Patent GB-1317915-A (GB)
Title: Identification system
IPC: G06K19/077
Filed: 1970-06-30
Abstract: 1317915 Selective signalling J DETHLOFF and H GROTTRUP 30 June 1970 [30 June 1969] 31558/70 Headings G4A and G4H [Also in Division H4] A system for identifying identificants 1, each identificant including a correlator device 11 having a number of inputs and outputs, of which each input is connected to a respective output to provide encoded information which identifies the relevant identificant, comprises a plurality of such identificants and an identificator (remainder of Fig. 1), for evaluating the encoded information of any of the identificants, the identificator having a transmitter 2, 3, 4, 5 which emits a pulse modulated high frequency signal to a receiver 6, 7 in an identificant being evaluated, the signals being demodulated (7) and the resulting pulses fed to a switching means 9, 10 which produces output signals to energize in sequence the inputs of the correlator device 11, whose resultant output signals preset in the identificant a transmitting device 12, 13 which is operable to emit an identifying sequence of signals each differing from the others, and such signals being received by the identificator and stored in a memory device 19. In the construction shown in Fig. 1 a pulse generator 2 of the transmitter produces a sequence of ten identical pulses with identical spacing which via an amplifier 5 modulate the high frequency produced by a high frequency generator 3 so that it produces sequence of ten identical signals; the demodulator 7 of the receiver produces ten pulses from the signals received from the transmitter these being passed to a stage 8 which sharpens the pulses: from the stage 8 the ten pulses are passed to a decade counter 9 of the switching device outputs of which in binary form are passed to a decoder 10 of the switching device which produces decimal output signals 0-9 which in turn are passed to the ten inputs of the device 11; the device 11 has ten outputs one for each input with the connecting leads between them being disposed in any desired order and the ten outputs are connected to a pulse generator 12 of the transmitting devices 12, 13 to preset the generator, the generator 12 producing the identifying sequence of signals; each signal consisting of one or more pulses, the number depending upon the output of the device 11 which has preset the generator 12. Thus the 1 output of the decoder presets the pulse generator to produce one pulse, the 2 output of the decoder presets the pulse generator 12 to produce two pulses and so on with the 9 output of the decoder presetting the pulse generator to produce 9 pulses; the sequence in which the various pulse signals are produced varies according to the interconnections of the device 11. The pulse generator 12 only produces each signal when it receives a pulse from the receiver 6, 7 these being received through a delay device 15 and a pulse shaper 16. From the transmitting coil 13 the sequence of signals are transmitted to a receiving coil 20 in the identifying device where they are passed to an amplifier 21 which routes them to a pulse shaper 22 which in turn is connected to a counter 23. Binary outputs of counter 23 are connected to a decoder 24 the decimal outputs of which are connected via amplifiers to horizontal lines of the memory device 19. In addition the outputs from the pulse shaper 22 are applied to a second counter 27 which counts all the pulses received by the coil 20, this is a constant number for a correct identificant in the identificator irrespective of the connections of the device 11, if the count is incorrect an alarm operates to notify an incorrect identificant. The vertical columns of the memory device 19 are connected to the decimal outputs of a decoder 18 which is driven by a decade counter 17 which receives its input from the pulse generator 2, the result is that pulses are stored in the memory device corresponding to the particular identificant which has been inserted into the identificator and can be used for any desired purpose. Power for the various circuit elements in the identificant are provided by a generator 29 which feeds a coil 30, power from this is picked up in the identificant by a coil 31 which feeds the received power to a rectifier 32 from which all the circuit elements are powered.