Nokia 9000i, Руководство по обслуживанию

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After Sales
Technical Documentation
RAE/RAK–1N
Baseband
Page 2–18
Original, 08/96
Clocking scheme
ASIC
MCU
RFI
VCXO
RF System Clock
26 MHz
MCU Clock
26 MHz
RFI Clock 13 MHz
Sleep Mode:
135.4kHz
OSCILLATOR
DSP Clock
60.2 MHz
differential sine
wave
Codec Main Clock
and data Transfer
clock
512kHz
Codec Sync Clock
8 kHz
enable
AUDIO
CODEC
DSP
DBUSSYNC 8kHz
SIMCLK
3.25 / 1.625
MHz
MCU Clock
13 MHz
SCL
DBUSCLK 512kHz
Figure 3. Clocking Scheme
Most of the clocks are generated from the 26 MHz VCXO frequency by
the ASIC:
– 26 MHz clock for the MCU. SCL divides this by two and supplies a
13 MHz clock to the MCU.
–
13 MHz for the RFI. The ASIC also generates 135.4 kHz sleep mode
clock for the RFI.
– 3.25 MHz clock for SIM. When there is no data transfer between the
SIM card and the baseband the clock can be reduced to 1.625 MHz.
Some SIM cards also allows the clock to be stopped in that mode.
–
512 kHz main clock for the codec and for the data transfer between
the DSP and the codec.
–
8 kHz synchronisation clock for data transfer between the DSP and
the codec.
–
512 kHz clock and 8 kHz sync. clock for the DBUS data transfer