KR960014684B1 - Voice scrambling system with random drift - Google Patents

Abstract

The system comprises; a video buffer means for outputting the inputted composite video signal by buffering it; a composite sync separating means for extracting a composite sync signal from the buffering composite video signal; a horizontal sync separating means for extracting only the horizontal sync signal from the extracted composite sync signal; a time delay means for respectively delaying the extracted horizontal sync signal a different time from a predetermined minimum time to a maximum time, and generating the horizontal sync signal having 210 phase mutually; a random number generating means for generating the pseudo random data having 10 bits; a slicer switching means for selecting one among the horizontal sync signals having 210 different phase mutually which are produced from the time delay means according to the pseudo random data having 10 bits outputted from the random number generating means; and a filtering means for filtering only the central frequency of the horizontal sync signal selected from the slicer switching means, and outputting it to a scrambler carrier.

Description

Random drift voice, scrambling system

1 is a block diagram of a conventional scrambling system.

FIG. 2A is a waveform diagram of a scrambled composite composite video signal input to FIG.

2b is a waveform diagram of an original composite video signal descrambled.

3 is a schematic diagram of a voice scrambling system according to the present invention.

4A is a detailed circuit diagram of the image buffer 1 of FIG.

4b is a detailed circuit diagram of the composite synchronous separator 2 of FIG.

4c is a detailed circuit diagram of the horizontal synchronous separator 3 of FIG.

4d is a detailed circuit diagram of the random number generator 5 of FIG.

5 is a horizontal synchronous signal waveform diagram according to the bandpass filter 7 of FIG.

* Explanation of symbols for main parts of the drawings

1: Image buffer 2: Synchronous separator

3: horizontal synchronous separator 4: time delay

5: Random Number Generator 6: Slicer Switch

7: Bandpass filter TR1-TR3: Transistor

3a: multivibrator 5a-5j: deflip-flop

OXR1: Exclusive Ogate R1-R9: Resistance

C1-C3: Capacitor

The present invention relates to an encryptor for analog speech, wherein the phase shift of a spectrum shifting carrier used in a particular spectrum inverted analog speech scrambler is randomly changed and scrambled according to a number generated at every horizontal synchronization period by an irregular number generator. The present invention relates to a voice scrambling system with random drift.

As shown in FIG. 1, the conventional scrambling system has an analog / digital converter 1 and an analog / digital converter for converting a digital signal using an analog composite video signal CVS as an input. From line memories (2) and (3) for storing and outputting the output signal of (1), and a synchronous separator (4) for separating horizontal synchronization from the composite video signal (CVS), and the synchronous separator (4). A clock generator 5 for generating a sampling clock using the output horizontal synchronization signal as an input, and the analog / digital converter 1 and the line memory 2, (using the clock signal of the clock generator 5); 3) a digital / analog converter 6 for converting a digital signal input from 3) into an analog signal, and a random number generator 10 for the random number generator 10 in the vertical blanking period of the composite video signal CVS. Extract initial data A data processor 8 for storing output data of the data slicer 7, a microprocessor 9 for controlling the random number generator 10 using the data RAM 8, and a microprocessor 9 from the microprocessor 9; The random number generator 10 which generates an irregular number by inputting initial data, and the address generator 11 which provides an address to the line memory 2 and 3 by the output of the random number generator 10 are shown. Configured.

Referring to the operation and the problems with the conventional scrambling system configured as described above are as follows.

First, when the scrambled composite video signal CVS as shown in FIG. 2 (a) passes through the scrambling system as shown in FIG. 1, it is restored to the normal original composite video signal as shown in FIG.

Note that the addresses in the line memories 2 and 3 for the cutting point P shown in FIG. 2B are centered around the cutting point P corresponding to this address. The complex video signal CVS is scrambled.

Since the position of the cutting pointer P is irregularly generated by the random number generator 10 for each horizontal line, the scrambled image is similar to the noise screen so that the viewer cannot recognize the original image at all. The lambdon number generator 10 transmits a code for initial data for each field during the vertical retrace period at the transmitter side. The signal is received by the data slicer 7 and stored in the data RAM 8. 9) since the initial data is supplied to the random number generator 10, the data on the cutting point P generated at the transmitting side can be accurately known at the receiving side.

Because the random number generator 10 of the scrambler on the transmitting side and the descrambler on the receiving side are configured in the same manner, if the initial data provided for each field is the same, the value of the cutting point P generated for each horizontal scan line is the same.

When the cutting point P value generated in this way is supplied to the address generator 11, the address generator 11 can read the image signal stored as shown in FIG. 2B as shown in FIG. The address is supplied to the line memories (2) and (3), and the use of two line memories (2) and (3) is to operate the read / writes in opposite directions one by one horizontal line. Assume that the resolutions of the / digital converter 1 and the digital / analog converter 6 are 8 bits, and 1024 times are sampled for one horizontal line.

However, such a conventional system cuts an arbitrary point of the composite video signal section by using a cutting point value generated by a random generator and scrambles it by the line rotation method. Since the band is exceeded, there is a problem in that image quality deteriorates.

In view of the above-described problems, the present invention provides an image buffer for buffering a composite video signal to an encoder system, a composite synchronous separator for splitting a composite synchronous signal from the composite video signal, and a horizontal synchronous splitting for a composite synchronous signal. The horizontal synchronous separator and the time delay for generating horizontal synchronous with different phases after inputting the horizontal synchronous separator are used to generate the phase of the spectral shifting carrier at every horizontal synchronous period by an irregular number generator. Invented to scramble by changing irregularly according to the number, the structure of the present invention will be described in detail below with reference to the accompanying drawings.

타임지연소자를 이용하여 2¹⁰개의 서로 다른 위상을 가진 수평동기를 발생하는 타임지연기(4)와, 그 타임지연기(4)로부터 발생된 2¹⁰개의 서로 다른 수평동기신호를 입력으로 하여 랜덤번호발생기(5)에서 출력된 10비트의 의사램덤(Pseudorandom) 데이타에 따라 2¹⁰개의 서로 다른 위상을 가진 수평동기신호중에서 하나를 선택하는 슬라이서 스위치(6)와, 상기 슬라이서 스위치(6)로부터 선택된 수평동기신호에서 수평동기주파수의 정현파를 발생시키는 대역통과 필터(7)로 구성된다.3 is a configuration diagram of an audio scrambling system using random drift according to the present invention. As shown in FIG. 3, an image buffer 1 for inputting a composite video signal CVS to a encoder system and a video buffer 1 thereof A horizontal synchronous signal is input by using the composite synchronous separator 2 for separating the composite synchronous signal from the composite video signal CVS using the output signal of the input signal, and the composite synchronous signal output from the composite synchronous separator 2 as input. After inputting the horizontal synchronous signal to separate

By using the time delay element, a time delay generator 4 generating horizontal synchronization having 2 ¹⁰ different phases and 2 ¹⁰ different horizontal synchronization signals generated from the time delay 4 are inputted. 5) a slicer switch 6 for selecting one of horizontal sync signals having 2 to ¹⁰ different phases according to the 10-bit pseudorandom data output from 5), and a horizontal sync signal selected from the slicer switch 6 It consists of a band pass filter (7) for generating a sinusoidal wave of the horizontal synchronization frequency in.

FIG. 4A is a detailed circuit diagram of the image buffer 1 of FIG. 3. As shown therein, the resistor R1 inputting the composite video signal CVS includes the capacitor C1 and the resistor R2 ( After voltage dividing to R3), the power supply Vcc is connected to the base of the transistor TR1 to which the collector is applied, the emitter of the transistor TR1 is connected to the output terminal out, and through the resistor R4. Construct by grounding.

FIG. 4B is a detailed circuit diagram of the composite synchronous separator 2 of FIG. 3, and as shown therein, the input terminal IN of the composite synchronous separator 2 connected to the output terminal out of the image buffer 1 is shown. ) Is divided through the resistor R5 and the capacitor C2 at the resistor R6 to which the bias voltage B ⁺ is applied, and then the emitter is connected to the base of the transistor TR2 to which the transistor is grounded. The collector is connected to the output terminal (out) and is configured by connecting to the bias voltage (B ⁺ ) terminal through the resistor (R7).

에 부트리거 입력단자(A')를 콜렉터에 바이어스전압(B+)이 인가되는 트랜지스터(TR3)의 베이스에 연결하여 그 에미터를 출력단자(out)와, 저항(R8)을 통해 접지시켜 구성한다.(C) of FIG. 4 is a detailed circuit diagram of the horizontal synchronous separator 3 of FIG. 3, and as shown therein, the multi-vibrator 3a having the output terminal out of the composite synchronous separator 2 configured in the horizontal synchronous separator 3 is shown. Is connected to the input terminal (IN) of the multiplier, and the periodic terminal (T1) (T2) of the multivibrator (3a) is connected to the bias voltage (B +) terminal through the capacitor (C3) and the resistor (R9), and the multi Inverting output terminal of the vibrator 3a

The E Boot trigger input terminal A 'is connected to the base of the transistor TR3 to which the bias voltage B + is applied to the collector, and the emitter is grounded through the output terminal out and the resistor R8. .

FIG. 4D is a detailed circuit diagram of the random number generator 5 of FIG. 3, and as shown therein, the input / output terminal D of the 10-bit flip-flop 5a-5j configured in the random number generator 5 is shown. ) Q is sequentially connected, and the output terminal Q of the de-flop flop 5j and the output terminal Q of the de-flop flop 5a are deflected flop 5a through an exclusive ogate XOR1. ) Is connected to the input terminal (D), but in the output terminal (Q) of the flip-flop (5a-5j), the most significant bit (MSB) and least significant bit (LSB: Lest Signficant Bit) A signal of (LSB) is generated.

Referring to the effect of the present invention configured as described above is as follows.

The composite image signal CVS is divided by the resistor R1 and the capacitor C1 through the resistor R1 and the capacitor C1 of the image buffer 1, and the transistor TR1 is periodically turned off and buffered. Next, a resistor R5 and a capacitor C2 configured in the composite synchronous separator 2 are applied to the base of the transistor TR2, and the transistor TR2 is buffered and output from the transistor TR1 of the image buffer 1. When the composite synchronous signal is separated from the composite video signal CVS and applied to the input terminal IN of the multivibrator 3a configured in the horizontal synchronous separator 3, the multivibrator 3a is separated from the composite synchronous separator 2. The vertical synchronizing signal is removed from the output composite synchronizing signal, and only the horizontal synchronizing signal is separated and applied to the input of the 2 ^{10 time} delay units 4 through the transistor TR3.

Therefore, the time delay unit 4 delays the original horizontal synchronous signal outputted from the horizontal synchronous separator 3 from 62.1 n sec to 62.1 × 20 ¹⁰ n sec, thereby providing a horizontal synchronous signal fH having 2 ¹⁰ different phases. The slicer switch 6 is composed of a deflip-flop 5a-5j and an exclusive ogate XOR1 to generate an irregularity of the random number generator 5 generating the least significant bit signal LSB from the most significant bit signal MSB. According to the data, one of the horizontal synchronization signals having different phases delayed from 62.1n sec. To 62.1 × 20 ¹⁰ n sec. From the time delay unit 4 is selected and applied to the bandpass filter 7. The filter 7 filters only the center frequency fH of the horizontal synchronizing signal selected from the slicer switch 6 to make the horizontal synchronizing signal sinusoidal, and then converts it to the spectral shifting fundamental of the spectral inverting analog voice scrambler. Used to.

Here, the principle of generating the sine wave of the horizontal synchronization center frequency fH using the band pass filter 7 in the horizontal synchronization signal output from the time delay unit 4 is shown in FIG.

함수에 따르므로 중심주파수가 fH인 대역통과필터(7)를 이용하여 수평동기 중심주파수(fH)만 필터 아웃(Filter out)하면 수평동기 중심주파수(fH)의 정현파가 발생되는 것이다.That is, it has sinusoidal spectrum of several harmonics of horizontal synchronous center frequency (fH), and their amplitude is

According to the function, if only the horizontal synchronous center frequency fH is filtered out using the band pass filter 7 having the center frequency fH, a sine wave of the horizontal synchronous center frequency fH is generated.

In addition, when spectral inversion analog scrambling changes the phase of the carrier irregularly, the principle applied to the encoder is as follows.

Spectral inversion scrambling is achieved by shifting the original speech spectrum to a carrier at the horizontal synchronization center frequency (fH) and filtering it to 0-fH with a lowpass filter.

The phase shifting is expressed as an equation as follows.

[Formula 1]

Here, the subscript P.S means phase shifted and means "0" first voice.

That is, the phase shift voice is multiplied by Cos 2π fHt in the initial voice.

Descrambling multiplies Cos 2π fHt by Equation (1) to filter out only the initial voice baseband with a lowpass filter. If you express it as a formula

[Formula 2]

However, if the phase of the carrier wave (Cos 2π fHt) used in the scrambler is changed irregularly, it is expressed as follows.

[Formula 3]

Where E. P. S means coded phase shift and 0 (t) is randomly variable.

In this case, the descrambling process in the descrambler

[Formula 4]

When descrambling the scrambling voice coded in Equation (4), Cos 0 (t) is multiplied by the first voice.

이면 음성이 완전히 사라지게 되고 0(t)가 서서히 변화하면 통신에서 일어나는 패딩 표과가 생기게 된다.Again, to find the first voice here, we need to multiply it by Cos 0 (t) and filter it, in which case the spectrum of 0 (t) must be larger than the voice bandwidth. However, 0 (t) is an irregular value that only the scrambler knows, so we can hardly find the first voice. Extreme case

If it is, then the voice disappears completely, and if the 0 (t) changes slowly, there will be padding results in the communication.

As described above, the present invention can be effectively applied to the spectral inverted analog speech scrambling method, so that the present invention can be used in a PAY television receiver system.

Claims (4)

An image buffer means for buffering and outputting an input composite video signal, a compound synchronous separating means for extracting a composite synchronous signal from the buffered composite video signal, and a horizontal synchronous separation for extracting only a horizontal synchronous signal from the extracted composite synchronous signal Means, time delay means for delaying the extracted horizontal synchronization signal from a set minimum time to a maximum time, respectively, to generate horizontal synchronization signals having 2 ¹⁰ different phases, and a 10-bit pseudo random. Slicer switching means for selecting one of random number generating means for generating data and horizontal sync signals having 2 to ¹⁰ different phases obtained from said time delay means according to 10-bit pseudo random data obtained from said random number generating means; Filter only the center frequency of the horizontal synchronization signal selected by the slicer switching means. And a band pass filtering means for ringing and outputting the scrambler carrier. According to claim 1, Time magazine delegation of speech scrambling system using the random drift in the time delay is the time delay from sikimreul characterized 62.1n sec to 62.1 * 2 ¹⁰ n sec in time from the lowest to the highest time. The horizontal synchronous separating means includes: a multi-vibrator for removing vertical synchronous signals from the input composite synchronous signal and delaying only the horizontal synchronous signal for its time constant, and buffering the horizontal synchronous signal outputted from the multi-vibrator. A voice scrambling system by random drift, characterized in that the switching element input to the time delay means. 2. The flip-flop according to claim 1, wherein the random number generating means is connected in series to each other to generate a flip-flop for generating one bit of data among 10-bit data from the least significant bit to the most significant bit, and the output of the least significant flip flop and the most significant flip flop. And an exclusive logical sum element whose exclusive logical sum is used as the input of the most significant flip-flop.

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