common-mode rejection

noun

UK /ˈkɒmən məʊd rɪˈdʒɛkʃən/

US /ˈkɑːmən moʊd rɪˈdʒɛkʃən/

It is when a device ignores noise that is the same on both of its input wires.

The amplifier's common-mode rejection kept the hum from the power lines out of the recording.

SYNONYMS

CMR differential rejection noise rejection interference suppression

RELATED WORDS

differential amplifier op-amp signal-to-noise ratio balanced line instrumentation amplifier

OTHER MEANINGS

2. The ability of a measuring circuit to cancel voltages that appear equally at both inputs.

Good common-mode rejection is essential when measuring tiny signals in an electrically noisy lab.

3. A figure of merit, usually given in decibels, describing how well a differential input rejects shared interference.

The datasheet lists a common-mode rejection of 120 dB at low frequencies.

4. The principle behind balanced audio cables, where identical noise on both conductors is subtracted out.

Balanced microphones rely on common-mode rejection to stay quiet over long cable runs.