Television synchronization of a real time ultrasonic sector scanner

The interaction of the scan rates of ultrasonic scanning and television recording systems often causes portions of the resultant television image to be either over- or under-scanned. This results in objectionable bright and dark sectors within the ultrasonic image on a television monitor during single-frame playback. The usual method for dealing with this problem is to exchange time resolution for image quality when preparing pictures for analysis or presentation. Time resolution can be preserved by operating the ultrasonic scanner at a scan rate one-half of the television frame rate and phase locking the ultrasonic scanner to the television system so that each angular scan of the ultrasonic system is initiated coincident with the beginning of each television frame.