Hi,

Which subject did you enrol for in GATE? And Where did you enrol? Answering your query, take the subject that you have done your B.Tech or B.E in. The syllabus for GATE is based on your engineering so you will find it easy. Besides, that will be the eligibility for M.Tech or PSU. 

Can you please clarify your query? Are you asking for preparations? If yes then please mention your branch.