Automatic gain control (AGC) device for global system for mobile communication (GSM) digital optical fiber frequency-selecting repeater and quick adaptive time slot method for AGC device

Abstract

The invention discloses an automatic gain control (AGC) device for a global system for mobile communication (GSM) digital optical fiber frequency-selecting repeater and a quick adaptive time slot method for the AGC device. The AGC device comprises a core logic processing device, a coprocessor, an analog/digital converter (ADC), a radio frequency (RF) numerical control attenuator, an RF frequency mixer and a low noise amplifier. The quick adaptive time slot method for the AGC device comprises an adaptive time slot recovering process and a quick automatic gain control process. The invention has the advantages that a time slot recovering threshold value is calculated adaptively, the steps of installing and debugging by engineering staff are reduced, a signal level input into the ADC can be adjusted to a target level value by the adjusting process, an overall adjusting period is short, signal quality is not influenced substantially, the gain balance of an uplink and a downlink which have small signal time slots can be ensured, and the connection quality of users is ensured.

Description

technical field [0001] The invention relates to an AGC device of a GSM digital optical fiber frequency selection repeater and a fast self-adaptive time slot method thereof [0002] , belonging to the field of mobile communications. Background technique [0003] The existing GSM digital optical fiber frequency selection repeater AGC device includes an attenuator, an analog frequency mixer, an analog / digital converter, and a logic processing device. The prior art design method is to directly count the quantized digital signal level of the uplink ADC converter, and restore the time slot information of the uplink signal according to the artificially set time slot judgment threshold. During the time slot signal period, the statistical signal level The average value is compared with the target level value. According to the comparison result, the value is adjusted with a certain step size to adjust the gain of the attenuator at the front end of the ADC converter. This is equivalen...

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Problems solved by technology

[0005] 1) Setting the time slot recovery threshold increases the difficulty of installation and debugging for engineers, and it is difficult to obtain a more appropriate threshold

[0006] 2) The probability of misjudgment is high if the uplink signal level value is directly used as the criterion for judging the time slot signal conversion, because the uplink signal has a large fluctuation range of the signal level reaching the repeater due to factors such as fading and multipath, and it is difficult to accurately Recover time slot signal conversion information

[0007] 3) Multiple adjustment processes are required to adjust the signal level input to the ADC converter to the target level value. The entire adjustment period is long, which will damage the carrier and other carrier signals and affect the signal quality.

[0008] 4) During AGC adjustment, small signal time slots will be attenuated together, which will cause small signal users to deteriorate or even drop calls, while analog signal repeaters and broadband digital repeaters cannot target a single carrier signal. gain compensation

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