DE978013C - Method and device for establishing the synchronization of the key devices in encrypted facsimile transmissions - Google Patents

Description

cause insertion to suppression of clock pulses automatically if inserted Impulses do not lead to synchronism.

which indicates the achieved synchronization acoustically or optically.

3. Device for performing the method according to claim 1 and 2, characterized 35 (clock periods) earlier or later than the transmitter by a phase comparison device (35), side key pulse generator,
which blocks the correction device, if after 2. during an existing connection

long interruptions in the sender and receiver end or occur The pulse sequence is not in phase, due to fading in a radio link, the Rectifier bridge (37) for the automatic fixed 40 synchronizing action of the transmitter clock generator position the synchronization, through an AND gate (39), gate on the receiver clock generator. Both genera soft only in the case of phase equality and lacking gates then move slowly by a few bars Synchronism is permeable by an period apart. In the event of interruptions from 1 pulse generator (45), deviations occur up to 2 minutes due to an electronic counter, only one (47) and a downstream electronic 45 clock period or a maximum of two clock periods betra switch (52), which together make the changeover, since the frequency constancy of the clock generator

stabilizing tuning forks is so large that no major deviations occur during the times mentioned.
So in the cases mentioned under 3 it is z. B. the following:

Various weather maps are constantly being issued by the weather map centers using the facsimile method.

sent, both unencrypted and

encrypted, depending on whether it is a weather map for commercial or military recipients. Both the unencrypted and the encrypted weather maps are of interest to the various Receiver only one weather card at a time

The invention relates to a method and a 60 or a few weather maps so that one device to establish the synchronization of the individual receivers at different times, the all key devices in the case of encrypted facsimile transmissions, they are exactly known, in which the broadcasts are included. have to. With each new weather map, from

The smooth running of the transmission ensures that the transmitter receives new start and phase signals for the Encrypted facsimile information requires a facsimile receiver to be sent out, but not new ones Exact synchronization of the sender and receiver-side key start signals, since the key always knows key devices or the mother cycle that controls these runs and key sections that have already been used generators. It is not enough that the sender cannot be used again.

When encrypted weather maps are being sent out, the broadcasting station initially becomes one the key pulse generator on the transmitter side for a certain time known to all authorized participants started. The key pulse generators of those recipients who switch on from the beginning of the broadcast want, can then - regardless of starting and phasing the facsimile devices - through start the transmitter. However, this is not amenable to those recipients who are going to later Want to switch on times in the encrypted broadcasts. Because these recipients need up to at the time of switching on their transmission channel generally for other purposes, so that this is not may be blocked with the transmission of unused key pulse sequences. Such recipients must their local key pulse generators start at the same time as the transmitter Key pulse generator is started, independently of this and without its first subject to synchronizing action. Just before the recipient enters the weather map broadcast switches on, which can be the case many hours later, the receiver-side key pulse generator must be synchronized with the transmitter end and brought into phase before the adjustment synchronization can be started. The former happens by receiving the encrypted Facsimile signals through which the receiver-side clock generator is drawn.

In the cases mentioned under 3, the synchronization deviations are mostly very large for the key pulse generators involved. So in still tolerable time synchronization of the transmitter-side with the receiver-side key pulse generator or Clock is reached, the agreed key start time must be as accurate as possible, approximately to 1 second, be respected. It is useful if the receiver lags behind the sender, because then the direction of corrective action to be taken is known. To delay the recipient Achieving with certainty is a time lag of the receiver compared to the sender provided by 1 see.

If you choose z. B. the frequency of the follow-up cycle 100 Hz, so every second to the 2000 clock steps with which the clock works, 100 clocks added (faded in). Compared to the Transmitters must be made up for by the receiver if the time limit is 1 see 2000 cycles. It therefore takes 20 seconds until synchronization has been achieved. This time is still considered to be sustainable. It It is useful if the synchronization correction takes place a few minutes before the recipient joins the transmission switched on, started.

According to the invention, the method for producing the synchronization consists in that the to integer Multiples of a clock period shifted against each other, two identical processes, in two identical ones Key pulse generators generate key pulse trains by hand-operated or automatic Adding (fading in) or suppressing (fading out) individual clock pulses or clock pulse sequences, which temporarily accelerate or decelerate the receiver-side key pulse generator, in Is brought synchronism.

Figures 1 to 3 show three exemplary embodiments of the invention.

F i g. 1 is the block diagram of a correction device for the receiver side, which is less Number of missing cycles enables manual correction;

F i g. 2 is the block diagram of a correction device, which can compensate for up to five incorrect clocks with pre- or Lag corrects automatically;

F i g. 3 is the block diagram of a lead correction device, which with a relatively large forward speed of 100 Hz the receiver accelerated until synchronization is achieved.

In Fig. 1 the secret signals come from far away Subscriber via the line 1 to the synchronization device 2 and further to the clock generator 3. The synchronization device is a filter which selects a certain frequency from the incoming secret signals sifts out and brings it into a form that is suitable for taking the generator 3 along. The clock generator 3 sends clock pulses with a clock frequency of 2000 Hz to the via line 4 and the "And" gate S. Key pulse generator 6. The key pulse generator delivers key pulses in the rhythm of these cycles via line 7 to mixing device 8.

The line 1 is also with the quantizer 9 tied together. The received secret signals are in the quantization device in the clock system of the clock generator 3 classified by being based on integer multiples of the clock period certain time quantum can be shortened or lengthened, and the quantized secret signals become Also fed to the mixing device 8 via the line 10. Are the key pulse generators of the The transmitter and the receiver are synchronized, so the received and the internal mix Device generated key pulses in the mixing device of the receiver to zero, so that on line 11 no voltage occurs. But if the synchronization between transmitter and receiver is disturbed, then occurs Voltage on line 11, which consists of 50% pulses, 50% non-pulses, so that the mean value of the voltage at the output of the line 11 is 50% of a continuous signal. This tension is the criterion for recognizing the correct operating status of the system. Are these 50% of the maximum voltage is present, the synchronization is disturbed. Is a much smaller voltage than 50% of the maximum value is present, there is synchronism, but the secret signals are Facsimile signals superimposed. If the output voltage is zero, there is also synchronization, however, no message signal is transmitted. Finally, the voltage on line 11 is the same the maximum value, then a facsimile continuous signal is given when the key devices are synchronized. The line 11 is connected to the synchronization display device 12, through which the signal lamp 13 and the control loudspeaker 14 are fed. The loudspeaker 14 is very useful for checking, because the key signals emit a typical crackling noise that is easy to recognize acoustically is.

If this noise persists after the key devices have been started, the synchronization is disturbed. First the receiving participant does not know whether his device is ahead or behind the sender. Perhaps he suspects from experience that errors in the start-up mainly consist in running behind and tried first of all, through additional impulses

5 6

the receiver-side key pulse sequence in advance is the number of steps by which the key is pushed. For this purpose, he presses the button 15. pulse generator 6 is to be reset. As soon As a result, voltage is applied to the differentiating element. When synchronism is achieved, the voltage is applied to the line 16, which generates a pulse that is small compared to the mean voltage across the line 11, which device 17 the electronic switch 18 in the working 5 in the absence of synchronization. Both acoustically position. In this way, voltage is applied to the line through the loudspeaker 14 as well as optically through the device 19, whereby the "and" gate 20 is prepared. Signal lamp 13 shows this state immediately. The clock pulse following this switchover is a prerequisite for the proper functioning of the Line 4 can pass the gate 20 and is a correction device that the clock is the Line 21 voltage to the monostable sound generator 3 generated pulses in phase with the over ter 22. This goes into working position, but falls after the long-distance line has received secret signals, a short time, which is equal to half the clock. To determine whether this is the case, is the control period of the clock generator 3, i. H. 0.25 m / sec, device 35 is provided, which is automatically returns to the rest position. speed of the impulses in the long-distance line 1 with the impulse-thereby reaches over the line 23 voltage to 15 sen of the generator 3, the lamp 36 feeds. Only at the differentiator 24, which may light up the keys 15 or 26 via the line 25 Impulse to the key pulse generator 6 is to be made, because only then is the guarantee for it and advances it by one step. This given that the synchronization of the transmitter and the receiving pulse falls in the middle of the catcher determined by the generator 3 by integer multiples of the clock period Clock period. The now following bar 20 is disturbing.

The pulse on line 4 generates the key shown in FIG. 2 shows the circuit of one of the circuits shown in FIG. 1

series of impulses one step further ahead, similar, but with automatic correction, work.

Key impulse. The pulse on line 25 arrives at the plant. The on line 11, the output of the

also to switch 18 and causes its back-mixing device 8, occurring voltage is the

circuit. 25 rectifier bridge 37 is supplied. This is so

If the synchronization is correct due to the additional pulse, that when the input voltage reaches a certain

has been achieved between sender and receiver, then has the correct value, which in this case 50% of the

the voltage on line 11 disappears. If the maximum voltage remains at the output, line 38,

but if there is tension, there is still no equal - tension also occurs. The output voltage

run reached. The receiving party tries to 30 is zero when the voltage line 11 is from

by pressing key 15 again, the key deviates from the mean value mentioned. - Tension

Selimpulssequence to advance a further impulse on line 38 occurs only when the

ben. He repeats this experiment five or six times. Synchronism is disturbed. This tension comes to

If the attempts remain unsuccessful, then the deviation is the AND gate 39, which is via the line 40 with

to suspect in the leading direction. The key 35 of the phase control device 35 is connected.

Selimpulssequence must first of all to the advanced From the description of Fig. 1 it is known

five to six impulses are pushed back, so that only when the secret secrecy is in phase

then by further pulse shifting synchronism with the pulses of generator 3 the correction

to reach. door may be made. That's why the

To the key pulse generator 6 to a 40 passage of the gate 39 depending on the state of the

To delay step, the button 26 is pressed. There phase comparator 35, and the voltage

When voltage reaches the differentiating element 27, line 38 can only pass gate 39 on

by means of a pulse on line 28, which if an opening voltage is given via line 40

rather, the electronic switch 29 is in the working position. The trigger 42 switches on via the line 41,

position. Via the line 30 the "and" - 45 which is via the line 43 and the AND gate 44 den

Gate 31 prepared so that the next following clock pulse generator 45 switches on. This delivers with a

pulse on line 4 via gate 31 to the switch frequency of 100 Hz needle-shaped pulses to the

32 arrives, which goes into working position. As a result, line 46, which disappears with the counter 47 and the on line 33 the voltage which is connected to AND gates 48 and 49. About Leidas And Gate 5 had previously been open. The gate 5 locks, 50 device 50 is preparatory voltage on the Andso that the next clock pulse on line 4 gate 48, so that the first pulse on line 46 can not get to the key pulse generator 6. the gate 48 can pass and the electronic However, this pulse reaches the switch 32 and brings switch 18 into the working position. With it got switches it back to the rest position. Thus voltage on line 19, whereby the AND gate 20 there is again voltage on line 33, which the 55 is being prepared. This process as the first fol-and-gate 5 opens for further impulses on line 4. The low clock pulse on line 4 passes gate 20 These come back to the key pulse generator and switch the monostable switch 22. As gate 6. So a single clock pulse has been omitted from the description of FIG. 1 known, generated been det, and the key pulse train is one of the monostable switches 22 when switching back over Step back. 60 the differentiator 24 on line 25 a pulse,

When switching back the switch 32 on the line which the key pulse generator 6 by one

33 generated voltage is generated in the differential step continues and the downshift of the decorative member 34 a pulse which causes the switch switch 18. The forwarding of key 29 and brings it back to rest. selimpulsgenerators is determined by the dimensioning of the As a result, the AND gate 31 is pulsed for further clock switches 22 exactly in the middle of a clock period locked. To the key pulse generator 6 puts, so that the subsequent clock pulse to Lehreew in order to postpone further individual steps, device 4 must already have the next but one key pulse the key 26 are pressed as often as the testifies. So each pulse on line 46 adds one

7 8

Pulse between two clock pulses, and each time half mixed in mixer 8 not to zero. At the If the key pulse generator 6 is a step line 11 remains as a result of the mixing one advanced. This happens as often as this pre-signal voltage describes 50% of the maximum voltage does not lead to synchronism, which is initially. You passed the rectifier bridge 37 and

will be accepted. 5 prepares the AND gate 39. If through the syn-

The pulses on line 46 also control the counting device 2 of the clock generator 3 with the ler 47. Each pulse switches the counter to a received secret pulse synchronized and in Step further. At a certain step, e.g. B. has been brought phase, tension arises on the the fifth, voltage is applied to line 51, line 40, and gate 39 becomes permeable. That one- and the switch 52 goes into the working position. As a result, the voltage generated on the line 41 is shattered If the voltage on the line 50 disappears, the trigger 42 is switched on and voltage is applied to the and the gate 48 is switched on for further pulses on the line 43, whereby the pulse generator 45 46 impermeable. At the same time, however, is created. As with the system, this delivers Voltage on the line 53, whereby the gate 49 of FIG. 2 described, needle pulses to the Leivprepared will. The now following impulse at 15 tung46. The first of these needle pulses switches the Line 46 passes gate 49 and switches switch 18 into the working position. With it got Switch 29 in the working position. So that voltage reaches the AND gate 20 via the line 19, Voltage on the line 30, and the gate 31 which is thereby prepared. The next one prepared. The rest of the process is the same as that supplied by the clock generator 3 to the line 4 described in Fig. 1: 20 clock pulse passes the gate 20 and switches the

The following clock pulse on line 4 passes the monostable switch 22 on. After a half Gate 31 and toggles switch 32, thereby setting the clock period, that is according to the selected example The voltage on the line 33 disappears and the 0.25 msec, the switch 22 automatically switches to its Gate 5 is blocked. The further following clock pulse returns to the rest position, whereby on line 23 on the line 4 is hidden and does not come 25 voltage is generated. Through the differentiator 24 to the key pulse generator 6, which thereby turns this voltage change into a pulse Clock pulse is delayed. As with F i g. 1 gained, via line 25 to both the wrote, the voltage on the line 33 switches the key pulse generator 6 and there the. Over the differentiator 34 the switch 29 back, causes generation of a key pulse, as well as which thus switches the switch 18 back to the rest position46 for a subsequent pulse on the line 30 becomes receptive. Each of these impulses returns.

causes the key pulse train to remain behind. The second pulse of the pulse generator 45 causes

by one step. over the line 46 again the activation of the

If switch 18 is synchronized with one of these pulses, voltage is applied to line 19 Key pulse train of the receiver with that of the 35 arrives. The clock pulse following this pulse on Transmitter delivered key pulse sequence achieved, so the line 4 energizes again the monostable sound disappears the voltage at the output of the mixer 22, which when switching back a further device 8, line 11. Thus, the additional pulse via the differentiating element 24 disappears voltage generated at the output 38 of the rectifier bridge 37 and the line 25 and thus an additional also the voltage on line 41. The 40 key pulse triggers. Every further pulse of the Im trigger 42 returns to its rest position, and the pulse generator 45 causes another additional one also through the line 43 without voltage and further key pulse, which between two clock pulses the pulse generator 45 is stopped. When reaching is pushed. At the assumed frequency the synchronization and the switching back of the trigger from 100 Hz of the pulse generator 45 fetches the key-42 If voltage reaches the fac- 45 pulse generator 6 of the receiving station 100 steps via the line 54 simile device 55, which is thereby switched on. per second on. If the time difference between

If the attempt at correction does not result in the early start of the key devices at the transmitter and

which is still in the trailing direction at the receivers 1 second, the cor-

16 steps to the goal, the 16th counter correction device on the receiving side 20 see um

step of the counter 47 voltage on the line 56. 5 ° synchronization of the receiver with the transmitter to achieve

As a result, the signal lamp 57 lights up and shows len. When this is achieved, the tension disappears

to the receiving subscriber that the correct signal is at the output 11 of the mixing device 8

attempt has failed. At the same time, the gate, the balance of the bridge 37 is disturbed, the tension

44 impermeable, so that the pulse generator 45 is connected to the output line 38 and thus also to

will hold. In this case a restart of the 55 of the line 41 disappears, and the switch 42

Key pulse generators at the transmitter and the receiver return to its rest position. He switches thereby

catcher required. the voltage from the line 43, whereby the

F i g. 3 shows the block diagram of a device pulse generator 45 is stopped and no further ones

with automatic advance correction. There will be pulses on line 46 more. The scarf-

assume that the receiver's key system to 60 ter 42 also applies voltage to line 54, where-

is started at an agreed time. In order to be prepared by the gate 58 and by later

To determine the direction of correction, the receiver-hitting signal voltages on line 11 should open

side key system for a short time, e.g. B. net is. These signal voltages are decoded

Start 1 second later than the transmitter end. The facsimile signals which are sent to the facsimile machine 55

Secret 65 arriving from the transmitter are routed via line 1.

pulse sequence and the key pulse genera- The counterpart of this advance correction, namely

The key pulse sequence generated in gate 6 is immediately the follow-up correction, is possible if the key

not congruent after the start and the receiver's pulse generator starts earlier than

that of the sender. A new circuit diagram is dispensed with, as the one provided for the delay in the same way Switching means according to FIG. 2, that is switch 29, gate 31, switch 32 and the gate S, instead of the switch 18, the gate 20,

10

the switch 22 and the differentiating element 24 in FIG. 3 used to think. Controlling this Switching means takes place through the trigger 42 and the pulse generator 45 according to FIG. 3, until the synchronization is reached.

For this purpose 3 sheets of drawings

Claims (3)

Patent claims: 1. Process for establishing synchronization of the key devices in encrypted facsimile transmissions, characterized in that the sequence shifted relative to one another by integer multiples of a clock period two identical key pulse sequences generated in two identical key pulse generators manual or automatic addition (fade in) or suppression (fade out) individual clock pulses or clock pulse sequences, which the receiver-side key pulse generator accelerate or decelerate temporarily, is brought into synchronization. 2. Apparatus for performing the method according to claim 1, characterized by a Manual button (15) for inserting a clock pulse, a downstream monostable electronic Switch (22), which ensures that the additional pulse in the middle of a clock period falls, through a manual key (26) to suppress a clock pulse, through one through the Clock pulses of the clock generator (3) controlled electronic switch (32), by one of this Switch-dependent AND gate (5), through which, when the button (26) is pressed, a cycle side key pulse generator and the receiving side key pulse generator synchronously and in Phase are, but it is also required that the number of since the simultaneous Turn on all key pulse generators up to any later point in time generated key pulses at the sender and at the receivers are exactly the same. This state should be synchronized are designated. The deviations caused by the lack of synchronization of the key pulse generators on the transmitter side and the recipient sides are of three types: 1. Deviations when starting the key devices due to interference pulses. 2. Deviations caused by interruption of the transmission channel, e.g. B. by fadings at Radio operation, coming about. 3. Deviations that arise when the facsimile sender and facsimile receiver are different agreed times. Corresponding to these three possible deviations are the corrective measures to be taken to choose different for the production of the synchronism. The deviations according to 1. and 2. are always only pulse from the generator (3) is blocked, and 30 is very small. Is after 1. the start of the key devices succeeded by a display device (12, 13, 14), out of sync and in phase, z. B. due to interference pulses in the transmission channel during the key start signal, the receiver-side starts Key pulse generator by a few cycle times