baseband processing module

Then this paper put forward a scheme to bring baseband processing module into digital repeater to achieve frequency-hopping synchronizd with base station. Thirdly, types and performances of frequency-hopping in GSM are described, analysis about performance improvements after bring frequency-hopping into digital repeater ,and the blue Print of frequency-hopping module is also given. Fourthly, it introduces the design philosophy and system framework, then the detail module division is also given. Fifthly, technologies involved in DDC/DUC, GMSK demodulation and channel decoder module are describes in detail, which are signal sampling theory, interpolation and decimation theory, Viterbi demodulate and Veterbi decode, etc. Then FPGA implementation about each module is presented. Finally, testing about GSM frequency-hopping digital repeater system are given according to the national test criteria.GSM frequency-hopping digital repeater is noise free under the control of Slot synchronous clock, it means that it don't output noise when there is no useful signal. The system abstracts frequency-hopping information, switches the working frequency accurately to achieve the Frequency Hop Synchronization with base station. The Adverse Impact to GSM network which is caused by digital repeater can be avoid or reduced in under the RF frequency-hopping working condition.