Electronic jamming system

• US 4,103,236 A
• Filed: 09/18/1961
• Issued: 07/25/1978
• Est. Priority Date: 09/22/1960
• Status: Expired due to Term

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Prost, Hans, Deserno, Peter
• Primary Examiner(s): Birmiel, Howard A.
• Application Number:
  US04/154,913
• Time in Patent Office: 6,154 Days
• Field of Search: 250/17 JA, 325/132, 325/18
• US Class Current: 455/1
• CPC Class Codes: H04K 3/42 characterized by the control of the jamming frequency or wavelength
• CPC Class Codes: H04K 3/45 characterized by including monitoring of the target or target signal, e.g. in reactive jammers or follower jammers for example by means of an alternation of jamming phases and monitoring phases, called "look-through mode"

Abstract

1. A method of jamming wireless communications having a frequency falling within a predetermined frequency band, by means of a powerful jamming transmission, comprising the steps of separating out from the predetermined frequency band, by an electrical filtering operation, a suspect transmission signal falling therein, producing an interference signal band having a band width sufficient to include all filtered frequencies, separating out, by an electrical filtering operation, a signal having a frequency corresponding to the frequency of the previously filtered suspect signal, from said interference signal band, and utilizing said last filtered signal at the interference frequency in the wireless transmission of a jamming signal, the frequency of which corresponds to the frequency of the suspect transmission signal so detected.

Claims

1. A method of jamming wireless communications having a frequency falling within a predetermined frequency band, by means of a powerful jamming transmission, comprising the steps of separating out from the predetermined frequency band, by an electrical filtering operation, a suspect transmission signal falling therein, producing an interference signal band having a band width sufficient to include all filtered frequencies, separating out, by an electrical filtering operation, a signal having a frequency corresponding to the frequency of the previously filtered suspect signal, from said interference signal band, and utilizing said last filtered signal at the interference frequency in the wireless transmission of a jamming signal, the frequency of which corresponds to the frequency of the suspect transmission signal so detected.

2. A method of jamming wireless communications as defined in claim 1, wherein said suspect transmission signal is converted to a signal of an intermediate frequency falling within a predetermined intermediate frequency band, filtering from said intermediate frequency band a signal corresponding to the intermediate frequency representing the suspect signal, producing said interference signal with a band width corresponding to that of said intermediate frequency band, filtering from said interference signal a signal having the frequency corresponding to the intermediate frequency of the suspect signal, and converting said filtered signal having such interference frequency to the frequency of said suspect signal to form the jamming signal to be transmitted.

3. A method of jamming wireless communications as defined in claim 1, comprising the steps of simultaneously respectively filtering from the predetermined frequency band, all suspect transmission signals, simultaneously respectively filtering from said interference signal all signals having frequencies corresponding to the previously filtered suspect signals, and simultaneously transmitting a jamming signal for each detected suspect transmission signal.

4. A method of jamming wireless communications as defined in claim 1, wherein all suspect transmission signals, falling within said predetermined frequency band, are converted to respective signals having intermediate frequencies falling within a predetermined intermediate frequency band, filtering from said intermediate frequency band all signals having intermediate frequencies representing respective suspect signals, producing said interference signal with a band width corresponding to that of said intermediate frequency band, respectively filtering from said interference signal all signals having frequencies corresponding to the intermediate frequencies of the respective suspect signals, and respectively converting said filtered signals having interference frequencies to signals having the respective frequencies of the corresponding suspect signals to form the respective jamming signals to be transmitted.

5. A method of jamming wireless communications, operating on frequencies falling within a predetermined frequency band, by means of a powerful jamming transmission, comprising the steps of alternatively detecting suspect transmissions over a predetermined wave range and radiating jamming signals upon a wave length of any suspect transmission so detected, simultaneously testing during a detection period said frequency band in a multitude of mutually bordering narrow frequency channels so as to ascertain suspect transmission therein, marking each channel upon determining a transmission therein, and passing over each so marked channel a signal having an interference frequency spectrum, forming from each of the latter a corresponding jamming signal and simultaneously transmitting all jamming signals so formed.

6. A system for jamming wireless communications within a predetermined wave band, with the aid of a powerful jamming transmitter, employing detection periods followed by jamming periods, means for controlling the duration of the respective periods, means for automatically selecting a respective frequency representative of the transmitted frequency of each suspect transmitter ascertained during the detection period, means for producing a signal comprising an interference frequency spectrum having a band width corresponding to said predetermined wave band, means cooperable with said selection means for obtaining from said interference frequency spectrum the respective frequencies thereof corresponding to each selected frequency, and means utilizing each respective interference frequency for forming and transmitting during the following jamming period a corresponding jamming signal having the frequency of the corresponding suspect transmitter.

7. In a system according to claim 22, wherein said selection means includes a series of mutually bordering frequency measuring channels for effecting during the detection period a frequency analysis of the ascertained received frequency, said channels covering said predetermined wave band.

8. In a system according to claim 7, wherein said frequency measuring channels comprise a corresponding number of channel filters.

9. In a system according to claim 8, wherein said system is provided, at the transmitting side, with a series of transmitter channels and transmitter filters corresponding in number to the frequency measuring channels and frequency measuring filters.

10. A system according to claim 9, wherein a series of common channels and channel filters are employed for the frequency measurement and the transmitting, respectively, and means for switching said common channels and filters from the detection operation to the jamming transmission operation and vice versa.

11. A system according to claim 10, comprising means for effecting at least one conversion of the received frequency into a lower frequency position prior to frequency analysis thereof, and effecting reconversion to the original frequency position at the transmitter side.

12. A system according to claim 11, comprising suitable switch means for designating the received frequencies, and circuit means for operatively actuating said switch means over the involved frequency measuring channels and channel filters by the received frequencies ascertained in the detection periods.

13. A system according to claim 12, comprising a noise generator for producing the jamming frequency spectrum, and means for connecting said generator in an intermediate frequency position to the transmitter over the transmitter channels and transmitter filters corresponding to the ascertained received frequencies.

14. A system according to claim 13, comprising switching means for blocking given jamming channels.

15. A system according to claim 7, comprising means for automatically regulating the amplification of the jamming transmitting means so as to maintain in the presence of fluctuating numbers of jamming channels a maximum output power.

16. A system according to claim 15, wherein the formation of harmonic waves, in channels which are to be held free for communication, is prevented by means including linear amplifier means and feedback coupling, respectively.