Loran c receiver

Abstract

A Loran C receiver is disclosed which has a scanned type keyboard including data entry, primary function and special function keys. The primary function keys include an automatic key for selecting automatic operation. A microprocessor is controlled by the keyboard, a timing means, a real time interrupt, a counter, a groundwave phase and envelope sample strobe generator, a delayed phase channel sample strobe generator and a latches and multiplexer. The timing means orients the microprocessor as to time and triggers the counter. The counter provides the proper count to the groundwave phase and envelope strobe generator and delayed phase channel sample strobe generator for producing a plurality of sampling signals for the latches and multiplexer. The real time interrupt produces a data ready or cycle done signal for the microprocessor. The latches of the latches and multiplexer sample at selected time intervals digitized phase indicating outputs representative of the RF signals received by the receiver from master and secondary stations of a GRI. The multiplexer multiplexes the digitized phase information into the microprocessor in response to a command from the microprocessor. The command is given after receipt of the data ready (cycle done) signal. The microprocessor then processes the digitized phase information for GRI searching, coarse envelope and cycle identification of the master and secondary stations of the GRI and determining sequentially for display at regular intervals the time differences between the master station and each slave station.