Low voltage GM-C filters and OTAs for HDSL2

Increasing demand for high-speed data services in recent years has led to the evolution of digital subscriber line (DSL) technology. Lower implementation costs make DSLs attractive since, they can be implemented over existing telephone lines without any major structural changes. In order to provide reliable high-speed services using DSLs, it is necessary to design spectral shaping filters, that shape the transmit signal such that it complies with the time and frequency templates allowed in the network. This paper investigates possible analog filter types that would meet the requirements for use in second generation high bit-rate digital subscriber line (HDSL2) technology employing overlapped pulse amplitude modulation (PAM) transmission with interlocked spectra (OPTIS) as the modulation scheme. It also includes designs of two low voltage operational transconductance amplifiers (OTAs), one of which has been further used to design and implement the desired filter. Experimental results are also presented.