SU841091A1 - Device for shaping multiposition biorthogonal noise-like signals - Google Patents

Description

one

The invention relates to a pulse technique and can be used in communication lines with discrete transmission of information.

A device for generating noise-like signals is known, comprising a generator, a shift register with a half-adder in a feedback circuit, a converter, blocks of elements And and half-adders, a shift register iX

However, its use in discrete information transmission systems is difficult, firstly, because of an insufficient number of signals with the required correlation properties, and secondly, because of the complexity of generating the desired signal to the appropriate code combination of information pulses.

The closest in technical essence to the present invention is a noise-like signal generator, which contains a clock pulse generator, the output of which is connected to clock inputs of n-bit shift registers with linear feedback, the output of the main register is connected to an additional register through a modulo two , but

the initial state setup block is connected to the setup input of the initial register state,

The known generator generates N-2 signals with correlation properties close to the properties of the M-sequence, where n is the number of bits in the shift register of the generator of the M-sequence 2.

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However, the known generator does not allow increasing the ensemble of the generated signals and increasing the noise immunity while maintaining the volumes of the shift registers.

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The purpose of the invention is to increase noise immunity when expanding the ensemble of the generated signals.

This goal is achieved by the fact that the device for forming multipositional biorthogonal noise-like signals, containing two n-bit shift registers with linear feedback, the clock inputs of which are connected to the output of the generator

5 clock pulses, the bit inputs of the first n-bit register with linear feedback are connected to the outputs of the initial state setting block, the output of the second n-bit 0 shift register with linear feedback is connected to the first input of the modulo two, additionally, a modulo-two adder unit was introduced, a t-bit shift register, a decoder, a memory element and a controlled inverter, the output of which is connected to the second input of the adder for module two, the first input is connected to the output of the first n-bit shift register and with linear feedback, the second input of the controlled inverter is connected to the output of the memory element, the first input of which is connected via a descrambler to the discharge outputs of the second n-bit shift register with the linear reverse connection and directly to the control the input of the setup of the initial states, the inputs of which through the modulo-adders block two are connected to the outputs, except for the last, additional g-bit register of the shift, the input of which is connected to the output of the clock pulse generator, and the last output is connected to modulo-two control input of the block and with the second input of the memory element. The drawing shows the functional diagram of the device. The device contains a generator of 1 clock pulses, bit registers 2, 3 of shift with linear feedback 4, adder 5 modulo two block b of setting the initial state, block 7 modulators dv shift register 8, decoder 9, controlling the inverter 10, the memory element 11, the input buses 12 and the output bus 13. The p-bit registers 2 and the shift with -linear feedbacks 4 and, the generator 1, form two generators 14 and 15 of the sequence. The device works as follows. The digital information of the message source over bus 12 is written into the t-bit register with 8 clocks of 1 clock pulse generator. The principle of operation of the device is based on the fact that the input information sequence is transmitted by bundles of m information pulses. In addition, each combination of m information pulses corresponds to a noise-like signal with a three-level cross-correlation function at the output of the device. All such signals should be N 2. Since the device forms biorthogonal codes, the N / 2 signals are direct and the rest are opposite. Therefore, in generators 14 and 15 M-sequences, it is possible to dispense with n m-1-bit registers 2 and 3 of the shift to obtain the required signal ensemble. To increase the noise immunity, the direct and opposite signals are transmitted respectively to those combinations of information pulses, which are also opposite. For example, if combinations of five information pulses 00000, 00001, 00010 are transmitted by signals S, S, S.J, then combinations 11111 11110, 11101 are transmitted by signals S, 83, Sj. Since the code distance between the opposite signals is greatest, the probability of receiving S instead of 5, and hence the probability of the maximum number of ch. errors in the combination of information pulses, the smallest. The splitting of N 2 combinations into direct and opposite is performed according to the value of the higher bit of the N-bit register 8 at the time of the rewriting signal at the output of the decoder 9. At zero, the direct signals are transmitted at the highest bit, and the opposite are at one. A rewriting signal at the output of the decoder 9 of the 15 m-sequence generator appears after the transmission of the next signal is completed and allows the setting of a new initial state in the generator 2 shift register 14 and the memory element 11. If the last bit of register 8 is in the zero state at the moment of rewriting, then the combination of information pulses, through the controlled inverter 10 and the initial state setting block 6, is written into the n-bit shift register 2 unchanged. The memory element 11 at its output produces zero potential and the m-sequence of the generator 14 passes through the block 7 modulo-two adders without change. When it is added modulo two with the M sequence of generator 15, a direct signal is generated at the output of the spider 5. With the unit in the last bit of the t-bit register 8, the information code recorded in its first bits is inverted and the initial combination corresponding to the direct signal is written in the n-bit shift register 2. In this case, the output of the memory element 11 appears 1 and the M-sequence of the generator 15 is inverted by the inverter 10, and the opposite signal is formed at the output of the adder 5. For example, if two combinations 01011 and 101QO are transmitted (the most significant bit is underlined), then in the first combination in the n-bit register 2 the initial state 1011 is set and the signal S is generated. If we denote the signal of the generator 15 by Q, then at the output of the adder 5, the signal Sj @ Q appears. When the second combination is transmitted, the combination 1011 is also written to the n-bit register 2, and the signal at the output of the adder 5 Q © Q, t. e. opposite to the first, the use of the proposed device makes it relatively easy to form multi-position noise-like signals with good mutually correlation properties, increases the noise immunity of the transmitted information and expands the ensemble of signals used, since with a register length of M-sequence generators equal to n 2 claims An apparatus for generating multi-position biorthogonal noise-like signals comprising two And the linear shift register registers with linear feedback, the clock inputs of which are connected to the output of the clock pulses generator, the bit inputs of the first n discharge register with linear feedback are connected to the outputs of the initial state setting block, the output of the second n-bit shift register with linear feedback is connected to the first input of the adder and module two, characterized in that, in order to improve the noise immunity of the noise when expanding the ensemble of the generated signals, an adder unit is added to it About module two, a t-bit shift register, a decoder, a memory element and a controlled inverter, the output of which is connected to the second input of a modulo-two adder, the first move is connected to the output of the first n-bit shift register with linear feedback, the second input of the controlled inverter is connected to the output of the memory element, the first input of which is connected via a decoder with the discharge outputs of the second n-bit shift register with linear feedback and directly with the control input of the initial state setting unit, the moves of which through the block of adders along the module two are connected to the outputs, except for the last, additional t-bit of the dns shift register, whose input is connected to the output of the clock generator, and the last output is connected to the control input of the block of converters modulo two and the entry of the memory element. Sources of information taken into account in the examination 1, USSR Copyright Certificate №573858, cl. H 03 K 3/84, 1975, 2. USSR author's certificate No. 280532, cl. H 03 K 3/84, 1968.

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Claims (1)

Claim A device for generating multi-15 biorthogonal noise-like signals containing two p-bit shift registers with linear feedback, the clock inputs of which are connected to the output of a clock generator 20, the bit inputs of the first η-bit register with linear feedback are connected to the outputs initial state setting unit, the output of the second ji-bit shift register 25 with linear feedback is connected to the first input of the adder modulo two, characterized in that, in order to increase the noise immunity noise ychivosti upon expansion of the ensemble formed by the signals in it ^connection is further administered block adders modulo two, m-bit shift register, decoder, a memory element and a controllable inverter, whose output is connected to the second input of the adder of modulo two, the first ^ turn connected to the output the first p-bit shift register with linear feedback, the second input of the controlled inverter is connected to the output of the memory element, the first input of which is connected through the decoder to the bit outputs of the second η-bit shift register linear feedback and directly with the control input of the initial state setting unit, the inputs of which through the adder unit are modulo · two connected to the outputs, except for the last additional t-bit shift register, the input of which is connected to the output of the clock generator, and the last output is connected with the control input of the adder block modulo two and with the second input of the memory element.