Patent GB-1030782-A (GB)
Title: Improvements in and relating to automatic radio transmitting devices
Inventor: DAVY JOHN RUPERT
IPC: H04L15/22
Filed: 1963-03-26
Abstract: 1,030,782. Automatic transmitters. BARB & STROUD Ltd. March 31, 1964 [March 26, 1963], No. 11841/63. Heading H4L. A keying device for automatically transmitting a predetermined message comprises a control unit (means 20, 21 and 22) for storing the complete message in binary code, a store unit 23 for holding successively individual phrases of the message read out from the control unit, a decoder 26 for receiving successively individual elements of each phrase from the store unit, converting them from binary to morse code and passing them to the output of the device, and a timing unit (means 25, 27 and 31) for controlling the read-out from the control and store units in response to signals received from the decoder. The timing unit comprises a pulse generator 31, which feeds pulses into the timing logic unit 25 and a timing counter unit 27 which has four states 00, 01, 10 and 11 and which is charged from one state to the next by the trailing edge of a pulse from generator 31. A dot is represented in store unit 23 by the binary code 01, a dash by 10 and a space by 11. Where the device is for use in a sunken submarine the message may comprise in succession: (1) An identification number, e.g. " 001," repeated three times; (2) A distress call " SOS," transmitted six times; (3) A code word, e.g. " SUBSUNK " transmitted three times; (4) A continuous tone transmission for direction-finding purposes. Assume that a phase of the message containing about fifteen morse elements has been written by the control unit into the store unit 23, and the next element to be read out of store unit 23 is a dash (10). The first pulse TP1 from generator 31 will cause the dash element to be read into staticison 28, where the pulses representing the dash element are lengthened before being passed to the decoder 26, and the timing counter to change state to 01. The decoder 26 determines that the just read out element is a dash and sends a corresponding signal to the timing logic unit 25 and that the next two pulses TP2 and TP3 from generator 31 merely cause the state of timing counter 27 to change firstly to 10, and then to 11. The fourth pulse TP4 from generator 31 clears the staticison 28 and returns the state of the timing counter 27 to 00, such that the system is ready for the next element in store unit 23. The procedure is the same when the element read out from store unit 23 is a dash. When the element read-out from the store unit 23 by pulse TP 1 is a dot, the decoder 26 sends a signal to the timing logic unit such that the state of timing counter 27 is changed to 10 before it is changed to 11 by the trailing edge of pulse TP1. The second pulse TP2 from generator 31 clears the staticisor 28 and returns the state of the timing counter 27 to 00. The dashes and spaces produced and transmitted therefrom have three times the duration of the dots. The last element in the phrase stored in store unit 23 has a binary code 00 and when this is read into staticisor 28, decoder 26 sends a signal to timing logic unit 25 such that pulse TP2 advances control counter 20 and pulse TP3 causes a new phrase to be written into store unit 23. The control counter 20 is connected directly to output logic unit 29 to provide the continuous tone transmission.