Recently, there have been increased interests in utilizing the existing premises copper wring for high-speed data transmission. The reason is due to copper media`s low cost, widespread deployment and availability for a 10Mb/s Ethernet network (10Base-T). Because copper media in general, and specifically Category-3 UTP(unshielded twisted-pair) is very lossy medium that was designed to support low-speed, voice-based communications, 10Base-T has no performance guarantees if transmitted on a cable over 100 meters.
Numerous high-bit rate digital communication technologies that employ UTP wring at longer loop length are currently being used and proposed. These include ADSL (asymmetric digital subscriber lines), HDSL (high-speed digital subscriber lines), VDSL (very high-speed digital subscriber lines) and so on. The aforementioned technologies necessitate the use of highly complex digital communication algorithms and also need auxiliary transceivers or modems for data coding compatible with algorithms from 10/100Base- T outputs. This is because most PCs sold today come with a 10/100Base- T interface.
In this paper, we present an adaptive analog equalizer providing robust 10Mbps data transmission (10Base-T) at loop length up to 400 meters. It doesn`t necessitate the use of highly complex digital communication algorithms, therefore doesn`t need any auxiliary transceivers or modems. The equalizer with high frequency gain boost capability is controlled automatically by the proposed AZC (Adaptive Zero Control) loop according to cable length. It is implemented using AMS 0.8 μm CMOS technology.
