Mixed radar/graphics indicator

Abstract

A radar indicator comprising a source of radar image signals having a first (r,.theta.) format and a digital scan converter responsive to the radar image signals for converting the radar image signals from the first format to digital radar image signals having a second (X-Y) format. The digital scan converter includes an image memory for supplying the digital radar image signals having the second (X-Y) format. A source of external video image signals having the second format, including video synchronization signals is provided. A synchronization signal stripper and clock signal generator circuit is responsive to the video synchronization signals of the external video image signals for generating a clock signal synchronized with the synchronization signals of the external video image signals. The clock signal is applied to the image memory of the digital scan converter for causing controlled read-out of the digital radar image signals in a manner synchronized with the image signals of the source of external video image signal. Video processing circuitry responsive to the synchronized digital radar image signals develop a radar video signal from the synchronized radar image signals, and a video mixer circuit mixes in a controlled manner the external video image signal with the synchronized radar video signals. The mixed external video images with the radar video images are subsequently displayed.

Dependencies are inferred from the claim text.