Vorsis AirAura, Руководство пользователя

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The higher capacitance of generic analog cables slows down the rise time of the
digital data signals which can impair the ability of the AES3 receiver to accurately
detect digital signal transitions. This results in increased jitter, or at the extreme,
no audio at all.
Where to Install AirAura
The best location for installing AirAura, or any other “on-air” processor, is at the
transmitter site. However this requires that a discrete Left/Right STL, either
analog or digital, be involved in the signal path. The benefit of a transmitter site
installation is that it enables the use of AirAura’s built-in lab-grade stereo encoder
allowing more precise control of modulation peaks.
The transmitter site location also allows the operation of AirAura’s highly
oversampled composite clipper to be used to create an additional loudness
advantage. The Vorsis composite clipper algorithm is more forgiving than those
found in other products, and in combination with our pilot and SCA protection
filters can create additional loudness without the usual audio and spectral grunge
that composite clippers typically create.
We recommend that the processor (any processor) be interfaced to the
transmitter using the exciter’s composite stereo multiplex input. The exciter’s
AES3 digital input may be ‘clean’, but it also precludes the ability to gain
additional loudness through the use of AirAura’s intelligent oversampled
composite clipping. Depending on the sample rates being used the exciter’s AES
digital input can also exhibit somewhat inferior peak control than the composite
input.
If AirAura is located at the studio and an STL is used to send the program
material to the transmitter there are several issues that need to be considered.
Analog Left/Right STL:
Older analog discrete left/right STL’s can suffer from an inability to control audio
peaks because of inadequate bandwidth in their IF circuits or poor low frequency
performance. Individual STL’s rarely have identical audio group delay in both
channels which affects stereo separation when the signal is converted to the
multiplex composite domain. Such STL’s also usually suffer from AFC bounce
when handling processed low frequency material and that can rob modulation
capability.
Composite Analog STL;
An analog composite STL has several advantages over the analog left/right STL
just described. These STL’s typically have better audio performance than an
analog discrete STL, and most have the capability to piggyback subcarriers on
the composite audio. This means that most SCA and RDS generators can be
located at the studio end of the STL along with the audio processor. If nothing
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