ml2251 Oki Semiconductor, ml2251 Datasheet - Page 26

• Manufacturer Part Number: ml2251
• Description: 2-channel Mixing Oki Adpcm Algorithm-based Speech Synthesis Lsi
• Manufacturer: Oki Semiconductor

Voice Synthesis Algorithm
The ML2250 family 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 4 data areas: voice (i.e., phrase) control area, test 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 test area stores the data for testing.
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.
ROM Addresses (ML2252)
max: 0x1FFFF
max: 0x1FFFF
Applied waveform
0x007FF
0x00800
0x00808
0x00807
0x00000
Depends on creation of ROM
Phrase Control Table area
Voice control area
(16 Kbit Fixed)
Voice area
Test 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
FEDL2250DIGEST-06
ML2250 family
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