Reference noise is ___________.
A. a 1000 Hz, -90 dBm tone
B. a noise that creates the same interfering effect as a 1000Hz, -90dBm tone
C. a noise that creates zero dBrn in a voice channel
D. B and C above
A. a 1000 Hz, -90 dBm tone
B. a noise that creates the same interfering effect as a 1000Hz, -90dBm tone
C. a noise that creates zero dBrn in a voice channel
D. B and C above