Given that, I cannot provide a real published academic or engineering paper on that exact model. But I can provide you with an that addresses the core challenge of upgrading HDMI on a 2012 PVR. You can use this as a template for your own research or modification project. Paper Title: “Retrofit HDMI Fidelity in Legacy 2012 PVRs: A Case Study of Signal Path Degradation and Upgrade Feasibility in the ‘Iclass 9898xs’ Class Recorder”
However, based on my knowledge base, the Iclass 9898xs is not a documented mainstream consumer electronics model (like a Topfield, Humax, or Sky box). It may be a generic/branded PVR from a lesser-known manufacturer, a regional model, or a typo (perhaps you meant Icecrypt or iCord ?). Iclass 9898 xs pvr hdmi upgrade 2012 hit