator.

gr_io_signature_sptr gr_block::input_signature  )  const [inline]
 

std::string gr_block::name  )  const [inline]
 

int gr_block::output_multiple  )  const [inline]
 

gr_io_signature_sptr gr_block::output_signature  )  const [inline]
 

double gr_block::relative_rate  )  const [inline]
 

return the approximate output rate / input rate

void gr_block::set_detail gr_block_detail_sptr  detail  )  [inline]
 

void gr_block::set_input_signature gr_io_signature_sptr  iosig  )  [inline, protected]
 

may only be called during constructor

void gr_block::set_output_multiple int  multiple  ) 
 

Constrain the noutput_items argument passed to forecast and general_work.

set_output_multiple causes the scheduler to ensure that the noutput_items argument passed to forecast and general_work will be an integer multiple of

Parameters:
multiple The default value of output multiple is 1.

void gr_block::set_output_signature gr_io_signature_sptr  iosig  )  [inline, protected]
 

may only be called during constructor

void gr_block::set_relative_rate double  relative_rate  ) 
 

Set the approximate output rate / input rate.

Provide a hint to the buffer allocator and scheduler. The default relative_rate is 1.0

decimators have relative_rates < 1.0 interpolators have relative_rates > 1.0

long gr_block::unique_id  )  const [inline]
 


The documentation for this class was generated from the following files:
Generated on Tue Mar 29 23:45:36 2005 for GNU Radio 2.x by  doxygen 1.4.2