Complementary filter design for testing of IS-95 code division multiple access wireless communication systems

In this paper, a simple design of a complementary filter is presented for performance measurement of an IS-95 code division multiple access wireless communication system (1995). The complementary filter is required to meet the design requirements, which are specified in IS-97 document (1994). The purpose of employing the complementary filter in test equipment is to remove intersymbol interference introduced by the base station transmit-filter and the transmit-phase equalizer. Five window functions, which do not affect the desirable response at the proper sampling times, are applied to the desirable output. The output of a window Is set to be the output of the complementary filter. Then, the complementary filter is obtained by taking a deconvolution of the output response of the window with the impulse response resulted by cascading the base station transmit-filter and the transmit-equalizer. It is found that the output of the complementary filter with the Kaiser window function meets all requirements specified in IS-97. In addition, it is observed that the Kaiser window has the smallest number of the filter coefficients among all windows considered in this paper. Therefore, the complementary filter with the Kaiser window is recommended for implementation of the IS-95 system measurement