Pulses per quarter note
Pulses per quarter note, also known as pulses per quarter, and ticks per quarter note, is the smallest unit of time used for sequencing note and automation events, both by step sequencers and in the MIDI standard.
If the resolution is too low, the performance recorded into the sequencer may sound artificial, losing all the subtle variations in timing that give the music a "human" feeling. Purposefully quantised music can have resolutions as low as 24 or even 4 PPQN. At the other end of the spectrum, modern computer-based MIDI sequencers designed to capture more nuance may use 960 PPQN and beyond.
This resolution is a measure of time relative to tempo since the tempo defines the length of a quarter note and so the duration of each pulse. The resulting PPQN per MIDI-Clock is thus related to the TimeBase in Miroseconds defined as 60.000.000 x MicroTempo = Beats per minute.
