Method for jam-resistant communication transmission

• US 4,843,612 A
• Filed: 06/08/1981
• Issued: 06/27/1989
• Est. Priority Date: 06/23/1980
• Status: Expired due to Term

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Brusch, Josef, Hanni, Manfred, Hechfellner, Kurt
• Primary Examiner(s): Cangialosi, Salvatore
• Application Number:
  US06/274,142
• Time in Patent Office: 2,941 Days
• Field of Search: 375/1, 375/2.1, 375/2.2, 179/15 A, 179/15 M, 179/1.5 R, 455/26-30, 380/34
• US Class Current: 375/133
• CPC Class Codes: H04B 1/713 using frequency hopping

Abstract

A method for jam-resistant transmission speech signals by radio which have been processed via vocoders, utilizing spread spectrum multiple access modulation (SSMA) or rapid frequency hopping (FH) provides, with respect to the danger of an inherent jamming brought about when a great number of stations simultaneously use the same frequency band for the same radio channel frequency group, activation and deactivation of the transmitter and receiver at the rate of the internal system frame clock pulse during a frame clock pulse period only when useful information is present. In this manner, in the case of simplexcommunication connections, on the average approximately 40% and, in the case of duplex operation, more than 60%, of the transmitting time can be saved, and hence, the inherent jamming of the system can be reduced in a corresponding fashion.

Claims

1. In a method for jam-resistant communication of useful signals between transmitting means of a transmitting station and receiving means of a receiving station in which a speech signal to be transmitted is fed to the transmitting means via a vocoder analyzer and in which the received signal is fed from the receiving means via a vocoder synthesizer to a receiver output, and in which the system operates with frame clock pulses, the improvement therein comprising the steps of:

generating a first information signal in the vocoder analyzer indicating whether a speech signal is present or absent within a frame period;

applying the first information signal to the transmitting means to switch the same on during the presence of a useful signal to transmit the coded useful signal to the receiving means and off during the time that a useful signal is not present during a respective time element of a frame period;

receiving the transmitted signal;

deriving from the signals received a second information signal indicating the presence or absence of a useful signal at the transmitting station; and

applying the second information signal to the vocoder analyzer to switch the same on or off, respectively, when a useful signal is present or not present.

2. The improved method of claim 1, comprising the step of:

transmitting the vocoder synthesizer signal in accordance with spread spectrum multiple access modulation.