RDA5820 Просмотр технического описания (PDF) - Unspecified

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RDA5820

SINGLE-CHIP BROADCAST FM TRANSCEIVER

Unspecified 

RDA Microelectronics, Inc.

RDA5820 FM Transceiver V1.3

Figure 3-2. RDA5820 FM Transmit Block Diagram

3.3 FM Transmitter

The transmitter uses a digital modulate

structure. Audio signals (LIN and RIN) are

amplified by PGAs firstly, then converted to

digital codes by ADCs. The DSP core finishes

audio coding and FM modulate, pre-emphasis.

The syntersizer2 transmits the digital FM data

to VCO2. The PA (Power Amplifier) amplify the

FM signal.

The PGA gain and PA gain are adjustable by

set according registers bits (PGA_GAIN[2:0]

and PA_GAIN[5:0]).

PGA_GAIN V-LIN(VPP) PGA_GAIN V-LIN(VPP)

[2:0]

[2:0]

000

1.20V

100

0.075V

001

0.60V

101

0.037V

010

0.30V

110

0.018V

011

0.15V

111

0.009V

3.4 Audio Amplify

Audio signals (LIN and RIN) can also directly

send to audio amplifier in DACs and driving the

headphone through LOUT and ROUT ports.

3.5 I2S

The RDA5820 supports directly digital FM

transmit. The digital signals can input through

chip’s ports GPIO1/2/3, then transmits directly

through synthersizer2 and PA.

Also transmit to DAC and send out through

LOUT and ROUT ports.

I2S mode support master and slave mode.

3.6 PA

The PA (Power Amplifier) work frequency band is

65~115MHz, and output power is linearly

adjustable. The PA use linear structure for better

frequency distortion performance.

3.7 Synthesizer1

The frequency synthesizer 1 (including

synthesizer1 and VCO1 ) generates the local

oscillator signal which divide to quadrature, then

be used to downconvert the RF input to a

constant low intermediate frequency (IF). The

synthesizer reference clock is 32.768 KHz.

The synthesizer1 frequency is defined by bits

CHAN[9:0] with the range from 65MHz to

115MHz.

The synthesizer1 also generates reference to

synthesizer2 under FM TX (transmit) mode.

The information contained herein is the exclusive property of RDA and shall not be distributed, reproduced, or disclosed in whole or in

part without prior written permission of RDA.

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