Kirisun DP990, Service Manual

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DP990/DP995service manual
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During power-off, the ON/OFF SWITCH is off, the input port PWR_SWITCH_DET detects a low-level power-on
signal, and the output port PWR_CTL outputs a low level to turn off the PMOS.
3.6.2. Audio Circuit
This circuit achieves audio input and output.
An audio codec TLV320AIC14 achieves the conversion between and processing of analog audio signals and digital
signals. An audio amplifier LM4951A amplifies analog audio signals and provides power drive. An IF subsystem
AD9864 converts and processes IF signals, and inputs modulated serial digital signals into a DSP. The DSP
processes digital audio signals, including coding and decoding audio signals. A DAC5614 converts the digital
signals output by the DSP into analog signals.
Flow of Audio Signals
The microphone converts audio signals into electrical signals, which are then amplified by the PGA of the codec
and sampled by the ADC of the codec. The signals are then converted into digital audio signals, sent to the DSP for
processing, sent to the DAC (TLV5614) to convert to modulated signals. The RF module modulates and amplifies
the signals. Finally, the signals are transmitted via the antenna.
The RF signals received by the RF module are converted by the IF subsystem AD9864 and then sent to the DSP for
demodulation and processing. The signals are then input to the digital audio processor of the codec for processing,
and then converted into analog audio signals by the DAC of the codec. The signals are then amplified by the
external audio amplifier (LM4951A) and then pass the audio switch MAX20327 to drive the internal/external
speaker.
Peripheral Modules