Back to results
US 4,232,186 AGranted
Method of and means for generating complex electrical coding waves for secret communications
AssigneeRCA Corporation
InventorAlda V. Bedford
Life of this patent
Estimating the term…
Loading patent…
Loading patent…
AssigneeRCA Corporation
InventorAlda V. Bedford
Estimating the term…
10. Apparatus for generating a complex wave comprising means for generating a plurality of different concurrent short period series of pulses, a plurality of electrical networks, means for applying a different one of said series of pulses to each of said electrical networks, means for deriving a plurality of differently delayed unmodulated pulse signals from each of said networks in response to said applied series of pulses, means for combining said derived signals from predetermined ones of said networks, and means for selecting in a predetermined manner said delayed signal components, and means for deriving from said selected signal components a complex wave having a period longer than either of said selected pulse periods, said complex wave having a substantially longer period than either of said short period pulse series.
In a secret communication system, the method of producing a complex coding wave which is a function of the voltages produced at successive time intervals in a plurality of electrical networks which method comprises generating a plurality of different concurrent short period series of pulses, applying a different one of said series of pulses to each of said networks to derive delayed unmodulated pulse signal components from each pulse of each of said series of pulses combining said delayed pulse signal components in predetermined polarities, and deriving from said combined components said complex wave, said complex wave having a substantially longer period than either of said short period pulse series.
In a secret communication system, the method of utilizing a plurality of delay networks for generating a complex coding wave comprising generating a plurality of different concurrent short period series of pulses, applying a different one of said series of pulses to each of said delay networks to derive therefrom delayed unmodulated pulse components from each pulse of each of said series of pulses, changing the polarity of at least some of said delayed pulse components, and combining said delayed pulse componenets and said delayed pulse components of different polarities to form said complex wave, said complex wave having a substantially longer period than either of said short period pulse series.
In a secret communication system, the method of producing a complex coding wave which is the algebraic sum of the voltages produced at different points in a plurality of electrical networks, which comprises creating a plurality of concurrent short period series of discrete electrical pulses, applying a different one of said series of pulses to each of said networks to derive therefrom unmodulated pulse signal components at different time intervals, combining said derived pulse components in predetermined polarities, and deriving from said combined components said complex wave, said complex wave having a substantially longer period than either of said short period pulse series.
In a secret communication system, the method of producing a code wave which is a function of the voltages produced at different time intervals in a plurality of electrical networks, which comprises producing a plurality of concurrent short period series of pulses, applying a different one of said series of pulses to each of said networks to derive therefrom delayed unmodulated pulse components, combining said derived pulse signal components in predetermined polarity to form said code wave, said complex wave having a substantially longer period than either of said short period pulse series and periodically changing said time intervals and said pulse signal component polarities in a prescribed irregular order to change said code wave.
The method of secret communication which comprises producing a message signal, producing a plurality of series of pulses, applying a different one of said series of pulses to different ones of a plurality of electrical networks to derive therefrom delayed pulse components, changing the polarity of at least some of said delayed components, combining said delayed components and the delayed components of different polarity to form a complex code wave, modifying said message signal with said code wave to derive a coded signal, transmitting said coded signal to a point of reception, producing a second complex code wave at said point of reception, said second code wave having an envelope which is substantially the reciprocal of the envelope of said original code wave, receiving said transmitted coded signal, and modifying said received coded signal by said second code wave to reproduce said message signal.
The method of secret communication which comprises producing a message signal, producing a plurality of series of pulses, applying a different one of said series of pulses to different ones of a plurality of electrical networks to derive therefrom delayed pulse components, changing the polarity of at least some of said delayed components, combining said delayed components and said delayed components of different polarities to form a code wave, multiplying the instantaneous magnitudes of said message signal by the instantaneous magnitudes of said code wave to obtain a coded signal, transmitting said coded signal to a point of reception, receiving said transmitted coded signal, producing a second code wave at said point of reception, said second code wave having an envelope which is substantially the reciprocal of the envelope of said original code wave, and multiplying the instantaneous magnitudes of said received coded signal by the instantaneous magnitudes of said second code wave to reproduce said transmitted message signal.
The method of secret communication which comprises producing a message signal, producing a plurality of different series of pulses, applying a different one of said series of pulses to different ones of a plurality of electrical networks to derive therefrom delayed pulse components, changing the polarity of at least some of said delayed components, combining said derived components and said delayed components of different polarities to form a complex code wave, modifying said message signal by said code wave to obtain a coded signal, transmitting said coded signal to a point of reception, receiving said transmitted coded signal, producing a second code wave at said point of reception of which the instantaneous magnitudes are substantially the reciprocal of the instantaneous magnitudes of said original code wave, synchronizing said second code wave with said original code wave, and modifying said coded signal by said second code wave to render said message signal intelligible.
The method of secret communication which comprises producing a message signal, producing a plurality of different series of pulses, applying a different one of said series of pulses to different ones of a plurality of electrical networks to derive therefrom delayed pulse components, changing the polarity of at least some of said delayed components, combining said delayed components and said delayed components of different polarities to form a code wave, multiplying the instantaneous magnitudes of said message signal by the instantaneous magnitudes of said code wave to obtain a coded signal, transmitting said coded signal to a point of reception, receiving said transmitted coded signal, producing a second code wave at said point of reception, said second code wave having instantaneous magnitudes which are substantially the reciprocal of said original code wave, synchronizing said second code wave with said original code wave. and multiplying the instantaneous magnitudes of said received coded signal by the instantaneous magnitudes of said second code wave to render said message signal intelligible.
The method of producing a complex wave which comprises producing a plurality of different concurrent short period series of pulses, reversing the polarity of predetermined ones of said pulses to provide a succession of incremental voltages of predetermined polarity, and combining said voltages, and deriving from said combined voltages a complex wave as an aggregate of said incremental voltages, said complex wave having a substantially longer period than either of said short period pulse series.
Apparatus for generating a complex wave comprising means for generating a plurality of different concurrent short period series of pulses, a plurality of electrical networks, means for applying a different one of said series of pulses to each of said electrical networks, means for deriving a plurality of differently delayed unmodulated pulse signals from each of said networks in response to said applied series of pulses, means for combining said derived signals from predetermined ones of said networks, and means for selecting in a predetermined manner said delayed signal components, and means for deriving from said selected signal components a complex wave having a period longer than either of said selected pulse periods, said complex wave having a substantially longer period than either of said short period pulse series.
Apparatus for generating a complex wave comprising means for generating a plurality of different series of pulses, a plurality of electrical networks, means for applying a different one of said series of pulses to each of said electrical networks, means for deriving a plurality of differently delayed signals from each of said networks in response to said applied series of pulses, means for changing the polarity of at least some of said delayed signal components, means for combining said derived signals and said signals of delayed different polarity from predetermined ones of said networks, and means for selecting in a predetermined manner said delayed signal components to produce said complex wave.
The method of secret communication which comprises producing a message signal, producing a plurality of different series of pulses, applying a different one of said series of pulses to different ones of a plurality of electrical delay networks whereby pulse waves having different time delay characteristics are produced at predetermined points in each of said delay networks, combining predetermined ones of said delayed series of pulses to form a complex code wave, altering said message signal by said code wave to form an unintelligible coded wave, transmitting said coded wave to a receiving station, receiving said transmitted coded wave at said receiving station, generating a second code wave at said receiving station, said second code wave having instantaneous magnitudes which are substantially identical to said first mentioned code wave, deriving a decoding wave from said second code wave having instantaneous magnitudes which are substantially the reciprocal of the instantaneous magnitudes of said second coded wave, and altering said received coded wave by said reciprocal wave to decode said transmitted coded wave.
The method of generating a complex wave which comprises producing a plurality of concurrent short period series of recurrent discrete pulses, applying a different one of said series of pulses to different ones of a plurality of electrical delay networks whereby different pulse waves having predetermined different time delay characteristics are produced at predetermined points in each of said delay networks, selecting and mixing predetermined ones of a plurality of said delayed series of pulses, and means for deriving from said mixed pulses a complex wave having a longer period than either of said mixed pulse periods, said complex wave having a substantially longer period than either of said short period pulse series.
Apparatus for generating a complex electrical wave comprising a plurality of electrical networks, means for concurrently exciting said networks at different non-harmonically related signal frequencies, means for concurrently deriving a plurality of differently delayed signal components from each of said networks, means for combining said derived signal components to derive a complex wave having a longer period than either of said combined signal periods, and means for deriving from said combined signal components a complex wave having a longer period than either of said combined signal periods.
An electrical switching device comprising a plurality of movable switch contact elements, a plurality of fixed switch contact elements juxtaposed with said movable elements so that predetermined ones of said movable contact elements selectively bridge predetermined others of said contact elements, and means for positioning different ones of said movable contact elements at different relative rates with respect to others of said movable elements.
The method of producing a relatively long period complex electrical pulse wave which comprises producing a first complex pulse wave having a relatively short period, concurrently producing a second complex pulse wave having a different relatively short period and modulating said first and second short period pulse waves to produce said long period wave.
The method of producing a relatively long period complex electrical pulse wave which comprises producing a first complex pulse wave having a relatively short period, concurrently producing a second complex pulse wave having a different relatively short period, limiting said first and second short period pulse waves, and multiplying said limited short period pulse waves to produce said complex long period wave.
Dependencies are inferred from the claim text.
Drawings are temporarily unavailable. Open the PDF at USPTO
Term ended 4 Nov 1997 (estimated)
USPTO file history isn’t available for this patent, so only indexed dates are shown.
The present invention relates to secret telecommunication systems and more particularly to an improved method of and means for generating, employing, and synchronizing complex coding and decoding signals in such systems.
The invention, by way of example, will be described hereinafter as an improvement in coding wave generators which may be employed in a secret telecommunication system of the type described in applicant's copending U.S. application Ser. No. 536,630, filed May 20, 1944, now U.S. Pat. No. 2,401,405, granted June 4, 1946. The copending application discloses a system wherein, for example, a speech signal comprising a complex wave S is modified by means of a coding signal comprising a complex wave K in a manner whereby the instantaneous ordinates of the resulting coded signals are the product SK of the corresponding instantaneous ordinates of the speech signal and the coding signal. The resulting unintelligible coded signals are transmitted by any conventional means to a receiver wherein the coded signals are combined with decoding signals generated in the receiver and having instantaneous ordinates corresponding to the reciprocal of the corresponding instantaneous ordinates of the coding signal component of the transmitted signal. The final signals, therefore, are derived from the product of the transmitted signal SK and the decoding signal l/K. The coding and decoding signal generators at the transmitter and receiver, respectively, are disclosed in said copending application as synchronized by means of special synchronizing pulse signals each comprising a first signal pulse immediately followed by a second signal pulse of opposite polarity, which pulses may be superimposed upon the coded signals SK. At the receiver, the reversal in polarity between the two synchronizing pulses is employed to synchronize the decoding wave generator.
The instant invention comprises an improvement over the coding wave generator described in said copending application, which also is described and claimed in applicant's copending application, Serial No. 514,351, filed Dec. 15, 1943, now U.S. Pat. No. 2,401,403, granted June 4, 1946. Applicant's prior generator employed an eighty section delay network excited by 100 pulses per second, the delayed pulses at a plurality of points in the network being combined in predetermined polarities by a continuously changing selecting mechanism to provide a complex wave having a network periodicity of 0.01 second which, because of the switching mechanism, is non-repetitive for a period of about five minutes. The instant invention provides greatly increased security by employing two separate delay networks, each having about 40 sections, which are separately excited by pulses of different rates and switched by a more complex differential speed selecting mechanism to provide a much more complex coding wave having a combined network periodicity of about 0.4 second, which by means of the switching is non-repetitive for a period of about one hour. Thus by employing the instant invention the complexity and repetition rate of the code wave is comparable to that obtainable with a single delay network of the order of 3000 sections, which would be highly impracticable.
The invention will be described in greater detail by reference to the accompanying drawings of which
FIG. 1 is a schematic, partly block diagram of a complete secret telecommunication system employing the invention,
FIG. 2 is a series of graphs illustrating the transmitter synchronizing circuits of one of the wave generators of the system of FIG. 1,
Similar reference characters are applied to similar elements throughout the drawings.
Referring to FIG. 1, the coding wave generator which may be employed alternately for both transmitting and receiving coded speech signals includes a conventional free running multivibrator circuit 1 which generates pulses at a rate, for example, of 47.7 pulses per second. A typical multivibrator of this type, the frequency of which may be controlled by recurrent applied control pulses, is described in U.S. Pat. No. 2,266,526, granted to E. L. C. White on Dec. 16, 1941. The generated pulses are applied to the input of a first conventional delay network 2 comprising a plurality of series-connected inductors 3, 5, 7, 9, 11 and a plurality of shunt-connected capacitors 4, 6, 8, 10, 12, 14. The remote terminals of the resultant pulse delay network 2 are terminated by a resistor 13 matching the surge impedance of the network. It should be understood that the delay network 2 may include, for example, forty-one filter sections as indicated by the dash lines interconnecting the filter sections 7, 8 and 9, 10, and that equalizers and booster amplifiers may be inserted in the delay network at desired points to maintain pulse amplitude relations at optimum values.
Pulses applied by the multivibrator 1 to the input of the delay network 2 provide similar pulses at the junction of each of the succeeding series inductors 3, 5, 7, 9, 11, whereby each succeeding pulse is delayed a predetermined amount with respect to pulses occurring at other prior network terminals. A complex coding wave thus may be obtained in response to each pulse applied to the delay network by combining in either polarity differently delayed pulses derived from a plurality of such predetermined points along the delay network.