Clock synchronization apparatus and method for radio frequency remote unit

Abstract

The invention provides a clock synchronization device of a radio frequency zoom out unit, comprising an optical module, an SerDes, an FPGA, a PFD, wherein the clock synchronization device of the radio frequency zoom out unit also comprises a digital loop filter, a direct digital frequency synthesizer (DDS), a DAC, an analog filter, a clock dispenser. The optical module is connected with one end of the SerDes, the PFD, the digital loop filter, the DDS, the DAC, the analog filter and the clock dispenser. The output end of the analog filter is accessed with the input end of the PFD, and the other end of the clock dispenser is respectively connected with the SerDes, the FPGA and the radio frequency circuit of the receiver and transmitter, the ADC and the DAC integrated in the adio frequency zoom out unit. The device adopts the whole digital phase locked loop, with low cost, overcomes the drawback of the aggravating performance after aging, wherein the system has high reliability, which provides the high accuracy clock system, and effectively eliminates the jitter of the recovery clock.

Description

technical field [0001] The invention relates to a clock synchronization technology in the field of optical fiber transmission, in particular to a clock synchronization device and a method for a radio remote unit. Background technique [0002] Radio remote units have been widely used in mobile communication systems. The use of radio remote units can solve problems such as difficult site selection of equipment rooms and reduce feeder loss, and improve system efficiency. The clock synchronization technology is the key technology of the remote radio unit. [0003] The transceiver composed of analog-to-digital converter (ADC), digital-to-analog converter (DAC) and radio frequency (RF) circuit is integrated in the remote radio unit. The working clock of the transceiver affects the receiving sensitivity and transmission modulation accuracy of the system, etc. index. The remote radio unit performs data exchange from the base station or the remote radio unit at the upper level thr...

AI Technical Summary

Problems solved by technology

[0006] (1) The cost is high, and the GPS receiver that needs to be installed is expensive

[0007] (2) It is difficult to select a GPS antenna point. When the RRU is located indoors for indoor coverage, the satellite signal is not very good, which makes it difficult to select a GPS antenna point, and the flexible use of the radio remote unit is limited.

[0010] Therefore, the current clock synchronization scheme is difficult to obtain a good price / performance ratio, and the clock accuracy is not high enough, which reduces the competitiveness of the product

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