This article presents a novel eight-ary modulation technique with improved signal-to-noise ratio (SNR) compared to conventional pulse amplitude modulation 8 (PAM-8). The proposed SNR-enhanced 8-ary (SNRE-8) scheme modulates pulse width, position, and amplitude to improve the SNR. The proposed SNRE-8 modulation leverages the wireline channel loss to perform the modulation. Digital decoding of mutually exclusive eyes generated by the proposed SNRE-8 modulation further improves the eye margin at the receiver. A 27-Gb/s transceiver is implemented in a 65-nm CMOS process employing the proposed modulation. A PAM-8 transmitter is implemented on the same chip for comparison purposes. Compared to the PAM-8 modulation, the proposed SNRE-8 modulation shows an average SNR improvement of 10.6 dB at the near-end eye at the cost of 6.6% eye width reduction. With the aid of a time-domain feed-forward equalizer (FFE) and a continuous-time linear equalizer (CTLE), the proposed SNRE-8 transceiver achieves a bit error rate (BER) of 10−810^{-8} on a 9-dB loss channel with an energy efficiency of 5.39 pJ/bit.

中文翻译：

---

用于使用脉冲宽度、位置和幅度调制的有线收发器的 SNR 增强型 8 进制 (SNRE-8) 调制技术


本文介绍了一种新颖的八进制调制技术，与传统的脉冲幅度调制 8 (PAM-8) 相比，该技术具有改进的信噪比 (SNR)。所提出的 SNR 增强 8 进制 (SNRE-8) 方案通过调制脉冲宽度、位置和幅度来提高 SNR。提议的 SNRE-8 调制利用有线信道损耗来执行调制。由所提出的 SNRE-8 调制生成的互斥眼图的数字解码进一步改善了接收器处的眼图余量。 27 Gb/s 收发器采用所提出的调制技术在 65 nm CMOS 工艺中实现。为了进行比较，在同一芯片上实现了 PAM-8 发送器。与 PAM-8 调制相比，所提出的 SNRE-8 调制显示近端眼图的平均 SNR 提高了 10.6 dB，但眼图宽度减少了 6.6%。借助时域前馈均衡器 (FFE) 和连续时间线性均衡器 (CTLE)，所提出的 SNRE-8 收发器可实现 10−810^{-8} 的误码率 (BER) 9dB 损耗通道，能效为 5.39 pJ/bit。