R.V.R. Elettronica TRDS4001, Руководство пользователя

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TRDS4001
8 / 18 User Manual Rev. 5.2 - 23/06/06
The registry of transmission is at packages of lenght 104 bits (87.6 ms) named
GROUPS, each of them composed of 4 blocks of 26 bits.
Every block is composed of 16 bits of information and of 10 bits of protection, which
are properly studied to allow the recovery of an erroneous word with a maximum of 5
wrong bits.
They are provided with 16 separete blocks of which 6 are still not defined; every
group begins with a PI identification code (Program Identification) which has the
double intent to synchronize the receiver and to identify the channel which transmits
the signal.
The pourpose of the encoder TRDS4001 is to manage the principal services defined
by the standard CENELEC EN 50067 as: PI, PS, PTY, TP, AF, TA, DI, M/S, PIN, RT,
EON, TDC, IH, CT.
As follows, we’ll mention a short description about the function of each of these
services.
PI - PROGRAM IDENTIFICATION : it’s the identification code of the radio. Its more
important application is to allow the receiver, in case of bad reception, to implement
the "Automatic Frequency Change"; this happens when there is a signal with the
same PI and of better level than the syntonized one.
PS - PROGRAM SERVICE : it’s the visualized text on the receiver display, which
has to be of maximum 8 characters, as this is the standard dimension of receivers
displays. The TRDS4001 characteristic is to store up to 8 messages and the time of
transmission of each of them. Every message can be composed from 1 to 16 words
of 8 characters, and it’s possible to select the permanence time on the display of
each of the 16 separate words.
PTY - PROGRAM TYPE : it’s the identification of the "Program Type" which is on air
(example News, Sport, Rock, etc.) It’s used to qualify on the receiver the automatical
research of the program type desired.
TP - TRAFFIC PROGRAM IDENTIFICATION : this service indicates with a signal
on the receiver display that the program we’re receiving includes traffic news.
AF - ALTERNATIVE FREQUENCIES : it’s the frequencies list of different
transmitters which transmit the same program in the adjacent receiving areas.
The list is memorized by the receiver and used to reduce the commutation time
beetwen the different transmitters of the same program.
TA - TRAFFIC-ANNOUNCEMENT IDENTIFICATION : it’ used to indicate to the
car-driver that the traffic news are on air. The receiver could use the signal in one
of the following modes:
a) To switch automatically from the Tape (or from the Compact Disk) to the radio;
b) To automatically switch on the radio when the traffic news begin;