161 lines
6.8 KiB
C
161 lines
6.8 KiB
C
/** @file
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Pulse slicer functions.
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Binary slicers (PWM/PPM/Manchester/...) using a pulse data structure as input
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Copyright (C) 2015 Tommy Vestermark
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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*/
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#ifndef INCLUDE_PULSE_SLICER_H_
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#define INCLUDE_PULSE_SLICER_H_
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#include "pulse_detect.h"
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#include "r_device.h"
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/// Demodulate a Pulse Code Modulation signal.
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///
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/// Demodulate a Pulse Code Modulation (PCM) signal where bit width
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/// is fixed and each bit starts with a pulse or not. It may be either
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/// Return-to-Zero (RZ) encoding, where pulses are shorter than bit width
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/// or Non-Return-to-Zero (NRZ) encoding, where pulses are equal to bit width
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/// The presence of a pulse is:
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/// - Presence of a pulse equals 1
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/// - Absence of a pulse equals 0
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///
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/// @param pulses The pulse sequence to demodulate
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/// @param device Modulation parameters of
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/// - short_width: Nominal width of pulse [us]
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/// - long_width: Nominal width of bit period [us]
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/// - gap_limit: Maximum gap size before new row of bits (optional) [us]
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/// - reset_limit: Maximum gap size before End Of Message [us].
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/// - tolerance: Maximum deviation from nominal widths (optional, default 25%) [us]
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/// @return number of events processed
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int pulse_slicer_pcm(pulse_data_t const *pulses, r_device *device);
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/// Demodulate a Pulse Position Modulation signal.
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///
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/// Demodulate a Pulse Position Modulation (PPM) signal consisting of pulses with variable gap.
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/// Pulse width may be fixed or variable.
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/// Gap between pulses determine the encoding:
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/// - Short gap will add a 0 bit
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/// - Long gap will add a 1 bit
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///
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/// @param pulses The pulse sequence to demodulate
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/// @param device Modulation parameters of
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/// - short_width: Nominal width of '0' [us]
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/// - long_width: Nominal width of '1' [us]
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/// - reset_limit: Maximum gap size before End Of Message [us].
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/// - gap_limit: Maximum gap size before new row of bits [us]
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/// - tolerance: Maximum deviation from nominal widths (optional, raw if 0) [us]
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/// @return number of events processed
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int pulse_slicer_ppm(pulse_data_t const *pulses, r_device *device);
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/// Demodulate a Pulse Width Modulation signal.
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///
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/// Demodulate a Pulse Width Modulation (PWM) signal consisting of short, long, and optional sync pulses.
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/// Gap between pulses may be of fixed size or variable (e.g. fixed period)
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/// - Short pulse will add a 1 bit
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/// - Long pulse will add a 0 bit
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/// - Sync pulse (optional) will add a new row to bitbuffer
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///
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/// @param pulses The pulse sequence to demodulate
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/// @param device Modulation parameters of
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/// - short_width: Nominal width of '1' [us]
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/// - long_width: Nominal width of '0' [us]
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/// - reset_limit: Maximum gap size before End Of Message [us].
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/// - gap_limit: Maximum gap size before new row of bits [us]
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/// - sync_width: Nominal width of sync pulse (optional) [us]
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/// - tolerance: Maximum deviation from nominal widths (optional, raw if 0) [us]
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/// @return number of events processed
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int pulse_slicer_pwm(pulse_data_t const *pulses, r_device *device);
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/// Demodulate a Manchester encoded signal with a hardcoded zerobit in front.
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///
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/// Demodulate a Manchester encoded signal where first rising edge is counted as a databit
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/// and therefore always will be zero (Most likely a hardcoded Oregon Scientific peculiarity)
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///
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/// Clock is recovered from the data based on pulse width. When time since last bit is more
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/// than 1.5 times the clock half period (short_width) it is declared a data edge where:
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/// - Rising edge means bit = 0
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/// - Falling edge means bit = 1
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///
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/// @param pulses The pulse sequence to demodulate
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/// @param device Modulation parameters of
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/// - short_width: Nominal width of clock half period [us]
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/// - long_width: Not used
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/// - reset_limit: Maximum gap size before End Of Message [us].
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/// @return number of events processed
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int pulse_slicer_manchester_zerobit(pulse_data_t const *pulses, r_device *device);
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/// Demodulate a Differential Manchester Coded signal.
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///
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/// No level shift within the clock cycle translates to a logic 0
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/// One level shift within the clock cycle translates to a logic 1
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/// Each clock cycle begins with a level shift
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///
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/// +---+ +---+ +-------+ + high
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/// | | | | | | |
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/// | | | | | | |
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/// + +---+ +---+ +-------+ low
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///
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/// ^ ^ ^ ^ ^ clock cycle
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/// | 1 | 1 | 0 | 0 | translates as
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///
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/// @param pulses The pulse sequence to demodulate
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/// @param device Modulation parameters of
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/// - short_width: Width in samples of '1' [us]
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/// - long_width: Width in samples of '0' [us]
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/// - reset_limit: Maximum gap size before End Of Message [us].
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/// - tolerance: Maximum deviation from nominal widths [us]
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/// @return number of events processed
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int pulse_slicer_dmc(pulse_data_t const *pulses, r_device *device);
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/// Demodulate a raw Pulse Interval and Width Modulation signal.
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///
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/// Each level shift is a new bit.
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/// A short interval is a logic 1, a long interval a logic 0
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///
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/// @param pulses The pulse sequence to demodulate
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/// @param device Modulation parameters of
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/// - short_width: Nominal width of a bit [us]
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/// - long_width: Maximum width of a run of bits [us]
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/// - reset_limit: Maximum gap size before End Of Message [us].
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/// - tolerance: Maximum deviation from nominal widths [us]
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/// @return number of events processed
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int pulse_slicer_piwm_raw(pulse_data_t const *pulses, r_device *device);
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/// Demodulate a differential Pulse Interval and Width Modulation signal.
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///
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/// Each level shift is a new bit.
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/// A short interval is a logic 1, a long interval a logic 0
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///
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/// @param pulses The pulse sequence to demodulate
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/// @param device Modulation parameters of
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/// - short_width: Nominal width of '1' [us]
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/// - long_width: Nominal width of '0' [us]
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/// - reset_limit: Maximum gap size before End Of Message [us].
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/// - tolerance: Maximum deviation from nominal widths [us]
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/// @return number of events processed
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int pulse_slicer_piwm_dc(pulse_data_t const *pulses, r_device *device);
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int pulse_slicer_nrzs(pulse_data_t const *pulses, r_device *device);
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int pulse_slicer_osv1(pulse_data_t const *pulses, r_device *device);
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/// Simulate demodulation using a given signal code string.
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///
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/// The (optionally "0x" prefixed) hex code is processed into a bitbuffer_t.
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/// Each row is optionally prefixed with a length enclosed in braces "{}" or
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/// separated with a slash "/" character. Whitespace is ignored.
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///
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/// @param code The pulse sequence to demodulate in text format
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/// @param device Device params are disregarded.
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/// @return number of events processed
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int pulse_slicer_string(const char *code, r_device *device);
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#endif /* INCLUDE_PULSE_SLICER_H_ */
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