SOLIDYNE 462
dsp - broadcast digital processor
Page 25
6.2 Solidyne 462dsp/AM psycho acoustic digital processor
6.2.1 Blocks
diagram
6.2.2 24 BITS @ 192 KHZ A/D CONVERTER
This module converts the analogical audio signal
to digital audio, with 24 bits of resolution with a
sample rate of 192 KHz.
Digital Input / Resampler
AES-3 input supports resolutions of 16/24 bits and
Fs from 32 up to 208 KHz.
An stage called
resampler
converts the digital
input signal to 24 bits / 96 KHz; the resolution that
the processor uses internally.
From here and until the signal returns to the
analogical domain (D/A converter), all process
descript are made into the DSP’s using complex
algorithms.
REMEMBER
•
In case of failure in the digital signal, the unit
automatically changes to the analogical inputs.
6.2.3 PEAK SIMETRIZER
It is known that, by a particularity disposition of
the vocal cords, the sonorous emissions that
these generate are asymmetric triangular pulses.
The three cavities that filter and shape these
formants, to obtain the vocal sounds, do not
modify this intrinsic characteristic of the human
voice. All the spoken word and still sung is
strongly asymmetric.
This creates an important reduction of the
energy of the audio signal, particularly when it
pass through a compressor, because the
compressor sets its compression level for the
greater peak, does not concern its polarity. In
this way, when a polarity is fit to the 100%, the
opposite polarity hardly surpasses 50%, due to
the asymmetry. The fact that the music sounds
louder than the human voice, after pass through a
compressor is a phenomenon well-known. This
is because the musical sounds are symmetrical,
whereas the human voice is not.
In order to correct this problem, WITHOUT
INTRODUCING ANY ALTERATION AT THE
SOUND QUALITY, peak asymmetry canceller is
used.
