There are many topics in writing master's thesis of electronic information specialty. Here are some possible options:

Signal processing algorithm in electronic information engineering: This topic involves signal acquisition, processing and analysis, as well as the design and application of various digital signal processing algorithms.

Design and application of embedded system: This topic involves the software and hardware design of embedded system and its application in various practical application scenarios, such as smart home and medical equipment.

Application of Internet of Things technology in electronic information engineering: This topic involves the principle, application and development trend of Internet of Things technology, as well as its application and realization in electronic information engineering.

Network security problems and protective measures in electronic information engineering: This topic involves the network security problems existing in electronic information engineering, as well as the design and implementation of various protective measures, such as encryption algorithms and firewalls.

System integration and optimization in electronic information engineering: This topic involves the integration and optimization of various systems in electronic information engineering, and how to improve the performance and stability of the system.

These are just some possible choices, and there are many other topics to write about, depending on your interest and research background. When selecting a topic for a master's thesis, it is necessary to choose a topic with research value and practical application value, and combine the research direction of the tutor and the conditions of the laboratory as much as possible.