ml2240 Oki Semiconductor, ml2240 Datasheet - Page 17

• Manufacturer Part Number: ml2240
• Description: 4-channel Mixing Oki Adpcm Algorithm-based Speech Synthesis Lsi
• Manufacturer: Oki Semiconductor

Voice Synthesis Algorithm
The ML2240 contains 5 algorithm types to match the characteristic of playback voice: 2-bit ADPCM 2 algorithm,
4-bit ADPCM 2 algorithm, 8-bit PCM algorithm, 8-bit non-linear PCM algorithm, and 16-bit PCM algorithm.
Key feature of each algorithm is described in the table below.
Memory Allocation and Creating Voice Data
The ROM is partitioned into 3 data areas: voice (i.e., phrase) control area, voice area, and phrase control table area.
The voice control area manages the ROM’s voice data. It controls the start/end addresses of voice data, usage/not
usage of the phrase control table function and so on. The voice control area stores voice control data for 256
phrases.
The voice area stores the actual waveform data.
The phrase control table area stores data for effective use of voice data. As for the details, please refer to the Phrase
control table Function.
There is no phrase control table area if the phrase control table is not used.
The ROM data is created using a development tool.
OKI Semiconductor
Oki 2-bit ADPCM2
Oki 4-bit ADPCM2
Oki 8-bit Nonlinear PCM
8-bit PCM
16-bit PCM
Voice synthesis algorithm
Normal voice waveform
Normal voice waveform
High-frequency components
inclusive sound effect etc.
High-frequency components
inclusive sound effect etc.
High-frequency components
inclusive sound effect etc.
max: 0xFFFFFF
max: 0xFFFFFF
ROM Addresses (ML2240 byte mode)
0x0007FF
0x000800
0x000000
Applied waveform
Depends on creation of ROM
Phrase control table area
Voice control area
(16 Kbit Fixed)
Voice area
data.
Oki’s specific speech synthesis algorithm of low
bit rate with improved 2-bit ADPCM.
Oki’s specific speech synthesis algorithm of
improved waveform follow-up with improved
4-bit ADPCM.
Algorithm which plays back mid-range of
waveform as 10-bit equivalent voice quality.
Normal 8-bit PCM algorithm
Normal 16-bit PCM algorithm
Feature
FEDL2240DIGEST-02
ML2240 Family
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