User's Manual

AT71-250 Transmitter Owner’s Manual

2. Main Features

 Via the 4 lines x 40 columns display keypad located at the front panel it is possible to

manage, configure all functions of the equipment and each one of the RF power

drawer.

 Via the hyper-terminal it is also possible to manage, configure all of the functions of

the transmitter.

 Digital Filter, type Finite Impulse Power (FIR) built-in at the 8VSB Modulator.

 Automatic non linear pre-correction.

 Automatic linear equalization.

 Built in oscillators synthesized via serial-PLL, locked at a 10MHz OCXO reference or

external equivalent reference, e.g. GPS signal.

 The UHF RF power amplifier was implemented with LDMOS transistors, operating

highly linearly at higher gain under high efficiency and absolute controlled thermal

conditions.

 Automatic control over the quiescent operational electrical current value on the RF

main power transistors, under temperature variations.

 Self-protection against over-current on the RF main power amplifiers.

 Each RF power module carries its own +50 volts full bridge type switching power

supply.

 Automatic Level Control (ALC) control, which keeps the RF on-channel output level

constant, even with a +3 dB overall system gain variation.

 System fault indication shown on the front panel, including current and past alarms log.

 Low noise, variable speed fans for the air cooling system.

 Modular design, built with SMD (Surface Mounted Devices), easing the maintenance

and service.

 Outstanding overall field system performance.

 19” rack cabinet.