Is It OK for an academic to have broad research interests? First of all I am a second year M.Sc. Student in Computer science, working on information networks and enjoy my research a lot. In my B.Sc. final Project I had worked on intrusion detection systems, which was actually a computer network protocol related area and irrelevant to my current field.

I should mention that actually I am not frustrated with my current research or topics that I was working during B.Sc. But the problem is that I am also so excited about other nearly irrelevant topics.

For example I have passed about two courses in signal processing and now sometimes I am thinking about continue my PhD in that field. I am also interested in algorithms and CS theory, etc.

I want to know is It OK to have such broad activity in your resume or this can flag me as picky person regard that I finished successfully every project that I had been started and it can be verified in Recommendation Letters and so on.
There is nothing wrong in showing interest in various topics, as long as you obtain deep results in at least some of them.

Without having any deep results in some of the fields, it really looks bad, because it looks like that you are unable to advance enough in something to push the topic forward. It more looks like you chicken out of any serious job, because, frankly, in most disciplines the way to obtain deep results is quite painful.

But, as long as you obtain reasonably deep results in your topics of interest, you should be fine. Then, it shows that you are willing to learn new things, able to tackle problems that you don't know for a long time etc.

However, bear in mind that the boundary between the 1st case (no deep results) and the 2nd case can be very thin, and different people may consider it differently. For the sake of a Masters or a PhD, I think that each of them should be quite narrowly focused. On the other hand, it does not harm at all if you have a thesis on your primary field that contains good results, and at the same time you publish something in a secondary field.

Last, but not least, you have to remember one more thing: Who is funding you? Does he mind that he spends his project money on you and you work on something else? Your supervisor should be aware of the fact that you work on something else and should, at least to some extent, approve it.