DP485 Service Manual
9
3C: Transistor X500 (12.8M TCXO)
5T: RF Pre-drive Amplifier Circuit Q502 (2SC5108), Q503 (2SC3356)
DC-DC: PMU IC1 (HS8851), U500 (RDA1846S)
4.7.IC Description
4.7.1.Features of AT1846S
a. Integrated CMOS RF front-end
b. High linearity low-noise amplifier and mixer
c. Low IF receiver path
⚫ Automatic DC offset calibration circuit
⚫ High performance analogue/digital converter and digital/analogue converter
⚫ Fully-integrated receiver filter
⚫ Digital AGC
⚫ Modulation and demodulation technique based on digital signal processing technology
d. TX path of direct frequency synthesis
⚫ Modulation method of direct frequency synthesis
⚫ TX filter based on digital signal processing technology
⚫ TX modulation gain number is adjustable
⚫ Digital voice activates TX control
e. High-performance fractional PLL frequency synthesizer
⚫ Fully-integrated in-chip RF VCO
⚫ Fully-integrated internal loop filter
⚫ Low phase noise
⚫ Fast lock of phase
⚫ High-frequency resolution with random frequency adjustable
⚫ Built-in transistor frequency error calibration circuit
f. Sleep mode of ultra-low loss
g. Three wire serial digital interface control
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