gr::digital::decision_feedback_equalizer Class Reference

Decision Feedback Equalizer. More...

#include <gnuradio/digital/decision_feedback_equalizer.h>

Public Types
typedef std::shared_ptr< decision_feedback_equalizer >	sptr
Public Types inherited from gr::block
enum	work_return_t { WORK_CALLED_PRODUCE = -2 , WORK_DONE = -1 }
	Magic return values from general_work. More...
enum	tag_propagation_policy_t { TPP_DONT = 0 , TPP_ALL_TO_ALL = 1 , TPP_ONE_TO_ONE = 2 , TPP_CUSTOM = 3 }
	enum to represent different tag propagation policies. More...

Public Member Functions
virtual void	set_taps (const std::vector< gr_complex > &taps)=0
virtual std::vector< gr_complex >	taps () const =0
virtual int	equalize (const gr_complex *input_samples, gr_complex *output_symbols, unsigned int num_inputs, unsigned int max_num_outputs, std::vector< unsigned int > training_start_samples=std::vector< unsigned int >(0), bool history_included=false, gr_complex *taps=nullptr, unsigned short *state=nullptr)=0
	Public "work" function - equalize a block of input samples. More...
Public Member Functions inherited from gr::sync_decimator
unsigned	decimation () const
void	set_decimation (unsigned decimation)
void	forecast (int noutput_items, gr_vector_int &ninput_items_required) override
	Estimate input requirements given output request. More...
int	general_work (int noutput_items, gr_vector_int &ninput_items, gr_vector_const_void_star &input_items, gr_vector_void_star &output_items) override
	compute output items from input items More...
int	fixed_rate_ninput_to_noutput (int ninput) override
	Given ninput samples, return number of output samples that will be produced. N.B. this is only defined if fixed_rate returns true. Generally speaking, you don't need to override this. More...
int	fixed_rate_noutput_to_ninput (int noutput) override
	Given noutput samples, return number of input samples required to produce noutput. N.B. this is only defined if fixed_rate returns true. Generally speaking, you don't need to override this. More...
Public Member Functions inherited from gr::sync_block
virtual int	work (int noutput_items, gr_vector_const_void_star &input_items, gr_vector_void_star &output_items)=0
	just like gr::block::general_work, only this arranges to call consume_each for you More...
Public Member Functions inherited from gr::block
	~block () override
unsigned	history () const
void	set_history (unsigned history)
void	declare_sample_delay (int which, unsigned delay)
void	declare_sample_delay (unsigned delay)
unsigned	sample_delay (int which) const
bool	fixed_rate () const
	Return true if this block has a fixed input to output rate. More...
virtual bool	start ()
	Called to enable drivers, etc for i/o devices. More...
virtual bool	stop ()
	Called to disable drivers, etc for i/o devices. More...
void	set_output_multiple (int multiple)
	Constrain the noutput_items argument passed to forecast and general_work. More...
int	output_multiple () const
bool	output_multiple_set () const
void	set_alignment (int multiple)
	Constrains buffers to work on a set item alignment (for SIMD) More...
int	alignment () const
void	set_unaligned (int na)
int	unaligned () const
void	set_is_unaligned (bool u)
bool	is_unaligned () const
void	consume (int which_input, int how_many_items)
	Tell the scheduler how_many_items of input stream which_input were consumed. More...
void	consume_each (int how_many_items)
	Tell the scheduler how_many_items were consumed on each input stream. More...
void	produce (int which_output, int how_many_items)
	Tell the scheduler how_many_items were produced on output stream which_output. More...
void	set_relative_rate (double relative_rate)
	Set the approximate output rate / input rate. More...
void	set_inverse_relative_rate (double inverse_relative_rate)
	Set the approximate output rate / input rate using its reciprocal. More...
void	set_relative_rate (uint64_t interpolation, uint64_t decimation)
	Set the approximate output rate / input rate as an integer ratio. More...
double	relative_rate () const
	return the approximate output rate / input rate More...
uint64_t	relative_rate_i () const
	return the numerator, or interpolation rate, of the approximate output rate / input rate More...
uint64_t	relative_rate_d () const
	return the denominator, or decimation rate, of the approximate output rate / input rate More...
mpq_class &	mp_relative_rate ()
	return a reference to the multiple precision rational representation of the approximate output rate / input rate More...
uint64_t	nitems_read (unsigned int which_input)
	Return the number of items read on input stream which_input. More...
uint64_t	nitems_written (unsigned int which_output)
	Return the number of items written on output stream which_output. More...
tag_propagation_policy_t	tag_propagation_policy ()
	Asks for the policy used by the scheduler to moved tags downstream. More...
void	set_tag_propagation_policy (tag_propagation_policy_t p)
	Set the policy by the scheduler to determine how tags are moved downstream. More...
int	min_noutput_items () const
	Return the minimum number of output items this block can produce during a call to work. More...
void	set_min_noutput_items (int m)
	Set the minimum number of output items this block can produce during a call to work. More...
int	max_noutput_items ()
	Return the maximum number of output items this block will handle during a call to work. More...
void	set_max_noutput_items (int m)
	Set the maximum number of output items this block will handle during a call to work. More...
void	unset_max_noutput_items ()
	Clear the switch for using the max_noutput_items value of this block. More...
bool	is_set_max_noutput_items ()
	Ask the block if the flag is or is not set to use the internal value of max_noutput_items during a call to work. More...
void	expand_minmax_buffer (int port)
long	max_output_buffer (size_t i)
	Returns max buffer size on output port i. More...
void	set_max_output_buffer (long max_output_buffer)
	Request limit on max buffer size on all output ports. More...
void	set_max_output_buffer (int port, long max_output_buffer)
	Request limit on max buffer size on output port port. More...
long	min_output_buffer (size_t i)
	Returns min buffer size on output port i. More...
void	set_min_output_buffer (long min_output_buffer)
	Request limit on the minimum buffer size on all output ports. More...
void	set_min_output_buffer (int port, long min_output_buffer)
	Request limit on min buffer size on output port port. More...
void	set_blkd_input_timer_value (unsigned int timer_value_ms)
	DEPRECATED Configure the timer set when input is blocked port. More...
unsigned int	blkd_input_timer_value ()
	DEPRECATED Returns timer value set when input is blocked. More...
void	allocate_detail (int ninputs, int noutputs, const std::vector< int > &downstream_max_nitems_vec, const std::vector< uint64_t > &downstream_lcm_nitems_vec, const std::vector< uint32_t > &downstream_max_out_mult_vec)
	Allocate the block_detail and necessary output buffers for this block. More...
buffer_sptr	replace_buffer (size_t src_port, size_t dst_port, block_sptr block_owner)
	Replace the block's buffer with a new one owned by the block_owner parameter. More...
float	pc_noutput_items ()
	Gets instantaneous noutput_items performance counter. More...
float	pc_noutput_items_avg ()
	Gets average noutput_items performance counter. More...
float	pc_noutput_items_var ()
	Gets variance of noutput_items performance counter. More...
float	pc_nproduced ()
	Gets instantaneous num items produced performance counter. More...
float	pc_nproduced_avg ()
	Gets average num items produced performance counter. More...
float	pc_nproduced_var ()
	Gets variance of num items produced performance counter. More...
float	pc_input_buffers_full (int which)
	Gets instantaneous fullness of which input buffer. More...
float	pc_input_buffers_full_avg (int which)
	Gets average fullness of which input buffer. More...
float	pc_input_buffers_full_var (int which)
	Gets variance of fullness of which input buffer. More...
std::vector< float >	pc_input_buffers_full ()
	Gets instantaneous fullness of all input buffers. More...
std::vector< float >	pc_input_buffers_full_avg ()
	Gets average fullness of all input buffers. More...
std::vector< float >	pc_input_buffers_full_var ()
	Gets variance of fullness of all input buffers. More...
float	pc_output_buffers_full (int which)
	Gets instantaneous fullness of which output buffer. More...
float	pc_output_buffers_full_avg (int which)
	Gets average fullness of which output buffer. More...
float	pc_output_buffers_full_var (int which)
	Gets variance of fullness of which output buffer. More...
std::vector< float >	pc_output_buffers_full ()
	Gets instantaneous fullness of all output buffers. More...
std::vector< float >	pc_output_buffers_full_avg ()
	Gets average fullness of all output buffers. More...
std::vector< float >	pc_output_buffers_full_var ()
	Gets variance of fullness of all output buffers. More...
float	pc_work_time ()
	Gets instantaneous clock cycles spent in work. More...
float	pc_work_time_avg ()
	Gets average clock cycles spent in work. More...
float	pc_work_time_var ()
	Gets average clock cycles spent in work. More...
float	pc_work_time_total ()
	Gets total clock cycles spent in work. More...
float	pc_throughput_avg ()
	Gets average throughput. More...
void	reset_perf_counters ()
	Resets the performance counters. More...
void	setup_pc_rpc ()
	Sets up export of perf. counters to ControlPort. Only called by the scheduler. More...
bool	is_pc_rpc_set () const
	Checks if this block is already exporting perf. counters to ControlPort. More...
void	no_pc_rpc ()
	If the block calls this in its constructor, it's perf. counters will not be exported. More...
void	set_processor_affinity (const std::vector< int > &mask) override
	Set the thread's affinity to processor core n. More...
void	unset_processor_affinity () override
	Remove processor affinity to a specific core. More...
std::vector< int >	processor_affinity () override
	Get the current processor affinity. More...
int	active_thread_priority ()
	Get the current thread priority in use. More...
int	thread_priority ()
	Get the current thread priority stored. More...
int	set_thread_priority (int priority)
	Set the current thread priority. More...
bool	update_rate () const
void	system_handler (pmt::pmt_t msg)
	the system message handler More...
void	set_log_level (const std::string &level) override
	Set the logger's output level. More...
std::string	log_level () override
	Get the logger's output level. More...
bool	finished ()
	returns true when execution has completed due to a message connection More...
block_detail_sptr	detail () const
void	set_detail (block_detail_sptr detail)
void	notify_msg_neighbors ()
	Tell msg neighbors we are finished. More...
void	clear_finished ()
	Make sure we don't think we are finished. More...
std::string	identifier () const
Public Member Functions inherited from gr::basic_block
pmt::pmt_t	message_subscribers (pmt::pmt_t port)
	~basic_block () override
long	unique_id () const
long	symbolic_id () const
std::string	name () const
std::string	symbol_name () const
std::string	identifier () const
gr::io_signature::sptr	input_signature () const
gr::io_signature::sptr	output_signature () const
basic_block_sptr	to_basic_block ()
bool	alias_set () const
std::string	alias () const
pmt::pmt_t	alias_pmt () const
void	set_block_alias (std::string name)
void	message_port_register_in (pmt::pmt_t port_id)
void	message_port_register_out (pmt::pmt_t port_id)
void	message_port_pub (pmt::pmt_t port_id, pmt::pmt_t msg)
void	message_port_sub (pmt::pmt_t port_id, pmt::pmt_t target)
void	message_port_unsub (pmt::pmt_t port_id, pmt::pmt_t target)
virtual bool	message_port_is_hier (pmt::pmt_t port_id)
virtual bool	message_port_is_hier_in (pmt::pmt_t port_id)
virtual bool	message_port_is_hier_out (pmt::pmt_t port_id)
pmt::pmt_t	message_ports_in ()
	Get input message port names. More...
pmt::pmt_t	message_ports_out ()
	Get output message port names. More...
void	_post (pmt::pmt_t which_port, pmt::pmt_t msg)
bool	empty_p (pmt::pmt_t which_port)
	is the queue empty? More...
bool	empty_p ()
bool	empty_handled_p (pmt::pmt_t which_port)
	are all msg ports with handlers empty? More...
bool	empty_handled_p ()
size_t	nmsgs (pmt::pmt_t which_port)
	How many messages in the queue? More...
void	insert_tail (pmt::pmt_t which_port, pmt::pmt_t msg)
pmt::pmt_t	delete_head_nowait (pmt::pmt_t which_port)
msg_queue_t::iterator	get_iterator (pmt::pmt_t which_port)
void	erase_msg (pmt::pmt_t which_port, msg_queue_t::iterator it)
virtual bool	has_msg_port (pmt::pmt_t which_port)
const msg_queue_map_t &	get_msg_map (void) const
virtual void	setup_rpc ()
	Set up the RPC registered variables. More...
bool	is_rpc_set ()
	Ask if this block has been registered to the RPC. More...
void	rpc_set ()
	When the block is registered with the RPC, set this. More...
virtual bool	check_topology (int ninputs, int noutputs)
	Confirm that ninputs and noutputs is an acceptable combination. More...
template<typename T >
void	set_msg_handler (pmt::pmt_t which_port, T msg_handler)
	Set the callback that is fired when messages are available. More...
Public Member Functions inherited from gr::msg_accepter
	msg_accepter ()
	~msg_accepter () override
void	post (pmt::pmt_t which_port, pmt::pmt_t msg) override
	send msg to msg_accepter on port which_port More...
Public Member Functions inherited from gr::messages::msg_accepter
	msg_accepter ()

Static Public Member Functions
static sptr	make (unsigned num_taps_forward, unsigned num_taps_feedback, unsigned sps, adaptive_algorithm_sptr alg, bool adapt_after_training=true, std::vector< gr_complex > training_sequence=std::vector< gr_complex >(), const std::string &training_start_tag="")
	Return a shared_ptr to a new instance of gr::digital::decision_feedback_equalizer. More...

Additional Inherited Members
Protected Types inherited from gr::basic_block
enum	vcolor { WHITE , GREY , BLACK }
Protected Member Functions inherited from gr::sync_decimator
	sync_decimator (void)
	sync_decimator (const std::string &name, gr::io_signature::sptr input_signature, gr::io_signature::sptr output_signature, unsigned decimation)
Protected Member Functions inherited from gr::sync_block
	sync_block (void)
	sync_block (const std::string &name, gr::io_signature::sptr input_signature, gr::io_signature::sptr output_signature)
Protected Member Functions inherited from gr::block
	block (void)
	block (const std::string &name, gr::io_signature::sptr input_signature, gr::io_signature::sptr output_signature)
void	set_fixed_rate (bool fixed_rate)
void	add_item_tag (unsigned int which_output, uint64_t abs_offset, const pmt::pmt_t &key, const pmt::pmt_t &value, const pmt::pmt_t &srcid=pmt::PMT_F)
	Adds a new tag onto the given output buffer. More...
void	add_item_tag (unsigned int which_output, const tag_t &tag)
	Adds a new tag onto the given output buffer. More...
void	remove_item_tag (unsigned int which_input, uint64_t abs_offset, const pmt::pmt_t &key, const pmt::pmt_t &value, const pmt::pmt_t &srcid=pmt::PMT_F)
	DEPRECATED. Will be removed in 3.8. More...
void	remove_item_tag (unsigned int which_input, const tag_t &tag)
	DEPRECATED. Will be removed in 3.8. More...
void	get_tags_in_range (std::vector< tag_t > &v, unsigned int which_input, uint64_t abs_start, uint64_t abs_end)
	Given a [start,end), returns a vector of all tags in the range. More...
void	get_tags_in_range (std::vector< tag_t > &v, unsigned int which_input, uint64_t abs_start, uint64_t abs_end, const pmt::pmt_t &key)
	Given a [start,end), returns a vector of all tags in the range with a given key. More...
void	get_tags_in_window (std::vector< tag_t > &v, unsigned int which_input, uint64_t rel_start, uint64_t rel_end)
	Gets all tags within the relative window of the current call to work. More...
void	get_tags_in_window (std::vector< tag_t > &v, unsigned int which_input, uint64_t rel_start, uint64_t rel_end, const pmt::pmt_t &key)
	Operates like gr::block::get_tags_in_window with the ability to only return tags with the specified key. More...
void	enable_update_rate (bool en)
buffer_sptr	allocate_buffer (size_t port, int downstream_max_nitems, uint64_t downstream_lcm_nitems, uint32_t downstream_max_out_mult)
	Allocate a buffer for the given output port of this block. Note that the downstream max number of items must be passed in to this function for consideration. More...
Protected Member Functions inherited from gr::basic_block
	basic_block (void)
	basic_block (const std::string &name, gr::io_signature::sptr input_signature, gr::io_signature::sptr output_signature)
	Protected constructor prevents instantiation by non-derived classes. More...
void	set_input_signature (gr::io_signature::sptr iosig)
	may only be called during constructor More...
void	set_output_signature (gr::io_signature::sptr iosig)
	may only be called during constructor More...
void	set_color (vcolor color)
	Allow the flowgraph to set for sorting and partitioning. More...
vcolor	color () const
virtual bool	has_msg_handler (pmt::pmt_t which_port)
	Tests if there is a handler attached to port which_port. More...
virtual void	dispatch_msg (pmt::pmt_t which_port, pmt::pmt_t msg)
template<typename Derived >
std::shared_ptr< Derived >	shared_from_base ()
	This is meant to be called by derived classes (e.g. block) to get a shared pointer internally. This is needed because std::enable_shared_from_this doesn't seem to work with derived classes in an inheritance hierarchy. More...
Protected Attributes inherited from gr::block
std::vector< long >	d_max_output_buffer
std::vector< long >	d_min_output_buffer
unsigned int	d_blkd_input_timer_value = 250
gr::thread::mutex	d_setlock
const pmt::pmt_t	d_pmt_done
const pmt::pmt_t	d_system_port
Protected Attributes inherited from gr::basic_block
std::string	d_name
gr::io_signature::sptr	d_input_signature
gr::io_signature::sptr	d_output_signature
long	d_unique_id
long	d_symbolic_id
std::string	d_symbol_name
std::string	d_symbol_alias
vcolor	d_color
bool	d_rpc_set
gr::logger_ptr	d_logger
gr::logger_ptr	d_debug_logger
	Default logger. More...
msg_queue_map_t	msg_queue
	Verbose logger. More...
std::vector< rpcbasic_sptr >	d_rpc_vars
pmt::pmt_t	d_message_subscribers

Detailed Description

Decision Feedback Equalizer.

Member Typedef Documentation

sptr

typedef std::shared_ptr<decision_feedback_equalizer> gr::digital::decision_feedback_equalizer::sptr

Member Function Documentation

equalize()

virtual int gr::digital::decision_feedback_equalizer::equalize ( const gr_complex *  input_samples, gr_complex *  output_symbols, unsigned int  num_inputs, unsigned int  max_num_outputs, std::vector< unsigned int >  training_start_samples = std::vector< unsigned int >(0), bool  history_included = false, gr_complex *  taps = nullptr, unsigned short *  state = nullptr  )

pure virtual

Public "work" function - equalize a block of input samples.

Behaves similar to the block's work function, but made public to be able to be called outside the GNU Radio scheduler on bursty data

Parameters

input_samples	Buffer of input samples to equalize
output_symbols	Buffer of output symbols post equalization
num_inputs	Number of input samples provided
max_num_outputs	Size of output_symbols buffer to write into
training_start_samples	Vector of starting positions of training sequences within the input_samples buffer
history_included	Flag to indicate whether history has been provided at the beginning of the input_samples buffer, as would normally be provided in a work() call. The work() function of this block sets this to true, but in bursty operation, this should be set to false
taps	Optional output vector buffer of tap weights calculated at each sample of the output
state	Optional output state of the equalizer for debug {IDLE, TRAINING, DD}

make()

static sptr gr::digital::decision_feedback_equalizer::make ( unsigned  num_taps_forward, unsigned  num_taps_feedback, unsigned  sps, adaptive_algorithm_sptr  alg, bool  adapt_after_training = true, std::vector< gr_complex >  training_sequence = std::vector< gr_complex >(), const std::string &  training_start_tag = ""  )

static

Return a shared_ptr to a new instance of gr::digital::decision_feedback_equalizer.

The Decision Feedback Equalizer block equalizes the incoming signal using an FIR filter representing both the forward and feedback taps

If provided with a training sequence and a training start tag, data aided equalization will be performed starting with the tagged sample. If training-based equalization is active and the training sequence ends, then optionally decision directed equalization will be performed given the adapt_after_training If no training sequence or no tag is provided, decision directed equalization will be performed This equalizer decimates to the symbol rate according to the samples per symbol param

Parameters

num_taps_forward	Number of feedforward taps for the FIR filter
num_taps_feedback	Number of feedback taps for the FIR filter
sps	int - Samples per Symbol
alg	Adaptive algorithm object
training_sequence	Sequence of samples that will be used to train the equalizer. Provide empty vector to default to DD equalizer
adapt_after_training	bool - set true to continue DD training after training sequence has been used up
training_start_tag	string - tag that indicates the start of the training sequence in the incoming data

set_taps()

virtual void gr::digital::decision_feedback_equalizer::set_taps ( const std::vector< gr_complex > &  taps )

pure virtual

taps()

virtual std::vector<gr_complex> gr::digital::decision_feedback_equalizer::taps ( ) const

pure virtual

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

• decision_feedback_equalizer.h