Indoor Broadband Transmitter – ITX02-2000
1
IM402513-10 Rev –
1.0 INTRODUCTION
The ITX02-2000 shown in Figure 1 is a solid-state broadband transmitter, which converts a
VHF, input signal of 222 to 408 MHz to a microwave signal of 2.5 to 2.686 GHz.
The ITX02-2000 transmitter consists of eight assemblies:
1. Driver Chassis - for converting the incoming VHF signal to microwave. The Driver
chassis contains all components necessary for upconversion, i.e. local oscillator, mixer,
as well as bandpass and notch filters.
2. Power Amplifier - input signal is amplified to a maximum level consistent with the
Carrier to Composite Triple Beat (C/CTB) specification by state of the art GaAs FET
microwave power amplifiers in a parallel, power-quadrupling configuration. The power
amplifiers are protected from failure due to overheating by an internal temperature
sensor. The sensor circuit automatically switches off the amplifier when the amplifier
temperature exceeds 167 degrees F (75 degrees C).
3. Power supply system - a redundant 12 VDC system consisting of three current
sharing modules with hot-plug replacement capability. Each module has an 84 Amp
capability. Only two modules are required to run the system, making the third one a
built-in spare. A +5 VDC voltage regulator is used to power the power amplifier TTL
circuit. The Driver chassis and fans are powered by the +12 VDC power supply.
4. Monitoring and Diagnostic Circuits - To facilitate operational monitoring and
diagnostics of: VHF input, VHF output, Driver RF output, and Transmitter RF output.
Diagnostic DC voltages can also be continuously monitored with the built-in meter on
the Meter Panel.
5. On-Delay Timer Assembly - Delays power to the amplifier. This is done to avoid a
big current surge when the transmitter is first turned on.
6. Internal Downconverter - For ease of monitoring the Transmitter’s output, a
downconverter has been mounted inside. The downconverter takes a sample of the
output and converts it to VHF. This VHF output signal can then be measured with a
Field Strength Meter or a TV monitor.
The ITX02-2000 transmitter can be equipped to operate on either 120 or 240 VAC at 50 or 60
Hz. This option is specified by customer request, and each unit is shipped according to this
specification.
Complete specifications are listed in Section 6.0.
