GNU Radio 3.6.1 C++ API
digital_probe_mpsk_snr_est_c Class Reference

A probe for computing SNR of a signal. More...

#include <digital_probe_mpsk_snr_est_c.h>

Inheritance diagram for digital_probe_mpsk_snr_est_c:
gr_sync_block gr_block gr_basic_block gr_msg_accepter gruel::msg_accepter

Public Member Functions

 ~digital_probe_mpsk_snr_est_c ()
int work (int noutput_items, gr_vector_const_void_star &input_items, gr_vector_void_star &output_items)
 just like gr_block::general_work, only this arranges to call consume_each for you
double snr ()
 Return the estimated signal-to-noise ratio in decibels.
snr_est_type_t type () const
 Return the type of estimator in use.
int msg_nsample () const
 Return how many samples between SNR messages.
double alpha () const
 Get the running-average coefficient.
void set_type (snr_est_type_t t)
 Set type of estimator to use.
void set_msg_nsample (int n)
 Set the number of samples between SNR messages.
void set_alpha (double alpha)
 Set the running-average coefficient.
- Public Member Functions inherited from gr_sync_block
void forecast (int noutput_items, gr_vector_int &ninput_items_required)
 Estimate input requirements given output request.
int general_work (int noutput_items, gr_vector_int &ninput_items, gr_vector_const_void_star &input_items, gr_vector_void_star &output_items)
 compute output items from input items
int fixed_rate_ninput_to_noutput (int ninput)
 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.
int fixed_rate_noutput_to_ninput (int noutput)
 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.
- Public Member Functions inherited from gr_block
virtual ~gr_block ()
unsigned history () const
void set_history (unsigned history)
bool fixed_rate () const
 Return true if this block has a fixed input to output rate.
virtual bool start ()
 Called to enable drivers, etc for i/o devices.
virtual bool stop ()
 Called to disable drivers, etc for i/o devices.
void set_output_multiple (int multiple)
 Constrain the noutput_items argument passed to forecast and general_work.
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)
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.
void consume_each (int how_many_items)
 Tell the scheduler how_many_items were consumed on each input stream.
void produce (int which_output, int how_many_items)
 Tell the scheduler how_many_items were produced on output stream which_output.
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
uint64_t nitems_read (unsigned int which_input)
 Return the number of items read on input stream which_input.
uint64_t nitems_written (unsigned int which_output)
 Return the number of items written on output stream which_output.
tag_propagation_policy_t tag_propagation_policy ()
 Asks for the policy used by the scheduler to moved tags downstream.
void set_tag_propagation_policy (tag_propagation_policy_t p)
 Set the policy by the scheduler to determine how tags are moved downstream.
gr_block_detail_sptr detail () const
void set_detail (gr_block_detail_sptr detail)
- Public Member Functions inherited from gr_basic_block
virtual ~gr_basic_block ()
long unique_id () const
std::string name () const
gr_io_signature_sptr input_signature () const
gr_io_signature_sptr output_signature () const
gr_basic_block_sptr to_basic_block ()
virtual bool check_topology (int ninputs, int noutputs)
 Confirm that ninputs and noutputs is an acceptable combination.
template<typename T >
void set_msg_handler (T msg_handler)
 Set the callback that is fired when messages are available.
- Public Member Functions inherited from gr_msg_accepter
 gr_msg_accepter ()
 ~gr_msg_accepter ()
void post (pmt::pmt_t msg)
 send msg to msg_accepter
- Public Member Functions inherited from gruel::msg_accepter
 msg_accepter ()
virtual ~msg_accepter ()

Friends

DIGITAL_API
digital_probe_mpsk_snr_est_c_sptr 
digital_make_probe_mpsk_snr_est_c (snr_est_type_t type, int msg_nsamples, double alpha)

Additional Inherited Members

- Public Types inherited from gr_block
enum  { 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 }
- Protected Types inherited from gr_basic_block
enum  vcolor { WHITE, GREY, BLACK }
- Protected Member Functions inherited from gr_sync_block
 gr_sync_block (void)
 gr_sync_block (const std::string &name, gr_io_signature_sptr input_signature, gr_io_signature_sptr output_signature)
- 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
vcolor d_color

Detailed Description

A probe for computing SNR of a signal.

This is a probe block (a sink) that can be used to monitor and retrieve estimations of the signal SNR. This probe is designed for use with M-PSK signals especially. The type of estimator is specified as the type parameter in the constructor. The estimators tend to trade off performance for accuracy, although experimentation should be done to figure out the right approach for a given implementation. Further, the current set of estimators are designed and proven theoretically under AWGN conditions; some amount of error should be assumed and/or estimated for real channel conditions.

Constructor & Destructor Documentation

digital_probe_mpsk_snr_est_c::~digital_probe_mpsk_snr_est_c ( )

Member Function Documentation

double digital_probe_mpsk_snr_est_c::alpha ( ) const

Get the running-average coefficient.

int digital_probe_mpsk_snr_est_c::msg_nsample ( ) const

Return how many samples between SNR messages.

void digital_probe_mpsk_snr_est_c::set_alpha ( double  alpha)

Set the running-average coefficient.

void digital_probe_mpsk_snr_est_c::set_msg_nsample ( int  n)

Set the number of samples between SNR messages.

void digital_probe_mpsk_snr_est_c::set_type ( snr_est_type_t  t)

Set type of estimator to use.

double digital_probe_mpsk_snr_est_c::snr ( )

Return the estimated signal-to-noise ratio in decibels.

snr_est_type_t digital_probe_mpsk_snr_est_c::type ( ) const

Return the type of estimator in use.

int digital_probe_mpsk_snr_est_c::work ( int  noutput_items,
gr_vector_const_void_star input_items,
gr_vector_void_star output_items 
)
virtual

just like gr_block::general_work, only this arranges to call consume_each for you

The user must override work to define the signal processing code

Implements gr_sync_block.

Friends And Related Function Documentation

DIGITAL_API digital_probe_mpsk_snr_est_c_sptr digital_make_probe_mpsk_snr_est_c ( snr_est_type_t  type,
int  msg_nsamples,
double  alpha 
)
friend

Factory function returning shared pointer of this class

 Parameters:

 \param type: the type of estimator to use \ref ref_snr_est_types
 "snr_est_type_t" for details about the available types.
 \param msg_nsamples: [not implemented yet] after this many
 samples, a message containing the SNR (key='snr') will be sent
 \param alpha: the update rate of internal running average
 calculations.

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