The Signal generator module can be used to generate various test signals.
AV sync reference
White time/frame counter on black background. At every full second the frame inverts and is accompanied by 1000 sine wave at -18 dBFS.
Colour bar pattern (white, yellow, cyan, green, magenta, red, blue, and black) with software, CPU & video information. Audio is a 1000 Hz sine wave at -18 dBFS.