spandsp  1.99.0
power_meter.h
1 /*
2  * SpanDSP - a series of DSP components for telephony
3  *
4  * power_meter.h
5  *
6  * Written by Steve Underwood <steveu@coppice.org>
7  *
8  * Copyright (C) 2003 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 
26 #if !defined(_SPANDSP_POWER_METER_H_)
27 #define _SPANDSP_POWER_METER_H_
28 
29 /*! \page power_meter_page Power metering
30 
31 \section power_meter_page_sec_1 What does it do?
32 The power metering module implements a simple IIR type running power meter. The damping
33 factor of the IIR is selectable when the meter instance is created.
34 
35 Note that the definition of dBOv is quite vague in most places - is it peak since wave,
36 peak square wave, etc.? This code is based on the well defined wording in RFC3389:
37 
38 "For example, in the case of a u-law system, the reference would be a square wave with
39 values +/-8031, and this square wave represents 0dBov. This translates into 6.18dBm0".
40 
41 \section power_meter_page_sec_2 How does it work?
42 */
43 
44 /*!
45  Power meter descriptor. This defines the working state for a
46  single instance of a power measurement device.
47 */
48 typedef struct power_meter_s power_meter_t;
49 
51 
52 #if defined(__cplusplus)
53 extern "C"
54 {
55 #endif
56 
57 /*! Initialise a power meter context.
58  \brief Initialise a power meter context.
59  \param s The power meter context.
60  \param shift The shift to be used by the IIR filter.
61  \return The power meter context. */
62 SPAN_DECLARE(power_meter_t *) power_meter_init(power_meter_t *s, int shift);
63 
64 SPAN_DECLARE(int) power_meter_release(power_meter_t *s);
65 
66 SPAN_DECLARE(int) power_meter_free(power_meter_t *s);
67 
68 /*! Change the damping factor of a power meter context.
69  \brief Change the damping factor of a power meter context.
70  \param s The power meter context.
71  \param shift The new shift to be used by the IIR filter.
72  \return The power meter context. */
73 SPAN_DECLARE(power_meter_t *) power_meter_damping(power_meter_t *s, int shift);
74 
75 /*! Update a power meter.
76  \brief Update a power meter.
77  \param s The power meter context.
78  \param amp The amplitude of the new audio sample.
79  \return The current power meter reading. */
80 SPAN_DECLARE(int32_t) power_meter_update(power_meter_t *s, int16_t amp);
81 
82 /*! Get the current power meter reading.
83  \brief Get the current power meter reading.
84  \param s The power meter context.
85  \return The current power meter reading. */
86 SPAN_DECLARE(int32_t) power_meter_current(power_meter_t *s);
87 
88 /*! Get the current power meter reading, in dBm0.
89  \brief Get the current power meter reading, in dBm0.
90  \param s The power meter context.
91  \return The current power meter reading, in dBm0. */
92 SPAN_DECLARE(float) power_meter_current_dbm0(power_meter_t *s);
93 
94 /*! Get the current power meter reading, in dBOv.
95  \brief Get the current power meter reading, in dBOv.
96  \param s The power meter context.
97  \return The current power meter reading, in dBOv. */
98 SPAN_DECLARE(float) power_meter_current_dbov(power_meter_t *s);
99 
100 /*! Get the power meter reading which represents a specified power level in dBm0.
101  \brief Get the current power meter reading, in dBm0.
102  \param level A power level, in dB0m.
103  \return The equivalent power meter reading. */
104 SPAN_DECLARE(int32_t) power_meter_level_dbm0(float level);
105 
106 /*! Get the power meter reading which represents a specified power level in dBOv.
107  \brief Get the current power meter reading, in dBOv.
108  \param level A power level, in dBOv.
109  \return The equivalent power meter reading. */
110 SPAN_DECLARE(int32_t) power_meter_level_dbov(float level);
111 
112 SPAN_DECLARE(int32_t) power_surge_detector(power_surge_detector_state_t *s, int16_t amp);
113 
114 /*! Get the current surge detector short term meter reading, in dBm0.
115  \brief Get the current surge detector meter reading, in dBm0.
116  \param s The power surge detector context.
117  \return The current power surge detector power reading, in dBm0. */
119 
120 /*! Get the current surge detector short term meter reading, in dBOv.
121  \brief Get the current surge detector meter reading, in dBOv.
122  \param s The power surge detector context.
123  \return The current power surge detector power reading, in dBOv. */
125 
126 SPAN_DECLARE(power_surge_detector_state_t *) power_surge_detector_init(power_surge_detector_state_t *s, float min, float surge);
127 
128 SPAN_DECLARE(int) power_surge_detector_release(power_surge_detector_state_t *s);
129 
130 SPAN_DECLARE(int) power_surge_detector_free(power_surge_detector_state_t *s);
131 
132 #if defined(__cplusplus)
133 }
134 #endif
135 
136 #endif
137 /*- End of file ------------------------------------------------------------*/
int32_t power_meter_current(power_meter_t *s)
Get the current power meter reading.
Definition: power_meter.c:122
Definition: private/power_meter.h:33
Definition: private/power_meter.h:42
float power_surge_detector_current_dbov(power_surge_detector_state_t *s)
Get the current surge detector meter reading, in dBOv.
Definition: power_meter.c:180
int32_t power_meter_update(power_meter_t *s, int16_t amp)
Update a power meter.
Definition: power_meter.c:92
float power_meter_current_dbm0(power_meter_t *s)
Get the current power meter reading, in dBm0.
Definition: power_meter.c:128
float power_meter_current_dbov(power_meter_t *s)
Get the current power meter reading, in dBOv.
Definition: power_meter.c:137
int32_t power_meter_level_dbm0(float level)
Get the current power meter reading, in dBm0.
Definition: power_meter.c:99
float power_surge_detector_current_dbm0(power_surge_detector_state_t *s)
Get the current surge detector meter reading, in dBm0.
Definition: power_meter.c:174
int32_t power_meter_level_dbov(float level)
Get the current power meter reading, in dBOv.
Definition: power_meter.c:111
power_meter_t * power_meter_init(power_meter_t *s, int shift)
Initialise a power meter context.
Definition: power_meter.c:58
power_meter_t * power_meter_damping(power_meter_t *s, int shift)
Change the damping factor of a power meter context.
Definition: power_meter.c:85