Abstract: An audio test device and method provide a visual display of audio parameters for plural audio channels. One audio channel at least temporarily is deemed a reference channel and other channels become relative channel for comparison. Samples from the reference and relative channels produce relative amplitude and relative phase difference values that are plotted on the display. The difference values for pairs of relative channel and reference channel data samples can be plotted as pixels in pie shaped plot segments or other two dimensional plots, one for each relative channel. The relative amplitude and phase differences are presented as positions of pixels along the axes of the plot. This arrangement is particularly useful in showing the current amplitude and phase condition of a multi-channel audio signal. In addition, the amplitude and relative phase data for the channels can be logged over a long time period (a day or more) to show the amplitude and phase conditions as changing over time.

Abstract: A testing device and method for a digital video processing system is coupleable to an input and output of the processing system, and inserts video and audio marking information into the input to test system operation. The test device inserts a video marker and an audio marker data code for a single audio channel, preferably in the same digital input frame. The device then monitors the same audio channel and also all the other audio channels at the output, while monitoring for the video marker. The device indicates the occurrence and timing of results that appear at the outputs, the relative timing of the output audio mark(s) versus the video mark, an alarm in the event that an output mark is not found or found on an unexpected channel, etc. The test device successively exercises the audio and video portions of the processing system while also providing numeric timing measurements that are useful for proper setup and operation.