2.2 Transmit
TX is composed of the modulation loop, power amplifier and antenna
switch. PLL is mainly in the internal MT6253, I / Q signal first
enters into the MT6253, after entering the PLL the signal is
modulated to RF, and then it outputs from the chip to PA, converts
into electromagnetic energy through antenna by the antenna
switch after enlarged.
PA:
This part adopts voltage control to achieve and its role is to amplify
the signal power in accordance with the requirements. It is divided
to two different power levels through VRAMP signal. The transmit
signal of GSM is 5 to 19, power is from 3.2MW to 2W while DCS is
0 ~ 15, power from 1MW ~ 1W. PA is time-sharing work controlled
by TX-EN chip, the output power of PA is controlled by VRAMP
(APC) through the voltage. PA is intermittent work, by the BS to
achieve the choice of frequency bands.
2.3 Receive
Antenna RX - MT6253 (RX_VCO mixer) - band-pass - Amplification -
filter - Amplification - RX_VCO mixer - CPU
Summary of Contents for E146
Page 1: ...E146_Maintenance Instruction Prepared by xiaoyu wan Approved by Date 2010 9 28...
Page 8: ...2 4 Common RF Malfunction Detection and Maintenance Flow Chart of MS Transmit malfunctio...
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Page 14: ...3 4 2 Detection and Maintenance Flow Chart of No download malfunction...
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