SU789868A1 - Spectrum analyser - Google Patents

Description

(54) SPECTRUM ANALYZER The invention relates to radio metering technology, in particular to electrical signal spectrum analyzers. Spectrum analyzers containing multipliers, basic function generators, and a calculator are known l. Well-known analyzers allow one to determine the decomposition coefficients of an input signal by a given basic system of functions and do not allow one to determine the decomposition coefficients for other basic systems of functions. Analyzers are also known that contain an input data conversion unit, a Kroneker product calculation unit, consisting of keys, adders and subtractors, a delay, synchronization and reset unit, a control unit and a sync pulse generator 2l. A disadvantage of the known analyzers is the limitation of the spectral transformations of the input signal only to the Walsh transform class. The objective 1} of concluding is to expand the class of spectral transformations. This goal is achieved by the fact that a spectrum analyzer containing an input signal conversion unit whose outputs are connected to the inputs of the N units of the Kronecker computation unit, each of which consists of two input keys, an adder and a subtractor, two channels in the way of the computation unit consisting of series-connected synchronization block, cyclic block, delay and reset and census block, the input of the first of which is connected to the output of the adder, the input of the second channel is connected to the output of the subtractor, and the outputs of the wallpaper The channels are connected alternately to the corresponding inputs of the input keys of the Kronecker computation unit, the control unit whose input is connected to the output of the clock generator, one output is connected to the input of the input signal conversion unit, and the other is connected to the weighting factor generator, additionally contains in each block of the Kronecker product calculation two pairs of multipliers, one inputs of each of which are combined and connected to the output of the input dny keys, and other inputs are connected to the outputs of the generator

the weight functions, the even and odd inputs of each pair are also combined, the inputs of the adder are connected to the outputs of the odd multipliers of each pair, the inputs of the subtractor are connected to the outputs of the even multipliers of each pair, the output of the adder is connected to the input of the first channel, and the output of the subtractor is connected to the input of the second channel.

The drawing shows the structures on the analyzer circuit.

It consists of block 1 of the input data conversion, blocks. 2 calculations of the Kronecker product, input keys 3, adder 4 -, subtractor 5, synchronization blocks b, cyclic delay blocks 7, reset and rewrite blocks 8, control block 9, clock generator 10, generator 11 weight factors, block 12 weights multipliers 13

The input data conversion unit 1 has outputs, of which each i-th is connected to the input of the i-th input control key 3. The outputs of the odd-numbered reset and rewrite blocks 8 are alternately connected to the inputs of the first N / 2 control keys 3, and the even-numbered outputs to the inputs of the remaining N / 2 keys.

The weight coefficients generator 11, made in the form of a multichannel sine-cosine function transducer, provides for simultaneous receiving at its outputs N / 2 pairs of signals, different in size s i p f, which determine the weighting factors. Each pair of signals SSCH and sin is fed respectively to the k-th block 2 of the Kronecker product calculation at the second inputs of the multipliers 13. The values of the angles H are given by the block 12 specifying the weights, which can be used as a program-driver block, the memory of which is written selected angles s. The change in the values of the angles 4, and accordingly the weighting factors generated by the generator 11, is carried out according to the commands given to the block 12 from the block 9 of the control. Clock pulses are supplied to the control unit from a generator of 10 sync pulses. From the auxiliary outputs of this generator, the clock pulses also go to the input keys 3 of the control and blocks 6-8 and ensure their synchronous operation.

The spectrum analyzer works in the following way.

The input signal is input to the input data conversion unit 1, where it is sampled and its samples are stored. The operation of unit 1 is controlled by 5poc 9 control. with the arrival of the first clock sync pulse generated in block 10, each of the input samples from block 1 is fed through the corresponding control input key 3 to the first inputs of two adjacent multipliers 13. One of them multiplies (weights) the input sample by a weighting factor equal to the cosine value The selected angle, the other, by a weighting factor equal to the sine value of the same angle. In each block 2, the input samples, weighted by multipliers 13, are summed in pairs in an adder, 4, and subtracted from. subtractor 5. Next, weighted sums and differences of input samples through synchronization blocks b are sent to cyclic delay blocks 7, where they are memorized, and with the arrival of the next tat sync pulse, they are rewritten into blocks 8 and fed to the keys of control 3 for the recursive transformation procedure. This procedure of transforming the input samples cyclically repeats n times, as a result of which an iterative calculation of the spectrum of the input signal occurs in the basis, which is determined by given weight coefficients cosV and S i. The values of the corresponding spectral coefficients are formed at the outputs of the adder 4 and subtractor 5 and arrive at the output terminals.

In the proposed analysis: .vope spectra of the spectral transformation matrix matrix are determined by the weighting coefficients introduced into it by the generator 11, the block 12 and the multipliers 13 connected by the above method, and take the form:

cos} si pc,

in

V

A matrix of this kind as well as a matrix of the core of a Walsh transformation satisfies the condition of orthonormality for any given

angles S, which creates the possibility of using the proposed device spectral analysis of signals fi a wide class of complete systems of orthonormal functions. Specifying Vy Angles. on each recursive transformation procedure, input samples may be different, which further expands the number of possible bases for the spectral analysis of signals. The choice of basis in

The proposed spectrum analyzer is determined by setting the values of the angles O and Ilty. For example, to obtain a transformation in the Walsh basis, it is necessary to set all the angles the same

and equal to the value of P ,.

The possibility of rearrangement of bases for almost unlimited, their number favorably distinguishes the proposed spectrum analyzer from the known ones. This quality allows one to choose for analyzing signals such a basis that meets a given requirement, for example, provides a better signal extraction. Against a background of interference or, for example, provides a higher resolution in the separation of several signals. Due to this quality, the proposed spectrum analyzer can be effectively used in such areas as spectral analysis of random processes, detection of signals against background noise, image processing, pattern recognition.

Claims (2)

1. Frank L. Theory of signals. M., 1974, p.63. 2. US patent number 3879605, cl. G On f 15/34, 1974.