ml2251 Oki Semiconductor, ml2251 Datasheet - Page 28

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

Mixing Function
The ML2250 family can perform simultaneous mixing of 2 channels. It is possible to specify PLAY and STOP for
each channel separately.
• Precautions for Waveform Clamp at the Time of Channels Mixing
• Mixing of Different Sampling Frequency
Figures below show a case when a sampling frequency group played back a different sampling frequency group.
OKI Semiconductor
When mixing of channels is done, the clamp occurrence possibility increases from the mixing calculation point
of view. If it is known beforehand that the clamp will occur, then adjust the sound volume by VOL command.
It is not possible to perform analog mixing by a different sampling frequency.
When performing analog mixing, the sampling frequency group of the first playback channel is selected.
Therefore, please note that if analog mixing is performed by a sampling frequency group other than the selected
sampling frequency group, then the playback will not be of constant speed: some times faster and at other times
slower.
The available sampling groups for analog mixing by a different sampling frequency are listed below.
4.0 kHz, 8.0 kHz, 16.0 kHz, 32.0 kHz
5.3 kHz, 10.6 kHz, 21.3 kHz, 42.7 kHz
6.0kHz, 12.0kHz, 24.0kHz, 48.0kHz
6.4 kHz, 12.8 kHz, 25.6 kHz
Channel 1
Channel 2
Channel 1
Channel 2
Figure 1 In Case a Different Sampling Frequency Played Back
Figure 2 In Case a Different Sampling Frequency Played Back
during Playback of the Other Channel Playback
after the End of the Other Channel
fs = 25.6 kHz (Invalid. Played back as fs = 32.0 kHz.)
fs = 16.0 kHz
fs = 16.0 kHz
··· (Group 4)
End of channel 1
··· (Group 1)
··· (Group 2)
··· (Group 3)
Normal playback if not played back by
other channel.
fs = 25.6 kHz (Valid)
FEDL2250DIGEST-06
ML2250 family
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