mixed base numeration system; mixed base notation
Technical computing term for a numeral system where each digit position may have a different base, such as in time (hours, minutes, seconds) or calendar dates.
The representation of time is an example of a mixed base numeration system.
Compound of 混合 (mixed), 基底 (base), 記数法 (numeration system). A technical term likely coined in modern Japanese for computing contexts.