R.V.R. Elettronica PTX-LCD, User Manual

Page: 60 / 62

PTX-LCD
56 / 58 User Manual Rev. 2.3 - 18/07/07
11.10 AUDINP-DIG board (optional)
The option “/AUDINP-DIG” allows the PTX-LCD exciters to be inserted in the
systemsthat use digital audio distribuition.
This option is designed to replace without any special adjustment the standard
audio input section, allowing the upgrade doesn’t require firmware modification of
the exciter (Releasexx04xxxx).
If digital input is present, it is automatically selected by the embedded logics.
Through an external command, it is possible to force the selection of the analog
input instead of the digital one (a jack to be connected to ground).
A manual switch allows to select balanced or unbalanced digital input.
Through two trimmers it is possible to adjust the level of the converted digital input
to normalize the R and L signals with respect to the level set for analog input.
The D/A conversion is performed by a 24 bit converter with a sampling frequency
automatically selectable from 32 to 96 KHz.
This option supports S/PDIF, AES/EBU, IEC958 and EIAJ CP340/1201 data
formats.
11.10.1 Functional description
The option section is placed on the rear part of the PTX-LCD and is directly
connected to the audio motherboard using a strip line connector. It is composed of
three different boards.
The first board (Fig. 11-15) contains the balanced analog input and the trimmers to
adjust the level for each analog input and the relative filters; this board is the same
used in the PTX-LCD without AUDINP-DIG. The second board (Fig. 11-16) contains
the level regulations and the switches for the software-based audio configuration.
The third section (Fig. 11-17) attends to conversion of the digital signal into analog
left and right signals with the respective trimmers for the adjustment levels. This section
provides also the selection of digital or analog input: the digital input are select
automatically when they are present or, through the jack connector "Dig/Analog switch"
connected to ground, selects the analog input. A manual switch is present to select
the unbalanced (TOSLINK and S/PDIF) or balanced (AES/EBU) digital input.