GB803695A - Improvements in or relating to circuit arrangements for generating repetitive electrical signals in morse or other code - Google Patents

Abstract

803,695. Morse code signal generators. MULLARD, Ltd. March 13,1957, No. 8281/57. Class 40 (1). [Also in Group XL (c)] A circuit for generating Morse or other character code signals comprises a dash generator circuit 1 and a dot generator circuit 2 which are alternatively arranged to provide an output at O under the control of a multivibrator circuit 3 which has a second multivibrator circuit 6 locked thereto having one period equal to the time occupied by the signal representing "SOS" and the other period equal to the required spacing between "SOS" signals. The output from the multivibrator 6 controls a gate 5 in the output lead. Alternatively the multivibrator 6 may not be locked to the multivibrator 3 but may periodically inhibit its action so that either circuit 1 or circuit 2 produces a continuous succession of pulses which are blocked at the gate 5. When the multivibrator 3 is not inhibited the gate 5 is open to pass a sequence of dots and dashes. The pulse generator circuits 1, 2 may be crosscoupled multivibrator circuits employing junction transistors. The control circuit 3 may also be of this type in which case the dash and dot multivibrators may have a common transistor T12, Fig. 2, a transistor T1 being used for one pulse generator and a transistor T2 in the other pulse generator. Voltages obtained from the control unit are applied alternatively to the terminals C1, C2 to inhibit the respective pulse generator circuits.