HIGH FREQUENCY DIGITAL COMMUNICATION SYSTEM: AN/GRC(XW-3) AND CV-1355(XA-1)/ARC.
Final engineering rept. for Mar 60-Mar 64,
NATIONAL CASH REGISTER CO DAYTON OHIO
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The High Frequency Digital Communication Systems consists of an airborne digital-to-digital converter and the ground station receiving and transmitting equipment. Briefly, the digital-to-digital converter accepts standard Fieldata code at 50 bits per second and converts the 20 millisecond marks and spaces into a series of 6-23 millisecond cos to the 2nd power shaped intermediate frequency pulses. These IF pulses, which are 50 overlapped and linearly summed from six IF subcarriers, are sent to the transceiver equipment for transmission on a 3 kilocycle bandwidth channel. During reception, the transceiver delivers the 6-23 millisecond pulses, distorted by the propagation path, to the airborne converter, which separates the received signal into the six subchannels so that markspace decisions can be made on the basis of the sequence of the pulses. The converter also provides relay switching of the necessary functions such as AGG, keyline, finish tune signal, etc., for compatibility and operation with modified ANARC-58 and ANARC-65 radio sets. Author