telemetry_decoder_libs

Classes
class	Tlm_Conf
class	Viterbi_Decoder
	Class that implements a Viterbi decoder. More...

Functions
int	parity_counter (int symbol, int length)
	Determines if a symbol has odd (1) or even (0) parity Output parameters: More...
int	nsc_enc_bit (int state_out_p[], int input, int state_in, const int g[], int KK, int nn)
	Convolutionally encodes a single bit using a rate 1/n encoder. Takes in one input bit at a time, and produces a n-bit output. More...
void	nsc_transit (int output_p[], int trans_p[], int input, int g[], int KK, int nn)
	Function that creates the transit and output vectors. More...
float	Gamma (const float rec_array[], int symbol, int nn)
	Computes the branch metric used for decoding. More...
void	Viterbi (int output_u_int[], const int out0[], const int state0[], const int out1[], const int state1[], const float input_c[], int KK, int nn, int LL)
	Uses the Viterbi algorithm to perform hard-decision decoding of a convolutional code. More...
int	save_tlm_matfile (const std::string &dumpfile)
bool	tlm_remove_file (const std::string &file_to_remove)

Variables
const float	MAXLOG = 1e7

Detailed Description

Utilities for the decoding of GNSS navigation messages.

Function Documentation

Gamma()

float Gamma ( const float  rec_array[], int  symbol, int  nn  )

inline

Computes the branch metric used for decoding.

Returns

(returned float) The metric between the hypothetical symbol and the received vector

Parameters

[in]	rec_array	The received vector, of length nn
[in]	symbol	The hypothetical symbol
[in]	nn	The length of the received vector

Definition at line 149 of file convolutional.h.

nsc_enc_bit()

int nsc_enc_bit ( int  state_out_p[], int  input, int  state_in, const int  g[], int  KK, int  nn  )

inline

Convolutionally encodes a single bit using a rate 1/n encoder. Takes in one input bit at a time, and produces a n-bit output.

Parameters

[in]	input	The input data bit (i.e. a 0 or 1).
[in]	state_in	The starting state of the encoder (an int from 0 to 2^m-1).
[in]	g[]	An n-element vector containing the code generators in binary form.
[in]	KK	The constraint length of the convolutional code.
[out]	output_p[]	An n-element vector containing the encoded bits.
[out]	state_out_p[]	An integer containing the final state of the encoder (i.e. the state after encoding this bit)

This function is used by nsc_transit()

Definition at line 90 of file convolutional.h.

References parity_counter().

Referenced by nsc_transit().

nsc_transit()

void nsc_transit ( int  output_p[], int  trans_p[], int  input, int  g[], int  KK, int  nn  )

inline

Function that creates the transit and output vectors.

Definition at line 120 of file convolutional.h.

References nsc_enc_bit().

parity_counter()

int parity_counter ( int  symbol, int  length  )

inline

Determines if a symbol has odd (1) or even (0) parity Output parameters:

Returns

(returned int): The symbol's parity = 1 for odd and 0 for even

Parameters

[in]	symbol	The integer-valued symbol
[in]	length	The highest bit position in the symbol

This function is used by nsc_enc_bit(), rsc_enc_bit(), and rsc_tail()

Definition at line 62 of file convolutional.h.

Referenced by nsc_enc_bit().

Viterbi()

void Viterbi ( int  output_u_int[], const int  out0[], const int  state0[], const int  out1[], const int  state1[], const float  input_c[], int  KK, int  nn, int  LL  )

inline

Uses the Viterbi algorithm to perform hard-decision decoding of a convolutional code.

Parameters

[in]	out0[]	The output bits for each state if input is a 0.
[in]	state0[]	The next state if input is a 0.
[in]	out1[]	The output bits for each state if input is a 1.
[in]	state1[]	The next state if input is a 1.
[in]	r[]	The received signal in LLR-form. For BPSK, must be in form r = 2*a*y/(sigma^2).
[in]	KK	The constraint length of the convolutional code.
[in]	LL	The number of data bits.
[out]	output_u_int[]	Hard decisions on the data bits

Definition at line 181 of file convolutional.h.