Arterial stiffness is a core marker of vascular ageing, and pulse wave velocity (PWV) is widely used for its non- invasive assessment. However, conventional beat-level PWV is pressure-confounded and does not directly characterise within- beat hyperelastic behavior. In addition, no established automated ultrasound framework currently exists for direct incremental PWV estimation in routine point-of-care workflows. We develop a computerised multichannel RF-ultrasound method that estimates two systolic fiducial wave speeds and defines incremental PWV as ∆PWV = PWV2 − PWV1. We also construct a controlled in silico test bed to characterise sensitivity to frame rate, RF sampling rate, SNR, and channel count. Results show that frame-rate reduction via dropped-frame reconstruction causes substantial timing error at low frame rates, followed by a saturation region beyond which additional frame- rate increase provides marginal benefit. RF sampling sweeps show progressively increasing error as sampling is reduced, consistent with degraded fiducial morphology and timing local- ization. SNR analysis identifies a usable operating band and demonstrates that multichannel regression is markedly more robust than two-channel estimation, especially in low-SNR con- ditions; under selected operating conditions, incremental-PWV error remains below expected physiological within-beat PWV change. These findings indicate that reliable incremental PWV estima- tion is feasible when temporal resolution, sampling fidelity, and synchronization constraints are jointly satisfied and multichannel fitting is used. Clinically, this supports automated ultrasound- based incremental PWV as a scalable tool for early vascular- ageing assessment and longitudinal risk monitoring