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comparison spandsp-0.0.6pre17/src/spandsp/bert.h @ 4:26cd8f1ef0b1
import spandsp-0.0.6pre17
author | Peter Meerwald <pmeerw@cosy.sbg.ac.at> |
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date | Fri, 25 Jun 2010 15:50:58 +0200 |
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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 1.23 2009/02/10 13:06:47 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 bert_state_s bert_state_t; | |
110 | |
111 #if defined(__cplusplus) | |
112 extern "C" | |
113 { | |
114 #endif | |
115 | |
116 /*! Return a short description of a BERT event. | |
117 \param event The event type. | |
118 \return A pointer to a short text string describing the event. */ | |
119 SPAN_DECLARE(const char *) bert_event_to_str(int event); | |
120 | |
121 /*! Initialise a BERT context. | |
122 \param s The BERT context. | |
123 \param limit The maximum test duration. | |
124 \param pattern One of the supported BERT signal patterns. | |
125 \param resync_len ??? | |
126 \param resync_percent The percentage of bad bits which will cause a resync. | |
127 \return The BERT context. */ | |
128 SPAN_DECLARE(bert_state_t *) bert_init(bert_state_t *s, int limit, int pattern, int resync_len, int resync_percent); | |
129 | |
130 SPAN_DECLARE(int) bert_release(bert_state_t *s); | |
131 | |
132 SPAN_DECLARE(int) bert_free(bert_state_t *s); | |
133 | |
134 /*! Get the next bit of the BERT sequence from the generator. | |
135 \param s The BERT context. | |
136 \return The bit. */ | |
137 SPAN_DECLARE(int) bert_get_bit(bert_state_t *s); | |
138 | |
139 /*! Put the next bit of the BERT sequence to the analyser. | |
140 \param s The BERT context. | |
141 \param bit The bit. */ | |
142 SPAN_DECLARE(void) bert_put_bit(bert_state_t *s, int bit); | |
143 | |
144 /*! Set the callback function for reporting the test status. | |
145 \param s The BERT context. | |
146 \param freq The required frequency of regular reports. | |
147 \param reporter The callback function. | |
148 \param user_data An opaque pointer passed to the reporter routine. */ | |
149 SPAN_DECLARE(void) bert_set_report(bert_state_t *s, int freq, bert_report_func_t reporter, void *user_data); | |
150 | |
151 /*! Get the results of the BERT. | |
152 \param s The BERT context. | |
153 \param results The results. | |
154 \return The size of the result structure. */ | |
155 SPAN_DECLARE(int) bert_result(bert_state_t *s, bert_results_t *results); | |
156 | |
157 #if defined(__cplusplus) | |
158 } | |
159 #endif | |
160 | |
161 #endif | |
162 /*- End of file ------------------------------------------------------------*/ |