Download or read book Adaptive Analog Equalization of Multimode Fiber Channels Using 0.13um CMOS Technology written by Mahyar Kargar and published by . This book was released on 2009 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt: An adaptive analog high-speed decision feedback equalizer (DFE) to combat the inter-symbol interference (ISI) caused mainly by modal dispersion in multimode optical fiber (MMF) channels has been realized in CMOS technology. The MMF channel non-idealities have been throughly investigated and simulated. Based on simulation results from MATLAB and ModeSYS, a 3-tap fractionally- spaced feedforward equalizer and a 3-tap adaptive feedback equalizer showed enough equalization capability to compensate for up to 300 m of legacy MMF. The DFE chip consists of a 3-tap T/2-spaced feedforward filter, used to cancel the pre-cursor ISI, and a 3-tap T-spaced feedback filter used to cancel the post-cursor ISI. A novel modified Cherry-Hooper stage is designed as the delay element in the feedforward path. A Delay-Locked Loop (DLL) plus a gain-control loop are also realized to control the delay and gain respectively, of each delay element in the feedforward path. A slicer incorporating a high-speed CML structure with inductive peaking as a bandwidth enhancement technique is realized. High-speed CML D Flip-Flops are used as delay elements in the feedback path. The Least Mean-Square (LMS) algorithm is used to adapt the coefficients in the feedback path. The DFE output is applied to a 10 Gb/s binary clock and data recovery (CDR) circuit to extract the clock from slicer output and providing it to the DFFs. The DFE output data is retimed with the recovered clock from CDR. Retimed data and recovered clock are applied to output 50 (omega) drivers to observe the chip performance. The adaptive DFE was able to equalize 10 Gb/s PRBS data corrupted by a 300 m-long MMF and 12-inch FR4 trace with measured BER