3.3 26 MHz Clock (DCXO)
DCXO (Digitally Controlled Crystal Oscillator) and VCTCXO (Voltage Controlled Temperature
Compensated Crystal Oscillator) are two different techniques used To maintain the mobile’s reference
oscillator’s accuracy over time. The reference oscillator’s accuracy over time will vary due to initial
crystal frequency offset, temperature drift and aging.
These static and dynamic frequency variations have to be compensated, otherwise the mobile would
be in danger of losing connection to the network.
The technique used to perform the frequency compensation is generally termed Automatic Frequency
Control (AFC).
To summarize the operation of DCXO, GSM Baseband processor will calculate the AFC compensation
(which is continuously updated) required based on the measured frequency error. Then the required
AFC compensation is sent to the LUXO (Lineari-Zation Unit of Crystal Oscillator), which in turns
control the DCXO core and generates The 26MHz system clock.
3. TECHNICAL BRIEF
- 24 -
Figure. 3-3 E-GoldVoice DCXO Overview
Содержание KG270
Страница 1: ...Date April 2007 Issue 1 0 Service Manual Model KG270 MG160 Service Manual KG270 MG160 ...
Страница 3: ... 4 ...
Страница 81: ...5 DOWNLOAD 82 5 DOWNLOAD 5 1 Download Setup Configure system like figure 5 1 Figure 9 1 Download Setup ...
Страница 87: ... 88 6 BLOCK DIAGRAM 6 BLOCK DIAGRAM ...
Страница 92: ... 93 8 PCB LAYOUT ...
Страница 93: ... 94 8 PCB LAYOUT ...
Страница 104: ... 105 10 CALIBRATION 10 2 3 Click SETTING Memu 10 2 4 Setup Ezlooks menu such as the following fugure KG278 ...
Страница 106: ...10 CALIBRATION 107 10 2 7 Select MODEL 10 2 8 Click START for RF calibration 10 2 9 RF Calibration finish KG278 ...
Страница 107: ...10 CALIBRATION 108 10 2 10 Calibration data will be saved to the following folder ...
Страница 113: ... 114 ...
Страница 124: ...Note ...
Страница 125: ...Note ...