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comparison doc/Buzzer-melodies @ 889:834b5645a123

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doc/Buzzer-melodies: note the fact that Mot C1xx official fw uses PWT
author Mychaela Falconia <falcon@freecalypso.org>
date Sun, 03 Apr 2022 04:39:26 +0000
parents 8ff9bce1b56e
children 76cc910c508e
comparison
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888:b8ecdf54a957 889:834b5645a123
51 you are seeking to play ringtones that are composed of musical notes, use of PWT 51 you are seeking to play ringtones that are composed of musical notes, use of PWT
52 should be considered mandatory rather than optional. OTOH, if you are playing 52 should be considered mandatory rather than optional. OTOH, if you are playing
53 non-musical tones like SIT that are defined in absolute Hz, then BU will often 53 non-musical tones like SIT that are defined in absolute Hz, then BU will often
54 work better. 54 work better.
55 55
56 Motorola C1xx official firmware uses PWT mode to play its ringtones, both
57 built-in and user-composed, and we have successfully extracted some of those
58 professional-quality PWT melodies from at least one C1xx firmware version.
59
56 Concept of buzzer melodies 60 Concept of buzzer melodies
57 ========================== 61 ==========================
58 62
59 The Calypso buzzer (either BU or PWT) is monophonic, meaning that it can only 63 The Calypso buzzer (either BU or PWT) is monophonic, meaning that it can only
60 play one note at a time. Given this constraint, a playable buzzer melody can be 64 play one note at a time. Given this constraint, a playable buzzer melody can be
93 facility: 97 facility:
94 98
95 * Regarding the choice between BU or PWT driving, PWT has been chosen. All 99 * Regarding the choice between BU or PWT driving, PWT has been chosen. All
96 melodies created for playing via BUZM need to consist of musical notes F4 100 melodies created for playing via BUZM need to consist of musical notes F4
97 through E8 (scientific pitch notation, 349 to 5274 Hz), as supported by 101 through E8 (scientific pitch notation, 349 to 5274 Hz), as supported by
98 Calypso PWT block. 102 Calypso PWT block. This design decision matches Mot C1xx official firmware.
99 103
100 * Each melody is a sequence of sounded tones (PWT), either directly abutted or 104 * Each melody is a sequence of sounded tones (PWT), either directly abutted or
101 separated by pauses. In actual implementation, each melody is a sequence of 105 separated by pauses. In actual implementation, each melody is a sequence of
102 directly abutted entries, where each entry can be either a sounded tone or a 106 directly abutted entries, where each entry can be either a sounded tone or a
103 pause. Each entry (tone or silence) has a duration, reckoned in TDMA frames 107 pause. Each entry (tone or silence) has a duration, reckoned in TDMA frames