GB1315873A - Telecommunications systems - Google Patents

Telecommunications systems

Info

Publication number
GB1315873A
GB1315873A GB2166571A GB2166571A GB1315873A GB 1315873 A GB1315873 A GB 1315873A GB 2166571 A GB2166571 A GB 2166571A GB 2166571 A GB2166571 A GB 2166571A GB 1315873 A GB1315873 A GB 1315873A
Authority
GB
United Kingdom
Prior art keywords
function
modulation
frequency
delay
pfi
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
Application number
GB2166571A
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.)
Filing date
Publication date
Application filed by Siemens AG filed Critical Siemens AG
Publication of GB1315873A publication Critical patent/GB1315873A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04K—SECRET COMMUNICATION; JAMMING OF COMMUNICATION
    • H04K3/00—Jamming of communication; Counter-measures
    • H04K3/20—Countermeasures against jamming
    • H04K3/25—Countermeasures against jamming based on characteristics of target signal or of transmission, e.g. using direct sequence spread spectrum or fast frequency hopping
    • 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
    • G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
    • G01S13/06—Systems determining position data of a target
    • G01S13/08—Systems for measuring distance only
    • G01S13/10—Systems for measuring distance only using transmission of interrupted, pulse modulated waves
    • G01S13/26—Systems for measuring distance only using transmission of interrupted, pulse modulated waves wherein the transmitted pulses use a frequency- or phase-modulated carrier wave
    • G01S13/28—Systems for measuring distance only using transmission of interrupted, pulse modulated waves wherein the transmitted pulses use a frequency- or phase-modulated carrier wave with time compression of received pulses
    • G01S13/284—Systems for measuring distance only using transmission of interrupted, pulse modulated waves wherein the transmitted pulses use a frequency- or phase-modulated carrier wave with time compression of received pulses using coded pulses
    • G01S13/288—Systems for measuring distance only using transmission of interrupted, pulse modulated waves wherein the transmitted pulses use a frequency- or phase-modulated carrier wave with time compression of received pulses using coded pulses phase modulated
    • 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
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04K—SECRET COMMUNICATION; JAMMING OF COMMUNICATION
    • H04K3/00—Jamming of communication; Counter-measures
    • H04K3/80—Jamming or countermeasure characterized by its function
    • H04K3/82—Jamming or countermeasure characterized by its function related to preventing surveillance, interception or detection
    • H04K3/827—Jamming or countermeasure characterized by its function related to preventing surveillance, interception or detection using characteristics of target signal or of transmission, e.g. using direct sequence spread spectrum or fast frequency hopping

Landscapes

  • 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)
  • Compression, Expansion, Code Conversion, And Decoders (AREA)
  • Radar Systems Or Details Thereof (AREA)

Abstract

1315873 Frequency modulation systems SIEMENS AG 19 April 1971 [24 Feb 1970] 21665/71 Heading H4P A plurality of code elements having a discontinuous modulation function have each element subjected to a further modulation before transmission and at the receiver compression is carried out both on the additional and discontinuous modulation functions. The additional modulation may be a function of the frequency. Received signals are applied to pulse compression filters PFI, PFII followed by demodulators DI, DII: the outputs are fed through a subtracting device S feeding a delay element VG designed as a delay line or a shift register provided with a series of tappings into monitoring circuits USI, USII. Due to the delay in VG the outputs on the tappings are available simultaneously. A switch control unit SU controlled by a code generator SC distributes values + 1, - 1 such distribution being controlled according to generator SC so that all the outputs are of like sign which are added in AN as an output D with a stage SAG being set at a threshold level. If an incorrect signal is received at A, in the example given there would not be seven identical amplitudes fed into AN i.e. an incorrect character would result in - 1 instead of + 1 thus reducing the output of AN by two units hence output D does not reach the value set by thres - hold circuit SAG. A seven unit character is illustrated in Fig. 2a the broken lines rising towards the right indicating that frequency of each element rises with passage of time (+1) and conversely in a falling direction (-1). Pulse compression filter PFI is arranged so that frequencies with a rising f.m. function are dealt with compressively and with a falling f.m. function, dispersively, and it is known to employ devices which produce a frequency dependent delay in signals. Pulse compression filter PFII has an f.m. function inverse to that of PFI with a clearly defined maxima occurring with a falling function (- 1) and only a small secondary maxima with rising f.m. (+1) this being described more fully with relation to Figs. 2b, 2c (not shown). The additional modulation may be frequency keyed or phase shift. As the correctness of the incoming signals is monitored by the coding sequence in SC the arrangement may be applied to a "secure" system or may be utilized in "friend or foe" systems employing secondary radars.
GB2166571A 1970-02-24 1971-04-19 Telecommunications systems Expired GB1315873A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19702008560 DE2008560C3 (en) 1970-02-24 1970-02-24 Message transmission system using pulse code modulation and pulse compression on the receiver side

Publications (1)

Publication Number Publication Date
GB1315873A true GB1315873A (en) 1973-05-02

Family

ID=5763234

Family Applications (1)

Application Number Title Priority Date Filing Date
GB2166571A Expired GB1315873A (en) 1970-02-24 1971-04-19 Telecommunications systems

Country Status (3)

Country Link
DE (1) DE2008560C3 (en)
GB (1) GB1315873A (en)
NL (1) NL7102464A (en)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NO129973B (en) * 1972-10-16 1974-06-17 Kongsberg Vapenfab As
FR2248517B1 (en) * 1973-10-23 1978-08-04 Sercel Rech Const Elect
DE2365675C1 (en) * 1973-11-09 1988-11-10 Siemens AG, 1000 Berlin und 8000 München Query-response system with a primary radar and with filters in the response station
CH613527A5 (en) * 1976-02-27 1979-09-28 Patelhold Patentverwertung Circuit arrangement for separating responses arriving simultaneously in a secondary radar system
DE2808545C2 (en) * 1978-02-28 1984-10-25 Siemens AG, 1000 Berlin und 8000 München Combined radar and communications equipment

Also Published As

Publication number Publication date
DE2008560C3 (en) 1974-03-07
DE2008560A1 (en) 1971-09-09
NL7102464A (en) 1971-08-26
DE2008560B2 (en) 1973-07-12

Similar Documents

Publication Publication Date Title
US2415359A (en) Wave-signal translating system
GB1079928A (en) A data transmission system
GB1017322A (en) Improvements in and relating to pulse signal transmission and receiving systems
US2534264A (en) Pulse width discriminator
US2851617A (en) Bipolarity gate
GB1087860A (en) Improvements in or relating to pulse transmission apparatus
GB634372A (en) Improvements in or relating to pulse modulation signalling systems
GB1315873A (en) Telecommunications systems
GB1179378A (en) Improvements in or relating to Data Transmission Systems
GB910453A (en) Improvements in or relating to data transmission systems
GB1289378A (en)
GB604817A (en) Improvements relating to multi-channel pulse communication systems
GB842235A (en) Facsimile transmission systems
GB1064250A (en) Code checking circuit and multifrequency data receiver
GB862856A (en) Improvements in and relating to secondary radar systems
GB935694A (en) Radar system
SU430426A1 (en) RECEIVER REQUIREMENTS FOR SERVICE DEVICES FOR GROUP TELEPHONE
GB1058908A (en) Improvements in electrical signalling systems
JPS5739610A (en) Broadband ccd delay line
FR2528640B1 (en)
GB1020361A (en) A circuit arrangement for the conversion of a serial sequence of binary data
GB986012A (en) Method of receiving voice-frequency code signals
GB996835A (en) Multi-frequency code signalling method
GB1495929A (en) Communication systems
JPS5497301A (en) Signal transmission system

Legal Events

Date Code Title Description
PS Patent sealed
PLNP Patent lapsed through nonpayment of renewal fees