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comparison spandsp-0.0.6pre17/src/spandsp/bert.h @ 4:26cd8f1ef0b1

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import spandsp-0.0.6pre17
author Peter Meerwald <pmeerw@cosy.sbg.ac.at>
date Fri, 25 Jun 2010 15:50:58 +0200
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3:c6c5a16ce2f2 4:26cd8f1ef0b1
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 ------------------------------------------------------------*/

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