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
To Next Page
Loading...
