mirror of
https://github.com/f4exb/sdrangel.git
synced 2024-11-08 17:46:03 -05:00
210 lines
6.7 KiB
C++
210 lines
6.7 KiB
C++
/*---------------------------------------------------------------------------*\
|
|
|
|
FILE........: fsk.h
|
|
AUTHOR......: Brady O'Brien
|
|
DATE CREATED: 6 January 2016
|
|
|
|
C Implementation of 2FSK/4FSK modulator/demodulator, based on octave/fsk_horus.m
|
|
|
|
\*---------------------------------------------------------------------------*/
|
|
|
|
/*
|
|
Copyright (C) 2016 David Rowe
|
|
|
|
All rights reserved.
|
|
|
|
This program is free software; you can redistribute it and/or modify
|
|
it under the terms of the GNU Lesser General Public License version 2.1, as
|
|
published by the Free Software Foundation. This program is
|
|
distributed in the hope that it will be useful, but WITHOUT ANY
|
|
WARRANTY; without even the implied warranty of MERCHANTABILITY or
|
|
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
|
|
License for more details.
|
|
|
|
You should have received a copy of the GNU Lesser General Public License
|
|
along with this program; if not, see <http://www.gnu.org/licenses/>.
|
|
*/
|
|
|
|
|
|
#ifndef __C2FSK_H
|
|
#define __C2FSK_H
|
|
#include <stdint.h>
|
|
#include "codec2/comp.h"
|
|
#include "kiss_fftr.h"
|
|
#include "modem_stats.h"
|
|
|
|
#define MODE_2FSK 2
|
|
#define MODE_4FSK 4
|
|
|
|
#define MODE_M_MAX 4
|
|
|
|
#define FSK_SCALE 16383
|
|
|
|
namespace FreeDV
|
|
{
|
|
|
|
struct FSK {
|
|
/* Static parameters set up by fsk_init */
|
|
int Ndft; /* buffer size for freq offset est fft */
|
|
int Fs; /* sample freq */
|
|
int N; /* processing buffer size */
|
|
int Rs; /* symbol rate */
|
|
int Ts; /* samples per symbol */
|
|
int Nmem; /* size of extra mem for timing adj */
|
|
int P; /* oversample rate for timing est/adj */
|
|
int Nsym; /* Number of symbols spat out in a processing frame */
|
|
int Nbits; /* Number of bits spat out in a processing frame */
|
|
int f1_tx; /* f1 for modulator */
|
|
int fs_tx; /* Space between TX freqs for modulatosr */
|
|
int mode; /* 2FSK or 4FSK */
|
|
int est_min; /* Minimum frequency for freq. estimator */
|
|
int est_max; /* Maximum frequency for freq. estimaotr */
|
|
int est_space; /* Minimum frequency spacing for freq. estimator */
|
|
float* hann_table; /* Precomputed or runtime computed hann window table */
|
|
|
|
/* Parameters used by demod */
|
|
COMP phi_c[MODE_M_MAX];
|
|
|
|
kiss_fft_cfg fft_cfg; /* Config for KISS FFT, used in freq est */
|
|
float norm_rx_timing; /* Normalized RX timing */
|
|
|
|
COMP* samp_old; /* Tail end of last batch of samples */
|
|
int nstash; /* How many elements are in there */
|
|
|
|
float* fft_est; /* Freq est FFT magnitude */
|
|
|
|
/* Memory used by demod but not important between demod frames */
|
|
|
|
/* Parameters used by mod */
|
|
COMP tx_phase_c; /* TX phase, but complex */
|
|
|
|
/* Statistics generated by demod */
|
|
float EbNodB; /* Estimated EbNo in dB */
|
|
float f_est[MODE_M_MAX];/* Estimated frequencies */
|
|
float ppm; /* Estimated PPM clock offset */
|
|
|
|
/* Parameters used by mod/demod and driving code */
|
|
int nin; /* Number of samples to feed the next demod cycle */
|
|
int burst_mode; /* enables/disables 'burst' mode */
|
|
|
|
/* modem statistic struct */
|
|
struct MODEM_STATS *stats;
|
|
int normalise_eye; /* enables/disables normalisation of eye diagram */
|
|
};
|
|
|
|
/*
|
|
* Create an FSK config/state struct from a set of config parameters
|
|
*
|
|
* int Fs - Sample frequency
|
|
* int Rs - Symbol rate
|
|
* int tx_f1 - '0' frequency
|
|
* int tx_fs - frequency spacing
|
|
*/
|
|
struct FSK * fsk_create(int Fs, int Rs, int M, int tx_f1, int tx_fs);
|
|
|
|
/*
|
|
* Create an FSK config/state struct from a set of config parameters
|
|
*
|
|
* int Fs - Sample frequency
|
|
* int Rs - Symbol rate
|
|
* int tx_f1 - '0' frequency
|
|
* int tx_fs - frequency spacing
|
|
*/
|
|
struct FSK * fsk_create_hbr(int Fs, int Rs, int P, int M, int tx_f1, int tx_fs);
|
|
|
|
/*
|
|
* Set a new number of symbols per processing frame
|
|
*/
|
|
void fsk_set_nsym(struct FSK *fsk,int nsym);
|
|
|
|
/*
|
|
* Set the minimum and maximum frequencies at which the freq. estimator can find tones
|
|
*/
|
|
void fsk_set_est_limits(struct FSK *fsk,int fmin, int fmax);
|
|
|
|
/*
|
|
* Clear the estimator states
|
|
*/
|
|
void fsk_clear_estimators(struct FSK *fsk);
|
|
|
|
/*
|
|
* Fills MODEM_STATS struct with demod statistics
|
|
*/
|
|
void fsk_get_demod_stats(struct FSK *fsk, struct MODEM_STATS *stats);
|
|
|
|
/*
|
|
* Destroy an FSK state struct and free it's memory
|
|
*
|
|
* struct FSK *fsk - FSK config/state struct to be destroyed
|
|
*/
|
|
void fsk_destroy(struct FSK *fsk);
|
|
|
|
/*
|
|
* Modulates Nsym bits into N samples
|
|
*
|
|
* struct FSK *fsk - FSK config/state struct, set up by fsk_create
|
|
* float fsk_out[] - Buffer for N samples of modulated FSK
|
|
* uint8_t tx_bits[] - Buffer containing Nbits unpacked bits
|
|
*/
|
|
void fsk_mod(struct FSK *fsk, float fsk_out[], uint8_t tx_bits[]);
|
|
|
|
/*
|
|
* Modulates Nsym bits into N samples
|
|
*
|
|
* struct FSK *fsk - FSK config/state struct, set up by fsk_create
|
|
* float fsk_out[] - Buffer for N samples of "voltage" used to modulate an external VCO
|
|
* uint8_t tx_bits[] - Buffer containing Nbits unpacked bits
|
|
*/
|
|
void fsk_mod_ext_vco(struct FSK *fsk, float vco_out[], uint8_t tx_bits[]);
|
|
|
|
/*
|
|
* Modulates Nsym bits into N complex samples
|
|
*
|
|
* struct FSK *fsk - FSK config/state struct, set up by fsk_create
|
|
* comp fsk_out[] - Buffer for N samples of modulated FSK
|
|
* uint8_t tx_bits[] - Buffer containing Nbits unpacked bits
|
|
*/
|
|
void fsk_mod_c(struct FSK *fsk, COMP fsk_out[], uint8_t tx_bits[]);
|
|
|
|
|
|
/*
|
|
* Returns the number of samples needed for the next fsk_demod() cycle
|
|
*
|
|
* struct FSK *fsk - FSK config/state struct, set up by fsk_create
|
|
* returns - number of samples to be fed into fsk_demod next cycle
|
|
*/
|
|
uint32_t fsk_nin(struct FSK *fsk);
|
|
|
|
|
|
/*
|
|
* Demodulate some number of FSK samples. The number of samples to be
|
|
* demodulated can be found by calling fsk_nin().
|
|
*
|
|
* struct FSK *fsk - FSK config/state struct, set up by fsk_create
|
|
* uint8_t rx_bits[] - Buffer for Nbits unpacked bits to be written
|
|
* float fsk_in[] - nin samples of modualted FSK
|
|
*/
|
|
void fsk_demod(struct FSK *fsk, uint8_t rx_bits[],COMP fsk_in[]);
|
|
|
|
/*
|
|
* Demodulate some number of FSK samples. The number of samples to be
|
|
* demodulated can be found by calling fsk_nin().
|
|
*
|
|
* struct FSK *fsk - FSK config/state struct, set up by fsk_create
|
|
* float rx_bits[] - Buffer for Nbits soft decision bits to be written
|
|
* float fsk_in[] - nin samples of modualted FSK
|
|
*/
|
|
void fsk_demod_sd(struct FSK *fsk, float rx_bits[],COMP fsk_in[]);
|
|
|
|
/* enables/disables normalisation of eye diagram samples */
|
|
|
|
void fsk_stats_normalise_eye(struct FSK *fsk, int normalise_enable);
|
|
|
|
/* Set the FSK modem into burst demod mode */
|
|
|
|
void fsk_enable_burst_mode(struct FSK *fsk,int nsyms);
|
|
|
|
} // FreeSV
|
|
|
|
#endif
|