high pitch vs high frequency

high pitch and high frequency both are nouns.

Word	Noun	Adjective	Verb	Adverb
high pitch	Yes	No	No	No
high frequency	Yes	No	No	No

As nouns, high pitch and high frequency are synonyms defined as:

high pitch and high frequency: a pitch that is perceived as above other pitches

high pitch (noun)	high frequency (noun)
a pitch that is perceived as above other pitches	a pitch that is perceived as above other pitches
	3 to 30 megahertz