Mixed-signal matched filter for high-rate communication systems

A mixed-signal programmable filter suitable for high-rate communication systems is addressed. The proposed filter has analogue input and analogue-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 Complementary Metal-Oxide Semiconductor (CMOS) transistors and thus can be integrated efficiently with the digital parts of systems. A cosine roll-off filter is designed and investigated by simulation in time and frequency domains. The results show that the proposed structure has a good speed-complexity-consumption trade-off.