A 56-Gb/s DAC/ADC-Based Multicarrier Transceiver With TX Polar DSP and RX MIMO-DSP for >40-dB Loss Channel

This letter presents a digital-to-analog-converter/analog-to-digital converter (DAC/ADC)-based multicarrier transceiver fabricated in a 22-nm FinFET technology. The multicarrier signaling scheme utilizes orthogonally spaced carriers for spectral efficient band spacing and exhibit jitter robustness compared to conventional baseband pulse amplitude-based signaling. The transmitter has a polar digital signal processor (DSP) to generate the equalized codes driving the 7-b phase DACs, and 7-b amplitude DACs with 2-b predistortion to yield 1.2-Vppd swing. The multicarrier receiver front-end ADC outputs are equalized with a MIMO DSP backend to compensate for the intersymbol interference and interchannel interference. The measured transceiver at 56 Gb/s through a 40.8-dB loss at 14-GHz channel showed a jitter tolerance of up to 1.21 psrms at BER $\lt 10{^{-}4 }$ with 7.82-pJ/bit power efficiency.