US3300582A - Solid state identification keyer - Google Patents

Solid state identification keyer Download PDF

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Publication number
US3300582A
US3300582A US286528A US28652863A US3300582A US 3300582 A US3300582 A US 3300582A US 286528 A US286528 A US 286528A US 28652863 A US28652863 A US 28652863A US 3300582 A US3300582 A US 3300582A
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US
United States
Prior art keywords
output
pulse
gate
dash
shift register
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US286528A
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English (en)
Inventor
Don I Himes
Robert M Aughey
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
TDK Micronas GmbH
ITT Inc
Original Assignee
Deutsche ITT Industries GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to GB1053138D priority Critical patent/GB1053138A/en
Application filed by Deutsche ITT Industries GmbH filed Critical Deutsche ITT Industries GmbH
Priority to US286528A priority patent/US3300582A/en
Priority to CH743964A priority patent/CH435362A/de
Priority to BE649035D priority patent/BE649035A/xx
Priority to NL6406591A priority patent/NL6406591A/xx
Application granted granted Critical
Publication of US3300582A publication Critical patent/US3300582A/en
Anticipated expiration legal-status Critical
Assigned to ITT CORPORATION reassignment ITT CORPORATION CHANGE OF NAME (SEE DOCUMENT FOR DETAILS). Assignors: INTERNATIONAL TELEPHONE AND TELEGRAPH CORPORATION
Expired - Lifetime legal-status Critical Current

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/74—Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems
    • G01S13/76—Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems wherein pulse-type signals are transmitted
    • G01S13/78—Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems wherein pulse-type signals are transmitted discriminating between different kinds of targets, e.g. IFF-radar, i.e. identification of friend or foe
    • G01S13/785—Distance Measuring Equipment [DME] systems
    • G01S13/788—Coders or decoders therefor; Special detection circuits
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L15/00—Apparatus or local circuits for transmitting or receiving dot-and-dash codes, e.g. Morse code
    • H04L15/04—Apparatus or circuits at the transmitting end
    • H04L15/22—Apparatus or circuits for sending one or a restricted number of signals, e.g. distress signals

Definitions

  • This invention relates to keyers and more particularly to a solid state identification keyer.
  • the radio beacon In certain radio navigation systems, such as Tacan, the radio beacon periodically transmits its identifying call in international Morse code, thus enabling the aircraft to determine which radio beacon it is in contact with.
  • the characters of the code consist of a train of pulse pairs generated at a fixed rate of 1350 cycles per second.
  • a mechanical keyer comprising a coding wheel cam and a switching arrangement cooperating therewith accomplishes the coding.
  • the coding wheel cam consists of peripheral segments which can be adjusted into or out of contact with the switching arrangement as required by the code.
  • mechanical keyers such as the one described, have demonstrated rather poor reliability in operation particularly under severe environmental conditions. Further, the time required to change the code is long and the procedure complicated.
  • Another object is to provide a solid state keyer with no moving parts.
  • a feature of this invention is an automatic keying apparatus comprising clock means to generate a starting pulse and another clock means to generate shift pulses which are coupled to a shift register having a plurality of outputs.
  • a plurality of switching means is coupled to each output of the shift register and the switching means connect the output of the shift register to a dot symbol and dash symbol generating means.
  • the outputs of the shift register are then coupled to dash symbol and dot symbol generating means by virtue of the switching position according to the desired code configuration.
  • FIGURE 1 is a block diagram of an embodiment of this invention
  • FIGURE 2 is a graph of waveforms useful in describing the operation of this invention.
  • FIGURE 3 is an expanded block diagram of this invention.
  • FIGURE 4 is a block diagram of the magnetic shift register used in this invention.
  • the basic unit of the keyer of this invention is a 21 bit magnetic core shift register and switching network 1 with serial input and parallel output.
  • the shift or clock rate of the register 1 is determined by a .250 second multivibrator or clock 2. This clock pulse rate is required because a Morse code dot length is .125 second and a dot is always followed by .125 second space.
  • a Morse code dash is .375 second and is always followed by a .125 second space. This specified spacing very con- ICC veniently fits the .250 second clock rate for the keyer.
  • the output of the clock 2 is fed via an inhibit gate 3 to trigger a two microsecond, one shot multivibrator 4 which generates a shift pulse.
  • the output of the two microsecond, one shot multivibrator 4 is fed to a core driver S which has suicient capacity to drive the cores of the magnetic shift register in the magnetic shift register and switching network 1. It is required that a series of four Morse code characters (3 letters and 1 number) be keyed once every 3() seconds.
  • the 30 second timing interval is generated by a 30 second multivibrator 6 whose outputs set a flip-flop once every 30 seconds.
  • the output of this flip-flop is gated via an AND gate 7 to an initial pulse gate 8 with a pulse from the clocking circuit of clock 2 to assure proper timing of the 1 insertion in the first core of the register.
  • the output of the initial pulse gate 8 triggers a 15 microsecond, one shot multivibrator or initial pulse generator 9 which is used to inseit a l in the first core of the register. This output is also used to reset the initial pulse gate 8 by way of gate 7.
  • the l in the first core is now shifted serially down the magnetic core register and out of the 21st core.
  • each of the 21 core parallel outputs is connected via an OR gate to the arms of 2l single pole, double throw switches, the outputs of which are connected to a dot line 10 or a dash line 11.
  • Each switch can be used to generate either a dot, a dash or a space making a total of 21 combinations.
  • the dot line 10 triggers a dot generator 12 which is a .125 second one shot multivibrator which generates the specified dot timing and this output is fed via a nor gate 13 to the keyer output which may be a transistor switch.
  • the dash line 11 is identical to the dot line except that due to the .375 second timing of the dash, the clock shift pulse must be inhibited during the dash interval.
  • the clock generator 2 is composed of a bistable flip-flop multivibrator and a unijunction transistor triggering circuit. This combination provides once each 250 milliseconds, a square wave of millisecond duration. The timing of this circuit can be adjusted by a variable resistance (not shown).
  • This clock output is inverted and fed to one input of the inhibit gate 3.
  • the other input to the inhibit gate 3 receives the inverted and delayed output from the dash generator 11 by way of a delay circuit 15.
  • the delay input to the inhibit gate 3 permits an inhibit gate output during the generation of a dot and at the beginning of the generation of a dash. It inhibits an output during the remainder of the generation of the dash.
  • the inhibit gate output triggers the shift pulse generator 4 which is a monostable multivibrator that provides a retimed and reshaped output consisting of a train of essentially square pulses of approximately 5 mircroseconds in duration. These pulses occur at a 250 millisecond rate except when inhibited by the output from the delay circuit 15.
  • the output of the shift pulse generator 4 is supplied to both a shift pulse inverter 16 and to the core driver 5 Where it is amplified, inverted and passed to the magnetic shift register 14.
  • the output from the first stage of the core driver 5 is reshaped, am-
  • the multivibrator 6 is triggered by a unijunction transistor circuit (not shown), the time constant of which is determined by a circuit that is adjustable. It provides an output pulse of 15 seconds duration once each 30 seconds. This output is used to trigger the gate control 7 which provides an output once each 30 seconds that is fed to the initial pulse gate 8.
  • the initial pulse gate 8 passes the gate control 7 signal to the initial pulse generator 9 unless it is in coincidence with the inverted shift pulse output. If the two pulses are in coincidence, the output of the initial pulse gate 8 is delayed for the duration of the initial pulse microseconds), after which time a pulse is passed to the initial pulse generator 9.
  • the initial pulse gate 8 is required in order to insure that the initial pulse and shift pulse do not occur simultaneously in the magnetic shift register causing a possible cancellation of input signals and a lack of output.
  • the initial pulse generator 9 is a one shot multivibrator which provides an output pulse of microsecond duration once each 30 seconds. The initial pulse is supplied to the first core of the magnetic shift register and is also used as a feedback via line 21 to turn off the output of the gate control 7. Since the 30 second generator 6 produces one pulse of l5 second duration each 30 seconds, the gate control 7 ip-op circuitry is required in order to reduce the pulse duration to approximately 50 microseconds. This insures that only one initial pulse is generated in each 30 second period. If the 15 second pulse output of generator 6 were permitted to pass directly to the initial pulse gate 8, the initial pulses would be generated at the clock rate during the 15 second pulse duration of the 30 second generator period.
  • the 30 second generator 6 through the gate control flip-tiop 7, the initial pulse gate 8 and the initial pulse generator 9 provides the initial pulse to the magnetic shift register 14.
  • the clock generator 2 through the inhibit gate 3, shift pulse generator 4 and core driver 5 provides both the shift pulse and the suppression pulse to the magnetic shift register 14.
  • the shift pulse reacts with the initial pulse and the magnetic properties of the cores in the magnetic shift register to provide consecutive outputs at the 1 through 21 switches shown in FIGURE 4.
  • the suppression pulse insures the transfer of the output of one core to the input of the next core.
  • the delay circuit insures that a dash output is completed before the next output is generated.
  • the initial pulse gate 8 insures that the initial pulse and the shift pulse do not occur simultaneously. This eliminates the possibility of a cancellation of input signals to the cores and the consequent lack of output from the cores.
  • FIGURE 4 there is shown the magnetic shift register 14 and switching network 25 of the keyer of this invention.
  • the initial pulse from the initial pulse generator 9, the shift pulses at the clock rate from the core driver 5, and the suppression pulses at the clock rate from the suppression pulse generator are supplied to the magnetic shift register 14.
  • the outputs of the magnetic shift register are shown as numbered A1 to A21, inclusive. These outputs are fed respectively to diode gates 26 and the output of each diode gate 26 is fed to the center connection 27 of a single pole double throw switch 28.
  • One side of each switch 28 is connected to a dot bus 30 and the other side of the switch is connected to a dash bus 31.
  • the signal is passed to either the dot bus or to the dash bus depending upon the position of the switch 28 associated with the particular magnetic shift register output.
  • the dot bus is connected to the input of a dot buffer amplifier 32 and the dash bus is connected to the input of a dash buffer amplifier 33.
  • the dot buffer amplifier 32 serves to amplify the signal received from the magnetic shift register 14. It provides a negative trigger pulse which turns on the dot generator 35.
  • the dot generator 35 consists of a monostable multivibrator circuit and a unijunction transistor trigger circuit (not shown in detail).
  • the negative trigger from the dot buffer amplifier 32 turns on the dot generator monostable multivibrator causing an output which as well as being applied to one input of the keyer gate 40 is also used to initiate the charging sequence within the circuitry associated with the unijunction transistor. After a prescribed time interval (0.125 second) has passed the unijunction transistor fires providing a pulse which turns on the off side of the monostable dot multivibrator thereby cutting off the circuit output.
  • a magnetic shift register output to the dash bus 31 causes the dash buffer amplifier 33 to trigger the dash monostable multivibrator generator 11 providing an output.
  • the unijunction timing circuit (not shown) of the dash generator provides a time constant of approximately 0.375 second. The functioning of the circuitry is the same as for the dot generator with the exception of the time constant.
  • the dash generator In addition to supplying an output to one input of the keyer gate 40, the dash generator also supplies an input to the delay circuit 15 which delays and inverts the dash output for use as an input to the inhibit gate 3which was described above.
  • the keyer gate 40 provides isolation for the dot and dash outputs and passes them to the solid state switch 41.. The output of the switch is then fed to the beacon transmitter.
  • An automatic keying apparatus comprising:
  • first clock means to generate starting pulses
  • first coupling means coupling the outputs of said first clock :means and said second clock means t0 said shift register
  • second coupling means coupling each said output of said shift register to a corresponding one of said plurality of switching means; dash symbol generating means; dot symbol generating means; said first coupling means including an inhibiting means coupled between said second clock means and said shift register and responsive to signals from said dash generator for inhibiting the application of shift pulses from said second clock means to said shift register during the generation of a dash symbol; and
  • third coupling means coupling the outputs of each of said switching means to said dash symbol generating means or to said dot symbol generating means according lto said preselected code.
  • said first clock means comprises:
  • a first multivibrator generating a pulse at the repetition rate of said preselected coded message
  • An automatic keying apparatus further comprising means coupling the output of said shift pulse inverter to said initial pulse gate whereby no output from said initial pulse gate occurs if there is a coincidence in time of the outputs of said shift pulse inverter and said gate control bistable multivibrator.
  • An automatic keying apparatus according to claim 4 wherein said dash generating means comprises:
  • a dash buffer coupling the dash output of said magnetic shift register to said dash generator.

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  • Engineering & Computer Science (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Signal Processing (AREA)
  • Synchronisation In Digital Transmission Systems (AREA)
  • Mobile Radio Communication Systems (AREA)
US286528A 1963-06-10 1963-06-10 Solid state identification keyer Expired - Lifetime US3300582A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
GB1053138D GB1053138A (xx) 1963-06-10
US286528A US3300582A (en) 1963-06-10 1963-06-10 Solid state identification keyer
CH743964A CH435362A (de) 1963-06-10 1964-06-08 Automatisches Tastgerät
BE649035D BE649035A (xx) 1963-06-10 1964-06-10
NL6406591A NL6406591A (xx) 1963-06-10 1964-06-10

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US286528A US3300582A (en) 1963-06-10 1963-06-10 Solid state identification keyer

Publications (1)

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US3300582A true US3300582A (en) 1967-01-24

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US286528A Expired - Lifetime US3300582A (en) 1963-06-10 1963-06-10 Solid state identification keyer

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US (1) US3300582A (xx)
BE (1) BE649035A (xx)
CH (1) CH435362A (xx)
GB (1) GB1053138A (xx)
NL (1) NL6406591A (xx)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3484782A (en) * 1967-06-16 1969-12-16 Communications Satellite Corp Biorthogonal code generator
US3585371A (en) * 1969-07-25 1971-06-15 Amp Inc Controlled sequence programming means
US3668684A (en) * 1970-12-28 1972-06-06 Us Navy Portable morse code signaling device
US3786494A (en) * 1972-04-28 1974-01-15 F Clark Electronic automated sos device

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2662112A (en) * 1952-04-16 1953-12-08 Nathaniel G A Dorfman Electronic code-typewritter system
US2810785A (en) * 1955-10-19 1957-10-22 Burroughs Corp Code typer
US2953642A (en) * 1958-02-03 1960-09-20 Curtiss Wright Corp Automatic digital signal keyer
US3007001A (en) * 1958-11-26 1961-10-31 Acf Ind Inc Call letter keyer

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2662112A (en) * 1952-04-16 1953-12-08 Nathaniel G A Dorfman Electronic code-typewritter system
US2810785A (en) * 1955-10-19 1957-10-22 Burroughs Corp Code typer
US2953642A (en) * 1958-02-03 1960-09-20 Curtiss Wright Corp Automatic digital signal keyer
US3007001A (en) * 1958-11-26 1961-10-31 Acf Ind Inc Call letter keyer

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3484782A (en) * 1967-06-16 1969-12-16 Communications Satellite Corp Biorthogonal code generator
US3585371A (en) * 1969-07-25 1971-06-15 Amp Inc Controlled sequence programming means
US3668684A (en) * 1970-12-28 1972-06-06 Us Navy Portable morse code signaling device
US3786494A (en) * 1972-04-28 1974-01-15 F Clark Electronic automated sos device

Also Published As

Publication number Publication date
NL6406591A (xx) 1964-12-11
GB1053138A (xx)
BE649035A (xx) 1964-12-10
CH435362A (de) 1967-05-15

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Owner name: ITT CORPORATION

Free format text: CHANGE OF NAME;ASSIGNOR:INTERNATIONAL TELEPHONE AND TELEGRAPH CORPORATION;REEL/FRAME:004389/0606

Effective date: 19831122