00001 /* 00002 * SpanDSP - a series of DSP components for telephony 00003 * 00004 * bert.h - Bit error rate tests. 00005 * 00006 * Written by Steve Underwood <steveu@coppice.org> 00007 * 00008 * Copyright (C) 2004 Steve Underwood 00009 * 00010 * All rights reserved. 00011 * 00012 * This program is free software; you can redistribute it and/or modify 00013 * it under the terms of the GNU Lesser General Public License version 2.1, 00014 * as published by the Free Software Foundation. 00015 * 00016 * This program is distributed in the hope that it will be useful, 00017 * but WITHOUT ANY WARRANTY; without even the implied warranty of 00018 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 00019 * GNU Lesser General Public License for more details. 00020 * 00021 * You should have received a copy of the GNU Lesser General Public 00022 * License along with this program; if not, write to the Free Software 00023 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 00024 * 00025 * $Id: bert.h,v 1.23 2009/02/10 13:06:47 steveu Exp $ 00026 */ 00027 00028 #if !defined(_SPANDSP_BERT_H_) 00029 #define _SPANDSP_BERT_H_ 00030 00031 /*! \page bert_page The Bit Error Rate tester 00032 \section bert_page_sec_1 What does it do? 00033 The Bit Error Rate tester generates a pseudo random bit stream. It also accepts such 00034 a pattern, synchronises to it, and checks the bit error rate in this stream. 00035 00036 \section bert_page_sec_2 How does it work? 00037 The Bit Error Rate tester generates a bit stream, with a repeating 2047 bit pseudo 00038 random pattern, using an 11 stage polynomial generator. It also accepts such a pattern, 00039 synchronises to it, and checks the bit error rate in this stream. If the error rate is 00040 excessive the tester assumes synchronisation has been lost, and it attempts to 00041 resynchronise with the stream. 00042 00043 The bit error rate is continuously assessed against decadic ranges - 00044 > 1 in 10^2 00045 > 1 in 10^3 00046 > 1 in 10^4 00047 > 1 in 10^5 00048 > 1 in 10^6 00049 > 1 in 10^7 00050 < 1 in 10^7 00051 To ensure fairly smooth results from this assessment, each decadic level is assessed 00052 over 10/error rate bits. That is, to assess if the signal's BER is above or below 1 in 10^5 00053 the software looks over 10*10^5 => 10^6 bits. 00054 */ 00055 00056 enum 00057 { 00058 BERT_REPORT_SYNCED = 0, 00059 BERT_REPORT_UNSYNCED, 00060 BERT_REPORT_REGULAR, 00061 BERT_REPORT_GT_10_2, 00062 BERT_REPORT_LT_10_2, 00063 BERT_REPORT_LT_10_3, 00064 BERT_REPORT_LT_10_4, 00065 BERT_REPORT_LT_10_5, 00066 BERT_REPORT_LT_10_6, 00067 BERT_REPORT_LT_10_7 00068 }; 00069 00070 /* The QBF strings should be: 00071 "VoyeZ Le BricK GeanT QuE J'ExaminE PreS Du WharF 123 456 7890 + - * : = $ % ( )" 00072 "ThE QuicK BrowN FoX JumpS OveR ThE LazY DoG 123 456 7890 + - * : = $ % ( )" 00073 */ 00074 00075 enum 00076 { 00077 BERT_PATTERN_ZEROS = 0, 00078 BERT_PATTERN_ONES, 00079 BERT_PATTERN_7_TO_1, 00080 BERT_PATTERN_3_TO_1, 00081 BERT_PATTERN_1_TO_1, 00082 BERT_PATTERN_1_TO_3, 00083 BERT_PATTERN_1_TO_7, 00084 BERT_PATTERN_QBF, 00085 BERT_PATTERN_ITU_O151_23, 00086 BERT_PATTERN_ITU_O151_20, 00087 BERT_PATTERN_ITU_O151_15, 00088 BERT_PATTERN_ITU_O152_11, 00089 BERT_PATTERN_ITU_O153_9 00090 }; 00091 00092 /*! 00093 Bit error rate tester (BERT) results descriptor. This is used to report the 00094 results of a BER test. 00095 */ 00096 typedef struct 00097 { 00098 int total_bits; 00099 int bad_bits; 00100 int resyncs; 00101 } bert_results_t; 00102 00103 typedef void (*bert_report_func_t)(void *user_data, int reason, bert_results_t *bert_results); 00104 00105 /*! 00106 Bit error rate tester (BERT) descriptor. This defines the working state for a 00107 single instance of the BERT. 00108 */ 00109 typedef struct bert_state_s bert_state_t; 00110 00111 #if defined(__cplusplus) 00112 extern "C" 00113 { 00114 #endif 00115 00116 /*! Return a short description of a BERT event. 00117 \param event The event type. 00118 \return A pointer to a short text string describing the event. */ 00119 SPAN_DECLARE(const char *) bert_event_to_str(int event); 00120 00121 /*! Initialise a BERT context. 00122 \param s The BERT context. 00123 \param limit The maximum test duration. 00124 \param pattern One of the supported BERT signal patterns. 00125 \param resync_len ??? 00126 \param resync_percent The percentage of bad bits which will cause a resync. 00127 \return The BERT context. */ 00128 SPAN_DECLARE(bert_state_t *) bert_init(bert_state_t *s, int limit, int pattern, int resync_len, int resync_percent); 00129 00130 SPAN_DECLARE(int) bert_release(bert_state_t *s); 00131 00132 SPAN_DECLARE(int) bert_free(bert_state_t *s); 00133 00134 /*! Get the next bit of the BERT sequence from the generator. 00135 \param s The BERT context. 00136 \return The bit. */ 00137 SPAN_DECLARE(int) bert_get_bit(bert_state_t *s); 00138 00139 /*! Put the next bit of the BERT sequence to the analyser. 00140 \param s The BERT context. 00141 \param bit The bit. */ 00142 SPAN_DECLARE(void) bert_put_bit(bert_state_t *s, int bit); 00143 00144 /*! Set the callback function for reporting the test status. 00145 \param s The BERT context. 00146 \param freq The required frequency of regular reports. 00147 \param reporter The callback function. 00148 \param user_data An opaque pointer passed to the reporter routine. */ 00149 SPAN_DECLARE(void) bert_set_report(bert_state_t *s, int freq, bert_report_func_t reporter, void *user_data); 00150 00151 /*! Get the results of the BERT. 00152 \param s The BERT context. 00153 \param results The results. 00154 \return The size of the result structure. */ 00155 SPAN_DECLARE(int) bert_result(bert_state_t *s, bert_results_t *results); 00156 00157 #if defined(__cplusplus) 00158 } 00159 #endif 00160 00161 #endif 00162 /*- End of file ------------------------------------------------------------*/