¡ Semiconductor
MSM9810
3. Sampling Frequency
Sampling frequency can be specified for each phrase in the address management area of external
ROM. For the sampling frequency, the following ten types can be selected when voice data is
created.
4.0 kHz, 8.0 kHz, 16.0 kHz, 32.0 kHz (Group 1)
5.3 kHz, 10.6 kHz, 21.3 kHz
(Group 2)
6.4 kHz, 12.8 kHz, 25.6 kHz
(Group 3)
3-1 Channel Synthesis
When the internal LPFs are used, use of a different sampling frequency than the selected
sampling frequency GroupX is not permitted for channel synthesis.
The internal LPF can be used by selecting "use of internal LPF" with the OPT command (see 9-
4 "OPT Command").
When the internal LPFs are not used, channel synthesis can be made using a different sampling
frequency as shown below.
When channels are synthesized, the sampling frequency Group of the first vocalizing channel
(one of the above Group 1 to 3) is selected. If the sampling frequency Group other than the
selected Group is used for channel synthesis, playback becomes fast or slow. Figure 3.1 and
Figure 3.2 show examples.
Channel 1
Channel 2
Channel 3
fS=16.0kHz
fS=32.0kHz (Valid)
fS=25.6 kHz (Invalid, playback with fS=32.0 kHz)
Figure 3.1 When channel 3 is played back using a different sampling frequency
while channel 1 and 2 are being played back.
Channel 1
fS=16.0kHz
Channel 2
fS=25.6kHz (Valid)
Channel 1 ends
Figure 3.2 Channel 2 is played back using different sampling frequency
after channel 1 was played back
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