EP0042587A1 - Method of transforming speech signals subdivided into signal segments for enciphered transmission, and apparatus for realizing this method - Google Patents

Method of transforming speech signals subdivided into signal segments for enciphered transmission, and apparatus for realizing this method Download PDF

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Publication number
EP0042587A1
EP0042587A1 EP81104666A EP81104666A EP0042587A1 EP 0042587 A1 EP0042587 A1 EP 0042587A1 EP 81104666 A EP81104666 A EP 81104666A EP 81104666 A EP81104666 A EP 81104666A EP 0042587 A1 EP0042587 A1 EP 0042587A1
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signal
reading
memories
analog
digital
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German (de)
French (fr)
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EP0042587B1 (en
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Caflisch Dr. Mengia
Richard Dr. Weber
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CRYPTO AG
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CRYPTO AG
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04K—SECRET COMMUNICATION; JAMMING OF COMMUNICATION
    • H04K1/00—Secret communication
    • H04K1/06—Secret communication by transmitting the information or elements thereof at unnatural speeds or in jumbled order or backwards

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  • the invention relates to a method for reshaping voice signals divided into signal sections for the encrypted transmission, the individual signal sections being temporally compressed by reading in and reading out from memories with different reading and reading speeds, and a device for carrying out the method.
  • the input signal to be encrypted is divided into sections.
  • the division can take place in terms of frequency or time or in both axes at the same time.
  • the signal sections obtained are permuted depending on the key.
  • the cipher then consists of a changed sequence of signal sections, with discontinuities occurring at the interfaces. Due to the finite band limit of the transmission channel, dispersion takes place. The joint is thus blurred, which results in crosstalk between two adjacent signal gaps.
  • the transmission channel also show group delay differences, which in practically all applications, this effect can be increased drastically, since the settling process of such a channel takes longer.
  • the dispersion can have a significant impact on speech quality after decryption. As a rule, this causes a strongly disturbing impulsive noise.
  • None of the methods mentioned is suitable for eliminating the effects caused in particular by jumps in amplitude at the joints of signal sections in the analog transmission of voice signals in encrypted form.
  • the object of the present invention is to remedy the disadvantages arising from the method mentioned at the outset and to avoid signal discontinuities in the ciphertext, so that the interfering effects can be eliminated by means of a suitable evaluation on the receiving side.
  • the basic idea of the method is that the signal is compressed in time and the time period thus obtained is used for double transmission of the critical signal components in the area of the joints (see FIG. 1).
  • the temporal compression and the associated increase in bandwidth are obtained by reading the signal to be processed into a memory at a specific speed and reading it out of it at an increased speed.
  • the signal components repeated in the acquired period can be provided with a weight function (cf. FIG. 4). With your help, a soft fade in and fade out can be realized. Only those signal components that have not been weighted are evaluated on the receiving side. Assembled correctly and stretched to the original length of time, they return the original signal.
  • Fig. La shows a possible format of the speech signal to be encrypted.
  • the signal sections here have a bandwidth B and a time length T.
  • This signal is read into a memory at a certain speed and read out in permuted order at 1 / s times the speed.
  • each signal section T experiences a temporal compression to the length sT, the bandwidth B increasing to B /.
  • Part of the information is read out a second time in the periods of time gained thereby, the switching intervals T U (see FIGS. 1 a and b). In this way it is possible to prevent discontinuities from occurring at the edges of the signal sections with the length T or sT, since the original signal curve is continued at these points during Tu / 2.
  • the actual impact point then occurs within the switching interval T U.
  • the signal part transmitted in the interval T U is blanked out in the receiver, since all of the information is contained in the remaining sections. These sections are read into the receiver-side memory at a certain speed and read out in reverse order at s times the speed (see FIG. 1c). As a result, the signal again receives the original bandwidth B.
  • the redundant signal component which is not required in the receiver and which is transmitted in the switching interval T U can for the transmission are provided with a weighting function which allows a switchover which is as soft as possible and thus shortens the transient processes on the transmission channel.
  • Fig. 2 shows schematic sections of a cipher s (t) at a joint.
  • the blanking function is missing
  • the cipher is weighted in a "soft" switchover function.
  • FIG. 2c A special case is shown in FIG. 2c.
  • the technical implementation is particularly simple here, but the desired properties are only partially achieved.
  • FIG. 3 shows the block diagram of a possible implementation of the exemplary embodiment described.
  • the speech signal to be encrypted is limited to bandwidth B.
  • the signal is read into a memory group 4 via an analog-digital converter 2 and a switch arrangement 3. This reading process takes place according to the scheme shown in Fig. 4.
  • This readout process the signal undergoes the transformation shown in FIGS. la and b. Thanks to the overlapping reading in at the beginning and at the end of each signal frame (cf. FIG.
  • the soft switchover shown in FIG. 2b is realized with the aid of the amplifier 7.
  • the ciphertext is then fed into the transmission channel via a transmission filter 8.
  • the control of the switches 3,5 and the variable amplifier kers 7 and the addressing of the memory 4 is carried out by a control unit 9.
  • the control unit 9 of the transmitter is capable of individually addressing or controlling the three memory parts and the switches of the switch arrangement 3. By repeating an address sequence when reading out, the relevant signal section can be read out and transmitted a second time, so that the situation shown in FIG. 1 arises.
  • the signal reaches memory 13 via a reception filter 10, an analog-digital converter 11 and a changeover switch 12.
  • control units 9 and 17 require the corresponding information for a key-dependent permutation of the signal blocks. This is supplied by a key stream generator, which is not explained in detail here.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Transmission Systems Not Characterized By The Medium Used For Transmission (AREA)
  • Time-Division Multiplex Systems (AREA)
  • Compression, Expansion, Code Conversion, And Decoders (AREA)
  • Communication Control (AREA)
  • Input Circuits Of Receivers And Coupling Of Receivers And Audio Equipment (AREA)
  • Reduction Or Emphasis Of Bandwidth Of Signals (AREA)

Abstract

1. Method for modifying speech signals divided into segments for ciphered transmission, wherein the individual signal segments (T) are compressed in time by reading them into storages and out of them with different rates, characterized in that the time intervals (Tu ) obtained by said compression are used of the repeated transmission of the edge portions of each signal segment, such that the original signal is continued at the intersection of each segment of the ciphered signals and characterized in that the ciphered signal is combined with a weighting function within the intervals (Tu ) obtained by said compression, such that in said intervals a desired switching function is generated.

Description

Die Erfindung betrifft ein Verfahren zur Umformung von für die verschlüsselte Uebertragung in Signalabschnitte unterteilten Sprachsignalen, wobei die einzelnen Signalabschnitte durch Ein- und Auslesen in bzw. aus Speichern mit unterschiedlichen Ein- und Auslesegeschwindigkeiten zeitlich gestaucht werden, sowie eine Vorrichtung zur Durchführung des Verfahrens.The invention relates to a method for reshaping voice signals divided into signal sections for the encrypted transmission, the individual signal sections being temporally compressed by reading in and reading out from memories with different reading and reading speeds, and a device for carrying out the method.

Bei der Mehrzahl von analogen Sprachschlüsselverfahren wird das zu verschlüsselnde Eingangssignal in Abschnitte unterteilt. Die Aufteilung kann frequenzmässig oder zeitlich oder in beiden Achsen zugleich erfolgen. Die erhaltenen Signalabschnitte werden schlüsselabhängig permutiert. Das Chiffrat besteht dann aus einer veränderten Folge von Signalabschnitten, wobei an den Nahtstellen Diskontinuitäten auftreten. Infolge der endlichen Bandgrenze des Uebertragungskanals findet eine Dispersion statt. Die Stossstelle wird also verwischt, was ein Uebersprechen zwischen zwei zeitlich benachbarten Signalanschnitten zur Folge hat. Weist der Uebertragungskanal neben der Bandbegrenzung noch Gruppenlaufzeitunterschiede auf, was in praktisch allen Anwendungen der Fall ist, so kann dieser Effekt noch drastisch verstärkt werden, da der Einschwingvorgang eines solchen Kanals länger dauert.In the majority of analog voice key methods, the input signal to be encrypted is divided into sections. The division can take place in terms of frequency or time or in both axes at the same time. The signal sections obtained are permuted depending on the key. The cipher then consists of a changed sequence of signal sections, with discontinuities occurring at the interfaces. Due to the finite band limit of the transmission channel, dispersion takes place. The joint is thus blurred, which results in crosstalk between two adjacent signal gaps. In addition to the band limitation, does the transmission channel also show group delay differences, which in practically all applications, this effect can be increased drastically, since the settling process of such a channel takes longer.

Die Dispersion kann eine erhebliche Beeinträchtigung der Sprachqualität nach der Entschlüsselung bewirken. In der Regel tritt dadurch ein stark störendes impulsartiges Geräusch auf.The dispersion can have a significant impact on speech quality after decryption. As a rule, this causes a strongly disturbing impulsive noise.

Im Zusammehang mit der Uebertragung von Audiosignalen in zeitkomprimierter Form über Videokanäle ist aus der US-PS 2 819 852 bekannt geworden, an den Rändern der entstehenden Signallücken eine Mehrfachübertragung vorzunehmen. Ferner ist es bei Multiplexverfahren mit Zeitkompression gemäss Proceedings of the I.E.F., Band III, Nr. 4, Seite 647 ff bekannt, Lücken zwischen Signalgruppen derart durch Füllsignale auszufüllen, dass bei der Uebertragung eine ausgeglichene Energieverteilung erreicht wird. Schliesslich wird gemäss GB-PS 1 407 196 bei einem Verfahren zum Aendern der Tonlage von Audiosignalen vorgeschlagen, die entstehenden Signallücken mittels Interpolation auszufüllen.In connection with the transmission of audio signals in time-compressed form via video channels, it has become known from US Pat. No. 2,819,852 to carry out a multiple transmission at the edges of the signal gaps which arise. Furthermore, in multiplex methods with time compression according to Proceedings of the I.E.F., Volume III, No. 4, page 647 ff, it is known to fill gaps between signal groups with fill signals in such a way that a balanced energy distribution is achieved during the transmission. Finally, according to GB-PS 1 407 196 it is proposed in a method for changing the pitch of audio signals to fill the resulting signal gaps by means of interpolation.

Keines der genannten Verfahren ist geeignet, die insbesonders durch Amplitudensprünge an den Stossstellen von Signalabschnitten bei der analogen Uebertragung von Sprachsignalen in verschlüsselter Form verursachten Effekte zu beseitigen.None of the methods mentioned is suitable for eliminating the effects caused in particular by jumps in amplitude at the joints of signal sections in the analog transmission of voice signals in encrypted form.

Die vorliegende Erfindung hat die Aufgabe, diese beim eingangs erwähnten Verfahren entstehenden Nachteile zu beheben und die Signalunstetigkeiten im Chiffrat zu vermeiden, so dass mittels geeigneter Auswertung auf der Empfangsseite die störenden Auswirkungen ausgeschaltet werden können.The object of the present invention is to remedy the disadvantages arising from the method mentioned at the outset and to avoid signal discontinuities in the ciphertext, so that the interfering effects can be eliminated by means of a suitable evaluation on the receiving side.

Diese Aufgabe wird durch die Merkmale gemäss den Ansprüchen 1 und 5 gelöst.This object is achieved by the features according to claims 1 and 5.

Dadurch gelingt es bei der analogen Verschlüsselung von Sprachsignalen, die Sprachqualität nach der Entschlüsselung zu erhöhen. Insbesondere werden die störenden Einflüsse der Bandbegrenzung des Uebertragungskanals bekämpft.This makes it possible with analog locking selection of voice signals to increase the voice quality after decryption. In particular, the disruptive influences of the band limitation of the transmission channel are combated.

Nachfolgend werden anhand der Zeichnungen die der Erfindung zugrundliegenden Prinzipien sowie ein Ausführungsbeispiel näher erläutert. Es zeigen:

  • Fig. la bis 1 c drei schematische Bandbreite-Zeit-Diagramme zur Erläuterung des erfindungsgemässen Verfahrens;
  • Fig. 2a bis 2c drei schematische Amplituden-Zeit-Diagramme im Umschaltbereich zwischen zwei Signalabschnitten;
  • Fig. 3 ein Blockschema eines möglichen Ausführungsbeispiels der Erfindung; und
  • Fig. 4 ein Ablaufdiagramm mit der Ein- und Auslesefolge in die sende- bzw. empfangsseitigen Speicher.
The principles underlying the invention and an exemplary embodiment are explained in more detail below with reference to the drawings. Show it:
  • Figures la to 1 c three schematic bandwidth-time diagrams to explain the inventive method.
  • 2a to 2c show three schematic amplitude-time diagrams in the switching range between two signal sections;
  • 3 shows a block diagram of a possible exemplary embodiment of the invention; and
  • Fig. 4 is a flowchart with the reading and reading sequence in the transmit or receive memories.

Die Grundidee des Verfahrens besteht darin, dass das Signal zeitlich gestaucht wird und der so gewonnene Zeitraum zur doppelten Uebertragung der kritischen Signalanteile im Bereich der Stossstellen benutzt wird (vgl. Fig. 1). Die zeitliche Stauchung und die damit verbundene Erhöhung der Bandbreite erhält man, indem das zu verarbeitende Signal mit einer bestimmten Geschwindigkeit in einen Speicher eingelesen und mit erhöhter Geschwindigkeit daraus ausgelesen wird. Die im gewonnen Zeitraum wiederholten Signalanteile können mit einer Gewichtsfunktion versehen werden (vgl. Fig. 4). Mit Ihrer Hilfe kann ein weiches Ein- und Ausblenden realisiert werden. Auf der Empfangsseite werden nur jene Signalanteile ausgewertet, die keine Gewichtung erfahren haben. Richtig zusammengesetzt und auf die ursprüngliche zeitliche Länge gedehnt, ergeben sie wieder das ursprüngliche Signal.The basic idea of the method is that the signal is compressed in time and the time period thus obtained is used for double transmission of the critical signal components in the area of the joints (see FIG. 1). The temporal compression and the associated increase in bandwidth are obtained by reading the signal to be processed into a memory at a specific speed and reading it out of it at an increased speed. The signal components repeated in the acquired period can be provided with a weight function (cf. FIG. 4). With your help, a soft fade in and fade out can be realized. Only those signal components that have not been weighted are evaluated on the receiving side. Assembled correctly and stretched to the original length of time, they return the original signal.

Bei spezieller Wahl der Gewichtsfunktion werden keine Signalanteile wiederholt. In diesem technisch besonders einfachen Fall verhindert man zwar keine Bandbreitenerhöhung. Dagegen wird auch hier das Uebersprechen zwischen benachbarten Signalabschnitten vermindert.With a special choice of the weight function, who which no signal components are repeated. In this technically particularly simple case, no increase in bandwidth is prevented. In contrast, crosstalk between adjacent signal sections is also reduced here.

Im folgenden wird das Verfahren anhand des Beispiels einer einfachen Zeitpaketvertauschung erläutert. Fig. la zeigt ein mögliches Format des zu verschlüsse.lnden Sprachsignals. Die Signalabschnitte weisen hier eine Bandbreite B und eine zeitliche Länge T auf. Dieses Signal wird mit einer bestimmten Geschwindigkeit in einen Speicher eingelesen und in permutierter Reihenfolge mit 1/s-facher Geschwindigkeit ausgelesen. Dadurch erfährt jeder Signalabschnitt T eine zeitliche Stauchung auf die Länge sT, wobei die Bandbreite B auf B/ anwächst. In den dadurch gewonnenen Zeitabschnitten, den Umschaltintervallen TU, wird ein Teil der Information ein zweites Mal ausgelesen (siehe Fig. la und b). Auf diese Weise kann verhindert werden, dass an den Rändern der Signalabschnitte mit der Länge T bzw. sT Unstetigkeiten auftreten, da an diesen Stellen der ursprüngliche Signalverlauf noch während Tu/2 fortgesetzt wird. Die eigentliche Stossstelle tritt dann innerhalb des Umschaltintervalls TU auf.In the following the method is explained using the example of a simple time packet exchange. Fig. La shows a possible format of the speech signal to be encrypted. The signal sections here have a bandwidth B and a time length T. This signal is read into a memory at a certain speed and read out in permuted order at 1 / s times the speed. As a result, each signal section T experiences a temporal compression to the length sT, the bandwidth B increasing to B /. Part of the information is read out a second time in the periods of time gained thereby, the switching intervals T U (see FIGS. 1 a and b). In this way it is possible to prevent discontinuities from occurring at the edges of the signal sections with the length T or sT, since the original signal curve is continued at these points during Tu / 2. The actual impact point then occurs within the switching interval T U.

Der im Intervall TU übertragene Signalteil wird im Empfänger ausgetastet, da ja die gesamte Information in den übrigen Abschnitten enthalten ist. diese Abschnitte werden mit einer bestimmten Geschwindigkeit in den empfangsseitigen Speicher eingelesen und in rückvertauschter Reihenfolge mit s-facher Geschwindigkeit ausgelesen (siehe Fig. lc). Das Signal erhält dadurch wieder die ursprüngliche Bandbreite B. Der im Empfänger nicht benötigte redundante Signalanteil, der im Umschaltintervall TU übertragen wird, kann zur Uebertragung mit einer Gewichtungsfunktion versehen werden, welche eine möglichst weiche Umschaltung erlaubt und damit die Einschwingvorgänge auf dem Uebertragungskanal verkürzt.The signal part transmitted in the interval T U is blanked out in the receiver, since all of the information is contained in the remaining sections. these sections are read into the receiver-side memory at a certain speed and read out in reverse order at s times the speed (see FIG. 1c). As a result, the signal again receives the original bandwidth B. The redundant signal component which is not required in the receiver and which is transmitted in the switching interval T U can for the transmission are provided with a weighting function which allows a switchover which is as soft as possible and thus shortens the transient processes on the transmission channel.

Fig. 2 zeigt schematische Ausschnitte eines Chiffrats s(t) an einer Stossstelle. In Fig. 2a fehlt die Austastfunktion, in Fig. 2b ist das Chiffrat in einer "weichen" Umschaltfunktion gewichtet. In Fig. 2c ist ein Spezialfall dargestellt. Hier ist die technische Realisierung besonders einfach, die erwünschten Eigenschaften werden aber nur teilweise erreicht.Fig. 2 shows schematic sections of a cipher s (t) at a joint. In Fig. 2a the blanking function is missing, in Fig. 2b the cipher is weighted in a "soft" switchover function. A special case is shown in FIG. 2c. The technical implementation is particularly simple here, but the desired properties are only partially achieved.

Fig. 3 zeigt das Blockschema einer möglichen Realisierung des beschriebenen Ausführungsbeispiels.3 shows the block diagram of a possible implementation of the exemplary embodiment described.

In einem Eingangsfilter 1 wird das zu verschlüsselnde Sprachsignal auf die Bandbreite B begrenzt. Ueber einen Analog-Digital-Wandler 2 und eine Schalteranordnung 3 wird das Signal in eine Speichergruppe 4 eingelesen. Dieser Einlesevorgang findet nach dem in Fig. 4 gezeigten Schema statt. Mit erhöhter Auslesegeschwindigkeit und in innerhalb eines Signalrahmens TR permutierter Reihenfolge gelangen die Signalabschnitte mit der Länge T (TR = n T;n ganzzahlig) über einen Umschalter 5 und einen Digital-Analog-Wandler 6 auf eine steuerbare Verstärkerstufe 7. Durch diesen Auslesevorgang erfährt das Signal die in Fig. la und b dargestellte Umformung. Dank dem überlappenden Einlesen zu Beginn und am Ende jedes Signalrahmens (vgl. Fig. 4) kann man das doppelte Auslesen derselben Signalausschnitte im Gebiete der Stossstellen nicht nur innerhalb eines Rahmens, sondern auch am Anfang und Ende jedes Rahmens verwirklichen. Die in Fig. 2b gezeigte weiche Umschaltung wird mit Hilfe des Verstärkers 7 realisiert. Ueber einen Sendefilter 8 wird das Chiffrat hernach in den Uebertragungskanal eingespeist. Die Steuerung der Schalter 3,5 und des variablen Verstärkers 7 sowie die Adressierung der Speicher 4 übernimmt eine Steuereinheit 9. Die Steuereinheit 9 des Senders ist dabei in der Lage, die drei Speicherteile und die Schalter der Schalteranordnung 3 einzeln zu adressieren bzw. zu steuern. Durch die Wiederholung einer Adressequenz beim Auslesen kann der betreffende Signalausschnitt ein zweites Mal ausgelesen und übertragen werden, so dass die in Fig. 1 gezeigte Situation entsteht.In an input filter 1, the speech signal to be encrypted is limited to bandwidth B. The signal is read into a memory group 4 via an analog-digital converter 2 and a switch arrangement 3. This reading process takes place according to the scheme shown in Fig. 4. With an increased readout speed and in a sequence permuted within a signal frame T R , the signal sections with the length T (T R = n T; n integer) reach a controllable amplifier stage 7 via a changeover switch 5 and a digital-analog converter 6. This readout process the signal undergoes the transformation shown in FIGS. la and b. Thanks to the overlapping reading in at the beginning and at the end of each signal frame (cf. FIG. 4), it is possible to double read out the same signal sections in the area of the joints not only within a frame, but also at the beginning and end of each frame. The soft switchover shown in FIG. 2b is realized with the aid of the amplifier 7. The ciphertext is then fed into the transmission channel via a transmission filter 8. The control of the switches 3,5 and the variable amplifier kers 7 and the addressing of the memory 4 is carried out by a control unit 9. The control unit 9 of the transmitter is capable of individually addressing or controlling the three memory parts and the switches of the switch arrangement 3. By repeating an address sequence when reading out, the relevant signal section can be read out and transmitted a second time, so that the situation shown in FIG. 1 arises.

Im Empfänger gelangt das Signal über einen Empfangsfilter 10, einen Analog-Digital-Wandler 11 und einen Umschalter 12 in Speicher 13.In the receiver, the signal reaches memory 13 via a reception filter 10, an analog-digital converter 11 and a changeover switch 12.

Im Gegensatz zum Sender, wo drei Speicher eingesetzt werden, um auf einfache Weise das überlappende Auslesen des Chiffrats an den Rändern des Rahmens T zu ermöglichen, genügen im Empfänger zwei Speicher. Mit verkleinerter Auslesegeschwindigkeit und in rückvertauschter Reihenfolge werden die Signalabschnitte über einen Umschalter 14 und einen Digital-Analog-Wandler 15 einem Ausgangsfilter 16 zugeführt. Auch im Empfänger werden die Umschalter 12,14 und die Adressierung der Speicher 13 von einer Steuereinheit 17 kontrolliert. Fig. 4 gibt einen Ueberblick über den Ein-und Ausleserhythmus im Sender und Empfänger.In contrast to the transmitter, where three memories are used in order to enable the cipher to be read out overlapping at the edges of the frame T in a simple manner, two memories are sufficient in the receiver. The signal sections are fed to an output filter 16 via a changeover switch 14 and a digital-to-analog converter 15 at a reduced readout speed and in reverse order. The changeover switches 12, 14 and the addressing of the memories 13 are also controlled by a control unit 17 in the receiver. 4 gives an overview of the reading and reading rhythm in the transmitter and receiver.

Für eine schlüsselabhängige Permutation der Signalblöcke benötigen die Steuereinheiten 9 und 17 die entsprechende Information. Diese liefert ein hier nicht näher erläuterter Schlüsselstromgenerator.The control units 9 and 17 require the corresponding information for a key-dependent permutation of the signal blocks. This is supplied by a key stream generator, which is not explained in detail here.

Mit dem erfindungsgemässen Verfahren gelingt es, die Sprachqualität nach der Entschlüsselung zu erhöhen und störende Einflüsse der Bandbegrenzung des Uebertragungskanals zu mildern.With the method according to the invention, it is possible to increase the speech quality after decryption and to mitigate disruptive influences of the band limitation of the transmission channel.

Claims (6)

1. Verfahren zur Umformung von für die verschlüsselte Uebertragung in Signalabschnitte unterteilten Sprachsignalen, wobei die einzelnen Signalabschnitte (T) durch Ein- und Auslesen in bzw. aus Speichern mit unterschiedlichen Ein- und Auslesegeschwindigkeiten zeitlich gestaucht werden, dadurch gekennzeichnet, dass die durch diese Stauchung verfügbar gewordenen Zeitabschnitte (Tu) zur doppelten Uebertragung der Signalanteile im Bereich der Stossstellen jedes Signalabschnittes benutzt werden, dergestalt, dass der ursprüngliche Verlauf des Signals an den Grenzen jedes Signalabschnittes im verschlüsselten Signal erhalten bleibt, und dass das verschlüsselte Signal innerhalb der durch die Stauchung gewonnenen Zeitabschnitte (T ) mit einer Gewichtungsfunktion versehen wird, dergestalt, dass innerhalb dieser Zeitabschnitte eine beliebige Umschaltfunktion erzielbar ist.1. A method for reshaping speech signals divided into signal sections for the encrypted transmission, the individual signal sections (T) being compressed in time by reading in and reading out from memories with different reading and reading speeds, characterized in that the compression caused by this compression time periods (T u ) that have become available are used for double transmission of the signal components in the area of the joints of each signal segment, in such a way that the original course of the signal at the boundaries of each signal segment is retained in the encrypted signal, and that the encrypted signal is within the range of the compression obtained time periods (T) is provided with a weighting function in such a way that any switchover function can be achieved within these time periods. 2. Verfahren nach Anspruch 1, dadurch gekennzeichnet, dass die Gewichtungsfunktion stetig ist und zu Beginn jedes Zeitabschnittes (Tu) den Wert 1 annimmt, anschliessend bis zum eigentlichen Umschaltzeitpunkt auf Null sinkt und dann bis zum Ende des Zeitabschnittes (Tu) wieder auf den Wert 1 steigt.2. The method according to claim 1, characterized in that the weighting function is continuous and assumes the value 1 at the beginning of each time period (T u ), then drops to zero until the actual changeover time and then up again until the end of the time period (T u ) the value 1 increases. 3. Verfahren nach Anspruch 1, dadurch gekennzeichnet, dass empfangsseitig die Zeitabschnitte (T ) ausgetastet und die Signalabschnitte auf ihre ursprüngliche zeitliche Länge gedehnt werden.3. The method according to claim 1, characterized in that the time segments (T) are blanked at the receiving end and the signal segments are stretched to their original temporal length. 4. Verfahren nach Anspruch 1 und 3, wobei sendeseitig mehrere Signalabschnitte (T) zu einem Signalrahmen (TR) zusammengefasst werden und die Verschlüsselung durch schlüsselabhängiges Vertauschen der Signalabschnitte (T) innerhalb des Signalrahmens vorgenommen wird, dadurch gekennzeichnet, dass die doppelte Uebertragung an den Stossstellen der Signalrahmen durch überlappendes Einlesen in verschiedene Speicher gefolgt von aufeinanderfolgendem Auslesen dieser Speicher mit erhöhter Geschwindigkeit erzielt wird und dass die doppelte Uebertragung an den Stossstellen der Signalabschnitte (T) innerhalb eines Signalrahmens (TR) durch doppeltes Auslesen von Grenzbereichen der Signalabschnitte (T) und entsprechend erhöhte Auslesegeschwindigkeit erreicht wird.4. The method according to claim 1 and 3, wherein a plurality of signal sections (T) are combined on the transmission side to form a signal frame (T R ) and the encryption is carried out by key-dependent interchanging of the signal sections (T) within the signal frame, characterized in that the double Transmission at the joints of the signal frames is achieved by overlapping reading into different memories followed by successive reading of these memories at an increased speed and that the double transmission at the joints of the signal sections (T) within a signal frame (T R ) is achieved by double reading of boundary areas of the signal sections (T) and correspondingly increased readout speed is reached. 5. Vorrichtung zur Durchführung des Verfahrens nach Anspruch 4 mit einer sendeseitigen Einrichtung, die einen Analog-Digital-Wandler (2) und einen Digital-Analog-Wandler (6) aufweist, dadurch gekennzeichnet, dass der Ausgang des Analog-Digital-Wandlers mit einer Schalteranordnung (3) verbunden ist, welche von einer mit ihr verbundenen Steuereinheit (9) derart betätigbar ist, dass das aus dem Analog-Digital-Wandler (2) stammende Signal in Form sich zeitlich überlappender Signalrahmen abwechselnd in je einen von mindestens drei mit der Schalteranordnung (3) verbundenen Speichern (4) einlesbar ist, wobei die Speicher (4) zur Vertauschung und zum teilweisen doppelten Auslesen der Signalabschnitte an den Stossstellen sowie zur Steuerung der Auslesegeschwindigkeit an die Steuereinheit (9) angeschlossen sind, dass die Speicher (4) ausgangsseitig über einen Umschalter (5), der zum Zusammensetzen der ausgelesenen Signalrahmen mit der Steuereinheit (9) verbunden ist, an den Digital-Analog-Wandler (6) angeschlossen sind und dass dem Digital-Analog-Wandler (6) ein ebenfalls mit der Steuereinheit (9) verbundener, variabler Verstärker nachgeschaltet ist.5. The device for performing the method according to claim 4 with a transmitting device, which has an analog-digital converter (2) and a digital-analog converter (6), characterized in that the output of the analog-digital converter with is connected to a switch arrangement (3) which can be actuated by a control unit (9) connected to it in such a way that the signal originating from the analog-digital converter (2) in the form of time-overlapping signal frames alternates with one of at least three The memories (4) connected to the switch arrangement (3) can be read in, the memories (4) being connected to the control unit (9) so that the memories (4.) can be exchanged and for partially reading out the signal sections twice at the joints and for controlling the reading speed ) on the output side via a changeover switch (5), which is connected to the control unit (9) for assembling the read signal frames, to the digital-to-analog converter r (6) are connected and that the digital-to-analog converter (6) is followed by a variable amplifier which is also connected to the control unit (9). 6. Vorrichtung nach Anspruch 5 mit einer empfangsseitigen Einrichtung, die einen Analog-Digital-Wandler (11) und einen Digital-Analog-Wandler (15) aufweist, dadurch gekennzeichnet, dass der Ausgang des Analog-Digital-Wandlers mit einem Umschalter (12) verbunden ist, welcher von einer mit ihm verbundenen Steuereinheit (17) derart betätigbar ist, dass die eintreffenden Signalrahmen abwechselnd in einen von mindestens zwei Speichern (13) einlesbar sind, wobei die Speicher zum Rückgängigmachen der Vertauschung der Signalabschnitte und zu deren Auslesung mit reduzierter Geschwindigkeit unter Austastung der doppelt übertragenen Signalanteile mit der Steuereinheit (1) verbunden sind, und dass die Speicher ausgangsseitig über einen weiteren Umschalter (14), der zum Zusammensetzen der ausgelesenen Signalrahmen ebenfalls mit der Steuereinheit (17) verbunden ist, an den Digital-Analog-Wandler (15) angeschlossen sind.6. The device according to claim 5 with a receiving device, which has an analog-to-digital converter (11) and a digital-to-analog converter (15) , characterized in that the output of the analog-digital converter is connected to a changeover switch (12) which can be actuated by a control unit (17) connected to it in such a way that the incoming signal frames alternately into one of at least two memories (13 ) can be read in, the memories for reversing the interchanging of the signal sections and for reading them out at a reduced speed while blanking out the double-transmitted signal components, are connected to the control unit (1), and that the memory on the output side is connected via a further switch (14) which is used for Composing the read signal frame is also connected to the control unit (17) to which digital-to-analog converter (15) are connected.
EP81104666A 1980-06-20 1981-06-17 Method of transforming speech signals subdivided into signal segments for enciphered transmission, and apparatus for realizing this method Expired EP0042587B1 (en)

Priority Applications (1)

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AT81104666T ATE7993T1 (en) 1980-06-20 1981-06-17 METHOD FOR TRANSFORMING SPEECH SIGNALS, WHICH ARE DIVIDED INTO SIGNAL SECTIONS FOR ENCRYPTED TRANSMISSION, AND DEVICE FOR CARRYING OUT THE METHOD.

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CH4763/80 1980-06-20
CH476380 1980-06-20

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EP0042587A1 true EP0042587A1 (en) 1981-12-30
EP0042587B1 EP0042587B1 (en) 1984-06-13

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JP (1) JPS5729100A (en)
AR (1) AR228273A1 (en)
AT (1) ATE7993T1 (en)
BR (1) BR8103891A (en)
DE (1) DE3164136D1 (en)
DK (1) DK271481A (en)
ES (1) ES503158A0 (en)
FI (1) FI811862L (en)
NO (1) NO812082L (en)

Cited By (5)

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Publication number Priority date Publication date Assignee Title
EP0112158A2 (en) * 1982-12-17 1984-06-27 Sony Corporation Scrambling systems for audio frequency signals
FR2541060A1 (en) * 1983-02-16 1984-08-17 Electroniques Et Const Method of scrambling information to be transmitted from a transmitting station to a receiving station
EP0116402A2 (en) * 1983-01-11 1984-08-22 Sony Corporation Scrambling systems for audio frequency signals
EP0219559A1 (en) * 1985-10-17 1987-04-29 ANT Nachrichtentechnik GmbH Mobile radio system for the transmission of digital as well as analogous signals
EP0322059A1 (en) * 1987-12-23 1989-06-28 Philips Electronique Grand Public Sound scrambling/descrambling system and method

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0314853U (en) * 1989-06-28 1991-02-14

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US3819852A (en) * 1972-08-29 1974-06-25 P Wolf Method of reducing the interference signals during the transmission of af signals in time-compressed form
GB1407196A (en) * 1971-11-16 1975-09-24 British Broadcasting Corp Apparatus for changing signal pitch
DE2834280A1 (en) * 1978-08-04 1980-02-21 Siemens Ag Scrambled speech transmission system - divides signals into time elements which are rearranged and read out at higher speed and gaps filled with additional signals

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GB1407196A (en) * 1971-11-16 1975-09-24 British Broadcasting Corp Apparatus for changing signal pitch
US3819852A (en) * 1972-08-29 1974-06-25 P Wolf Method of reducing the interference signals during the transmission of af signals in time-compressed form
DE2834280A1 (en) * 1978-08-04 1980-02-21 Siemens Ag Scrambled speech transmission system - divides signals into time elements which are rearranged and read out at higher speed and gaps filled with additional signals

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Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0112158A2 (en) * 1982-12-17 1984-06-27 Sony Corporation Scrambling systems for audio frequency signals
EP0112158A3 (en) * 1982-12-17 1985-11-27 Sony Corporation Scrambling systems for audio frequency signals
EP0116402A2 (en) * 1983-01-11 1984-08-22 Sony Corporation Scrambling systems for audio frequency signals
EP0116402A3 (en) * 1983-01-11 1987-09-16 Sony Corporation Scrambling systems for audio frequency signals
FR2541060A1 (en) * 1983-02-16 1984-08-17 Electroniques Et Const Method of scrambling information to be transmitted from a transmitting station to a receiving station
EP0219559A1 (en) * 1985-10-17 1987-04-29 ANT Nachrichtentechnik GmbH Mobile radio system for the transmission of digital as well as analogous signals
EP0322059A1 (en) * 1987-12-23 1989-06-28 Philips Electronique Grand Public Sound scrambling/descrambling system and method
FR2625391A1 (en) * 1987-12-23 1989-06-30 Radiotechnique Ind & Comm METHOD AND SYSTEM FOR INTERFERING / UNLOCKING SOUND

Also Published As

Publication number Publication date
DK271481A (en) 1981-12-21
EP0042587B1 (en) 1984-06-13
JPS5729100A (en) 1982-02-16
DE3164136D1 (en) 1984-07-19
BR8103891A (en) 1982-03-09
ATE7993T1 (en) 1984-06-15
NO812082L (en) 1981-12-21
AR228273A1 (en) 1983-02-15
FI811862L (en) 1981-12-21
ES8303853A1 (en) 1983-02-01
ES503158A0 (en) 1983-02-01

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