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SIRIO 2000T
SIRIO 2000T
SIRIO 2000T
SIRIO 2000T
SIRIO 2000T
Electronic Broadcast Equipment
2. GENERAL DESCRIPTION
SIRIO 2000T is a 2KW rated, direct-synthesis, high quality FM-modulated transmitter. Being digitally
controlled, it is extensively programmable by front panel, on field or remotely, in every respect: frequency,
power, channel sensitivity, preemphasis, functioning mode (mono, stereo, external mpx), clock, date and
many other parameters, without adjusting or replacing any part. A powerful 3-levels password system
allows an high degree of security and privacy as it may be required in different situations. The transmitter
requires little or no maintenance and its simple modular layout allows easy testing and servicing.
As required by a number of specifiical national standards, our transmitters incorporate a state of the art
low-pass audio filters on mono and stereo channels, and a sharp acting modulation limiter which is usually
set for a peak deviation of 75 kHz. Its use should never be avoided. If required a different deviation, this
can be obtained pre-setting. In any case the threshold shouldn't exceed a deviation higher than 150 kHz.
Output frequency is phase-locked to a temperature-compensated crystal oscillator, which insures
superior precision and stability. A very low noise, low distortion VCO produces an harmonics-free and
spurious-free signal. Each time the transmitter is turned on or the frequency is modified, a control circuit
inhibits the presence of output power until the transmitter is locked on the programmed frequency.
To lower the noise threshold, low-frequency inputs are fitted with balanced input circuitry. The input level
is precisely adjustable over a wide range by means of a 0.5dB step variable attenuator. The transmitter has
an auxiliary input, specifically designed for RDS and SCA encoders. A modulation output allows to control
other transmitters (or STLs) with the same internally processed high-quality mpx signal.
The alphanumeric display and the keyboard allow an easy and accurate metering, adjustment and
continuous monitoring of modulation levels, power, operation and other internal parameters. Such details
may be externally available on the same RS232 I/O port that may be used to remotely check or control the
transmitter. In addition to the serial I/O, some signals (RF power, On the air state,
Disable line
) are available
on a parallel I/O socket for easy interfacing with others analog controllers or supervisory systems.
A top-quality stereo encoder may be factory installed as an option. This even later in the field requiring
such an upgrade a minimum technical skill to be performed. The powerful internal software recognize the
encoder presence and automatically enables the related functions.
The RF power amplifier employs a broadband design and has plenty of reserve: the output power is
feedback controlled for increased stability to an higher level than the nominal . Allowed reflected power
is limited to conservative level to prevent output stage degradation; direct power is accordingly reduced not
to exceed the reflected power safety level. A sturdy telecom-grade high efficiency switch-mode power
supply allows operations even in unstable and noisy mains environment.
The temperature alarm circuitry reduces the output power in case of high room or esternal temperature
in order to remain anyway on the air, in spite of the adverse condition.
