Audio to Video Delay Measurement

VM700T Option 42

Features & Benefits

• Measures Timing Difference Between Audio and Video Through Different Transmission Paths
• Supports Both NTSC and PAL

Applications

• AV Delay Measurement in any Type of Transmission Path

Audio to Video Delay Measurement

The VM700T Opt. 42 measures the timing difference between the audio and video portions of a program arriving from different transmission paths. This option supports both the NTSC and PAL video standards. This measurement is designed to be used in conjunction with a Tektronix VITS200 NTSC VITS Inserter or VITS201 PAL Insertion Generator and a Tektronix ASG140 Audio Signal Generator or an ASG100 Audio Signal Generator.

The measurement requires both video and audio test signal connections to the VM700T. The audio timing measurement is made on either the left or right channels, using the first arriving audio signal as the audio trigger. Note that audio to video measurements can be made with the video trigger in the vertical interval or if the vertical interval is not passed, as in codecs, a full field video trigger can be used. The audio timing measurement is made on either the left or the right channel input; the measurement will look at both channels, and use the first arriving audio signal as the audio trigger.

To operate the audio to video delay measurement, the VITS inserter is connected to the audio generator with a special remote cable. A wiring diagram for construction of this special cable is included in the Opt. 42 supplemental manual insert. Once the VITS inserter is genlocked, it sends a control signal to the audio generator enabling an audio test tone. At the same instant, the VITS inserter outputs a special vertical interval video character ID or fully field standby message. Both audio and video signals are routed through your system and received by the VM700T for measurement. The video and audio signals are simultaneously gated off and on, once every 5 seconds. The time delay between the received signals at the VM700T is measured and displayed on an easy to read auto ranging graphic display.