GB1506559A – Data transmission systems
– Google Patents
GB1506559A – Data transmission systems
– Google Patents
Data transmission systems
Info
Publication number
GB1506559A
GB1506559A
GB220872A
GB220872A
GB1506559A
GB 1506559 A
GB1506559 A
GB 1506559A
GB 220872 A
GB220872 A
GB 220872A
GB 220872 A
GB220872 A
GB 220872A
GB 1506559 A
GB1506559 A
GB 1506559A
Authority
GB
United Kingdom
Prior art keywords
signal
frequency
modulated
converter
output
Prior art date
1971-03-05
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
Application number
GB220872A
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.)
Siemens AG
Original Assignee
Siemens AG
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.)
1971-03-05
Filing date
1972-01-17
Publication date
1978-04-05
1972-01-17
Application filed by Siemens AG
filed
Critical
Siemens AG
1978-04-05
Publication of GB1506559A
publication
Critical
patent/GB1506559A/en
Status
Expired
legal-status
Critical
Current
Links
Espacenet
Global Dossier
Discuss
Classifications
H—ELECTRICITY
H04—ELECTRIC COMMUNICATION TECHNIQUE
H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
H04N7/00—Television systems
H04N7/16—Analogue secrecy systems; Analogue subscription systems
H04N7/167—Systems rendering the television signal unintelligible and subsequently intelligible
H—ELECTRICITY
H04—ELECTRIC COMMUNICATION TECHNIQUE
H04K—SECRET COMMUNICATION; JAMMING OF COMMUNICATION
H04K1/00—Secret communication
H04K1/02—Secret communication by adding a second signal to make the desired signal unintelligible
Abstract
1506559 Data transmission systems SIEMENS AG 17 Jan 1972 [5 March 1971] 2208/72 Headings H4L and H4P In a data transmission system, intentional or unintentional electromagnetic interference is suppressed by rendering the bandwidth of the RF transmission very much wider than the bandwidth of the signal to be transmitted. Thus, at the transmitter, an analogue signal to be transmitted is converted either to a frequency-modulated signal or to a digitally-coded signal which is then phasemodulated by or mixed with a pseudo-random code signal prior to its transmission; at the receiver, the received phase-modulated signal is detected and subjected, once again, to the pseudo-random code signal with the result that the frequencymodulated signal or digitally coded signal is regained and subsequently re-converted to the analogue signal which is reproduced. At the transmitter (Fig. 1) a TV camera 1 and waveform generator circuit 2 form a complete video signal which is frequency-modulated in an oscillator 3 before being applied to a phasemodulator 6 controlled by a pseudo-random code signal from a generator 4. The output from phasemodulator 6 passes to a frequency converter 9 to produce a modulated RF carrier for transmission and thence to an amplifier 11 and directional antenna 12. A constant-frequency oscillator 10 may be used for frequency conversion in the converter 9, although the oscillator 10 may also be a frequency-hopping device, operated in accordance with a specific programme. In an alternative construction, the units 3 and 6 are replaced by a circuit-arrangement shown in broken-line fashion. Here, the video signal from generator 2 passes to an A/D converter 13 to form a binary signal (PCM, #-modulated or PCM-#- modulated). Subsequently, code words are formed in a coder 15 and a pseudo-random code signal from generator 4 is added to the output from coder 15 in a half-adder 16. Thereafter, the signal is phase-modulated in a modulator 17 coupled to an oscillator 18 which produces an output signal from unit 17 to correspond, in its frequency state, to the output from the phase-modulator 6 provided in the first construction. At the receiver (Fig. 2) the received phasemodulated signal is filtered and amplified in an RF stage 20 before passing to a frequency converter 21 coupled to an oscillator 22 which can be a constantfrequency device, or frequency-hopping device if such an oscillator 10 is employed in the transmitter. The emergent IF signal is fed via an amplifier 23 to a frequency converter 24 and a synchronizing device of a pseudo-random code signal generator 25 which produces a code signal of the same form as that used in the transmitter. The original frequency-modulated signal is regained at the output of converter 24, the video signal being regained from a frequency demodulator 27 and reproduced on a CRT 28. In an alternative construction corresponding to the alternative construction of transmitter, the frequency demodulator 27 is replaced by a circuitarrangement shown in broken lines. Here, the output from converter 24 is applied to a phase jump demodulator 29 coupled to a code word recognition circuit 30 containing either correlators or matched filters. The recognition circuit 30 also receives an input from a synchronizing signal separator 36. Analysis of the correlator or matched filter outputs occurs in a decision device 31 from which the output is stored, in a store 32, in digital form. Individual image element information in store 32 can be called up by CRT 28 via line 40; the signals called up are passed through a D/A converter 33 which outputs respectively luminance, frame sync. and line sync. signals.
GB220872A
1971-03-05
1972-01-17
Data transmission systems
Expired
GB1506559A
(en)
Applications Claiming Priority (1)
Application Number
Priority Date
Filing Date
Title
DE19712110468
DE2110468C1
(en)
1971-03-05
1971-03-05
Procedure for the transfer of information
Publications (1)
Publication Number
Publication Date
GB1506559A
true
GB1506559A
(en)
1978-04-05
Family
ID=5800567
Family Applications (1)
Application Number
Title
Priority Date
Filing Date
GB220872A
Expired
GB1506559A
(en)
1971-03-05
1972-01-17
Data transmission systems
Country Status (5)
Country
Link
DE
(1)
DE2110468C1
(en)
FR
(1)
FR2368837A1
(en)
GB
(1)
GB1506559A
(en)
IT
(1)
IT1019524B
(en)
NL
(1)
NL159257B
(en)
Cited By (4)
* Cited by examiner, † Cited by third party
Publication number
Priority date
Publication date
Assignee
Title
FR2509559A1
(en)
*
1981-07-10
1983-01-14
Thomson Csf
Digital DPSK TV signal secrecy transmission method – uses pseudo random changes in carrier frequency, frequency agile pass-band filtering and line synchronisation decoder
GB2288300A
(en)
*
1994-04-05
1995-10-11
Christopher Robert Turner
Video surveillance system using spread spectrum radio communication
GB2308949A
(en)
*
1996-01-08
1997-07-09
Ramar Technology Ltd
Remote meter reading system using pseudo-random code generated spread spectrum
GB2461590A
(en)
*
1982-08-11
2010-01-13
Electronique Serge Dassault
Elimination of interference introduced by switching of the respective channels of a pulse radar
Families Citing this family (1)
* Cited by examiner, † Cited by third party
Publication number
Priority date
Publication date
Assignee
Title
FR2706704B1
(en)
*
1993-06-09
1995-07-13
Alcatel Telspace
Spread spectrum digital transmission system obtained by low frequency pseudo-random coding of useful information and spread spectrum compression method used in such a system.
Family Cites Families (3)
* Cited by examiner, † Cited by third party
Publication number
Priority date
Publication date
Assignee
Title
CH311424A
(en)
*
1950-04-22
1955-11-30
Gretener Edgar Ing Dr
Method for the secrecy of speech in communication channels.
US3180927A
(en)
*
1961-09-07
1965-04-27
Itt
Cryptosecure transmission system
FR1444250A
(en)
*
1965-05-21
1966-07-01
Csf
Link synchronization device
1971
1971-03-05
DE
DE19712110468
patent/DE2110468C1/en
not_active
Expired
1972
1972-01-17
GB
GB220872A
patent/GB1506559A/en
not_active
Expired
1972-02-01
NL
NL7201298A
patent/NL159257B/en
not_active
IP Right Cessation
1972-03-02
IT
IT2132572A
patent/IT1019524B/en
active
1972-03-03
FR
FR7207453A
patent/FR2368837A1/en
active
Granted
Cited By (6)
* Cited by examiner, † Cited by third party
Publication number
Priority date
Publication date
Assignee
Title
FR2509559A1
(en)
*
1981-07-10
1983-01-14
Thomson Csf
Digital DPSK TV signal secrecy transmission method – uses pseudo random changes in carrier frequency, frequency agile pass-band filtering and line synchronisation decoder
GB2461590A
(en)
*
1982-08-11
2010-01-13
Electronique Serge Dassault
Elimination of interference introduced by switching of the respective channels of a pulse radar
GB2461590B
(en)
*
1982-08-11
2010-06-23
Electronique Serge Dassault
Process and device for elimination of the effect of clutter signals associated with switching of the receiving channels of a pulse radar
GB2288300A
(en)
*
1994-04-05
1995-10-11
Christopher Robert Turner
Video surveillance system using spread spectrum radio communication
GB2308949A
(en)
*
1996-01-08
1997-07-09
Ramar Technology Ltd
Remote meter reading system using pseudo-random code generated spread spectrum
GB2308949B
(en)
*
1996-01-08
1999-11-10
Ramar Technology Ltd
Remote meter reading system
Also Published As
Publication number
Publication date
IT1019524B
(en)
1977-11-30
NL159257B
(en)
1979-01-15
DE2110468C1
(en)
1978-04-27
FR2368837B1
(en)
1982-04-30
NL7201298A
(en)
1978-01-31
FR2368837A1
(en)
1978-05-19
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Legal Events
Date
Code
Title
Description
1978-08-16
PS
Patent sealed
1986-08-28
PCNP
Patent ceased through non-payment of renewal fee
