3. TECHNICAL BRIEF
- 28 -
(3) Transmitter Part
To minimize the post-PA filtering requirements and any additional post-power amp losses, the transmit path
consists of a vector modulator and a frequency translation loop. The translation loop consists of the
following:
• PFD and charge pump
• In-loop modulator
• One programmable divider
• Integrated transmit loop filter
• Two transmit VCOs and output buffers
A. Translation Loop
The translational loop includes a vector modulator and a frequency translation loop to minimize the post-PA
filtering requirements. the loop functions as a PLL with a mixer in the feedback path and a modulator in the
reference path. The loop provides a PFD and charge pump, integrated loop filters, two transmit VCOs,
down-conversion mixer in the feedback path, a frequency divider for frequency plan flexibility, and the
modulator. The mixers in the feedback path provide either high side or low side injection to provide flexibility
in the frequency plan. The modulator in the reference path uses a vector summing technique to reject the
unwanted image and to also sufficiently attenuate the 3rd and 5th harmonics. Therefore, no external IF
filters are required. The loop filter required for the transmit VCOs is integrated in the SKY74400.
B. Transmit VCOs
Two integrated transmit VCOs are designed to meet GSM850, EGSM900, DCS1800, and PCS1900
requirements. The transmit VCOs use the same DFC technique as the synthesizer section to lock the
translation loop. The rising edge on TXENA initializes the transmit DFC. The output buffers feed the signal
to the PAs. Two transmit buffers are provided, one for the low band VCO and the other for the high band
VCO.
Figure. 3-2 Crystal Oscillator BLOCK DIAGRAM
Z3X-BOX.COM
Содержание MG300d
Страница 1: ...Date January 2006 Issue 1 0 Service Manual Model MG300d Service Manual MG300d Z 3 X B O X C O M ...
Страница 23: ...3 TECHNICAL BRIEF 24 Figure 3 1 SKY74400 FUNCTIONAL BLOCK DIAGRAM Z 3 X B O X C O M ...
Страница 48: ...3 TECHNICAL BRIEF 49 3 7 CAMERA IC AIT813 U504 Figure 3 15 AIT813 APPLICATION BLOCKDIAGRAM Z 3 X B O X C O M ...
Страница 50: ...3 TECHNICAL BRIEF 51 3 8 MIDI IC YMU787 U703 Figure 3 24 YMU787 BLOCKDIAGRAM Z 3 X B O X C O M ...
Страница 70: ...4 TROUBLE SHOOTING 71 4 2 TX Trouble SKY74400 FEM 13Mhz OSCILLATOR Test Points Z 3 X B O X C O M ...
Страница 83: ...4 TROUBLE SHOOTING 84 4 6 LCD Trouble EMI FILTER CN600 Test Points Z 3 X B O X C O M ...
Страница 88: ...4 TROUBLE SHOOTING 89 Figure 1_Blue_RST Figure 2_DEBUG_Tx Rx Figure 3_PCM_SYNCS Tx Rx USCO Z 3 X B O X C O M ...
Страница 110: ...5 DOWNLOAD AND CALIBRATION 111 8 Push the START button Z 3 X B O X C O M ...
Страница 111: ...5 DOWNLOAD AND CALIBRATION 112 9 Phone test Finish is shown in below screen Z 3 X B O X C O M ...
Страница 112: ...6 BLOCK DIAGRAM 113 6 BLOCK DIAGRAM Z 3 X B O X C O M ...
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Страница 124: ... 125 MG300d 8 PCB LAYOUT Z 3 X B O X C O M ...
Страница 125: ... 126 MG300d 8 PCB LAYOUT Z 3 X B O X C O M ...
Страница 133: ...10 STAND ALONE TEST 134 Figure 10 2 HW test setting Figure 10 3 Ramping profile Z 3 X B O X C O M ...
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Страница 140: ... 141 12 EXPLODED VIEW REPLACEMENT PART LIST Z 3 X B O X C O M ...
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