Mixed-Signal Realization of Matched-Filters for High Rate Communication Systems

A mixed-signal programmable filter suitable for high-rate communication systems is addressed in this work. The proposed filter has analog input and analog-sampled outputs. The filter taps are stored in a digital memory and can be changed on the fly which is desirable in many practical applications such as adaptive filtering. The filter structure is based on a bank of digitally controlled transconductors along with small capacitors. The employed transconductors are based on simple CMOS transistors and thus can be integrated efficiently with the digital parts of systems. A cosine rolloff filter is designed and investigated by simulation in frequency domains. The results show that the proposed structure has a good speed-complexity-consumption trade-off.