Multi-tap decision feed-forward equalizer with precursor and postcursor taps

• Main Authors: Pfaff, Dirk, Palusa, Chaitanya, Lan, Po-Hsiang, Chen, Wei-Li, Abbott, Rob, Hsieh, Cheng-Hsiang
• Format: Patent
• Language: English
• Published: 02.02.2021
• Subjects: BASIC ELECTRONIC CIRCUITRY; ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; PULSE TECHNIQUE; RESONATORS; TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHICCOMMUNICATION

A multi-tap Differential Feedforward Equalizer (DFFE) configuration with both precursor and postcursor taps is provided. The DFFE has reduced noise and/or crosstalk characteristics when compared to a Feedforward Equalizer (FFE) since DFFE uses decision outputs of slicers as inputs to a finite impulse response (FIR) unlike FFE which uses actual analog signal inputs. The digital outputs of the tentative decision slicers are multiplied with tap coefficients to reduce noise. Further, since digital outputs are used as the multiplier inputs, the multipliers effectively work as adders which are less complex to implement. The decisions at the outputs of the tentative decision slicers are tentative and are used in a FIR filter to equalize the signal; the equalized signal may be provided as input to the next stage slicers. The bit-error-rate (BER) of the final stage decisions are lower or better than the BER of the previous stage tentative decisions.