JPS59214372A - Synchronization system - Google Patents

Abstract

PURPOSE:To improve the utilization of a circuit and obtain a small-sized, inexpensive secrecy device by sending the synchronism detection result of a vocoder to the secrecy device through the synchronizing pulse generating and inserting part, synchronism detection part, and synchronism acquiring part in the vocoder, and displaying a step-out state on the secrecy device in case of the step-out state. CONSTITUTION:The secrecy device 12' includes none of the synchronizing pulse generating and inserting part, synchronism detecting part, and synchronism acquiring part. Therefore, if the synchronism detecting part and synchronism acquiring part 19' in the vocoder 11' become unable to detect a frame signal in case of trouble, the vocoder 11' displays a step-out state by itself and sends information on that to the control signal receiving circuit 30' of the secrecy device 12' at the same time to send out an alarm signal, so that the secrecy device 12' also displays the step-out state. Frame synchronizing bits become normal when the vocoder recovers from the trouble, and the synchronism acquiring part 19' in the vocoder 11' performs resynchronization. Information on the completion of the resynchronization is sent to the control signal receiving circuit 30' on the completion of the resynchronization and the step-out state is reset. Therefore, transmit information capacity allotted for the synchronism monitoring and resynchronization between secrecy devices is unnecessary.

Description

[Detailed Description of the Invention] (a) Technical Field of the Invention The present invention provides a system in which the output of a telephone is transmitted through a voice encoding device (hereinafter referred to as a vocoder) to a digital concealment device (hereinafter referred to as a concealment device) together with a data terminal device. This method is applicable to communication systems in which multiple terminal stations are connected via analog lines, and each terminal station is equipped with a modem (hereinafter referred to as a modem) at the output stage of the concealed device, thereby improving line utilization and simplifying the concealed device. Synchronization method that can be converted into

(b) Technology background A communication system to which the present invention is applied will be described below.

FIG. 1 is a block diagram of an example of a communication system to which the present invention is applied.

In the figure, 1 and 2 are terminal stations, 3 is a switch, 4-1.4-2 is a modem, and 5-1.5-2 is a secret device 1 (, 6-1, 6-2
is a vocoder, 7-1.7-2 is a '4-phone machine, 8-1.8-
2 is a digital facsimile (hereinafter referred to as FAX), 9
゜10 indicates a transmission path.

The communication system in Figure 1 is between telephones 7-1, 7-2 and F.
This is a system that performs secret communication (i) between AX8-1, 8-2, and the transmission lines 9 and 10 are frequency division multiplex jK (hereinafter referred to as FDM).
ICH (0,3-3,4KHz)
), and transmission is performed at 9,600 bps.

For convenience of explanation, the number of terminal stations in FIG. 1 is expressed as two. To explain when transmitting from terminal station 1 to terminal station 2, the voice signal from telephone 7-1 is sent to vocoder 6-1.
1 into a digital signal, a secret device 5-1 into which the signal is converted using a special code, a modem 4-1 into an analog signal, and a transmission line 9. Switchboard 3. Transmission line 10
The signal is then converted into a digital signal by the modem 4-2 of the terminal station 2, decrypted by the ciphering device 5-2, and sent to the vocoder 6.
-2 synthesizes the voice and gives a voice signal to the telephone 7-2.

On the other hand, the signals from F and AX8-1 are converted into signals using a special code by the hidden device 5-1, and converted into analog signals by the modem 4-1.
1, and is multiplexed with the audio signal through the transmission line 9. Switchboard 3. The signal is converted into a digital signal by the modem 4-2 via the transmission path 10, decrypted by the ciphering device 4-2, and received at the FAX 8-2. At this time, the signal is separated from the voice signal by the modem 4-2 or the secret device 5-2. Note that FIG. 1 shows an example in which a FAX is used as the data terminal device.

(C) Prior Art and Problems First, a conventional vocoder and concealment device will be explained using FIG. 2.

FIG. 2 is a block diagram showing the circuit configuration of the vocoder and the concealment device.

In the figure, 11 is a vocoder, 12 is a concealment device, 13 is an analog-to-digital converter (hereinafter referred to as A/D converter), 14 is a voice analysis unit that extracts and analyzes the characteristics of the A/D converted audio signal, and 15 is a an encoding unit that encodes the audio-analyzed signal;
16 is a synchronization pulse generation and insertion unit for synchronizing the vocoders; 17 is a clock generation unit; 18 is a phase control oscillator that reproduces a clock from the received pulse and synchronizes it;
Reference numeral 9 denotes a synchronization detection unit that constantly monitors the reception take and detects the loss of synchronization 1, and a synchronization pull-in unit that performs synchronization pull-in in the case of resynchronization. Reference numeral 20 denotes a decoding unit that decodes serial received data into parallel signals of various components. , 21 is a speech synthesis unit that performs various processes on the decoded signal, synthesizes it, and extracts synthesized speech, and 22 is a scramble unit that scrambles the transmission data from each terminal and the special code generated by the code generation unit 28 and sends it out. , 23
24.25 is a phase control oscillation unit that reproduces the clock from the received pulse and synchronizes it. 26 constantly monitors the received data from the modem and performs synchronization. A synchronization detection section detects a deviation, a synchronization pull-in section performs synchronization pull-in in case of resynchronization, 27 is a descrambling section that returns the received signal scrambled with a special code to the original signal, and 28 U creates a special code for secrecy. code generator, 29 is a control signal transmitter that sends a signal to control the other party's hidden device, 30 is a receiving circuit for the ili control signal of the hidden device, ST is a transmission timing signal to the modem, and RT is a reception signal from the modem. Indicates a timing signal.

FIG. 2 is written mainly in the case of telephone transmission using the vocoder 11. The ``li'' AX signal is multiplexed with the ``telephone signal in the secret device 12 and sent out to the transmission line, but there is no problem with the Hunmu synchronization signal and the like as long as the transmission line is established without any abnormalities, so 8j (excluded from the light).

Next, the case of telephone transmission V will be explained. The voice signal from the telephone is converted into a digital signal by the A/D converter 13 of the vocoder 11, and then processed by the voice analyzer 14 to analyze characteristic parameters (spectral envelope, voiced/unvoiced).

Pitch synchronization, amplitude information, etc.) are extracted and encoded by the encoder 15. Thereafter, a frame synchronization bit is inserted in the synchronization pulse generation and insertion section 16, and the data is sent to the security device 12 as transmission data. The scramble unit 22 of the concealment device 12 conceals the transmission data using a special code from the code generation unit 28, the synchronization pulse generation and insertion unit 23 inserts a frame synchronization bit, and the data is sent to the transmission line via the modem. . On the other hand, the anonymized received data that has passed through the transmitter modem is synchronized by the synchronization detection and synchronization pull-in section 26, and the descrambling section 27 converts it into a special code from the code generation section 28 (other side code). 1
is sent to the synchronization detection and synchronization pull-in section 19 and synchronized.
The serial reception data is decoded into parallel signals of various DAs in the Enoki section 20, subjected to each d process in the speech synthesis section 21, and sent to the L4 speech machine for speech synthesis.

Conventionally, this synchronization monitoring and resynchronization method between hidden devices is
Of the total transmission information capacity (9600 bpS), a few pS are allocated for synchronization monitoring and resynchronization between secret devices, and the rest is allocated to telephones, faxes, etc. for specific bit systems and modem channels (boats). ICI-I (24
There is a dedicated channel system in which a channel (00 bps) is allocated for synchronization monitoring and resynchronization between secret devices, and the remaining channels are allocated for one call and FAX.

FIG. 3 is a block diagram of a conventional specific bit method, and FIG. 4 is a block diagram of a conventional dedicated channel allocation method.

In the figure, those with the same functions as those in FIG. 1 are designated by No. 1 Tsukasa-31.

33.37 is a secret device, 34.38 is a modem, 31, .
36 is FAX, 32i, -1 other data terminal, 35 is 9
A transmission line that transmits and receives a 600 bps signal is shown.

In the case of FIG. 3, the secret device C: 800 bps is allocated for synchronization monitoring and resynchronization of mutual groups7). Therefore, the information data that can be used as a terminal station is 9600-800 bps, or 8800 bps. This 8800b Koei coder 6-
1 has a capacity of 1 soobps, so 4800bps
and allocate 2400 bps to FAX 31 (it is possible to allocate 4000 bps, but FAX is a special product and will be expensive), and allocate 600 bps to data terminal 32 of Send.
8 is assigned.

For this reason, the line usage rate is 916ch, which is poor, and the time required for FAX 31 is twice as long as when it is 4800bps. Synchronous pulse generation and insertion section 2 in Fig. 2
3, a synchronization detection section, and a synchronization pull-in section 26 are required, and the p1 concealment device 33 is large and expensive.

In the case of FIG. 4, 2400 bps is allocated to the B port of the modem 38 for synchronization monitoring and resynchronization between secret devices. Therefore, the usage rate of line 1j is poor at 75 stations, and FAX 3
6 takes twice as long as the remaining 9 at 4800 bps, and the modem 38 multiplexes the drunken channel (A boat), the synchronization channel (B boat), and the fax channel (C boat). This requires accurate bit synchronization, which is complicated and expensive. Furthermore, in the concealment device 37, the synchronization pulse generation and insertion section 23, the synchronization detection section, and the synchronization pull-in section 26 shown in FIG. 2 are required for synchronization monitoring and resynchronization between the concealment devices. However, it has the disadvantage of being large and expensive.

(d) Purpose of the Invention The purpose of the present invention is to provide a synchronization system that overcomes the above two drawbacks, improves the line utilization rate, and allows the concealment device to be made smaller and cheaper.

(e) Structure of the Invention In order to achieve the above object, the present invention includes a synchronization pulse generation and insertion section and a synchronization detection section for performing synchronization word generation and resynchronization between the secret devices in the secret device. The vocoder does not have a synchronization pull-in section and generates a synchronization pulse in the vocoder, the -Mj input section, the synchronization detection section, and the synchronization pull-in section send the signal of the synchronization detection result in the vocoder to the concealment device.When the synchronization is out of synchronization, the secret A feature is that the out-of-synchronization state is also displayed on the device.

(f) Embodiments of the Invention Below, embodiments 1' and 1A of the present invention will be explained with reference to the drawings.

FIG. 5 is a block diagram showing the circuit configuration of a vocoder and a concealment device according to an embodiment of the present invention, and FIG. 6 is a block diagram of a telegraph system according to an embodiment of the present invention.

In FIG. 5, parts with the same functions as those in FIG. 2 are designated by the same reference numerals.

11' is a vocoder, 12' is a concealment device, 19' is a synchronization detection section and a synchronization pull-in section, 30' is a control signal receiving circuit, and 7-
1 and 9 (indicate a telephone and transmission equipment with the same functions as those shown in FIG. 1, and 4o indicate a FAX).

In the case of the present invention, as can be seen by comparing Fig. 5 and Fig. 2,
In FIG. 5, the concealment device 12' does not include the synchronization pulse generation and insertion section 23, synchronization detection section, and synchronization pull-in section 26 shown in FIG. For this reason, if a frame signal cannot be detected at the synchronization 4jI output section and synchronization pull-in section 19' of the vocoder j]' due to a failure in the transmission path, etc., the vocoder 11' displays an out-of-synchronization message and at the same time hides the information. The control signal receiving circuit 30' of the device 12' is caused to send out a transmission alarm signal, and the hidden device 12' also indicates that the synchronization is out of synchronization. When the transmission line fault is recovered and the data becomes normal, the frame synchronization focus becomes normal and synchronization is performed by the synchronization pull-in section 19' in the vocoder 11'. When the resynchronization is completed, the information is sent to the control signal receiving circuit 3σ to release the out-of-synchronization state. The other operations are similar to the conventional case explained in FIG. By doing so, the transmission information capacity allocated for synchronization monitoring and resynchronization between secret devices becomes unnecessary.

For this reason, as shown in Figure 6, when the total transmission capacity of 9600 bps is allocated to the vocoder 11' at 4800 bps, the remaining 4800 bps is allocated to the vocoder 11'.
All bps are allocated to FAX section 0. In this case F.A.
The X40 data is multiplexed with the data of the vocoder 11' by the secret device 12' and sent to the modem 41, allowing FAX transmission at 4800 bps. Although the above description has been made using a signal from a vocoder as an example, the present invention is also applicable to a terminal device that constructs a frame by itself and has a detection synchronization pull-in function.

(g) Effects of the Invention As explained in detail above, according to the present invention, there is no need to allocate a part of the total transmission information capacity for synchronization monitoring and resynchronization between secret devices, so the entire transmission information capacity is transferred to the telephone. It can be used for terminals such as FAX, and the line usage rate can be set to 1001, and the FAX section in particular can perform high-speed transmission and reception using 4800 bps.

Furthermore, since there is no synchronization pulse generation/insertion section, synchronization detection section, or synchronization pull-in section within the concealment device, there is an effect that the concealment device can be made smaller and lower in cost.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of an example of a communication system to which the present invention is applied, Fig. 2 is a block diagram of a circuit of a conventional speech encoding device and digital concealment device, and Fig. 3 is a block diagram of a conventional specific bit system. 4 is a block diagram of a conventional dedicated channel side vortex system, FIG. 5 is a block diagram of a circuit of a voice encoding device and a digital concealment device according to an embodiment of the present invention, and FIG. 6 is a block diagram of a circuit of an embodiment of the present invention. FIG. 2 is a block diagram of an example communication method. In the figure, 1 and 2 are terminal stations, 3 is an exchange, and 4-1. ．． 4-2゜34.38.41 is a modem, 5-1.5-2.12
．． 12'33.37 is a digital concealment device, 6-1.6
-2.11°11 is a voice encoding device, 7-1.7-2 is a telephone, 8-1. '8-2.31.36.40 is a digital facsimile. 9.10 is a transmission line, 13 is an analog-to-digital converter,
14 is a voice analysis section, 15 is a code section, 16.23 is a synchronization pulse generation and insertion section, 17 is a clock generation section, 18.2
4.25 is a phase control oscillation unit, 19° 19', 26 is a synchronization detection unit and synchronization pull-in unit, 20 is a decoding unit, 21 is a speech synthesis unit, 22 is a scrambling unit, 27 is a descrambling unit,
28 is a code generation section, 29 is a control signal transmission circuit, 30.
30' is a control signal receiving circuit, 32 is another data terminal, 3
5 indicates a transmission line.

Claims (1)

[Claims] The output of the telephone is connected to a digital concealed device (through a voice encoding device together with a data terminal), and the output of the digital concealed device is connected to the voice encoder in a communication system in which a plurality of terminal stations each having a modulation/demodulation device are connected via analog lines. A synchronization method characterized in that a signal of the synchronization detection result in the disguised device is sent to the concealment device, and the out-of-synchronization state is also displayed on the concealment device that reads when the synchronization is out of synchronization.