intermediate frequency; IF
Technical term in electronics, especially in superheterodyne receivers, referring to a frequency to which a carrier wave is shifted as an intermediate step in transmission or reception.
In the superheterodyne system, the received signal is converted to an intermediate frequency.
ＩＦ is the common abbreviation used in electronics for the frequency after conversion, while 中間周波数 is the full, more formal Japanese term for the same concept.
Compound of 中間 (intermediate) + 周波数 (frequency). A direct calque of the English term 'intermediate frequency'.