DE838766C - Method and arrangement for converting pulses - Google Patents

Description

The invention relates to an encryption system which was originally amplitude modulated Converts impulses into key impulse groups. They are encryption arrangements for the application of original amplitude-modulated pulses, for which this is encrypting signal or a subtractive remainder of this signal in each key cycle with one Reference signal is compared and depending on whether the amplitude of the to be encrypted Signal or the subtractive remainder is larger or smaller than the amplitude of the reference signal, the corresponding key pulse is generated or not, in the first case the reference signal is subtracted from the signal to be encrypted or its remainder.

In these encryption arrangements, the amplitude of the reference signal is variable and changes from one key cycle to the next according to the powers of two. In short, these encryption arrangements compare the amplitude A of the signal to be encrypted with the amplitude R of a reference signal. If A is greater than R, a key pulse is generated which corresponds to the first cycle of the key pulse group; then (AR) is formed and this value is compared with the new reference signal R / 2. If A is less than R, no key pulse is generated and the first cycle of the key pulse group is an empty cycle; then one compares A, without subtracting R , as in the previous case, with the new reference signal R / 2 etc. According to a feature of the encryption arrangement created by the invention, the amplitude of the reference signal is constant for all key cycles and the

The tude-modulated impulse or its subtly active remainder is amplified in a ratio of ι: 2 in each measure. In the first key cycle, according to the invention, the amplitude A of the pulse to be encrypted is compared with the amplitude R of a reference signal. If A is greater than R, a key pulse is generated; which corresponds to the first cycle of the final pulse group, whereupon the subtraction (AR) and the multiplication 2 (AR) ίο are carried out. This latter amplitude is in the second key cycle with the same reference signal with the amplitude 7? compared. If A is smaller than R, no key pulse is generated and the first cycle of the key pulse group is an empty cycle, after which the multiplication 2 A is carried out. This latter amplitude is compared with the same reference signal with the amplitude R in the second key cycle.

According to a further feature of the invention, the encryption arrangement comprises an electrical chain which consists of a two-stage comparison device with electron tubes: the first stage, the so-called subtraction threshold breaker, allows the original signal (A) or after being changed by subtraction and multiplication 2 (AR) through, if it is greater than the threshold value (R) and in this case delivers a signal whose amplitude is equal to the difference between the supplied signal and the threshold value [(AR) or 2 (AR) -R. . .] and at the same time a key impulse. When the first stage works, the second stage is locked at the same time.

The second stage, which forms a bypass to the first and therefore hereinafter referred to as

Shunt stage is called, leaves the original signal (A) or after modification by subtraction and multiplication 2 (AR). . . if it is smaller than the threshold value (R) of the previous stage without changing its amplitude.

Furthermore, the arrangement comprises a delay line which, if necessary, by subtraction changed signal delayed by an interval equal to the interval between the key clocks is, and a stage for doubling the amplitude of the possibly changed signal, which is on the input of the comparison device is fed back.

According to a further feature of the invention, the encryption arrangement comprises a delay line, which delays the modulated input pulse by a time interval which is equal to the transmission duration of a complete Key signal increased by an elementary interval, and an amplifier that delayed this Signal amplified up to such a value that it is in combination with that at the input of the doubler supplied signal a negative signal to lock the stages of the electronic Comparison device results.

The invention is explained below using a general scheme and an exemplary embodiment in conjunction with the drawing.

Fig. Ι shows the circuit diagram of the encryption arrangement according to the invention;

Fig. 2 shows an embodiment of an arrangement according to the invention;

Fig. 3 shows the shape of the various impulses in certain points, which are shown in the circuit diagrams Fig. Ι and 2 are given.

Fig. Ι shows the general circuit diagram of the encryption arrangement. The reference numbers are here the same as in the embodiment of Fig. 2. The amplitude-modulated pulses are, if necessary after reversal and reinforcement by steps not shown, in parallel fed to the input of a breaker with threshold value 5 and a shunt stage 8, the both have gain 1. The swell is constant and equal to half of the highest The value of the amplitude which the modulated pulse can assume. When the value of the modulated Pulse is greater than the threshold value of level 5, this on the one hand delivers a after 10 Key pulse, on the other hand after 8 a locking pulse and finally to the delay line 11 a pulse whose amplitude is equal to that of the incoming pulse, reduced by the threshold. When the size of the modulated pulse is smaller than that Threshold value of level 5, this remains locked and level 8, which no longer has a locking pulse receives, delivers to the delay line 11 a pulse, the amplitude of which is that of the incoming Momentum is the same. The pulse emerging from the delay line 11 is delayed around the elementary interval between two key pulses fed to the doubling stage 12, which doubles its amplitude. The out

12 exiting pulse is sent to the input of the comparison device 5, 8 as often fed back as Sohlüsselimpuls as clocks in the selected one Keys are present.

The delay line 14 and the amplifier

13 contribute to the activity of the encryption arrangement the number of operations required, d. H. on the number of key cycles, to restrict. The original modulated pulse is on line 14 at a time delayed, which is w times the elementary inter- m valls, which separates two key pulses, is where η is the number of key cycles. Further the pulse in 13 is amplified in such a way that the pulse emerging from 13, in combination with the pulse entering the doubler 12, a negative pulse at the output of this doubler to block the comparison device. This is then modulated for the reception of a new one original impulse ready.

Fig. 2 shows an embodiment of a Ver iao key arrangement according to the general Scheme of Fig. 1. The mode of operation of the arrangement according to Fig. 2 is illustrated using the pulse diagrams Fig. 3 explains which for different points of the electric chain the form iss and show the relative position of the pulses. The im-

pulses are aligned according to lines whose reference numerals represent the point on the electrical chain in Fig. 2 reflects where they are generated. The same reference numerals are given in Fig. Ι. A first tube ι receives on its grid via the input terminal 2 negative pulses 3, the are modulated in amplitude, and therefore positive pulses appear in their anode circuit, such as they are shown at 4. The pulses 4 are on the one hand the grids of two tubes 35 and 36, which are negatively biased by the battery 7, and on the other hand a first grid of a tube 8 fed which is negatively biased by the battery 9. The anode circuit of tube 35 is on the one hand with an output terminal 10 and on the other hand with a second grid of the tube 8 tied together.

The anodes of the tubes 36 and 8 are connected in parallel and their circle ends at the entrance of one Delay line 11, the output of which is led to the grid of a tube 32. This grid is also connected to the anode circuit of a tube 33, whose grid from the pulse 3 after delay is fed in line 14. The anode of tube 32 is with the anode of tube 1 tied together.

The height / 1 of the signal 4 can fluctuate between zero and a maximum value A ,, the z. B. corresponds to the I28fold quantification elementary value (two-digit key with seven clocks).

A value of // is assumed here, which is slightly larger than A / 2. The bias voltage 7 of the tubes 35 and 36 is regulated in such a way that a conductivity threshold of these tubes is established precisely for a value of A / 2 applied to the grids, so that in the intended case the signal 4 in these two tubes has an anode current as a function of the value h ~ A / 2 is generated.

Assuming that the gain of the tube 36 is one l>, a negative signal 15 with the level I1-A / 2 will then appear in its anode circuit. This signal 15 passes through the delay line 11 before it reaches the grid of the tube 32. The running time of the line 11 is assumed to be Θ , a value that corresponds to the time interval between two key cycles. The signal thus fed to this grid is shown at 16 (Fig. 3).

The tube 35, which operates at the same time as the tube 36, generates a negative pulse 17 which, when properly adapted and trimmed by circles connected to the terminal 10, not shown, becomes a key pulse. In addition, the pulse 17 is fed to the second grid of the tube 8, while the first grid of this tube receives the pulse 4. The tube 8 therefore remains locked despite the signal 4, and only the pulse 15 which emerges from the tube 36 reaches the line 11 and, after a delay Θ, the grid of the tube 32 with the previously calculated height I1-A / 2. As will be explained later, the tube 33 does not yet come into operation and can be temporarily overridden.

The gain of the tube 32 is controlled so that the incoming signal is amplified twice. At the end of the time Θ after the signal 4 with the value //, a signal 18 with the value 2 hA therefore occurs, which is fed to the grids of the tubes 35, 36 and 8.

It is now assumed that the value 2 hA of the signal 18 is smaller than the threshold value A / 2 and that for this reason the anode current of the tubes 35 and 36 remains zero, furthermore the pulse corresponding to the pulse 17 of the previous case is absent, as well as the corresponding key pulse and nothing happens to lock the tube 8. This tube, the bias voltage 9 of which makes the occurrence of the anode current coincide with the base line of the pulse 18 (4 above), is set in such a way that the pulse 18 is transmitted to the line 11 while maintaining its value 2 hA and only with reversed polarity which becomes negative (i8 °). The pulse which is thus applied to the grid of the tube 32 at the instant 2 θ is shown at 19 in Fig. 3 and, after amplification and inversion by the tube 32, gives the signal 20 with the value 4 h-2 A, which is returned to the grids of tubes 35, 36 and 8.

Depending on whether the value of this signal is greater or less than the threshold A / 2 of the tubes 35 and 36, one has to do with the first case under consideration (signal 4) or with the second case (signal 18).

Each time a key impulse is obtained (or not) based on a signal 17 that is at 10 (AbI). 2) occurs, and this is repeated as often as there are bars in the selected key. The delay line 14 and the tube τ, τ, help to limit the activity of the encryption arrangement to the number of operations required, e.g. B. in the case mentioned of a two-digit key with seven bars is 7.

For this purpose, the delay of line 14 is assumed to be 7 Θ and at the end of this time, after pulse 3 has occurred at input 2 of the system, a negative pulse 22 appears at the output of line 14 at 21, which * represents the positive pulse 23 generated in the anode circuit of the tube 33, which is fed to the grid of the tube 32 simultaneously with a signal 24 such as 16 coming from the line 11. The circuits are regulated in such a way that the resulting signal is always positive. The signal 25 generated in the anode circuit of the tube 32 will then always be negative and blocked by the grids of the tubes 35, 36 and 8, so that the entire arrangement is then ready again to receive a new, generally 1> ei 2 supplied pulse 3 "to encrypt.

It could be feared that in the case where the incoming signal 3 has the value zero or is very small, the pulse 23 does not exist or at any rate would be too weak to generate the pulse 24 1 * 5 to neutralize. To avoid this shortcoming,

one only needs to limit the modulation depth of the pulse 3 so that it never falls below a given minimum of the amplitude in the absolute value, or add a fixed pulse to the modulated pulse 3. The closures- | This does not change the system's capacity, provided that this change in the characteristics of pulse 3, and therefore also of : _f pulse 4, is taken into account when setting the bias voltages 7 and 9 of the tubes 35, 36 and 8.

Additional circuits can be added to the system described, for example to to give more precision to the implementation of the quantification.

The batteries 7 and 9 can be replaced with cathode-biased circuits Resistances. The same resistors or others can be arranged so that the Linearity of the characteristics, mainly of the tubes 1, 36, 8 and 32 is improved.

In general, 1, 35, 36, 32 and 33 pentodes will be used for the tubes, while the Tube 8 can be a five-lattice tube, the l> ei of this tube being shown in Fig. 2 only are the signal grating and the modulation grating.

With regard to the clarity of the diagrams

Fig. 3 shows the incoming pulses 3 as well as the various derived pulses with a duration much shorter than θ . In reality, they can be almost Θ in duration.

Claims (2)

Patent claims: i. Method of converting a through the variable amplitude of recurring Pulses represented the signal in a group of encrypted pulses, which are encrypted by a sequence made of comparisons between the amplitude of the signal and a reference amplitude with each comparison a key pulse is transmitted or not, depending according to whether the signal amplitude is greater than the reference amplitude or not, and at each Comparison the signal amplitude is reduced by an amount that of the reference amplitude is the same if the signal amplitude exceeds this reference amplitude, characterized in that that one and the same device with "electron tubes for all successive Comparisons are used if each signal passes through this facility several times and the amplitude of this signal is doubled after each comparison, so that the one used Reference amplitude is always the same for all successive comparisons. 2. Arrangement for carrying out the method according to claim 1, characterized by the use of an amplifier with a threshold equal to the reference amplitude is and at the input of which the signal to be encrypted is fed, this Amplifier has two output paths, one of which feeds the key pulses into one Consumer circuit transmits and the other with the input of the same threshold amplifier is connected via a delay line, the duration of which corresponds to the time interval between coincides with two successive key pulses, and onto this delay line a second amplifier follows, which provides twice the gain and also is controlled by the signal which is fed to the input of the entire arrangement becomes so that its gain at the end of a time of the duration of a key pulse group is made to zero. 1 sheet of drawings Q 5115 5.