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Show 3. Radio All solid state VHF transmitter/receiver. Modulation frequency from 300-3000 Hz. RF output power of 2 watts. It is connected to a gained directional antenna. Power Four 6 volt rechargeable batteries to provide + 12 VOC. Mounting Weatherproof case. Theory of Operation Command Signals: Six unique serial generations of an audio tone are used to selectively choose one of six command functions. The respective relays are activated by depressing the execute button on the control panel of the central station. The relay remains activated until the execute button is released. Relays with a latching mode can also be used, if it is required that a relay be turned on and left on until another command is received to turn it off. Ge·n erator Monitor: A unique serial audio tone initiates the transmission of up to seven signals from the generator monitor sensors. The following event take place: ( 1) One audio tone is transmitted from the control station. (2) The execute button is depressed to initiate the command, and the generator transmitter is turned on. (3) The generator transmitter remains on and starts transmitting the output of the multiplexer modulator. (4 ) The multiplexer sequentially switches a full scale calibration signal and the seve n .s ensor signals into the modulator. ( 5) Ge nerator transmitter is turned off at the end of the sequence. The contr ol station r eceiver demodulates the data and it is displayed on a met er a l ong with th e channel number . The interrogation pro cess can be initiated by a built-in timer, which permits the gene rator station t o be automatically interrogated at a selected interval. 4. Monitor Output R ecording Outputs are ava ilable for b oth a strip chart recorder and interface to a magnetic tape recorder. The m agnetic tape recorder output is a frequency of 3KHz 7. 5%. 356 |