Patent GB-804218-A (GB)
Title: Improved automatic electric circuit keying apparatus
Inventor: PHILLIPS RONALD WILLIAM
IPC: G09B9/26
Filed: 1956-12-05
Abstract: 804,218. Morse code signal generators. COMMUNICATIONS PATENTS, Ltd. Dec. 5, 1956, No. 37171/56. Class 40 (1). Apparatus for automatically producing electric signal pulses comprises a plurality of elements adapted to be sensed under the control of an impulsing system and when so sensed to bring about the keying of an electrical circuit and means operative as a result of one at least of said elements being thus sensed, to change the impulsing rate of said system and thereby modify the duration of the signal pulse which results from the consequent keying of the said circuit. In a first embodiment, Fig. 1, a single bank of a reverse-drive uniselector is used to initiate and control the duration of audio-frequency signals representatives of coded groups of Morse letters analogous to such as might be radiated as an identifying symbol from a radio beacon. The uniselector 10 has its wiper 11 stepped on de-energization of the coil 14. The contact groups a-d, f-i, k-n, p-s, are so connected to the line 15 for a short pulse or dot and the line 16 for a long pulse or dash as to represent the Morse letters of the required signal. When the D.C. source 13 is applied the delay relay RLA is energized to close contacts A/1, thereby energizing the delay relay RLB and open contact A/2 to step on the arm 11. As shown, relay RLD has also been energized to change over the contact D/1, thereby providing a short audio signal supplied by the source 17 in the telephones 18. Energization of the relay RLB opens the contacts B/1 to release the relay RLA whereupon contacts A/1 release relay RLB, thus completing the cycle. If the wiper 11 is connected through a contact to line 16, relay RLC will be energized, thus closing contacts C/1 to connect the condenser C3 across the delay relay RLA thereby increasing the period before its contacts operate, resulting in the wiper 11 remaining a longer time in this position and thus producing a longer audio signal, representing a dash in the telephones 18 since the contacts C/2 remain changed over for a longer period. A second embodiment, Fig. 3, employs a uniselector with two contact banks A, B, the arrangement of the relays RLA, RLB, and capacitors C1, C2, C3 being similar to Fig. 1, the wipers 19, 20 being stepped on de-energization of the coil 21 by change-over contacts A/3. A set of two metal coding plates is used to select those contacts of the uniselector banks required for the signal representing the predetermined code letters. As shown, the plates SL, QL, NL correspond to dashes and the plates SS, QS, NS correspond to dots for the respective Morse signals for the letters "S," "Q," "N." The plates are each arranged to co-operate with four spring-loaded contacts which enter holes in the plates, thereby opening circuits as required. The plates are commoned to a line 24 earthed by the change-over contacts A/3 when the relay RLA operates. If initially the relay RLA has changed over the contacts A/3 and the wipers 19, 20 have just been stepped to the first contacts a, a1 of the banks A, B, the relay RLE is energized via contacts SL1 to change over contacts E/1 energizing the relay RLG to produce a dot signal in the telephones 25 which lasts until the subsequent return of the contacts of the relay RLA. The wipers are stepped on and the next cycle commences. A dash will be produced when the relay RLF is energized to close the contacts F/3 and the relay RLE is not energized. Whenever both contacts E/2 and F/2 are closed the wipers become self-stepping at a rapid rate through the self-interrupting contacts 27. As modifications, the coding plates may have depressions or insulated plugs or protuberances instead of holes. A single plate with two rows of holes may replace the two coding plates (Fig. 4, not shown). A set of coded characters may be provided on a single plate, drum, disc or band (Figs. 5, 6, 7, not shown), a required group of characters being rapidly obtained from several such elements. The uniselector contacts may be replaced by photo-electric cells, with light beams instead of wiper arms. A third embodiment (Fig. 8, not shown) employs photo-electric cells. Other forms of code than Morse may be employed. The uniselector may be replaced by, for example, a multi-cathode counting tube. A visual display such as on a C.R.T. instead of audio signals may be provided.