RU2022352C1 - Digital spectrum analyzer - Google Patents

Abstract

FIELD: computer engineering. SUBSTANCE: digital spectrum analyzer has analog-to-digital converter 1, two main storage units 4,6, clock generator 9, frequency divider 7, and counters 8 of spectral factors and spectral conversion steps two Fermat's modulo adders 2,3, and Fermat's modulo multiplier 5. Spectral factors are computed in such spectrum analyzer by using recurrence formula in end field which provides for 3-5 times higher speed as compared to similar analyzers operating in complex number field. EFFECT: reduced hardware expenses, improved speed and accuracy in computing spectral factors. 1 dwg

Description

 The invention relates to computer technology and can be used in digital computer systems designed for signal processing, in particular for digital dynamic spectral analysis and correlation filtering of signals.

 Known digital spectrum analyzers used in the organization of spectral analysis of signals (ed. St. USSR N 932419, class G 06 F 15/332, 1982 and ed. St. USSR N 1365094, class G 06 F 15/332, 1988) .

 The closest in technical essence to the invention is a spectrum analyzer (ed. St. USSR N 1365094, class G 06 F 15/332, 1988), having an analog-to-digital converter (ADC), adders, multipliers, a generator and a clock distributor.

 The spectral analysis of signals in such an analyzer is carried out in the field of complex numbers, for which a harmonic generator is introduced into the analyzer, and operations in the adders and multipliers are performed on complex numbers in trigonometric form, which causes an increase in the volume of calculations and a decrease in their accuracy.

 The purpose of the invention is to reduce hardware costs, increase speed and accuracy.

, s = 1, 2, ..., где F_j(s) - значение j-го спектрального коэффициента на s-м шаге спектрального преобразования (F_j(0) = 0);
f_n-1(s) - (n - 1)-й отсчет исследуемого сигнала на s-м шаге спектрального преобразования (f_o(0) = 0);
α ≡ 2

2

-1

mod M_t - представление числа 2

в кольце целых чисел по mod M_t=(α²≡ 2 mod M_t) и α имеет порядок n);
M_t = 2^2t+ 1 - число Ферма; t - целое положительное число;
n = 2^t+2 - длина окна спектрального преобразования.The goal is achieved due to the fact that all calculations in the digital spectrum analyzer are performed on integers using shift and addition operations and the spectral conversion is performed using the reference formula
F _j (s) = [F _j (s - 1) + (f _n-1 (s) - f _o (s - 1))] α ^-j modM _t ,
j =

, s = 1, 2, ..., where F _j (s) is the value of the j-th spectral coefficient at the s-th step of the spectral transformation (F _j (0) = 0);
f _n-1 (s) - (n - 1) -th sample of the studied signal at the s-th step of the spectral transformation (f _o (0) = 0);
α ≡ 2

2

-1

mod M _t - representation of 2

in the ring of integers with respect to mod M _t = (α ² ≡ 2 mod M _t ) and α has order n);
M _t = 2 ^2t + 1 is the Fermat number; t is a positive integer;
n = 2 ^{t + 2} is the length of the spectral transform window.

 The drawing shows a structural diagram of a digital spectrum analyzer.

 The digital spectrum analyzer contains ADC 1, the input of which receives the signal under study. The output of the ADC 1 is connected to the first input of the adder 2 and the block 4 of RAM, designed to store samples of the signal under study the previous step of the spectral conversion. The output of block 4 is the second input of adder 2, which modulo forms the Fermat number, the difference between the last sample at the current and the first sample of the signal at the previous step of the spectral conversion. The output of adder 2 is connected to the first input of adder 3 modulo the Fermat number, the second input of which is connected to the RAM unit 6, designed to store the spectral coefficients calculated at the previous step from the output of the multiplier 5. In the multiplier 5, the spectral coefficients are calculated by multiplying by Fermat module arriving at its first input from the output of the adder 3 numbers to the number two to the appropriate degree. The numbers of the calculated coefficients go to the second input of the multiplier 5 from the output of the counter 10, to the input of which the pulses of the clock pulse generator (GTI) 9 are supplied, which, together with the frequency divider (DC) 7, the output of which is connected to the counter 8, controls the operation of the digital spectrum analyzer.

 Digital spectrum analyzer operates as follows.

. Номер текущего шага спектрального преобразования s соответствует показанию счетчика 8 числа шагов спектрального преобразования, подключенного к выходу ДЧ 7, а номер j вычисляемого спектрального коэффициента F_j(s) - текущему значению счетчика 10 числа спектральных коэффициентов, подключенного к выходу ГТИ 9. Через каждые n импульсов ГТИ 9 по сигналу от ДЧ 7 значение счетчика 10 обнуляется. Под воздействием импульса ДЧ 7 происходит считывание из блока 4 оперативной памяти значения f_о(s - 1) первого отсчета исследуемого сигнала на предшествующем (s - 1)-м шаге спектрального преобразования и запись в блок 4 последнего отсчета сигнала f_n-1(s) на текущем шаге спектрального преобразования s. Считанное значение f_j(s - 1) поступает на второй вход сумматора 2 по модулю числа Ферма, где формируется разность (f_n-1(s) - f_o(s - 1)) modM_t. Полученная разность подается на первый вход сумматора 3, где происходит ее сложение по модулю числа Ферма M_t с соответствующим j-м спектральным коэффициентом F_j(s - 1) предшествующего (s - 1)-го шага спектрального преобразования, который подается на второй вход сумматора 3 из блока 6 оперативной памяти по тактовому импульсу ГТИ 9. Результат сложения поступает из сумматора 3 в умножитель 5, где производится умножение по модулю Ферма на число 2

(значение j, соответствующее номеру вычисляемого спектрального коэффициента F_j(s), считывается в умножитель 5 со счетчика 10). Полученное в результате умножения значение спектрального коэффициента F_j(s) поступает на хранение в блок 6 оперативной памяти и на выход цифрового анализатора спектра, значения s и j считываются со счетчиков 8 и 10 соответственно, и под воздействием следующих импульсов ГТИ 9 и ДЧ 7 цикл работы цифрового анализатора спектра повторяется.When a start signal is applied to the input of the spectrum analyzer, the GTI 9 and DF 7 begin to generate control clock pulses. The studied signal f (t) is fed to the input of the ADC 1, from the output of which the discrete values of the signal samples go to the input of the RAM unit 4 and the first input of the adder 2. The information in the ADC 1, adder 2 and RAM unit 4 is changed under the influence of clock pulses DF 7 is n times less frequent than in other analyzer blocks, where n is the number of spectral transform coefficients F _j (s) calculated at each step s, i.e. j =

. The number of the current step of the spectral conversion s corresponds to the counter 8 of the number of steps of the spectral conversion connected to the output of the PM 7, and the number j of the calculated spectral coefficient F _j (s) corresponds to the current value of the counter 10 of the number of spectral coefficients connected to the output of the GTI 9. Every n GTI pulses 9 by the signal from the PM 7 counter value 10 is reset. Under the influence of the PM 7 pulse, the value f _о (s - 1) of the first sample of the signal under study at the previous (s - 1) th step of the spectral conversion is read from block 4 of the random access memory and the signal f _n-1 (s ) at the current step of the spectral transformation s. The read value f _j (s - 1) goes to the second input of adder 2 modulo the Fermat number, where the difference (f _n-1 (s) - f _o (s - 1)) modM _{t is formed} . The resulting difference is fed to the first input of adder 3, where it is added modulo the Fermat number M _t with the corresponding jth spectral coefficient F _j (s - 1) of the previous (s - 1) th step of the spectral transformation, which is fed to the second input adder 3 from block 6 of the RAM according to the clock pulse of the GTI 9. The result of addition comes from the adder 3 to the multiplier 5, where the Fermat multiplication is performed by the number 2

(the value j corresponding to the number of the calculated spectral coefficient F _j (s) is read into the multiplier 5 from the counter 10). The result of the multiplication of the value of the spectral coefficient F _j (s) is stored in the RAM unit 6 and the output of the digital spectrum analyzer, the values s and j are read from the counters 8 and 10, respectively, and under the influence of the following pulses GTI 9 and 7 The operation of the digital spectrum analyzer is repeated.

+1 реализуются на основе регистров сдвига и элементов двоичной логики. Блоки 4 и 6 оперативной памяти строятся из n = 2^t+2 элементов памяти разрядности 2^t. Умножение чисел на 2

, j=

, по модулю Mt в умножителе 5 при четных значениях n - j сводится к выполнению операций двоичного сдвига содержимого регистров умножителя и сложения по модулю M_t, при нечетных n - j осуществляется дополнительно умножение на 2

, которое с учетом двухразрядного двоичного представления 2

mod M_t=2

2

-1

mod M_t также реализуется с помощью операций сдвига и сложения по модулю Mt. Таким образом, все вычисления в предложенном цифровом анализаторе спектра производятся над целыми числами с помощью операций сдвига и сложения, что снижает аппаратурные затраты, повышает быстродействие и точность выполнения спектральных преобразований.Adders 2 and 3 modulo Fermat number M _t = 2

+1 are implemented based on shift registers and binary logic elements. Blocks 4 and 6 of RAM are built from n = 2 ^{t + 2} elements of memory capacity of 2 ^t . Multiplying numbers by 2

, j =

, modulo Mt in multiplier 5 for even values of n - j reduces to performing binary shift operations of the contents of the registers of the multiplier and addition modulo M _t , for odd n - j, an additional multiplication by 2

which, given the two-bit binary representation 2

mod M _t = 2

2

-1

mod M _{t is} also implemented using shift and addition operations modulo Mt. Thus, all calculations in the proposed digital spectrum analyzer are performed on integers using shift and addition operations, which reduces hardware costs, improves the speed and accuracy of spectral transformations.

Claims (1)

 A DIGITAL SPECTRA ANALYZER containing two RAM blocks, an analog-to-digital converter, a clock, a frequency divider, two adders and a multiplier, the analyzer information input connected to the analog-to-digital converter input of the same name, the output of which is connected to the first information input of the first adder and information input of the first block of random access memory, the recording and reading control input of which is connected to the clock input of the analog-to-digital converter and the output of a frequency ram, the input of which is connected to the clock first output of the clock generator, the output of the first RAM block is connected to the second information input of the first adder, the second output of the clock generator is connected to the write and read control input of the second RAM block, the output of which is connected to the first information the input of the second adder, characterized in that the analyzer contains two counters, the first and second adders are adders modulo Fermat numbers, the multiplier is smart a resident modulo Fermat numbers, while the analyzer start input is connected to the inputs of the analog-to-digital converter and clock generator of the same name, the reset input of which is connected to the analyzer of the same name, the second output of the clock generator is connected to the counting input of the first counter, the reset input of which is connected to the output of the frequency divider and the counting input of the second counter, the output of which is connected to the output of the current analyzer conversion current number, the output of the first counter is connected to the spec analyzer sweep coefficient and the first information input of the multiplier, the second information input of which is connected to the output of the second adder, the second information input of which is connected to the output of the first adder, the output of the multiplier is connected to the information input of the second RAM block and with the output of the analyzer spectral conversion value.