digitiser vs digitizer

digitiser and digitizer both are nouns.

Word	Noun	Adjective	Verb	Adverb
digitiser	Yes	No	No	No
digitizer	Yes	No	No	No

As nouns, digitiser and digitizer are synonyms defined as:

digitiser and digitizer: device for converting analogue signals into digital signals

Other synonyms of digitiser include analog-digital converter, analog-to-digital converter.

digitiser (noun)	digitizer (noun)
device for converting analogue signals into digital signals	device for converting analogue signals into digital signals