FEDL2250DIGEST-09

OKI Semiconductor

ML2250 family

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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

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.

Mixing of Different Sampling Frequency

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

··· (Group 1)

5.3 kHz, 10.6 kHz, 21.3 kHz, 42.7 kHz

··· (Group 2)

6.0kHz, 12.0kHz, 24.0kHz, 48.0kHz

··· (Group 3)

6.4 kHz, 12.8 kHz, 25.6 kHz

··· (Group 4)

Figures below show a case when a sampling frequency group played back a different sampling frequency group.

Channel 1

Channel 2

fs = 16.0 kHz

fs = 25.6 kHz (Invalid. Played back as fs = 32.0 kHz.)

Figure 1 In Case a Different Sampling Frequency Played Back

during Playback of the Other Channel Playback

Normal playback if not played back by

other channel.

Channel 1

Channel 2

fs = 16.0 kHz

fs = 25.6 kHz (Valid)

End of channel 1

Figure 2 In Case a Different Sampling Frequency Played Back

after the End of the Other Channel