The Design of Selecting Broad Band Signal Frequency Based on the FIR Digital Filters

With the rapid development of mobile communication technology, the requirements of the quality of receiver´s signal become more and more rigid. But nowadays a variety of wireless communications´ coverage generates weak signal area and blind spot. And the cost is too high to set up the analog or digital base station, the infrastructure is also more complicated than we thought. To provide a low cost and simple erection, the equipment with functions of a small base station is necessary. This paper is including a research of CDMA repeater wireless frequency selection system which is based on the FIR digital filter. The article first describes the development of modern mobile communication technology and then illustrates the finite impulse response (FIR) digital filter. It also demonstrates a study of CDMA repeater and proposes a method according to MATLAB window function to design FIR filter in a broadband signal in the repeater frequency selection program. Finally, a satisfactory results is obtained through the computer simulation. The program is simple, reliable, low cost and short design cycle. It proves a preferable prospect for selecting frequency applications in high-speed digital filter design and broadband signals.