Analog Camera Flickering?

I had connected a fixed lens Samsung Analog camera, using Ethernet cable. I had seen the image of this camera is flickering. When i changed the camera the flickering is not there. What could be the reason for the flickering of an analog camera ?? The camera is hardly 10m from the DVR

What kind of flickering and what camera is it? Could be iris, ICR etc.

Is the flickering on live and recorded video?

What is the frequency of the flickering? Is it rapid, like 50 Hz, or is a rolling image?