FreeCalypso > hg > fc-magnetite
view src/cs/layer1/gtt_include/ctm/wait_for_sync.h @ 248:35b17d54773d
helpers: build-date helper program written
author | Mychaela Falconia <falcon@freecalypso.org> |
---|---|
date | Thu, 03 Aug 2017 04:24:06 +0000 |
parents | 945cf7f506b2 |
children |
line wrap: on
line source
/* ******************************************************************************* * * COPYRIGHT (C) 2000 BY ERICSSON EUROLAB DEUTSCHLAND GmbH * 90411 NUERNBERG, GERMANY, Tel Int + 49 911 5217 100 * * The program(s) may be used and/or copied only with the * written permission from Ericsson or in accordance * with the terms and conditions stipulated in the agreement or * contract under which the program(s) have been supplied. * ******************************************************************************* * * File : wait_for_sync.h * Purpose : synchronization routine for the deinterleaver * ******************************************************************************* */ #ifndef wait_for_sync_h #define wait_for_sync_h "$Id: $" /* ******************************************************************************* * INCLUDE FILES ******************************************************************************* */ #include "ctm_typedefs.h" /* ******************************************************************************* * DECLARATION OF PROTOTYPES ******************************************************************************* */ typedef struct { WORD16 *shift_reg; /* shift register */ WORD16 *m_sequence; /* maximum length sequence (preamble) */ WORD16 *m_sequence_resync; /* maximum length sequence (resync) */ WORD16 *sync_index_vec; /* positions/indices of the preamble */ WORD16 *resync_index_vec; /* positions/indices of the resync sequence */ WORD16 length_shift_reg; /* length of the vector shift_reg */ WORD16 offset; /* */ WORD16 num_sync_bits; /* length of the preamble */ BOOL sync_found; /* true if receiver is "in sync" */ BOOL alreadyCTMreceived; /* true if burst has been received earlier */ WORD16 *xcorr1_shiftreg; WORD16 *xcorr2_shiftreg; UWORD16 cntSymbolsSinceEndOfBurst; } wait_for_sync_state_t; /* ----------------------------------------------------------------------- */ /* Function init_wait_for_sync() */ /* ***************************** */ /* Initialization of the synchronization detector. The dimensions of the */ /* corresponding interleaver at the TX side must be specified: */ /* B (horizontal) blocklength */ /* D (vertical) interlace factor */ /* num_sync_lines2 number of interleaver lines with additional sync bits */ /* ptr_wait_state pointer to the state variable of the sync detector */ /* ----------------------------------------------------------------------- */ void init_wait_for_sync(wait_for_sync_state_t *ptr_wait_state, WORD16 B, WORD16 D, WORD16 num_sync_lines2); /* *********************************************************************** * Shutdown_wait_for_sync() * * ************************ * * Deallocate dyamically created buffers. * * * * Input variables: * * intl_state : pointer to a variable of wait_for_sync_state_t * * containing the wait_for_sync state machine. * *********************************************************************** */ void Shutdown_wait_for_sync(wait_for_sync_state_t *ptr_wait_state); /* ----------------------------------------------------------------------- */ /* Function reinit_wait_for_sync() */ /* ******************************* */ /* Reinitialization of synchronization detector. This function is used in */ /* case that a burst has been finished and the transmitter has switched */ /* into idle mode. After calling reinit_wait_for_sync(), the function */ /* wait_for_sync() inhibits the transmission of the demodulated bits to */ /* the deinterleaver, until the next synchronization sequence can be */ /* detected. */ /* ----------------------------------------------------------------------- */ void reinit_wait_for_sync(wait_for_sync_state_t *ptr_wait_state); /* ----------------------------------------------------------------------- */ /* Function wait_for_sync() */ /* ************************ */ /* This function shall be inserted between the demodulator and the */ /* deinterleaver. The function searches the synchronization bitstream */ /* and cuts all received heading bits. As long as no sync is found, this */ /* function returns *ptr_num_valid_out_bits=0 so that the main program */ /* is able to skip the deinterleaver as long as no valid bits are */ /* available. If the sync info is found, the complete internal shift */ /* register is copied to out_bits so that wait_for_sync can be transparent */ /* and causes no delay for future calls. */ /* *ptr_wait_interval returns a value of 0 after such a synchronization */ /* indicating that this was a regular synchronization. */ /* */ /* Regularly, the initial preamble of each burst is used as sync info. */ /* In addition, the resynchronization sequences, which occur periodically */ /* during a running burst, are used as "back-up" synchronization in order */ /* to avoid loosing all characters of a burst, if the preamble was not */ /* detected. */ /* If the receiver is already synchronized on a running burst */ /* and the resynchronization sequence is detected, *ptr_resync_detected */ /* returns a non-negative value in the range 0...num_in_bits-1 indicating */ /* at which bit the resynchronization sequence has been detected. If no */ /* resynchronization has been detected, *ptr_resync_detected is -1. */ /* If the receiver is NOT synchronized and the resynchronization sequence */ /* is detected, the resynchronization sequence is used as initial */ /* synchronization. *ptr_wait_interval returns a value of 32 in this case */ /* due to the different alignments of the synchronizations based on the */ /* preamble or the resynchronization sequence, respectively. */ /* */ /* In order to carry all bits, the minimum length of the vector out_bits */ /* must be: */ /* in_bits.size()-1 + ptr_wait_state->shift_reg_length */ /* */ /* in_bits Vector with bits from the demodulator. The */ /* vector's length can be arbitrarily chosen, */ /* i.e. according to the block length of the */ /* signal processing of the main program. */ /* num_in_bits length of vector in_bits */ /* num_received_idle_symbols number of idle symbols received coherently */ /* out_bits Vector with bits for the deinterleaver. */ /* The number of the valid bits is indicated */ /* by *ptr_num_valid_out_bits. */ /* *ptr_num_valid_out_bits returns the number of valid output bits */ /* *ptr_wait_interval returns either 0 or 32 */ /* *ptr_resync_detected returns a value -1, 0,...num_in_bits */ /* *ptr_early_muting_required returns whether the original audio signal */ /* must not be forwarded. This is to guarantee */ /* that the preamble or resync sequence is */ /* detected only by the first CTM device, if */ /* several CTM devices are cascaded */ /* subsequently. */ /* *ptr_wait_state state information. This variable must be */ /* initialized with init_wait_for_sync() */ /* ----------------------------------------------------------------------- */ #if(TTY_SYNC_MCU_2 == 0) BOOL wait_for_sync(WORD16 *out_bits, WORD16 *in_bits, WORD16 num_in_bits, WORD16 num_received_idle_symbols, WORD16 *ptr_num_valid_out_bits, WORD16 *ptr_wait_interval, WORD16 *ptr_resync_detected, BOOL *ptr_early_muting_required, wait_for_sync_state_t *ptr_wait_state); #else BOOL wait_for_sync(WORD16 *out_bits, WORD16 *in_bits, WORD16 num_in_bits, WORD16 num_received_idle_symbols, WORD16 *ptr_num_valid_out_bits, WORD16 *ptr_wait_interval, WORD16 *ptr_resync_detected, BOOL *ptr_early_muting_required, wait_for_sync_state_t *ptr_wait_state, BOOL *sync_after_resync); #endif /* ----------------------------------------------------------------------- */ /* Function generate_resync_sequence() */ /* *********************************** */ /* Generation of the sequence for resynchronization. The sequence, which */ /* has a length according to the value of the constant RESYNC_SEQ_LENGTH, */ /* is written to the vector *sequence, which must have been allocated */ /* before calling this function. */ /* ----------------------------------------------------------------------- */ void generate_resync_sequence(WORD16 *sequence); #endif