most of the specializtion tracks in ECE need DSP, like networking, telecommunication, media processing, ebedded systems. etc. so i suppose it is a very important elective in ECE. take it seriously pls.
the course should not be too difficult if you are from EEE. the 2nd year course EE2009 should have prepared you well. the basic topics like Fourier Transform, Convolution, Sampling Theories etc. should all have been covered in 2009. DSP just digs deeper into it. you will need some knowledge of probablity also i think. if you work hard, there should be no problem. just don't get too freaked out.