WO1988002898A1

WO1988002898A1 - Control device comprising a charge coupling device and method using said device

Info

Publication number: WO1988002898A1
Application number: PCT/FR1987/000384
Authority: WO
Inventors: Yvon Fouche; Michel Chevalier
Original assignee: Thomson-Csf
Priority date: 1986-10-07
Filing date: 1987-10-06
Publication date: 1988-04-21
Also published as: AU8035787A; FR2604793A1; FR2604793B1

Abstract

Control device (414) comprising a charge coupling device and method using said device. The invention relates mainly to a control card (440) which, associated with its card reader (6), allows digital processing of the signal. For example, the control card (440) and/or the card reader (6) comprises a charge coupling device (414) making possible the convolution of said signal by a code by connecting certain cells (50i) of the charge coupling device to a line (500). The invention applies mainly to the reception of broadcasts, television programs or data.

Description

CONTROL DEVICE COMPRISING A LOAD TRANSFER DEVICE AND METHOD USING THE SAME

The present invention mainly relates to a control device comprising a charge transfer device (CCD in English terminology) and method using said device.

It is known to produce control cards, commonly called memory cards, making it possible to generate or control a secret code. The exchange rate between the known type of control cards and their reader is very low. Thus, control cards of known type are mainly used to verify that a secret code which is supplied to them is correct. In this case, the codes are used to validate the desired operations. Thus, the security provided by such a card is limited by the fact that the operations are executed outside the. menu. In addition, it should be noted that the computing power of control cards of known type is also limited. In all cases, the presence of a known type of control card increases the execution time of the tasks to be performed. The present invention relates to a high security control card participating in the operations to be carried out. The control card according to the invention comprises physical means (hardware) allowing the execution of the desired operations. The use of physical means allows a calculation much faster than a calculation using software (SOFTWARE in English terminology). The operations being executed inside the control card according to the invention, their use presents increased security. For example, a charge transfer device is used to perform a semi-digital calculation of convolution of a signal by a code. The code may for example be a secret code, the processing being entirely carried out inside the card, the device according to the invention guarantees maximum security.

To be able to use the enormous processing powers of the "device according to the invention it is advantageous to use means for transmitting information between the control card according to the invention and the device capable of being connected to it transmitting a large flow of information. For example, the optical fiber information transmission device is used.

The control card according to the present invention allows the convolution of a digital code with a signal, which can be either analog or digital. The code used is for example a secret pseudo-random code. In this case, the result, that is to say the moment when the amplitude of the convoluted signal is maximum, is only accessible if one has a card according to the invention whose adequate pseudo-random code. Thus it is possible to ensure the confidentiality of the services offered. This confidentiality makes it possible, for example, to bill the service offered, only the people who have paid having the card giving them access to said service. The convolution of a signal with a code allows for example the filtering of said signal.

On the other hand, the convolution of a signal by a code makes it possible to obtain the desired synchronizations. These synchronizations can for example allow the reception of television broadcasts.

In particular, it is possible to synchronize the scanning of a cathode ray tube.

On the other hand, it is possible to synchronize by radio clock. The use of clock synchronization can be used by services as varied as phase modulation transmissions or setting the clock time. The transmission in phase modulation or in phase and amplitude modulation can be advantageously used for the transmission of alphanumeric data, radio programs or television programs. Synchronizations of an emission clock with frequent reception horioges allow very high speed phase modulation transmissions. Indeed, the flow is in particular determined by the stability of the clocks, as well as by the signal / noise ratio. In an alternative embodiment of a device for transmitting data in phase modulation, or in phase and amplitude modulation, the control cards allowing convolution of the received signal with a code ensures the pre-synchronization of the transmission clock with reception clock. Fine synchronization being obtained by a correlation device.

The main object of the invention is a control card characterized in that, associated with a card reader, it is capable of generating a peak of convolution of a signal by a code from a signal device. by a code.

The invention also relates to a clock synchronization method characterized in that it comprises the steps: of transmitting a binary code. - reception of the code - introduction of the signal into a device for charge transfer of the signal sample

- shift of a cell of the charge transfer device up to: -

- obtaining a convolution peak on an output connected to certain cells of said charge transfer device, the cells connected to said output corresponding to 1 of the binary code.

The invention will be better understood by means of the description below and the appended figures given as nonlimiting examples among which: - Figure 1 is a diagram illustrating a first embodiment of the device according to the invention;

- Figure 2 is a diagram illustrating a second embodiment of the device according to the invention;

- Figure 3 is a diagram of a third embodiment of the device according to the invention.

In FIGS. 1 to 3, the same references have been used to designate the same elements.

In FIG. 1, one can see a control card 0 comprising a charge transfer device Ψ 1. The device to charge transfer 414 has n cells numbered 501 to 50n.

- Cells 501 to 50n are connected in series. At each clock pulse the signal propagates from each cell to the next cell in the direction of increasing references. At each impulse

^ clock, the first cell 501 receives the signal present on the input of the charge transfer device. Similarly, at each clock pulse, the value of the charge present in the last cell 50n is available at the output of the charge transfer device. To convolution a signal by a code

1 digital _Q connects to an output 500 the cells 50i corresponding to the value 1 of a binary code. The cells corresponding to the zero of

. binary code are not linked outside the charge transfer device 1. For example as illustrated in figure 1, if the code by which one wants to carry out the convolution begins with

₁₅ 101110 and ends with 0010 cells 501, 503, 504, 505 and

50 (n-l) are connected to output 500 respectively by lines 511,

513, 514, 515, 51 (n-1).

The voltage will be maximum at output 500 when the cells connected to said output will have charges corresponding to the maximum amplitude of the signal. Thus, to obtain synchronization at a given time, it suffices to send, taking into account the delay introduced by the processing, the signal modulated according to the same code as that contained in the control card 440. The delay between the introduction of the signal into the charge transfer device 414 and obtaining the synchronization peak on the output 500 corresponds mainly to the time necessary for the start of the signal to reach the cell 50n is therefore substantially equal to n times the corresponding time to a clock cycle.

To obtain a sharp synchronization peak it is advantageous to use the charge transfer device 414 comprising a large number n of cells.

Advantageously, n = kx 512, k being a strictly positive integer. It is thus possible to use the conventional type charge transfer device comprising 512 cells connected in series. Advantageously, the charge transfer device 414 is produced in the form of an integrated circuit. The exemplary embodiment illustrated in FIG. 1 allows synchronization on reception, for example of television programs. Thus the device illustrated in FIG. 1 comprises an antenna 4, an antenna amplifier 3 connected to the input of the charge transfer device 414. On the other hand, in addition to the synchronization signal present on the output 500, there is provided at the television receiver, not shown, the signal received by the antenna 4 either on a line 413 present at the output of the antenna amplifier 0, or at the output 520 of the charge transfer device 414. The signal present on the output 520 is identical to the signal, present on the output 413 delayed by ri clock cycles.

A card reader 6 supplies the control card 440 with all the signals 415 necessary for its proper functioning, such as for example the power supply and the charge shift clock signals between the cells.

In FIG. 2, an exemplary embodiment of the device according to the invention can be seen facilitating the modification of code by changing the control card 414. In the embodiment illustrated 0 in FIG. 2, the charge transfer device 414 is contained in a card reader, the control card 440 mainly comprising a permanent memory 700. Advantageously, the memory 700 is a read only memory. For example, memory 700 is a programmable read-only memory (PROM in English terminology 5) or an erasable read-only memory (EPROM in English terminology). A control card 414 mainly comprising a dead memory 414 700 is of very low cost. Thus, it is possible to frequently change the code used and thus make it necessary to change the cards of _Q control 414.

The memory 700 includes at least n cells 701 to 70n. Each cell is used to store a binary value. The n cells 701 to 70n are capable of being read, in parallel, simultaneously. The reading device 6 of the control card 440 includes a charge transfer device 414 comprising n cells referenced 501 to 50n. The reading device 6 comprises for example n binary multipliers, 1 bit, referenced 601 to 60n. The 1 bit binary multipliers 601 to 60n correspond to an "AND" logic gate. - The memory cell 701 is connected to a first input, and the cell 501 of the charge transfer device 414 to a second input of the multiplier 601.

The memory cell 702 is connected to a first input, and the cell 502 of the charge transfer device ^: 414 to a JQ second input of the multiplier 602.

The memory cell 703 is connected to a first input, and the cell 503 of the charge transfer device 414 to a second input of the multiplier 603.

The i ^th memory cell 70i is connected to a first 1 input and the i cell 50i of the charge transfer device 414 ^" to a second input of the i ^th multiplier 601.

So on to the memory cell 70n connected to a first input, and the cell 50n of the charge transfer device 14 connected to a second input of the multiplier 60n. 20 All the outputs of multipliers 601 to 60n are connected to a line 500.

Thus, the amplitude of the ^signal on line 500 is at a maximum when the sample of the signal present in the charge transfer device 414 corresponds to the code stored in the memory 700 of the 25 control board 440.

For example, the input of the charge transfer device 414 is connected to a reception antenna 4, for example by the intermediary of an amplifier 3, and possibly, of a frequency reduction device not shown. The antenna 4 is capable 0 of picking up microwave energy, for example television broadcasts.

On the other hand, the signal collected by the antenna 4 is present on line 413, the same signal delayed by n clock pulses is present on line 713 connected to the output of the device to charge transfer 414.

Thus, when a coded signal is transmitted to the device with load transfer 414, the latter delivers on output 500 a maximum signal amplitude when the coding of the signal corresponds to the code ^ stored in memory 700.

Advantageously, the devices 601 to 60n transmit the signal present in the cells 501 to 50n of the charge transfer device 414 only in the case where a 1 is present in the corresponding memory cell 701 to 70n. 10 The charge transfer device comprises power supplies necessary for its proper functioning, in particular the electrical power supply and the clock synchronization 415.

Thus, the control card 440 according to the present invention associated with its card reading device make it possible to perform very powerful signal processing. It is necessary to transfer the result of these treatments from the control card 440 to, for example, its reader 6. For very high data rates, it is necessary to use connection devices - with very high bandwidth, for example, we use connectors

I

20. electric microwave.

Advantageously, as can be seen in FIG. 3, optical fiber couplers are used.

FIG. 3 shows the variant embodiment corresponding to the control card 440 illustrated in FIG. 1.

Obviously, the association of the device illustrated in FIG. 2 with the fiber optic couplers is not beyond the scope of the present invention.

In a first alternative embodiment, not illustrated, of the device according to the invention the optical fibers are placed end to end.

This variant embodiment allows very good coupling between the optical fibers of the card and of the card reader. However, it requires alignment of high precision optical fibers.

Advantageously, transverse coupling is used between two optical fibers brought into contact over very long lengths by relation to the wavelength of the signal transmitted in said optical fibers. In the embodiment illustrated in FIG. 3, the control card 440 receives by fiber optic couplers, on the one hand the signal to be processed, on the other hand the clock synchronization signals. The control card 440 supplies the card reader device via a fiber optic coupler with a synchronization signal 500 obtained by the convolution of a signal by a code. In addition, the memory card 440 receives the necessary supplies, in particular the electrical supply necessary for the operation of the charge transfer device 414, as well as the active elements 402, 403 and 404 of the optical fiber couplers.

_" In the example illustrated in FIG. 3, convolution is obtained by connecting the outputs of a charge transfer device 414.

FIG. 3 illustrates an alternative embodiment of the device according to the invention in which the number of connectors has been reduced by suppressing the output of the charge transfer device 414 comprising the input signal delayed by n clock cycles .

The device according to the invention comprises, connected in series with an antenna 4, a frequency reduction device 82, an intermediate frequency amplifier 3, a device 401 for converting the electrical signal into a modulated light signal. The device 401 is for example a light-emitting diode (LED in English terminology), or a laser diode. The device 401 injects a modulated light signal into an optical fiber 407.

Advantageously, the optical fiber 407 comprises at its end a device 430 for absorbing light radiation. This avoids the formation of standing waves, as well as interference between the waves reflected by the end of the optical fiber 407 with the waves directly injected by the device 401.

The control card 440 includes an optical fiber 408 connected to a photoelectric detector 402. The photo- electric 402 is connected to the input of a charge transfer device 414.

On the other hand, at the card reader, the clock signal necessary for the operation of the charge transfer device 14 is converted by a device 406 into a light signal modulation. The light signal is injected into an optical fiber 412.

Advantageously, the fiber 412 comprises at its end a device 430 for absorbing light radiation.

The control card 440 comprises an optical fiber 410 connected to a photodetector 404 connected to the device with charge transfer 414.

The outputs of the cells of the charge transfer device 414 corresponding to 1 of the code are connected to a device "403 for modulating light radiation. The device 403 is connected to an optical fiber 409. Advantageously, the fiber 409 has at its end of a device 430 for absorbing light radiation. The devices for reading the card 440 comprises an optical fiber 411. The optical fiber 411 is connected to a photoelectric detector 405. The detector 405 is connected to a line 500 LJne electrical line 413 is connected to the output of the intermediate frequency amplifier 3.

In normal use the optical fibers 407 and 408, 410 and 412, 411 and 409 are placed side by side. Advantageously, said optical fibers are pressed against each other. Thus, part of the signal present on the fiber 407 is transmitted to the fiber 408.

Similarly, part of the signal present on the fiber 412 is transmitted to the optical fiber 10. Likewise part of the signal present on the optical fiber 409 is transmitted to the optical fiber 411. Advantageously, the optical fibers 407 to 412 are not optimized to minimize lateral radiation losses.

In FIG. 3, for the sake of clarity of this figure, not all the amplifiers have been shown making it possible to supply the optimal new electrics in particular to the devices 401, 406 and 403 as well as to the charge transfer device 414. The main object of the present invention is a control card 440 which, associated with its card reader 6, allows signal processing to be carried out. For example of an intermediate frequency signal or of a hyper signal requirement originating from the transmissions of television emission.

The main object of the invention is a ι ^• 440 control card for ensuring in cooperation with its card reader

6 convolution of a signal by a code.

The invention applies in particular to convolution calculations, to the synchronization of signals and / or clocks, as well as to the control of access to certain services enabled for example by said synchronization.

The invention applies mainly to the reception of television broadcasts, radio broadcasts or data transmissions.

Claims

1. Control card (440) characterized in that, associated with a card reader (6), it is capable of generating a peak of convolution of a signal by a code from a charge transfer device ( 440).

2. Control card according to claim 1 characterized in that it comprises a charge transfer device (414) of which certain cells (511, 513, 515, 516 4-1) are connected to an output (500) on which we can read the convolution peak.

3. Control card (440) according to claim 1 characterized in that it comprises a permanent memory (700) suscep¬ tible to store a word of at least n bit, n being the number of points on which we want to be able carry out the convolution of the signal by a code, as well as the connections capable of connecting n cells of said permanent memory (700) to devices (601 to ^* 60n) capable of connecting only the cells (501, 503, 504, 505,

5014-1) of a charge transfer device (414) corresponding to 1s of the word of n bit stored in the memory (700).

4. Control card (440) according to any one of the preceding reven¬ dications characterized in that it is capable of ensuring the synchronization of a clock by convolution of a signal with a code.

5. Control card (440) according to claim 4 characterized in that the clock synchronization allows the demodulation of phase modulated signals.

6. Control card (440) according to claim 5 characterized in that the processed signal is a television broadcast signal.

7. Control card (440) according to any one of the preceding reven¬ dications characterized in that it comprises communication devices (402, 403, 404, 408, 409, 410, 430) with its card reader (6) using optical fibers (408, 409, 410).

8. Control card (440) according to claim 7 characterized in that the transmission of information between the card (440) and the card reader (6) is carried out perpendicular to the axis of the optical fibers (407, 408 , 409, 410, 411, 412).

9. Clock synchronization method characterized by the fact that it comprises the steps - of transmitting a binary code

- reception of the code

- introduction of the signal into a charge transfer device (414) of the signal sample

- shift of a cell of the charge transfer device (414) to:

- Obtaining a convolution peak on an output (500) connected to certain cells of said charge transfer device (414), the cells connected to said output (500) corresponding to the I of the binary code.

10. A method of transmitting information using phase modulation, characterized in that it uses as clock reference a clock which is synchronized periodically by a method according to claim 9.