BENQ-SIEMENS E71 Service Manual page 13

Mobile phone

Hide thumbs Also See for E71:

Table of Contents

All loop filters for PM and AM loops are fully integrated within Bright. To achieve a good

output modulation spectrum it is necessary that the bandwidths of the PM loop and the AM

loop are quite well adjusted to their target bandwidth. For the PM loop there is an automatic

calibration mechanism within B6PLA running prior to each TX slot. The AM loop bandwidth

is calibrated only one time in the factory.

TxVCO

The TxVCO is integrated inside Bright. It consists of 256 VCO bands operating in the

frequency range 1648MHz to 1910MHz. The signal for the low bands GSM850 and

EGSM900 is generated by a 1/2 divider. Two independent output buffers, one for each

band, deliver the output signal to the PA module input. The choice of the appropriate VCO

band is done automatically and controlled by the internal state machine.

Filter

TxVCO

Modulator

Bright(D5932)

The required voltage

VDD_RF1/VDD_RF2

is provided by the ASIC

D1300

Technical Documentation

Release 1.0

TD_Repair_L3 _Theory of Operation_E71_R1.0.pdf

Page 13 of 35

Table of Contents