This thesis investigates the design of a high-speed digital datalink for intracardiac echocardiography (ICE) catheters that employ load modulation to address the critical challenge of cable-count reduction under power-consumption constraints. Load modulation offers a promising solution; however, at the multi-gigabit data rates required by the application, cable non-idealities, including transmission-line effects, dispersion, and skin effect, cause severe signal degradation, necessitating equalization. In this project, a frequency-dependent cable model that captures skin effect and dispersion is developed, and an adaptive Decision-Feedback Equal- izer (DFE) is employed to compensate for the distortion and Inter-Symbol Interference (ISI) introduced by the cable model.

This work develops a comprehensive system architecture for load modulation-based data transmission. Three modulation schemes are systematically compared: PAM-2, PAM-4, and PAM-8, each targeting 2.4 Gbit/s per channel to achieve 19.2 Gbit/s overall data rate using 8 parallel cables. An ideal testbench is used to determine the specifications for digitizing the received signal so that it can be passed to the equalizer.

A transmitter chip implementing a DLL, PP registers and Tri-state Buffers for serialization is designed and validated through circuit-level simulation. The chip is provided with a reference clock of 200 MHz and a 12 bit parallel data input. The serialized data is used to perform thermometer encoding and control a variable impedance by means of transistors in the triode region. Simulation results identify PAM-2 as the optimal modulation scheme due to its relaxed digitization requirements and superior noise robustness compared to higher-order modulation schemes.

The total power consumption per channel amounts to approximately 1.6 mW. Power consumption is dominated by the DLL, which accounts for approximately 90% of the total for a single channel. However, when scaling to the 8-channel system required to achieve the target data rate, the DLL can be shared across all channels, as it provides a common timing reference. This sharing results in a total system power consumption of only 3 mW, significantly lower than the target power budget of 20 mW. The on-chip energy consumption associated with load modulation yields to 45 fJ/bit.

The thesis confirm load modulation as a valid solution for digital datalink in the context of ICE catheters. While complete hardware realization remains future work, this work allows us to draw meaningful con- clusions regarding the implementation of such a datalink.