SU940157A1 - Pseudorandom number sequence generator - Google Patents

Description

one

The invention relates to computing and is intended for various devices where the synthesis of narrow-band random processes is necessary. ,

A known random signal generator containing a linearly varying voltage generator, a universal non-linear converter — a polytron, two multiplication units, two memory blocks, a counter, accumulating adder, a harmonic signal generator, a sensor of normal random numbers 1.

The specified generator allows to model narrow-band processes,. However, it is characterized by increased complexity, its use is not advisable for solving problems of a narrower class.

The closest in technical essence to the present invention is a pseudo-random narrowband signal generator containing an arithmetic unit, one group of inputs connected to a random number sensor via a switch block, the other to a master register, and outputs to the inputs of the adder, the second group of inputs of which is connected to the outputs through the forming register, the synchronizing input of which is connected to the clock input of the generator

, 0 and the trigger trigger input, Y and K whose inputs are connected to the transfer output of the high bit of the adder, and the output to the generator output through filter 2.

, 5 The known generator is characterized by simplicity of the circuit solution. However, the output filter should have a frequency response that is uniform within the width of the spectrum and have

20 large attenuation at frequencies corresponding to the harmonics of the signal. If the width of the signal spectrum and its center frequency are comparable, then this is necessary. so that the output filter has a high order, since its frequency characteristic affects the spectral properties of the signal, which can lead to a significant complication of the oscillator circuit. At the same time, when the oscillator center frequency is changed, a filter adjustment is required, which is difficult when using a high order filter. The purpose of the invention is to expand the range of the generated processes while maintaining the spectral characteristics of the signal from the generator output. To achieve this goal, a pseudo-random narrowband signal generator containing a primary pseudo-random number sensor, the output of which through a switch is connected to the first input of the first adder, the second input is connected to the output of the first code register, and the output of the first adder is connected to the first input The second adder, the output of which is connected to the input of the second register of the code, the output of which is connected to the second input of the second adder, has been introduced a code-voltage converter, a cyclic shift register and an electronic The NOT whose output is connected to the input of the first bit of the cyclic shift register, the output of the last row of which is connected to the input of the element NO, the transfer output of the higher bit of the second adder is connected to the input of the cyclic shift register, the synchronizing input of which is combined with the sync input of the second register code and is the clock input of the generator, the installation input of which is the installation input of the cyclic shift register, all the bit outputs of which, except for the last output of the last bit, are connected to The appropriate transformation code inputs ers - voltage, the output of which is the output of the generator. FIG. 1 shows a structural generator map; in fig. 2 - diagrams on the principle of its work. The generator contains the first adder 1 with two groups of inputs. Group A of inputs is connected to the primary sensor of 2 pseudo-random numbers through switch 3, group B of inputs to the first register of k code. The output of the first adder 1 is connected to the inputs A of the second adder 5. The inputs B of the second adder 5 are connected to its outputs via the second register b of the code, the synchronous wire of which is connected to the clock input 7 of the generator and the synchronous input of the cyclic shift register 8. The gate input of register 8 is connected to the high-end transfer output of the second adder 5, the setup input is connected to input 9 of the generator zero setting, and the first-bit information input is connected to the NM output of register 8 via the NOT element 10. The outputs of the N-1 register 8 are connected to chain of serially connected registers 1C .... 11 nj.q. The beginning and end of the chain are connected to the common wire through the terminating resistors 12 and 12, through the resistors H. , thus forming the resistive matrix R-2R. The connection point of the resistors 11L-1 and 1 T N of the kidney is connected to the x, 1-way through the output stage k. Elements 11-1 + form the converter 15 code - voltage. The generator works as follows. A pseudorandom number sensor 2 generates a sequence of independent (m + 1) bit numbers with a probability distribution close to uniform, which enters the input of the first adder 1 through switch 3, containing m keys that connect random number bits. Moreover, the zero bit of the sequence is used as a sign (O corresponds to a plus, and 1 to the minus number) and is fed to the input of the first adder 1 directly. At the same time, at the output of switch 3, we have a new sequence G (-), where n is the sequence number of the number from the output of the sensor 2 pseudo-random numbers; F frequency of changing numbers. In the first adder, the algebraic addition of the stream of numbers G (-S-) with the number H occurring in the first register of the code occurs, forming a new shifted sequence hf H sf, where h (1 is the sign function of the sequence corresponding to zero from the output of sensor 2 pseudo-random numbers. 5S The newly formed number sequence is fed to the input B of the second adder 5. In the initial state, the second register 6 of the code is reset and at the output of the second adder 5 we have the number 9 At the moment of arrival of the pulse at the input 7 reg Page 6 records the state at its input and at the output of adder 5 a double number 2 S is formed, at the next pulse it is 3 S, and so on, until the output of adder 5 does not exceed, where m is the number of main bits At this moment, at the inputs of register 6, we have a number equal to kS-2 S, where k is the pulse sequence number from the bus 8, and at the first transfer output of the highest m bit and at the gate input of the register 8 is one. + 1 pulse, the first bit of register 8 records the inverse state of the N th bit, and at the output of adder 5 we have the number (k + 1) 5-2, and n discharge transfer output m - zero, closing the syncro input of register 8. The register remembers the state before the next unit arrives at the gate input, in which the state shifts by one time the register 8 register. After passing 2 pulses at input 7 at the discharge transfer output yes m passes s units. Thus, if the pulse frequency on bus 7 is equal to d, then the pulse frequency at the output of riepeHoca. Sum of matrix 3 is equal to f. H + 4 () G () sl) fg (about 1 where H determines the center pulse frequency fu. G (-p-) determines the absolute deviation of the pulse frequency from the center; 4 {-g-) is the sign of the frequency deviation . From the transfer output of the adder 5, the pulses arrive at the gate input of the cyclic register 8. Moreover, the ring is closed by connecting the inverse output of the N-ro bit of register 9 with the input of the first digit. As the strobe pulses are HacTyji, at the first output of the register we have a square wave signal with a frequency of 2 N times lower than the frequency at its input (Fig. 2c (), at the second output - a similar pattern, but shifted by one period {, Fig. 2B), on the rest similarly. If the unit voltage is equal to and, and the voltage Ug is equal to zero, then at the input of the output stage the voltage value at any time can be determined by the following relation, if the value of resistors is 13 and twice as large as 12, UjmKj (K) MI Kj (it)., where j is the sequence number of the register register 9 1, with U.;. j- and --- f / fo, with and .. Uo As can be seen from FIG. 1 weight ratio will be smaller, the further the bit is separated from N / 1 bit. Consequently, as the pulses pass from trigger 8, an almost sinusoidal signal is formed at the input of the output stage, approximated by a sequence of rectangular pulses of duration T of different amplitude and frequency equal to (Fig. 2rj -n, H4f) 4f Hf) For obtaining satisfactory results the most optimal choice is N or 6 or 8, and the signal is sampled 12 and 16 times, respectively, for one period, which satisfies most practical cases. If it is necessary to interpolate the resulting signal and smooth out the jumps, then a simple second-order filter with a wide bandwidth can be used for this, which does not significantly affect the spectral characteristics of the signal. Thus, approximating the output signal by a sequence of square-wave pulses, the harmonic components closest to the fundamental frequency are greatly reduced, and processes with spectrum width comparable to the center frequency appear possible, using, if necessary, the simplest filter, which confirms the expansion.

generator functionality.

An additional advantage is the reduction of the frequency variation resolution, i.e.

P141

N1

Claims (2)

1. USSR author's certificate No. 50787, cl. G 06 F 1/02,. 2., USSR Copyright Certificate No. 2820 88 / 18-24, 1980. Fi9.1 VtVi - -J Vo I r: i 12 J w W Phi.1