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Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
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3.2 GSM Mode
3.2.1 GSM Receiver
The Dual-mode KF390’s receiver functions are operated by only one RFIC as follows:
• EGSM-900, DCS-1800, PCS-1900 and UMTS-2100 modes use the RTR6280 IC only. Each mode
has independent front-end circuits and down-converters, but they share common baseband circuits
(with only one mode active at a time). All receiver control functions are beginning with SBI
2
-controlled
parameters.
RF Front end consists of antenna, antenna switch module (DGM129M01) which includes three RX
saw filters (EGSM-900, DCS-1800 and PCS-1900). The antenna switch module allows multiple
operating bands and modes to share the same antenna. In KF390, a common antenna connects to
one of six paths: 1) UMTS-2100 Rx/Tx, 2) EGSM-900 Rx, 3) EGSM-900 Tx, 4) DCS-1800 Rx, and 5)
DCS-1800, PCS-1900 Tx(High Band Tx’s share the same path), 6) PCS-1900 Rx. UMTS operation
requires simultaneous reception and transmission, so the UMTS Rx/Tx connection is routed to a
duplexer that separates receive and transmit signals. GSM900, DCS1800, and PCS1900 operation is
time division duplexed, so only the receiver or transmitter is active at any time and a frequency
duplexer is not required.
2
The RFIC operating modes and circuit parameters are MSM-controlled through the proprietary 1- line Serial Bus Interface (SBI). The Application
Programming Interface (API) is used to implement SBI commands. The API is documented in AMSS Software - please see applicable AMSS
Software documentation for details.
[Table 1.1] Antenna Switch Module Control logic
Z3X-BOX.COM
Summary of Contents for KF390
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