HP 8901B Operation And Calibration Manual page 32

General Information Model 8901B
In FM broadcasting and communications, the signal-to-noise ratio is improved by giving the baseband
signal a high-frequency boost before applying it
to
the modulator. This is called pre-emphasis. The
boost is a simple
6
dB
per octave with the 3
dB
comer specified by a time constank for example,
75
ps
(which corresponds to a 3
dB
comer of 2.12 kHz) for commercial broadcast
FM. If
desired,
the demodulated FM can be de-emphasized to equalize the signal at the modulation output and at
the display.
1-18