Equalization and Near-End Crosstalk (NEXT) Noise Cancellation for 20-Gbit/sec 4-PAM Backplane Serial I/O Interconnections

FR4;0.18um-CMOS;Cancellation;Near-end crosstalk noise;Equalization;Backplane;4-PAM;20 Gbit/sec

Hur, Young Sik ; Electrical and Computer Engineering

University:Georgia Institute of Technology

Department:Electrical and Computer Engineering

关键词: FR4;    0.18um-CMOS;    Cancellation;    Near-end crosstalk noise;    Equalization;    Backplane;    4-PAM;    20 Gbit/sec;   

Others  :  https://smartech.gatech.edu/bitstream/1853/7522/1/hur_youngsik_200512_phd.pdf

美国|英语

来源: SMARTech Repository

【 摘 要 】

A combined solution of the Feed-Forward Equalizer (FFE) and Near-End Crosstalk (NEXT) noise cancellation technique was suggested. The techniques increase data throughput and improve link quality in the 20-in FR4 legacy backplane application. Backplane channel loss and coupling noise were measured and characterized to develop the corresponding behavioral channel model.The receiver-side FFE with 4-tap Finite Impulse Response (FIR) filter structure was adopted as the optimum equalizer topology. The 4-tap FIR filter consists of tap delay line with tap-spacing 33 ps and linear tap-gain amplifiers. The tap coefficients were calculated with the Minimum-Mean-Squared-Error (MMSE) algorithm. A 0.18-um CMOS 4-tap FIR filter IC was designed and fabricated. The experiment results showed the 20-Gbit/sec 4-PAM and 10-Gbit/sec NRZ signal were successfully equalized for the 20-in FR4 legacy backplane channel. Moreover, the suggested NEXT noise cancellation technique consists of coarse- and fine-cancellation stages. The 0.18-um CMOS building block ICs such as 7-tap FIR filter, tunable active Pole-Zero (PZ) filter, and a temporal alignment delay line were fabricated. The experiment results showed that 6-dB Signal-to-Noise Ratio (SNR) improvement was achieved by the developed NEXT noise cancellation technique.