User`s manual

100-M0074X1 20 of 24
www.cobham.com/gms
Output Power: Up to100mW (programmable) [200mW on some models]
Connector: SMA-F
Note: Transmitters should not be powered on without a load. Doing so could cause
the output PA to stop working. A proper heat sink is also required.
7.4 Modulation
Modulation Type: COFDM w/ QPSK, 16 QAM , or 64 QAM.
FEC: ½, 2/3, ¾, 7/8
Guard Intervals: 1/32, 1/16, 1/8, ¼
Spurious: 50dBc
Number of C-OFDM Carriers: 2k
C-OFDM MER: > -45dB
Standard: DVB-T compliant
7.5 Power
DC Input Voltage Range: 9 to 15 VDC
Power Consumption: 8.5 Watts to 10.8watts
7.6 Physical Dimensions (without mating connectors)
Size: 3.25 in. (W) x 4.5 in. (D) x 1.76 in. (H)
(8.26 cm x 11.43cm x 4.47cm)
Weight: 13.4 oz (379.9grams)
7.7 Environmental
Operational Temperature: -10 to +70 °C
Humidity: Up to 100% (non-condensing)
7.8 MDT-A Special Features
Security Option
The MDT-A can optionally be provided with an Advanced Encryption System (AES) for protecting the
signal in sensitive applications.
8.0 The D/C (Down Converter)/IF frequencies explained
8.1 IF Frequencies
• GMS’ MDRs (Messenger Digital Receivers) and MSRs (Messenger Smart Receivers) are capable of
receiving direct frequencies in the range of approximately 49 MHz to 861 MHz. If the transmitter
is not in this range then a down-converter is used to convert the frequency to this range. The
frequency from the down-converter is called the IF (intermediate frequency) which is fed to the
receiver.
Down-converters have a LO (local oscillator) which is mixed with the transmitter frequency (MDT-
A) and converts it to the IF frequency. MDRs need to know the LO (local oscillator) of the down-
converter and is factory programmed with this information (MSRs also need the LO information
but is not factory programmed with this information). The receiver then automatically calculates
the IF frequency once the RF (transmitter frequency) is entered. Thus as the desired RF frequency
is dialed in on the MDR (or MSR) the IF is taken care of automatically. For example, if the