A 3×3.8Gb/s four-wire high speed I/O link based on CDMA-like crosstalk cancellation

A 16 Gb/s four-wire CDMA-based high speed I/O link with transmitter timing adjustment

“…Such crosstalk is primarily caused by capacitive coupling between the adjacent channels and mismatches in circuit components, packages, and PCB traces. CDMA-based four-wire signaling [1] effectively resolves the crosstalk problem without sacrificing the benefits of simultaneous DM and CM signaling. Basically, the CDMA-based crosstalk cancellation technique [1] spreads the crosstalk spectrum [3] effectively reducing the in-band signal corruption and improving bit error rate (BER).…”

“…CDMA-based four-wire signaling [1] effectively resolves the crosstalk problem without sacrificing the benefits of simultaneous DM and CM signaling. Basically, the CDMA-based crosstalk cancellation technique [1] spreads the crosstalk spectrum [3] effectively reducing the in-band signal corruption and improving bit error rate (BER). However, achievable in-band crosstalk suppression may be limited in ISI dominated highspeed wire-line communication systems.…”

“…2 shows the data recovery process of the CM links without any DM-to-CM crosstalk. The phase of S RX (t) and integration clock (RX clock de-skew) is determined to maximize the signal power at the integrator output as described in [1]. Meanwhile, the DM-to-CM crosstalk, [D(t)] X , is spread by S RX (t) and then filtered by the integrator, as shown in the middle row in Fig.…”

“…Note that similar timing adjustment was also employed in [4] to compensate for differences in propagation delays of odd, even and static signal modes but not in the context of CDMA-based signaling systems. The paper is organized as follows: Section II summarizes the CDMA-based crosstalk cancellation technique of [1] and describes how TX timing adjustment is employed; Section III describes circuit implementation details, and Section IV presents measurement results.…”

Design Techniques for High-Speed I/Os: Challenges and Opportunities

“…A three-level differential encoding was used to obtain higher I/O pin efficiency [40]. A Codedivision-Multiple-Access (CDMA) based transceiver was proposed for parallel links to improve crosstalk rejection [41]. Kossel, et al showed that the use of Tomlinson-Harashima pre-coding initially proposed in [42,43] at transmitters can remove post-cursor ISI [44].…”