Clock Reference

A clock reference is an electronic signal sent to devices to ensure that they run at a precise speed, similar to the ticking of a metronome (a device used to keep time between musicians during a performance). When synchronizing two or more machines, the same clock reference is sent to both machines to ensure they are both running at exactly the same speed. NTSC and PAL are two of the most common speeds for clock reference.

When working with previously recorded material, the clock reference must match the speed of the original recording to ensure that the audio plays back at the correct speed and not slower or faster than originally intended.

When referenced incorrectly, digital audio signals will incur "clocking errors” - digital anomalies that are nearly impossible to eliminate in improperly made recordings. For example, if an NTSC element is fed PAL reference clock then the NTSC machine will not lock and will try to speed up playback to match the faster PAL clock.