RU2541147C1 - Function generator - Google Patents

Abstract

FIELD: radio engineering, communication.

SUBSTANCE: function generator comprises a comparator circuit, a multiplier, a first adder, first and second controlled integrators, an inverter, a relay element, first and second squaring devices, a second adder, a square-root computer and a triangular waveform generator.

EFFECT: broader functional capabilities and maintaining high linearity of a triangular waveform with variation of the amplitude of quadrature harmonic signals in a wide range.

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Description

The invention relates to radio engineering and communication and can be used in communication equipment, measuring and computer technology for the formation of quadrature harmonic signals of several frequencies and signals of various shapes of the same frequency.

A device [1] is known that contains a quadrature signal source, first and second module calculators, first and second quadrators, an adder, a multiplier, an amplifier, and a rectangular bipolar signal shaper, the output of which is connected to the third output of the functional generator, the second output of which is connected to the input of the shaper bipolar signals of a rectangular shape and with the output of the adder, the first, second, third and fourth inputs of which are connected to the outputs, respectively, of the first calculator module, the first quad a second module multiplier and a second quadrator, while the first input of the multiplier is connected to the first output of the quadrature signal source, as well as the inputs of the first module calculator and the first quadrator, the second multiplier input is connected to the second output of the quadrature signal source, and the inputs of the second module calculator and the second quadrator, and the amplifier is connected between the output of the multiplier and the first output of the functional generator.

The device generates sinusoidal, triangular waveforms, as well as a bipolar waveform of rectangular waveform. The formation of a triangular signal is possible only with a fixed (stable) value of the amplitude of the source of quadrature signals.

The closest device to the claimed invention in terms of essential features is the functional generator adopted for the prototype [2], which contains a comparison circuit, a multiplier, a first adder, first and second controlled integrators, an inverter, a relay element, first and second quadrators, a second adder and a square calculator a root connected between the output of the second adder and the second input of the comparison circuit, the output of which is connected to the first input of the multiplier, the output of which is connected to the first input of the first a matrator, the output of which is connected to the first input of the first controlled integrator, the output of which is connected to the first input of the second controlled integrator, the inverter input, the input of the first quadrator and the first output of the functional generator, the second output of which is connected to the second input of the first adder, the output of the second controlled integrator and the input the second quadrator, the output of which is connected to the second input of the second adder, the first input of which is connected to the output of the first quadrator, while connecting to the output of the inverter input relay element whose output is connected to the second input of the multiplier and the third output of the function generator, the first control bus which is connected to the second inputs of the first and second controllable integrators, and the second control bus of the function generator is coupled to the first input of the comparison circuit.

The device generates sinusoidal, triangular waveforms, as well as a bipolar waveform of rectangular waveform. The disadvantage of the device is the inability to maintain high linearity of the synthesized signal of a triangular shape when changing (adjusting) the amplitude of the quadrature signals.

The problem to which the invention is directed, is to expand the functionality of the device and maintain a high linearity of the triangular waveform when changing the amplitude of the quadrature harmonic signals over a wide range.

The specified technical result in the implementation of the invention is achieved by the fact that in a functional generator containing a comparison circuit, a multiplier, a first adder, first and second controlled integrators, an inverter, a relay element, the first and second quadrators, the second adder and the square root calculator included between the output of the second the adder and the second input of the comparison circuit, the output of which is connected to the first input of the multiplier, the output of which is connected to the first input of the first adder, the output of which is connected first the first input of the first controlled integrator, the output of which is connected to the first input of the second controlled integrator, the inverter input, the input of the first quadrator and the first output of the functional generator, the second output of which is connected to the second input of the first adder, the output of the second controlled integrator and the input of the second quadrator, to the output of which the second input of the second adder is connected, the first input of which is connected to the output of the first quadrator, while the input of the relay element, the output of which is connected to it is single with the second input of the multiplier and the third output of the functional generator, the first control bus of which is connected to the second inputs of the first and second controlled integrators, and the second control bus of the functional generator is connected to the first input of the comparison circuit, an additional triangular waveform driver is introduced, the first and second inputs of which connected to the outputs, respectively, of the first and second controlled integrators, the third, fourth outputs of the triangular signal conditioner are connected to the outputs of the second and first quadrants, respectively, and the fifth input of the triangular-shaped sigal former is connected to the output of the square root calculator, the first and second outputs of which are connected, respectively, with the fourth and fifth outputs of the functional generator.

In this case, the triangular signal shaper is made of the first and second module calculators, the first and second subtracters, the third adder and the divider, the output of which is connected to the second input of the third adder and the second output of the triangular signal shaper, the first output of which is connected to the output of the third adder, the first the input of which is connected to the output of the first subtractor, the output of the second subtractor is connected to the first input of the divider, the first calculator of the module is connected between the first input of the signal conditioner a rectangular shape and the first input of the first subtractor, while the third and fourth inputs of the triangular waveform generator are connected, respectively, to the first and second inputs of the second subtractor, and a second module calculator is connected between the second input of the triangular waveform driver and the second input of the first subtractor.

The analysis of the prior art by the applicant, including a search by patent and scientific and technical sources of information, established that the applicant did not find an analogue characterized by features identical to all the essential features of the claimed invention. Therefore, the claimed invention meets the condition of "novelty."

An introduction to the proposed functional generator of a triangular-shaped signal shaper made of two module calculators, two subtractors, an adder and a divider, as well as the organization of new connections between functional elements made it possible to expand the device’s functionality and maintain a high linearity of the triangular-shaped signal when the amplitude of the quadrature harmonic signals changes in wide limits.

The invention is illustrated by the structural diagram of the functional generator (figure 1) and graphs (figure 2 - figure 4), explaining the principle of operation of the functional generator.

The functional generator contains a comparison circuit 1, a multiplier 2, a first adder 3, a first 4 and a second 5 controlled integrators, an inverter 6, a relay element 7, a first 8 and a second 9 squares, a second adder 10, a square root calculator 11, and a triangular waveform former 14 made from the first 15 and second 16 calculators of the module, the first 17 and second 18 subtracters, the third adder 19 and the divider 20, while the square root calculator 11 is connected between the output of the second adder 10 and the second input of the comparison circuit 1, to the output of which the swarm is connected to the first input of the multiplier 2, the output of which is connected to the first input of the first adder 3, the output of which is connected to the first input of the first controlled integrator 4, the output of which is connected to the first input of the second controlled integrator 5, the input of the inverter 6, the input of the first quadrator 8, the first input a triangular signal shaper 14 and a first output of a functional generator, the second output of which is connected to the second input of the first adder 3, the output of the second controlled integrator 5, the second input of the shaper I have a triangular waveform 14 and an input of a second quadrator 9, the third input of a triangular waveform shaper 14 and a second input of a second adder 10, a first input of which is connected to the output of the first quadrator 8 and a fourth input of a triangular waveform 14, the first and second the outputs of which are connected, respectively, with the fourth and fifth outputs of the functional generator, the third output of which is connected to the second input of the multiplier 2 and the output of the relay element 7, the input of which is connected to the output inverter 6, while the second inputs of the first 4 and second 5 controlled integrators are connected to the first control bus 12 of the functional generator, the second control bus of which is connected to the first input of the comparison circuit 1, and the fifth input of the triangular waveform generator 14 is connected to the output of the square root 11 , the first and second inputs of which are connected to the inputs, respectively, of the first 15 and second 16 calculators of the modules, the third and fourth inputs of the signal shaper of a triangular shape 14 are connected, respectively about, with the first and second inputs of the second subtractor 18, the output of which is connected to the first input of the divider 20, the output of which is connected to the second input of the third adder 19 and the second output of the signal shaper of a triangular shape 14, to the first output of which the output of the third adder 19 is connected, the first input which is connected to the output of the first subtractor module 17, the first and second inputs of which are connected to the outputs, respectively, of the first 15 and second 16 calculators modules.

Functional generator operates as follows.

Sequentially connected and closed in a ring, the first 4 and second 5 controlled integrators, as well as the first adder 3 form an oscillatory system (CS) with two outputs (Fig. 1). The first 8 and second 9 quadrators, the second adder 10 and the square root calculator 11 form a voltage sensor (ND). The oscillation system, the voltage sensor, the relay element 7 with the inverter 6, the comparison circuit 1 and the multiplier 2 form a dual-circuit automatic control system (ATS).

When applying control voltages E _f and E ₀ to the corresponding inputs 12 and 13 of the ATS at the outputs of the first 4 and second 5 controlled integrators, that is, at the second and third outputs of the functional generator, after the end of the transient processes, harmonic oscillations N _{1 are} established (Fig. 2) (t) and N ₂ (f), shifted relative to each other by 90 el. degrees

$$N_{\mathrm{one}}\left(t\right)=A\sin \left({\omega }_{0}t\right),{\text{N}}_{\text{2}}\left(t\right)=A\cos \left({\omega }_{0}t\right),\text{(one)}$$

where A is the amplitude and ω ₀ is the circular frequency of the signals N ₁ (t) and N ₂ (t) associated with the cyclic frequency f _{0 by the} known relation ω ₀ = 2πf ₀ .

The frequency f _{0 is} determined by the value of the voltage E _f supplied to the input 12, and the amplitude value A is determined by the value of the reference voltage E ₀ supplied to the second input 13 of the functional generator.

At the output of the relay element 7 from the inverted signal N ₁ (t), a signal N ₃ (t) is generated, which is fed to the first output of the functional generator.

The voltage sensor operates as follows.

Upon receipt of a signal N ₁ (t) at the input of the first quadrator 8 and a signal N ₂ (t) at the input of the second quadrator 9, a signal is generated at the output of the second adder 10

$$E_{\mathrm{one}}=k_{\mathrm{one}}{m}_{\mathrm{one}}{A}^2{\sin }^2\left({\omega }_{0}t\right)+m_2{k}_2{A}^2{\cos }^2\left({\omega }_{0}t\right),\text{(2)}$$

where k ₁ and k ₂ are the transmission coefficients of the second adder 10, respectively, at the first and second input; m ₁ and m ₂ - transmission coefficients, respectively, of the first 8 and second 9 squarer.

When k ₁ m ₁ = k ₂ m ₂ = 1, expression (2) is simplified

$$E_{\mathrm{one}}=A^2\left[{\sin }^2\left({\omega }_{0}t\right)+{\cos }^2\left({\omega }_{0}t\right)\right]=A^2.\text{(3)}$$

At the output of the square root calculator 11, that is, at the output of the DN, a constant signal E _{2 is formed} , the amplitude of which is equal to the amplitude A of the quadrature signals N ₁ (t) and N ₂ (t), that is, E ₃ = A.

At the output of the comparison circuit 1, a mismatch signal is generated

$$U_e\left(t\right)=k_3{E}_0-k_{\mathrm{four}}{E}_2=k_3{E}_0-k_{\mathrm{four}}A,\text{(four)}$$

where k ₃ and k ₄ are the transmission coefficients of the comparison circuit 1, respectively, at the first and second input.

When k ₃ = k ₄ = 1, the error signal U _e (t) will be equal to the difference between the reference signal E ₀ and the signal E ₂ from the voltage sensor, that is, U _e (t) = E ₀ -A.

As the amplitude A of the quadrature signals N ₁ (t) and N ₂ (t) increases (decreases), the mismatch signal U _e (t) increases (decreases).

The presence of negative feedback will lead to the restoration of the previous value of the amplitude values of the quadrature signals, which will differ from the reference (predetermined) value of E ₀ by the value of the control error. The presence of integrating (astatic) units in a closed ATS reduces the control error (error signal) to almost zero.

Consider the principle of the formation of a quasilinear signal of a triangular shape N ₄ (t).

, который поступает на первый (неинвертирующий) вход первого вычитателя 17, а на выходе второго вычислителя модуля 16 - сигнал $$S_2=\left|N_2\left(t\right)\right|$$

, который поступает на второй (инвертирующий) вход первого вычитателя 17 (фиг.3).At the output of the first computer module 15, a signal is generated $$S_{\mathrm{one}}=\left|N_{\mathrm{one}}\left(t\right)\right|$$

, which is fed to the first (non-inverting) input of the first subtractor 17, and at the output of the second calculator of module 16, a signal $$S_2=\left|N_2\left(t\right)\right|$$

, which goes to the second (inverting) input of the first subtractor 17 (Fig.3).

As a result of the summation of the signals S ₁ and S ₂ at the output of the first subtractor 17, a quasilinear signal is generated

$$M_{\mathrm{one}}\left(t\right)=k_5\left|N_{\mathrm{one}}\left(t\right)\right|-k_6\left|N_2\left(t\right)\right|=\left[k_5\left|A\sin \left({\omega }_{0}t\right)\right|-k_6\left|A\cos \left({\omega }_{0}t\right)\right|\right],\text{(5)}$$

where k ₅ and k ₆ are the transmission coefficients of the first subtractor 17 at the first and second inputs, respectively.

When k ₅ = k ₆ = 1, the amplitude of the signal M ₁ (t) will be equal to the amplitude value A of the signals N ₁ (t) and N ₂ (t).

In Fig. 3, graphs are constructed illustrating the principle of the formation of the synthesized signal M ₁ (t) for the normalized amplitude value A ^* = 1. The value of the current angle x = ω ₀ t is expressed in radians.

The period T _{0 of the} fundamental signal harmonic M ₁ (t) is determined by the frequency ω ₀

T ₀ = 1 / f ₀ = 2π / ω ₀ ,

therefore, the fundamental frequency ω _{1 of the} synthesized triangular waveform M ₁ (t) is equal to twice the frequency ω _{0 of the} quadrature signals N ₁ (t) and N ₂ (t)

ω ₁ = 2ω ₀ (or f ₁ = 2f ₀ ).

In the areas of “forward travel” (from zero to π / 2) and “reverse travel” (from π / 2 to π), the signal M ₁ (t) has S-shaped characteristics, that is, it is “quasilinear”.

The linearization of the signal M ₁ (t) is as follows.

At the output of the second subtractor 18, a correction signal is generated

$$M_2\left(t\right)=k_7{m}_2{A}^2{\cos }^2\left({\omega }_{0}t\right)-k_8{m}_{\mathrm{one}}{A}^2{\sin }^2\left({\omega }_{0}t\right).\text{(6)}$$

where k ₇ and k ₈ are the transmission coefficients of the second subtractor 18, respectively, at the first and second input.

When k ₇ m ₂ = k ₈ m ₁ = 1, expression (6) is simplified

$$M_2\left(t\right)=A^2\left[{\cos }^2\left({\omega }_{0}t\right)-{\sin }^2\left({\omega }_{0}t\right)\right]=A^2\cos \left(2{\omega }_{0}t\right)=A^2\cos \left({\omega }_{\mathrm{one}}t\right),\text{(7)}$$

where ω ₁ = 2ω ₀ is the frequency of the harmonic signal M ₂ (t), equal to twice the value of the frequency ω _{0 of the} quadrature signals N ₁ (t) and N ₂ (t).

From (7) it follows that between the signal amplitude M ₂ (t) and the amplitude A of quadrature signals N ₁ (t) and N ₂ (t) there is a non-linear (quadratic) dependence. In this case, the synthesized signal M ₁ (t), whose amplitude is exactly equal to the amplitude value A of the quadrature signals N ₁ (t) and N ₂ (t), is supplied to the first input of the third adder 19.

When a cosine-shaped signal M ₂ (t) is applied directly to the second input of the third adder 19, a “virtual” signal “V (t)” will be generated at its output, that is, a signal obtained in the absence of a divider 20

$$"V\left(t\right)"=k_9{M}_{\mathrm{one}}\left(t\right)+k_{10}{M}_2\left(t\right).\text{(8)}$$

Moreover, for the normalized amplitude value A ^* = 1 of the quadrature signals N ₁ (t) and N ₂ (t), the optimal value of the transfer coefficient of the adder 19 at the first input is taken to be 1.25. The transfer coefficient of the adder 19 at the second input in this case is selected from the condition

$$K_{9}A*-k_{10}A{*}^2=\mathrm{one.}\text{(9)}$$

For a normalized (stable) value of the amplitude A * = 1 of the quadrature signals N ₁ (t) and N ₂ (t), the relation

$$k_{\mathrm{eleven}}-k_{12}=\mathrm{one.}\text{(10)}$$

If the amplitude A of the quadrature signals N ₁ (t) and N ₂ (t) changes (increases or decreases), then expression (10) will not be correct and the coefficients k ₉ and k ₁₀ should be calculated using the formula (9 )

In this case, for a given optimal value of the transmission coefficient k _{9 of the} adder 19, the optimal value of the transmission coefficient

$$k_{10}=\left(k_{9}A-\mathrm{one}\right)/A^2.\text{(eleven)}$$

From (11), the need arises for nonlinear correction of the coefficient k ₁₀ when the amplitude A of the quadrature signals N ₁ (t) and N ₂ (t) changes, which will significantly complicate the practical implementation of such a correction device.

The divider 20 can significantly simplify the implementation of the corrective device.

At the second input of the divider 20 from the output of the square root calculator 11, a constant voltage E _{2 is} supplied, the amplitude of which is exactly equal to the amplitude A of the quadrature signals N ₁ (t) and N ₂ (t).

At the output of the divider 20 is formed (figure 2) a cosine signal

$$S_k\left(t\right)=M_2\left(t\right)/E_m=A^2\cos \left({\omega }_{\mathrm{one}}t\right)/A=A\cos \left({\omega }_{\mathrm{one}}t\right),\text{(12)}$$

which goes to the fifth output of the functional generator and to the second input of the third adder 19, with N ₅ (t) = S _k (t).

As a result of the summation of the signals M ₁ (t) and S _k (t) at the output of the adder 19, a signal is generated (Fig. 4)

$$N_{\mathrm{four}}\left(t\right)=k_9{M}_{\mathrm{one}}\left(t\right)+k_{10}{S}_k\left(t\right),\text{(13)}$$

which goes to the fourth output of the functional generator (figure 1).

Since the amplitude of the correction signal S _k (t) now becomes equal to the value of A, there are no problems with the correction of the synthesized signal M ₁ (t), and for any changes in the amplitude A of the quadrature signals N ₁ (t) and N ₂ (t), then when adjusting them, the high linearity of the triangular waveform N ₄ (t) will be maintained.

The introduction of the correcting signal S _k (t) of a cosine shape to the second input of the adder 19 and the selection of the optimal values of the coefficients k ₉ and k _{10 of the} adder 19 significantly increased (more than 20 times) the linearity of the signal at the fourth output of the functional generator (Fig. 4).

Using the proposed invention will expand the functionality of the device and ensure its operability when changing the amplitude of the quadrature signals over a wide range.

Information sources

1. RF patent 101291, IPC ⁷ H03B 27/00. Function Generator / Dubrovin BC, Zyuzin AM; applicant and patent holder Non-governmental scientific and educational institution “Saransk House of Science and Technology of the Russian Union of Scientific and Engineering Public Organizations” (NNOU “Saransk House of Science and Technology RSNIIOO”). No. 2010137125/09; declared 09/06/2010; publ. 01/10/11, Bull. No. 1. - 8 p.: 5 ill.

2. Dubrovin V.S. Multi-circuit stabilization system of a controlled generator / V.S.Dubrovin, V.V. Nikulin // Bulletin of the Astrakhan State Technical University. Series: Management, Computing and Informatics. - 2013. - No. 1. - S.74-82.

Claims (2)

1. A functional generator containing a comparison circuit, a multiplier, a first adder, first and second controlled integrators, an inverter, a relay element, a first and second quadrator, a second adder and a square root calculator, connected between the output of the second adder and the second input of the comparison circuit, to the output which is connected to the first input of the multiplier, the output of which is connected to the first input of the first adder, the output of which is connected to the first input of the first controlled integrator, the output of which is connected to the first input of the WTO horn controlled integrator, the inverter input, the first quadrator input and the first output of the functional generator, the second output of which is connected to the second input of the first adder, the output of the second controlled integrator and the second quadrator input, the output of which is connected to the second input of the second adder, the first input of which is connected to the output the first quadrator, while the input of the relay element is connected to the inverter output, the output of which is connected to the second input of the multiplier and the third output of the functional generator, the first control bus of which is connected to the second inputs of the first and second controlled integrators, and the second control bus of the functional generator is connected to the first input of the comparison circuit, characterized in that a triangular signal shaper is introduced into it, the first and second inputs of which are connected to the outputs, respectively, the first and second controlled integrators, the third, fourth outputs of the triangular signal conditioner are connected to the outputs of the second and first quadrants, respectively, and to the output of the square root translator is connected to the fifth input of a triangular signal shaper, the first and second outputs of which are connected, respectively, with the fourth and fifth outputs of the functional generator. 2. The functional generator according to claim 1, characterized in that the triangular signal conditioner is made of the first and second module calculators, the first and second subtracters, the third adder and divider, the output of which is connected to the second input of the third adder and the second output of the triangular signal conditioner the first output of which is connected to the output of the third adder, the first input of which is connected to the output of the first subtractor, the output of the second subtractor is connected to the first input of the divider, the first calculator of the module n between the first input of the triangular waveform driver and the first input of the first subtracter, while the third and fourth inputs of the triangular waveform driver are connected, respectively, to the first and second inputs of the second subtractor, and between the second input of the triangular waveform driver and the second input of the first subtracter second module calculator.

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