R.V.R. Electronica PTX1000DDS, Руководство пользователя

Страница: 55 / 64

49
/ 54 User Manual Rev. 1.0 - 29/11/16
ELETTRONICA
PTX1000DDS
Card specifications are as follows:
•
Microprocessor
: 90F5436
• Flash Memory size : 1MBytes
• Static RAM size : 32KBytes
• Communication Interface : RS232-RS485 and I
2
C Bus
• EEPROM size : 2KBytes
• Self-diagnosis LED : 1 red led
7.7 TRDSP card
The TRDSP is a DSP-based digital circuit that performs the following tasks:
• input selection, level adjustment and processing (filtering and preemphasis)
• stereophonic coding
• RDS (Radio Data System) signal generation.
The TRDSP accepts audio inputs in digital form (AES/EBU) or Left and Right
analogue inputs that are immediately converted into digital format (A/D). A digital
input is automatically selected when present, but analogue input selection can be
forced with the appropriate software settings.
The MPX stereophonic signal “ (“Main”, “Sub” and 19 kHz subcarrier) is generated
directly in digital form, starting with the Left and Right digital (or digitalised)
channels.
The RDS is generated directly by DSP and then digitally added to the stereophonic
audio signal. The messages transmitted by the RDS coder are programmed using
a PC software supplied with the machine. It also possible to disable the internal
RDS coder and use an external coder.
The TRDSP includes a support panel with the input and output connectors.
The key advantage offered by the TRDSP option is enhanced performance in
terms of:
• Amplitude/frequency response (±0.01 dB, 30 Hz - 15 kHz)
• Stereophonic separation (65 dB, 30 Hz - 15 kHz)
• Distortion (< 0.03%)
In addition, the digitally processed signal enables frequency deviation limitation
while avoiding the distortion issues typically experienced with analogue clippers.
At TRDSP output, the total signal (MPX + RDS) is converted into analogue form
(D/A) and passed on to the standard up-converter section of PTX1000DDS .