JPS62290225A - Scramble/descramble system for narrow band transmission system - Google Patents

Abstract

PURPOSE:To improve a scramble effect and to cut down costs by sampling a transmission signal and its inversion signal with the aid of a clock signal subjected to pattern setting and its inversion signal, scrambling them through addition and descrambling them with the aid of a clock reproduction signal under the same constitution. CONSTITUTION:For outputting a prescribed clock pulse, the transmission signal A inputted to an input terminal 1 becomes a waveform B when it passes through the 1st switch means 3 and goes to a waveform C when it passes through the 2nd switching means 5. As a result, an output signal from an adder 7 becomes a waveform D, is completely deformed, and demonstrates a scramble effect. Since a clock pattern generator 9 sets the clock signal A to a sample pulse by a pattern having a frequency with different iterations, the scramble effect is further improved. A reception side operates in the reverse way of the above- mentioned procedure, and descramble is completed. A normal signal is outputted to an output terminal 8.

Description

[Detailed description of the invention]

3. Detailed description of the invention

[Industrial application field]

The present invention relates to a scrambling/descrambling method for a narrowband transmission system.

Summary of the Invention 1 The present invention samples a transmission signal and its inverted signal using a patterned clock signal and its inverted signal, and scrambles the signals by adding the samples.
This is a scramble/descramble method for a narrowband transmission system that uses the same configuration but uses a clock recovery signal to perform descrambling. [Prior art 1] In a narrowband transmission system, there are several known methods that scramble the transmitted signal and descramble it at the terminal to prevent eavesdropping on terminals other than the authorized one. . Particularly in transmission systems with narrow bandwidths, such as those used in telephones, devices with fairly complex configurations have been used until now, resulting in high costs. [Problems to be Solved by the Invention] Therefore, in a narrowband transmission system, a simple configuration is used to sample the transmission (a) and suppressed ΔM (AIIl).
A method has been proposed that multiplies (prirude MQduration). The present invention has been made based on the above circumstances, and aims to provide a scrambling/descrambling method for a narrowband transmission system that exhibits a sufficient scrambling effect and can reduce costs by simplifying the configuration. It is something. [Means for Solving the Problems] In order to achieve the above object, the present invention turns on and off a first switch means using a patterned clock signal to supply a transmission signal to an adder, and Scramble is performed by turning on and off the second switch means using an inverted signal of the clock signal and supplying an inverted signal of the transmission signal to the adder. It is characterized by scrambling. [Example] Hereinafter, the system of the present invention will be specifically explained with reference to the drawings. FIG. 1 is a circuit configuration diagram for scrambling a transmission signal. In the figure, reference numeral 1 is a transmission signal input terminal, 2 is a clock pulse generation circuit, and 9 is a reference clock pattern setting from the above-mentioned clock pulse generation circuit 2. 3 is a first switch means that is turned on and off by the clock signal from the generator 9; 4 is an inverter that inverts the clock signal; 5 is a clock pattern generator that generates sample pulses of different repetition frequencies; a second switch means 6 that is turned on and off by the inverted clock signal;
is an inverter for inverting the transmission signal, 7 is an adder, and 8 is an output terminal for the transmission signal. Therefore, the on/off states of the first and second switch means 3.5 are reversed, and the transmission signal is
Via one of the switch means 3.5 it is applied to the adder 7 and sent to the output terminal 8. In this case, since the transmission signal is inverted at the output from the inverter 6, the output to the output terminal 8 is not a regular signal but is a scrambled signal. That is, as shown in FIG.
2 (2))), the transmission signal A input to the input terminal 1 (see Fig. 2 (B)) passes through the first switch means 3 to output the waveform 8 (see Figure 2 (2)). 2(C)), and when passing through the second switch means 5, the waveform becomes C (see FIG. 20). Therefore, the output signal from the adder 1 has a waveform of D (see FIG. 2(e)), is completely transformed, and exhibits a scrambling effect. In particular, since the clock signal A is set by the clock pattern generator 9 to sample pulses with patterns of different repetition frequencies, the scrambling effect is further improved. On the receiving side, contrary to the above, the clock signal superimposed on the transmission signal is separated via the clock regeneration circuit 10, processed by the clock pattern generator 9, and the output pulse signal is sent to the first generator having the same configuration. Switch means 3. It is sent to the second switch means 5 for on/off control. Also,
Since the second switch means 5 includes an inverter 4 for reversing, both switch means 3.5 are controlled to be turned on and off alternately. The signals passing through both switch means 3 and 5 are reproduced by adder 1. The state changes of the signal in this case are as shown in FIGS. 4Q to 4E. That is, as shown in FIG. 3, the clock pulses output by the clock pattern generator 9 (FIG. 4 (2)
When outputting the transmission scramble signal A (see FIG. 4 (1))) input to the input terminal 1, the transmission scramble signal A (see FIG. )
When passing through the second switch means 5, the waveform becomes C (see FIG. When , the descrambling is completed and a normal signal (see FIG. 4(e)) is outputted to the output terminal 8.

【Effect of the invention】

As is clear from the above explanation, the narrowband transmission system scramble/descramble method of the present invention suppresses the transmission by sampling the transmitted signal C with a pattern-setting, repetitive sampling signal of a small frequency. A
Scrambling can be performed by multiplying by M, and conversely, it can be descrambled, resulting in a high scrambling effect. Furthermore, the configuration is simple and costs can be reduced.

[Brief explanation of drawings]

Fig. 1 is a circuit configuration diagram showing an embodiment for realizing the scrambling method of the present invention, Fig. 2 is a diagram showing signal waveforms in each part, and Fig. 3 is a circuit diagram showing an embodiment for realizing the descrambling method of the present invention. FIG. 4 is a circuit configuration diagram showing one embodiment. FIG. 4 is a diagram showing signal waveforms in each part. 1... Input terminal, 2... Clock pulse generation circuit,
3... first switch means, 4... inverter, 5
. . . second switch means, 6. inverter, 7.
...Adder, 8...Output terminal, 9...Clock pattern generator, 10...Clock regeneration circuit, 11
...Band pass filter.

Claims (1)

[Claims] Turning on and off the first switch means using the patterned clock signal to supply the transmission signal to the adder;
Scramble is performed by turning on and off the second switch means using an inverted signal of the clock signal and supplying an inverted signal of the transmission signal to the adder. Scrambling and scrambling of narrowband transmission systems characterized by scrambling
Descrambling method.