Abstract: A noise analyzer apparatus for a video signal produced by an X-ray imaging system corresponding to an image generates, in response to vertical and horizontal sync pulses, a two-level gating signal which is at a predetermined level solely during the times that intensity information contained in the video signal corresponds to pixels in an adjustably positionable window area of the image. A gated noise measuring circuit responsive to intensity information contained in the video signal and to the gating signal forms a signal which is a measure of a noise content solely within the window area of the image. A signal combiner combines the video signal and a signal derived from the gating signal to produce an augmented video signal containing in its intensity information a marker indicating the location of the window area.

Abstract: A sync separator separates vertical, field and horizontal synchronization signals from a video signal processed by a circuit under test which exhibits an artifact in the video. The cause of the artifact in the circuit under test is to be located using an oscilloscope. A line select circuit includes a delay responsive to the separated vertical and field signals for generating a marker signal and for positioning the marker signal via observation of the display produced by video signal under test. A trigger signal and marker generator refines the marker signal by causing the boundaries of the marker signal to coincide with corresponding horizontal sync pulses and produces an oscilloscope trigger signal having a transition which is formed by one of those boundaries. A combiner circuit combines the refined marker signal with the video signal under test for display so that the marker signal via the delay can be positioned on a region of interest in the video display.