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: http://www.naic.edu/aisr/sas/transmitter/trans-timing.html
Дата изменения: Tue Aug 12 01:20:19 2003 Дата индексирования: Sat Dec 22 15:09:25 2007 Кодировка: Поисковые слова: m 97 |
For testing purposes, this unit in the control console can generate the four pulses needed to control the transmitter: the receiver protection command, the beam on command, the rf on command and the rf phase command. But normally these commands are generated by a programmable pulse generator that is part of the computer data-taking interface. The program-generated pulses enter the timing generator as "Request pulses." Unless they violate restrictions put on duty cycle, pulse length, etc., the requests are passed on, unaltered, as commands to the transmitter circuitry. Otherwise the timing generator modifies them to make them acceptable. When this occurs, lights on the panel of the timing generator indicate what restrictions are being violated.
The excite circuitry is in the control console. Is output stage is a 3-watt amplifier. The output from this amplifier, 3 watts peak, is pulsed on and off synchronously with the high-power modulator. The exciter can apply bi-phase modulation to the drive signal. No amplitude modulator is included in the exciter., although the subsequent Intermediate Power Amplifier (IPA) and Power Amplifier (PA) stages are essentially linear amplifiers when they are not driven to saturation.