LG Electronics Inc.
LN510
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CHAPTER 3. Circuit Description
CHAPTER 3. Circuit Description
1. RF Transmit/Receive Part
1.1 Overview
The Tx and Rx part employs the Direct Conversion system. The Tx and Rx frequencies are respectively
824.04~848.97MHz and 869.04~893.97MHz for cellular and 1850~1910MHz and 1930~1990MHz for PCS.
The block diagram is shown in [Figure 1-1]. RF signals received through the antenna are seperated by
quintplexer. RF Signal fed into the low noise amplifier (in QSC6075T) through the quintplexer. Then, they
are combined with the signals of local oscillator (VCO) at the down conversion mixer(in QSC6075T) in
order to create Base-band frequency. Then, this signal is changed into digital signal by the analog to digital
converter (ADC, A/D Converter), and the digital circuit part of the QSC (Qualcomm Single Chip)6075T
processes the data from ADC. The digital processing part is a demodulator.
In the case of transmission, RF transmitter (in QSC6075T) receives QPSK-modulated analog signal from
the QSC6075T. In QSC6075T, the baseband quadrature signals are upconverted to the Cellular or PCS
frequency bands and amplified to provide signal drive capability to the power amp.
After that, the RF signal is amplified by the Power Amp in order to have enough power for radiation. Finally,
the RF signal is sent out to the cell site via the antenna after going through the coupler and quintplexer.
LG511C
Summary of Contents for LG511C
Page 1: ...Internal Use Only Service Manual LG511C Date September 2011 Issue 1 0 ...
Page 28: ...LG Electronics Inc LN510 27 168 Figure 1 1 Block Diagram of LG511C LG511C ...
Page 30: ...LG Electronics Inc LN510 29 168 LG511C ...
Page 50: ...LG Electronics Inc LN510 49 168 Waveform Waveform 4 1 1 c 4 1 1 d U1001 pin2 U1003 pin1 ...
Page 96: ...LG Electronics Inc LN510 95 168 1 ...
Page 98: ...LG Electronics Inc LN510 97 168 1 2 3 4 5 LG511C ...
Page 108: ...LG Electronics Inc LN510 107 168 Test points Test points 1 TP1 4 TP4 2 TP2 3 TP3 5 TP5 LG511C ...
Page 134: ...LG Electronics Inc LN510 133 168 Appendix Appendix ...
Page 136: ...LG Electronics Inc LN510 135 168 Appendix 2 Circuit diagram Appendix 2 Circuit diagram ...
Page 144: ...LG Electronics Inc LN510 143 168 Appendix 3 BGA Pin Map Appendix 3 BGA Pin Map ...
Page 145: ...LG Electronics Inc LN510 144 168 Not Used 3 1 U1601 BCM2070_BT 3 1 U1601 BCM2070_BT ...
Page 146: ...LG Electronics Inc LN510 145 168 3 2 U2001 QSC6075T 3 2 U2001 QSC6075T ...
Page 149: ...LG Electronics Inc LN510 148 168 3 5 U4002 LM49151_AUDIO AMP 3 5 U4002 LM49151_AUDIO AMP ...
Page 151: ...LG Electronics Inc LN510 150 168 Appendix 4 Component Layout Appendix 4 Component Layout ...
Page 152: ...LG Electronics Inc LN510 151 168 4 1 Main PCB Component Layout 4 1 Main PCB Component Layout ...
Page 161: ...LG Electronics Inc LN510 1 Appendix 6 Part List Appendix 6 Part List LG511C ...