GB1016284A - Privacy transmission systems - Google Patents

Privacy transmission systems


Publication number
GB1016284A GB4706362A GB4706362A GB1016284A GB 1016284 A GB1016284 A GB 1016284A GB 4706362 A GB4706362 A GB 4706362A GB 4706362 A GB4706362 A GB 4706362A GB 1016284 A GB1016284 A GB 1016284A
United Kingdom
Prior art keywords
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.)
Application number
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.)
Western Electric Co Inc
Original Assignee
Western Electric Co Inc
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 US159885A priority Critical patent/US3225142A/en
Application filed by Western Electric Co Inc filed Critical Western Electric Co Inc
Publication of GB1016284A publication Critical patent/GB1016284A/en
Expired legal-status Critical Current



    • H04K1/00Secret communication
    • H04K1/02Secret communication by adding a second signal to make the desired signal unintelligible
    • H04L9/00Cryptographic mechanisms or cryptographic arrangements for secret or secure communication


1,016,284. Secret transmissions. WESTERN ELECTRIC CO. Inc. Dec. 13, 1962 [Dec. 18, 1961], No. 47063/62. Heading H4R. A message signal is rendered secret by marking it with a number of spaced echoes of the signal itself. Preferably, reverse reverberation is employed, e.g. a number of spaced echoes of increasing amplitude preceding the signal. The reverse reverberation may be obtained by the circuit of Fig. 3 comprising a delay line 31 having a series of taps 32 ... 35 which are taken through amplifiers 37 . . . 40 having progressively increasing gain, the outputs being combined in an adder network 42 with the signal itself fed through a negative gain amplifier 41. The contributions of the several amplifiers are indicated in Fig. 2 (not shown). A number of such circuits may be employed in series, each having different parameters, and if desired, normal reverberation may be added. A somewhat similar circuit may be employed at the receiver for cancelling the reverse reverberation, or use may be made of the normal reverberator having a feedback loop described in Specification 1,001,518, Fig. 5 (not shown). In practice the delay line may be realized by a rotating magnetic drum having a single recording head and a number of spaced pick-up heads, Figs. 8, 10, 12 (not shown).
GB4706362A 1961-12-18 1962-12-13 Privacy transmission systems Expired GB1016284A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US159885A US3225142A (en) 1961-12-18 1961-12-18 Privacy system

Publications (1)

Publication Number Publication Date
GB1016284A true GB1016284A (en) 1966-01-05



Family Applications (1)

Application Number Title Priority Date Filing Date
GB4706362A Expired GB1016284A (en) 1961-12-18 1962-12-13 Privacy transmission systems

Country Status (2)

Country Link
US (1) US3225142A (en)
GB (1) GB1016284A (en)

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4361729A (en) * 1968-01-24 1982-11-30 American Standard Inc. Narrowband analog message privacy system
US4064505A (en) * 1971-09-30 1977-12-20 U.S. Philips Corporation Signal transmission circuit comprising a coder and a decoder
US3736369A (en) * 1972-03-13 1973-05-29 Theatre Vision Inc Technique for encoding and decoding scrambled t.v. transmissions by the simultaneous transmission of the encoding and decoding signals
CH574692A5 (en) * 1973-02-13 1976-04-15 Gretag Ag
US3867715A (en) * 1973-11-08 1975-02-18 Us Navy Underwater communications system
US4105863A (en) * 1976-12-20 1978-08-08 Bell Telephone Laboratories, Incorporated Arrangement for combining data symbols in accordance with a predetermined weighting function
US5253296A (en) * 1991-11-26 1993-10-12 Communication Electronics System for resisting interception of information

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2312897A (en) * 1939-07-14 1943-03-02 Patelhold Patentverwertung Method of transmitting signals
BE477658A (en) * 1941-07-09
US3012100A (en) * 1943-04-24 1961-12-05 Bell Telephone Labor Inc Telephone privacy system
US2953643A (en) * 1945-05-10 1960-09-20 Bell Telephone Labor Inc Inverted speech privacy using irregular inverting wave form
US2935604A (en) * 1951-12-01 1960-05-03 Toro Michael J Di Long range communication system

Also Published As

Publication number Publication date
US3225142A (en) 1965-12-21

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