MT-MR PLATINUM. POINT TO POINT AURAL RADIO RELAY SYSTEM
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containing all the information of the main audio program plus the SCA channels, that were contained int he original
RF signal received. This IF signal is then demodulated, separating the main audio program (stereo or mono) and
the three SCA or RDS channels, amplifying these signals to the correct output level in separate circuits, and finally
delivering these informations at receiver’s respective outputs. In case of receiving a composite multiplexed stereo
signal, this signal is fed directly to the Broadcast transmitter at station without any type of decoding or intermediate
device. Nevertheless, L+R audio component of the stereo signal can be locally monitored at the built-in speaker
included in this receiver, or also it can be heard by using external headphones, at operator’s choice.
As happens
with
transmitter,
thiss
receiver
is
normally
fed
by
an
internal Switching
Power
Supply,
delivering ±15 volts DC to feed all Receiver active circuits. This receiver, as transmitter also is, is delivered to
Customer having the additional facility of being able to be fed by a +15 vDC floating-battery system. This condition
is generally applied in sites and stations where the AC failures are frequent. Floating-battery system not only can be
used with AC battery chargers, but can be used with solar cells and/or wind generators, or using practically any
form of non-conventional energy sources.
MR Platinum receiver is completely shielded against external interferences, and can be operated in high RF-
contaminated environments, as Radio Broadcast Centers with multiple transmitters within the same room. Its low-
value (<6 dB) Noise Figure is reached thanks to the use of the low noise two-staged RF pre-amplifier included in
the Pre-Selector Filter casing. This RF pre-amplifier includes two RF low noise, surface-mounted transistors having
a cutoff frequency in the range of the microwaves spectrum, with superb intermodulation characteristics, increasing
receiver’s sensitivity, and enabling it to operate in long-hop links.
Also it’s required to mention the outstanding reference system used by local oscillator’s PLL as a secondary
frequency standard. This system uses a TCXO (Thermally-Controlled Xtal Oscillator) as low-frequency reference
standard for PLL phase-comparison circuits, making the frequency stability of this receiver to be exceptionally high
for its reduced cost.
All supervision and control elements including the Digital Display are situated in the Front Panel, whereas all
connectors and cables are located at Rear Panel. Supervision elements are only the strictly required for performing
all operational checks and to supervise Equipment’s and system status. Controls are reduced to a minimum in order
to simplify Equipment’s operation and maintenance.
4.2.- Technical Specifications.
Frequency Working Range ....................................................................From 200 to 960 MHz, in 20 MHz sub-bands.
Sensitivity ............................................................................................................ Stereo mode. 1 mV for S/N = 60 dB.
Monaural mode. 100 uV for S/N = 45 dB.
Selectivity .....................................................................................................................................± 100 KHz at –3 dB.
± 350 KHz at -70 dB.
Total Harmonic Distortion ................................................................................................................................< 0.3 %.
Stereo Channels Separation ............................................................................................ 45 dB from 50 to 15000 Hz.
Output Audio Level ............................................................................. For both stereo & mono modes: +8 dBm max.
