OTE VS 2001 - Level Translator; Power Unit; I;F Audio

VS 2001
Technical Handbook
Technical Description
Page 30 Marconi Proprietary information
P/N: 779-0373/02
Revision 02
2.3.1.3 Level Translator
The level Translator is the interface for the 3.3 V signals generated on the Base
Band card and addressed to the 5 V CMOS devices located on the R/T card.
Such signals are the following:
• Signals connected to R/T card and generated by the Time Base unit. Their
voltage level is translated from 3.3 V to 5 V.
• Signals of the serial synchronous interface and signals necessary for the DAC
programming. Their level is translated from 3.3 V to 5 V.
• Configuration signals (R/T and P.A. cards) for the transmission and reception
processes. The above mentioned signals are generated by the Time Base
and then converted from 3.3 V to 5 V.
2.3.1.4 Power Unit
This unit provides the power supply voltages for the Base Band card, the R/T card,
the P.A. card and the connected peripherals. The power supply voltages provided
by the power unit are derived from the vehicular battery.
The following power supply voltages are available:
• VBATT+: general power supply voltage provided by vehicular battery (12 V
nominal);
• VBATTINT: general power supply voltage interrupted by dual MOSFET (12 V
nominal less losses on MOSFET and protection circuitry);
• +8 V: power supply voltage dedicated to R/T card (7.2 V nominal);
• VMASTER: power supply voltage adjusted to approx. 6.5 V;
• 12 VTLC: power supply voltage dedicated to the remote control;
• VD5: 5 V for 5 V digital circuitry;
• VCC: 3.3 V for 3.3 V digital logic;
• VA3: 3.3 V for 3.3 V analogue circuitry;
• VC2: 2.5 V for DSP core.
2.3.1.5 I/F Audio
This unit provides the interface between the external audio devices (loudspeaker/
headset and microphone/handset) and the Digital Signal Processor device (DSP),
both in transmission phase (towards the loudspeaker/headset) and in reception
phase (from the microphone/handset).
The input main/rear microphone signal is approx. 200 mVrms. The Audio interface
provides the signal voltage level (2.5 Vpp) required by the CODEC voice
digitalisation device that samples the signal at 8 kHz on 13 significant bits. It
supplies the digitised value to the DSP on a dedicated DXS synchronous serial
line, with timings generated by the Time Base unit.