Strata Operations Guide
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HPU Description
For those applications requiring a higher RF output level, the HPU (High Power Unit) may be used to
boost the signal level to between 2 and 12 watts of microwave output power depending on the modulation
format used. Figure 4 below shows the functional architecture of the HPU device.
HPU
RF IN
RF OUT
Figure 4 – HPU Functional Diagram
Theory of Operation
The Strata TX system is comprised of the following primary components:
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Command and Control Power Supply module
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Combiner Circuit
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MPEG encoder/COFDM modulator module (digital mode)
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FMT (FM Transmitter) (analog mode)
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IF/RF Unit
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HPU (High Power Unit)
Note that some or all of these components may be included in a fully functional Strata TX system
depending on specific customer applications, e.g., switchable analog and digital transmitting system, etc.
Where switchable analog and digital video transmission is required, the Strata TX system installs the
digital and analog video modulator modules and the IF/RF module in separate housings. In this case a
TCU (Transmitter Control Unit) houses the MPEG/COFDM, FMT and Combiner circuits with the IF/RF
unit installed in a separate TXU (Transmitter Unit) housing. This arrangement also allows the video
modulation components (TCU) to be physically separated from the IF/RF up-converter by up to 600 feet.
Command and Control Power Supply
The TCU and TXU Command and Control/Power Supply modules contain external and internal
communications circuitry as well as supplying the necessary system voltages. The power supply portion
accepts a wide range DC input voltage (+10.5 to +48 volts) and distributes appropriate output voltages to
the various circuits. The command and control circuits handle inter-module communications and provide
external RS-232 communications to external peripheral equipment, such as a remote control device
(helicopter operation) or to a PC capable of running Windows based configuration software. An on-board
microprocessor manages the system configuration and operation of all modules to which it is connected,
i.e., MPEG/COFDM, FMT, IF/RF modules, etc. In addition, for those applications that employ both
TCU and TXU housings, a communications link superimposed over the inter-connecting IF coaxial cable
provides communications to all system modules. This ensures the TCU and TXU may control each
other’s operation, i.e., permit switching modes of operation, change system presets, etc.
