A MIDI timing reference signal used to synchronize pieces of equipment together. MIDI clock runs at a rate of 24 ppqn (pulses per quarter note). This means that the actual speed of the MIDI clock varies with the tempo of the clock generator (as contrasted with time code, which runs at a constant rate). Also note that MIDI clock does not carry any location information – the receiving device does not know what measure or beat it should be playing at any given time, just how fast it should be going.
