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23. Glossary
dBu
dBFS
Delay
Direct Out
DSP
Dynamics
EQ
Expander
Fader
Filters
Gain
Gate
GPI
POWER CORE User Manual
dBu is used to describe levels within the analogue domain, and is a measure of
absolute voltage level based on 0dBu = 0.775 Volts (RMS). dBu is often used to
indicate nominal broadcast operating levels. For example, in the EBU normal
broadcasting level = +6dBu.
dB Full Scale
dBFS is used to describe levels within the digital domain. 0dBFS describes the
system's internal clipping point; this is the maximum level which may be handled by
the system without signal distortion. For example, your system may be set for
+18dBu = 0dBFS. If your normal broadcast level is +6dBu then this leaves an
operating headroom of 12dB.
The signal output from a delay module is x ms behind the signal input to the module.
Delay is often applied to audio sources whose video has undergone digital video
processing; delay is required such the audio remains in sync with the video.
Direct Output
The direct output of a source channel is the output of the individual source. Direct
Outputs are often used to provide a record or 'snoop' feed of a single source, and may
be taken from various points within signal flow: pre fader, post fader, etc.
Digital Signal Processing
Digital signal processing (DSP) is the study of signals in a digital representation and
the processing methods of these signals.
Within POWER CORE, DSP is also used as the collective name given to the
processing chips, within the system unit's Master Board, which provide audio signal
processing such as equalization, dynamics and delay.
Dynamics is the collective terms given to audio processing which responds to
changes in signal level. For example, a Compressor, Limiter, Gate or Expander.
Equaliser.
An equaliser is a processor which changes the frequency characteristics of a signal,
for example to increase the amount of treble or bass components in the signal.
A dynamics processor used to magnify changes in the dynamic range of the input
signal. For example, to reduce noise in speech pauses. See also Compressor.
A potentiometer used to adjust the gain of a signal.
Filters are equaliser sections which are used to cut out or reduce specific frequency
bands within the signal. For example, a Low Pass Filter cuts out high frequencies so
will result in less treble to the sound. A High Pass Filter cuts out low frequencies, for
example you may use this to remove unwanted low frequencies like hum or rumble. A
Band Pass Filter cuts out both high and low frequencies allowing frequency
components within the band to pass through the signal; for example, you may use
this type of filter to create a telephone effect on a normal voice.
Adjusting the gain of a signal results in a change in the perceived level or amplitude.
An increase in gain (positive values) results in amplification and a reduction in gain
(negative values) in attenuation.
A dynamics processor used to remove unwanted signals below a certain threshold
level. For example, if a gate is applied to a presenter's microphone source, then when
they speak signal level exceeds the gate threshold and the gate opens, while if they
make a low level sound, like shuffling in their seat, the gate remains closed. The result
is that only the signal we want to hear is output from the source channel!
General Purpose Interface (IEEE488) is a standardised platform independent short-
range digital interface, to allow switching connections between broadcast equipment
from different manufacturers.
Version: V6.0.0/5
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