1 /* 2 * SpanDSP - a series of DSP components for telephony 3 * 4 * bert.h - Bit error rate tests. 5 * 6 * Written by Steve Underwood <steveu@coppice.org> 7 * 8 * Copyright (C) 2004 Steve Underwood 9 * 10 * All rights reserved. 11 * 12 * This program is free software; you can redistribute it and/or modify 13 * it under the terms of the GNU Lesser General Public License version 2.1, 14 * as published by the Free Software Foundation. 15 * 16 * This program is distributed in the hope that it will be useful, 17 * but WITHOUT ANY WARRANTY; without even the implied warranty of 18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 19 * GNU Lesser General Public License for more details. 20 * 21 * You should have received a copy of the GNU Lesser General Public 22 * License along with this program; if not, write to the Free Software 23 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 24 * 25 * $Id: bert.h,v 1.19 2008/04/17 14:26:59 steveu Exp $ 26 */ 27 28 #if !defined(_SPANDSP_BERT_H_) 29 #define _SPANDSP_BERT_H_ 30 31 /*! \page bert_page The Bit Error Rate tester 32 \section bert_page_sec_1 What does it do? 33 The Bit Error Rate tester generates a pseudo random bit stream. It also accepts such 34 a pattern, synchronises to it, and checks the bit error rate in this stream. 35 36 \section bert_page_sec_2 How does it work? 37 The Bit Error Rate tester generates a bit stream, with a repeating 2047 bit pseudo 38 random pattern, using an 11 stage polynomial generator. It also accepts such a pattern, 39 synchronises to it, and checks the bit error rate in this stream. If the error rate is 40 excessive the tester assumes synchronisation has been lost, and it attempts to 41 resynchronise with the stream. 42 43 The bit error rate is continuously assessed against decadic ranges - 44 > 1 in 10^2 45 > 1 in 10^3 46 > 1 in 10^4 47 > 1 in 10^5 48 > 1 in 10^6 49 > 1 in 10^7 50 < 1 in 10^7 51 To ensure fairly smooth results from this assessment, each decadic level is assessed 52 over 10/error rate bits. That is, to assess if the signal's BER is above or below 1 in 10^5 53 the software looks over 10*10^5 => 10^6 bits. 54 */ 55 56 enum 57 { 58 BERT_REPORT_SYNCED = 0, 59 BERT_REPORT_UNSYNCED, 60 BERT_REPORT_REGULAR, 61 BERT_REPORT_GT_10_2, 62 BERT_REPORT_LT_10_2, 63 BERT_REPORT_LT_10_3, 64 BERT_REPORT_LT_10_4, 65 BERT_REPORT_LT_10_5, 66 BERT_REPORT_LT_10_6, 67 BERT_REPORT_LT_10_7 68 }; 69 70 /* The QBF strings should be: 71 "VoyeZ Le BricK GeanT QuE J'ExaminE PreS Du WharF 123 456 7890 + - * : = $ % ( )" 72 "ThE QuicK BrowN FoX JumpS OveR ThE LazY DoG 123 456 7890 + - * : = $ % ( )" 73 */ 74 75 enum 76 { 77 BERT_PATTERN_ZEROS = 0, 78 BERT_PATTERN_ONES, 79 BERT_PATTERN_7_TO_1, 80 BERT_PATTERN_3_TO_1, 81 BERT_PATTERN_1_TO_1, 82 BERT_PATTERN_1_TO_3, 83 BERT_PATTERN_1_TO_7, 84 BERT_PATTERN_QBF, 85 BERT_PATTERN_ITU_O151_23, 86 BERT_PATTERN_ITU_O151_20, 87 BERT_PATTERN_ITU_O151_15, 88 BERT_PATTERN_ITU_O152_11, 89 BERT_PATTERN_ITU_O153_9 90 }; 91 92 /*! 93 Bit error rate tester (BERT) results descriptor. This is used to report the 94 results of a BER test. 95 */ 96 typedef struct 97 { 98 int total_bits; 99 int bad_bits; 100 int resyncs; 101 } bert_results_t; 102 103 typedef void (*bert_report_func_t)(void *user_data, int reason, bert_results_t *bert_results); 104 105 /*! 106 Bit error rate tester (BERT) descriptor. This defines the working state for a 107 single instance of the BERT. 108 */ 109 typedef struct 110 { 111 int pattern; 112 int pattern_class; 113 bert_report_func_t reporter; 114 void *user_data; 115 int report_frequency; 116 int limit; 117 118 uint32_t tx_reg; 119 int tx_step; 120 int tx_step_bit; 121 int tx_bits; 122 int tx_zeros; 123 124 uint32_t rx_reg; 125 uint32_t ref_reg; 126 uint32_t master_reg; 127 int rx_step; 128 int rx_step_bit; 129 int resync; 130 int rx_bits; 131 int rx_zeros; 132 int resync_len; 133 int resync_percent; 134 int resync_bad_bits; 135 int resync_cnt; 136 137 uint32_t mask; 138 int shift; 139 int shift2; 140 int max_zeros; 141 int invert; 142 int resync_time; 143 144 int decade_ptr[9]; 145 int decade_bad[9][10]; 146 int step; 147 int error_rate; 148 149 int bit_error_status; 150 int report_countdown; 151 152 bert_results_t results; 153 154 /*! \brief Error and flow logging control */ 155 logging_state_t logging; 156 } bert_state_t; 157 158 #if defined(__cplusplus) 159 extern "C" 160 { 161 #endif 162 163 /*! Return a short description of a BERT event. 164 \param event The event type. 165 \return A pointer to a short text string describing the event. */ 166 const char *bert_event_to_str(int event); 167 168 /*! Initialise a BERT context. 169 \param s The BERT context. 170 \param limit The maximum test duration. 171 \param pattern One of the supported BERT signal patterns. 172 \param resync_len ??? 173 \param resync_percent The percentage of bad bits which will cause a resync. 174 \return The BERT context. */ 175 bert_state_t *bert_init(bert_state_t *s, int limit, int pattern, int resync_len, int resync_percent); 176 177 /*! Get the next bit of the BERT sequence from the generator. 178 \param s The BERT context. 179 \return The bit. */ 180 int bert_get_bit(bert_state_t *s); 181 182 /*! Put the next bit of the BERT sequence to the analyser. 183 \param s The BERT context. 184 \param bit The bit. */ 185 void bert_put_bit(bert_state_t *s, int bit); 186 187 /*! Set the callback function for reporting the test status. 188 \param s The BERT context. 189 \param freq The required frequency of regular reports. 190 \param reporter The callback function. 191 \param user_data An opaque pointer passed to the reporter routine. */ 192 void bert_set_report(bert_state_t *s, int freq, bert_report_func_t reporter, void *user_data); 193 194 /*! Get the results of the BERT. 195 \param s The BERT context. 196 \param results The results. 197 \return The size of the result structure. */ 198 int bert_result(bert_state_t *s, bert_results_t *results); 199 200 #if defined(__cplusplus) 201 } 202 #endif 203 204 #endif 205 /*- End of file ------------------------------------------------------------*/ 206