R.V.R. Elettronica TRDS 4001, User Manual

Page: 17 / 62

TRDS 4001
13 / 36 User Manual Rev. 4.0 - 23/03/01
5. Electrical Description
5.1 Introduction
This chapter describes the TRDS4001 ENCODER function . For utility, the device is
divided in subassemblies which will be deeply discussed in the following paragraph.
5.2 Power Supply
The power supply section is composed from a 220 V transformer (double primary
110-110 V) which supplies a +12 V voltage for the analogical part and a +5 V
voltage for the digital logical one. In 24 V version (actually current model), in case
of range absence, the apparate automatical commutes the power supply on the
external battery, on guaranting the continuity of service.
5.3 RDS Circuit
It presents a microchecker which manages the production of RDS message. The
setted RDS message is preserved also in absence of primary power supply. The
RDS carrier wave at 57 Khz is produced on locking at the 19 Khz one of MPX
signal in input for the stereo transmission systems, or with an internal quartz
oscillator for the mono transmission systems. In the stereo systems the stereo led
lights. The into codifier microchecker could immediately modifythe transmitted
message; that guarantees the system very much fexible and adattable at the different
custumers necessities.
5.4 Audio Exchanger Circuit (Only For TRDS4001/SAT Version)
This circuit, which is present only in sat version, has the function, after pointing out the
audio signal absence which comes from the earth connection, to change over the
apparate on the sign which comes from the sat.
The commutation time is changeable from 20 to 45 seconds and it could be regulated
between the R6 trimmer.
We could have the audio signal threshold level regulation on setting the R9 trimmer
on the circuit.