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nificantly reduce audible intermodulation artifacts, particularly
those associated with vocal sibilants.
Navigate to:
Processing / FM HF-Limiter
:
The slider actually controls the attack time of the independent
high frequency limiter. A near-instantaneous attack (
10
) will
ensure that negligible high frequency clipping will occur. This
will sound somewhat dull, especially with pop-music sources,
but may keep artifacts to a minimum with more conservative
fare. As the slider is moved to the left and attack time in-
creased, more high-frequency peaks will slide through and be
clipped, rather than limited. This will sound brighter, although
clipping artifacts may be noticeable with
Attack
settings of
3
or
less. The factory default setting of
5
is a good compromise for
most broadcast formats.
As seen on the Block Diagram (Page 9), adaptive pre-emphasis
is used only for FM program transmission. It is a fulltime func-
tion for the composite/MPX outputs, but is applied to the ana-
log and digital line outputs only in their FM modes for feeding
an FM exciter with a built-in stereocoder.
The characteristics of adaptive pre-emphasis are set when the
pre-emphasis selection is made: 75 microseconds for the West-
ern Hemisphere, 50 microseconds for Europe and most other
export areas. Pre-emphasis verification is covered on Page 40.
COMPOSITE CLIPPING
Navigate to:
Processing / Composite Clipper
:
At the user’s discretion, up to 3dB of composite clipping may
be introduced. This is brute-force, flat-topped clipping of the
baseband signal, but before the 19kHz stereo pilot and RDS
subcarrier (if used) are added. Baseband clipping invariably in-
troduces harmonic components that can clutter the spectrum
above the program signal to a greater or lesser extent. Compo-
site clipping does provide some degree of loudness advantage
with somewhat less harshness than program signal clipping in
the L/R audio domain. Nonetheless, exercise this advantage
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