Realizing Method for automatic frequency tracking of mobile terminal system

An automatic frequency tracking, mobile terminal technology, applied in transmission systems, baseband system components, electrical components, etc., can solve the problem of low accuracy, and achieve the effect of reducing the impact of noise and high calculation accuracy

Inactive Publication Date: 2008-03-05
ZTE CORP
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  • Abstract
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Problems solved by technology

[0012] Therefore, the technical problem to be solved by the present invention is to provide an automatic frequency tracking method for mobile terminals, to overcome the shortcomings of low precision in the prior art and unable to meet the requirements of mobile communication systems, to generate reliable frequency adjustment signals, and to improve automatic frequency tracking. Frequency Tracking Performance

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  • Realizing Method for automatic frequency tracking of mobile terminal system
  • Realizing Method for automatic frequency tracking of mobile terminal system
  • Realizing Method for automatic frequency tracking of mobile terminal system

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Embodiment Construction

[0028] The method of the present invention will be described in detail below in conjunction with the accompanying drawings.

[0029] The automatic frequency tracking method of the present invention is aimed at the frequency calibration pulse FB of the mobile communication system, that is to say, before automatic frequency tracking, the initial position of the calibration pulse FB must be determined first, and symbol-level synchronization must be completed.

[0030] In the block diagram of the GPRS terminal receiver shown in Figure 1, the receiver includes an antenna, a radio frequency front end 12, a down converter 14, a local oscillator 18, an analog-to-digital converter 16, a digital signal processor 20, a digital-to-analog converter 22 and VCO 24. After the antenna receives the signal, it is coupled to the radio frequency front end 12, the output of the radio frequency front end 12 is coupled to the input of the down converter 14, the output of the down converter 14 is coup...

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Abstract

A tracking method in the present invention carries on derotating treatment for digit orthogonal signal at receiving end at first; and then calculates the phase of baseband signal after derotating treatment; and spreads it out to become a function similar to linear one as well as utilizes the curve-fitting to derivate a burst frequency deviation value to carry on frequency deviation peak value error detection for the frequency deviation value, and finally carries on the smoothing treatment for it and uses the treated frequency deviation value as the regulation signal for the voltage-controlled oscillator.

Description

technical field [0001] The invention relates to a mobile terminal system in the field of mobile communication, in particular to an automatic frequency tracking and control (AFC) method in a GSM or GPRS mobile terminal system. Background technique [0002] In mobile communication, there are two types of channel fading caused by frequency changes: one is the fading caused by the inherent frequency difference between the local oscillation frequencies of the base station and the mobile station; the other is the fading caused by the mobile station moving. Channel fading caused by the Puler frequency shift. The frequency difference of the former is caused by long-term or short-term frequency drift of physical devices, and belongs to slow fading; relatively speaking, the latter belongs to fast fading. Therefore, automatic frequency control technology (AFC) must be used in the mobile terminal to compensate for the two types of fading to ensure correct reception. [0003] Both GSM ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04Q7/32H04B1/12H04B1/10H04L25/02
Inventor 王磊
Owner ZTE CORP
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