Digital Fiber Optic Repeater(FOR) adopts software wireless technology, digital filter technology and digital transmission technology, conquer the limiting disadvantage of simulate fiber optic transmission distance, satisfy the requirements of large dynamic and low noise while long distance transmission. In a situation of changeless hardware platform, Digital FOR realizes function extension of device via upgrade device software, and the way is flexible and convenient for using. Digital FOR much excellent than Simulate FOR no matter in frequency selectivity, anti-jamming ability or in function extension.
Working Principle: the Donor Unit of Digital FOR couple the base station downlink signal, convert radio signal to intermediate frequency(IF) by Duplexer and frequency conversion module, then sample the simulate IF signal to digital signal by High Speed A/D Converter of IF Slab, thereby achieve Digital Down Converting. According to the mobile network requirements of different systems, FPGA achieve channelized processing, accomplish AGC and automatism noise elimination. FPGA also implement CPRI agreement to convert optic module to optic signal and send to Remote Unit. The Remote Unit of Digital FOR convert the optic signal to digital signal, IF Slab convert DUC which through FPGA and send it to D/A Converter. After D/A signal conversion, the signal transform to radio signal by frequency conversion module, then amplified by Power Amplifier and Low-noise Power Amplifier Integrative Module, lastly send via forwarding antenna. In the same way, forwarding antenna receive the uplink radio signal from mobile, after reverse similar amplification, transmit the enhanced uplink signal via optic transmission to radio signal which can be recognized by base station, then send it to base station antenna.
In the whole process, there is no interaction between Digital FOR digital signal transmission and optic transmission, thus the digital signal do not attenuate with the attenuation of optic signal, counteract the path loss of wireless signal between base station and repeater. So while high-speed long distance transmission, Digital FOR can still keep high dynamic range, ensure signal quality, and maximize the usage of spectrum source and network devices, corresponding to provide a bidirectional and transparent channel between base station and mobile phone, makes wireless signal expanded.
1.Adopting transmission interface comply with CPRI regulation, and applying Digital Optical Terminal Technology
2.Radio signal will not attenuate with the attenuation of optic signal, and its dynamic range will keep steady in long distance and Multi-Channel Shunt transmission system
3.Transmission BER is less than 10exp-12
4.Digitized RF signal via software wireless and dispose the signal in digital area, which greatly enhance the signal disposal and controllability of device