different frequency; inter-frequency
Technical term used in engineering contexts such as radio, signal processing, or power systems to describe signals or operations involving different frequencies.
We designed a filter to prevent interference between different frequencies.
In inter-frequency operation, the transmitter and receiver use separate frequencies.
周波数 means 'frequency' in general, while 異周波数 specifically refers to a different frequency or inter-frequency context.
Compound of 異 (い, 'different') + 周波数 (しゅうはすう, 'frequency'). A straightforward technical coinage.