RU2555241C1 - Function generator - Google Patents

Abstract

FIELD: radio engineering, communication.

SUBSTANCE: function generator includes a bipolar pulse generator, first and second short pulse generators, an inverter, first and second controlled integrators, a comparison circuit, a driver, a harmonic signal source and a comparator.

EFFECT: broader functional capabilities by obtaining at the outputs, along with a harmonic signal, triangular waveforms and bipolar rectangular waveforms, amplitude values of which remain stable when the frequency and amplitude of the original signal change.

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Description

The invention relates to the field of electronics and can be used in measuring equipment and automation.

A device [1] is known that contains a source of quadrature signals, two half-wave rectifiers, an adder and a shaper of bipolar rectangular pulses, the first and second outputs of the source of quadrature signals connected, respectively, to the inputs of the first and second half-wave rectifiers, the outputs of which are connected to the inputs of the adder, to the output of which is connected to the shaper of bipolar rectangular pulses, while the first, second and third outputs of the functional generator are connected, respectively, with the first the output source of the quadrature signals, with the output of the adder and the output of the shaper of bipolar rectangular pulses.

The synthesized signal of a triangular shape has S-shaped characteristics, both in the forward path (linearly increasing voltage) and in the reverse path (linearly decreasing voltage) and has a very low linearity [2], which significantly narrows the field of practical application of the circuit . In addition, the frequency of a triangular waveform and a rectangular bipolar waveform is twice the frequency of the original harmonic signal, which makes it impossible to obtain the same frequency values at all generator outputs with a fixed tuning of the generator. It should also be borne in mind that the formation of a “quasilinear” signal of a triangular shape requires quadrature harmonic signals, which, under conditions of frequency tuning over a wide range, also causes certain difficulties.

A device [3] is known that contains a triangular-shaped signal generator, the first output of which is connected to the output terminal of the relay function, and the second output is connected to the output terminal of the linear function and to the input of the functional converter, the output of which is connected to the output terminal of the sinusoidal function. In modern functional generators for generating a harmonic signal from a triangular waveform, the most widely used are diode functional converters, as well as converters using в field-effect transistors, which are based on the principle of piecewise-linear or piecewise-nonlinear approximation of voltage of a sinusoidal shape. However, the entire spectrum of basic requirements (low harmonic coefficient, the absence of a constant component in the sine waveform, a wide range of operating frequencies, the invariance to changes in the amplitude of the triangular waveform, low accuracy of the reproduction of the sine function with changing temperature and supply voltages, etc.) is enough it is difficult to ensure when using such functional converters [4].

The closest device to the claimed invention in terms of essential features is a signal frequency doubler [5] adopted as a prototype, comprising a bipolar pulse shaper, first and second short pulse shapers, an inverter, first and second controlled integrators, each of which is made of an integrating amplifier and a key , a comparison circuit and an output driver, while the first and second inputs of the comparison circuit are connected to the outputs, respectively, of the first and second controlled integrators, and an inverter is connected between the output of the bipolar signal shaper and the first input of the first controlled pulse integrator, the second input of which is connected to the output of the first short pulse shaper, the input of which is connected to the input of the bipolar pulse shaper and the input of the second short pulse shaper, the second input of the second controlled integrator is connected to its output, the first input of which is connected to the output of the bipolar pulse former, and the first input of the output former is connected to the output of the comparison circuit Vatel, whose output is connected to the output signal frequency doubler having an input connected to the generator of bipolar pulses and a second input of the output driver.

When a rectangular signal with an amplitude value that varies widely is applied to the device input, rectangular signals are generated at the device output, but with a frequency equal to twice the frequency of the input signal.

The problem to which the invention is directed is to expand the functionality of the device by receiving at its outputs, along with a harmonic signal, signals of a triangular shape and bipolar signals of a rectangular shape, the amplitude values of which remain stable when the frequency and amplitude of the input signal varies widely.

The technical result achieved by the implementation of the invention is to expand the functionality by receiving at its outputs, along with a harmonic signal, triangular waveforms and rectangular bipolar waveforms whose amplitude values remain stable when the frequency and amplitude of the input signal varies widely.

The specified technical result in the implementation of the invention is achieved by the fact that in a functional generator containing a bipolar pulse shaper, first and second short pulse shapers, an inverter, first and second controlled integrators, a comparison circuit and an output shaper, while the first and second inputs of the comparison circuit are connected to the outputs of the first and second controlled integrators, respectively, the inverter is connected between the output of the bipolar signal former and the first input of the first controlled integrator a rotor, the second input of which is connected to the output of the first short pulse shaper, the input of which is connected to the input of the bipolar pulse shaper and the input of the second short pulse shaper, to the output of which a second input of the second controlled integrator is connected, the first input of which is connected to the output of the bipolar pulse shaper, and to the output of the comparison circuit is connected to the first input of the output driver, the output of which is connected to the third output of the functional generator, the second output of which is connected is connected to the output of the bipolar pulse generator, an additional harmonic signal source and a comparator are introduced, the output of which is connected to the input of the bipolar pulse generator, one output of the harmonic signal source is connected to the first output of the functional generator and the non-inverting input of the comparator, the inverting input of which is connected to the common bus, the second and the third inputs of the output driver are connected to the outputs of the second and first drivers of short pulses, respectively, and the free output is used the harmonic signal point is connected to a common bus.

The bipolar pulse generator can be made of an adder and a reference voltage source, the positive terminal of which is connected to a common bus, and the negative terminal is connected to the second input of the adder, the first input of which is connected to the input of the bipolar pulse generator and the output of which is connected to the output of the adder.

The output driver can be made of a third controlled integrator, a sampling-storage device, a divider and a constant voltage source, the positive terminal of which is connected to a common bus, and the negative terminal to the first input of the third controlled integrator, the second input of which is connected to the second input of the output driver, the first the input of which is connected to the first input of the divider, the second input of which is connected to the output of the sampling-storage device, the first and second inputs of which are connected respectively to the output of the third managed integrator and the third input of the output driver, the output of which is connected to the divider output.

The first and second shapers of short pulses can be made of single vibrators.

The analysis of the prior art by the applicant, including a search by patent and scientific and technical sources of information, allowed to establish 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."

The introduction of a harmonic signal source and a comparator into the proposed functional generator, as well as the organization of new connections between functional elements, made it possible to expand the device’s functionality and receive, along with a harmonic signal, triangular-shaped signals and rectangular bipolar signals whose amplitude values remain stable when the frequency changes and the amplitude of the input signal over a wide range.

The invention is illustrated in the block diagram of the functional generator shown in FIG. 1, and graphs explaining the principle of operation of the functional generator, - in FIG. 2.

The functional generator contains a bipolar pulse shaper 1, first 2 and second 3 short pulse shapers, an inverter 4, first 5 and second 6 controlled integrators, a comparison circuit 7, an output shaper 8, a harmonic signal source 9 and a comparator 10, the inverting input of which is connected to a common by bus. The harmonic signal source 9 is connected between the common bus and the non-inverting input of the comparator 10, the output of which is connected to the input of the bipolar pulse shaper 1, between the output of which and the first input of the first controlled integrator 5 an inverter 4 is turned on. The first short-pulse shaper 2 is connected between the output of the comparator 10 and the second the input of the first controlled integrator 5, and the second short-pulse shaper 3 is connected between the output of the comparator 10 and the second input of the second controlled integrator 6. The first output fu the national generator is connected to a non-inverting input of the comparator 10, the inverting input of which is connected to a common bus, the second input of the functional generator is connected to the first input of the second controlled integrator 6 and the output of the bipolar pulse shaper 1, the input of which is connected to the output of the comparator 10, and the third output of the functional generator is connected with the output of the output driver 8, the first input of which is connected to the output of the comparison circuit 7, the first and second inputs of which are connected to the outputs, respectively, of the first about 5 and second 6 shapers of short pulses, while the second and third inputs of the output shaper 8 are connected to the outputs of the second 3 and first 2 shapers of short pulses, respectively.

The bipolar pulse generator 1 can be made of an adder 11 and a reference voltage source 12, the positive terminal of which is connected to a common bus, and the negative terminal is connected to the second input of the adder 11, the first input of which is connected to the input of the bipolar pulse generator 1 and the output of which is connected to the output of the adder eleven.

The output driver 8 can be made of a third controlled integrator 13, a sample-storage device 14, a divider 15 and a constant voltage source 16, the positive terminal of which is connected to a common bus, and the negative terminal to the first input of the third controlled integrator 13, the second input of which is connected to the second input of the output driver 8, the first input of which is connected to the first input of the divider 15, the second input of which is connected to the output of the sampling-storage device 14, the first input of which is connected to the output of the third controllable about the integrator 13, the second input of which is connected to the second input of the output driver 8, the third input and output of which are connected respectively to the second input of the sampling-storage device 14 and the output of the divider 15.

The first 2 and second 3 shapers of short pulses can be made of single vibrators.

Functional generator operates as follows.

When a harmonic signal S ₁ (t) = A ₁ sin (ωt) with the amplitude value A ₁ and frequency ω = 2πf is supplied to the non-inverting input of the comparator 10, a sequence of video pulses V (t) with the amplitude value U is generated (Fig. 2) _m1 .

The adder 11 and the constant voltage source 12 form a bipolar pulse shaper 1, at the output of which rectangular bipolar signals S ₂ (t) are generated, which arrive at the second output of the functional generator

where k ₁ and k ₂ are the transfer coefficients of the adder 11 at the corresponding inputs.

If the coefficients are equal, k ₁ = k ₂ = α and when choosing the value of the reference voltage E ₀₁ = U _m1 / 2, symmetric rectangular bipolar signals S ₂ (t) with amplitude values of U _m2 = α · U will be generated at the second output of the functional generator _m1 / 2.

Thus, the maximum values of U _m2 and -U _m2 (Fig. 2) of the signal S ₂ (t) will be determined by the value of the reference voltage U _{01 of the} source 12 and the values of the transfer coefficients of the adder 11.

Single vibrators 2 and 3, respectively, triggered by the trailing and leading edges of the video pulses, V (t) form the corresponding narrow strobe pulses D ₁ and D ₂ .

The signal S ₂ (t) is supplied directly to the first input of the second controlled integrator 6, and through the inverter 4 to the first input of the first controlled integrator 5.

All controlled integrators 5, 6 and 13 are inverting, so their output signals will be shifted by 180 electrical degrees relative to the input.

When bipolar signals arrive at the first inputs of controlled integrators 5 and 6, linearly changing signals L ₁ (t) and L ₂ (t) begin to form at their outputs (Fig. 2), the maximum (amplitude) values of which L _m1 and L _m2 will depend from the amplitude values U _{m2 of the} signal S ₂ (t) and time constants τ ₁ and τ _{2 of the} corresponding controlled integrators 5 and 6.

The strobe pulses D ₁ and D ₂ supplied to the second inputs of the controlled integrators 5 and 6 reset them, that is, they “bind” the corresponding signals L ₁ (t) and L ₂ (t) to the zero level, which eliminates bias (“creep” ») Of these signals due to the presence of various destabilizing factors and, above all, due to the zero-level drift of the integrators themselves.

Upon reaching the maximum values of L _m1 and L _m2 (Fig. 2), the polarity of the input signals arriving at the first inputs of the first 5 and second 6 controlled integrators, respectively, changes to the opposite, therefore, the formation of the falling sections of the signals L ₁ (t) and L ₂ ( t). Then, using the gate pulses D ₁ and D ₂ , the signals L ₁ (t) and L ₂ (t) are “tied” to the zero level, and the process of their formation is repeated.

Find the maximum value of L _ml (Fig. 2) of the signal L ₁ (t) using the expression

where U _m2 is the amplitude value of the signal S ₂ (t); τ ₁ is the time constant of the first controlled integrator 5; T ₀ = 1 / f is the period of the input signal S ₁ (t); x = ωt is the current value of the angle in radians.

By analogy, we calculate the maximum value L _{m2 of the} signal L ₂ (t)

where τ ₂ is the time constant of the second controlled integrator 6.

If the time constants are equal, τ ₁ = τ ₂ = τ, the maximum values of the signals L ₁ (t) and L ₂ {t) will be equal to

As a result of summing the signals L ₁ (t) and L ₂ (t) at the output of the comparison circuit 7, a signal is generated (Fig. 2)

where k ₃ and k ₄ are the transmission coefficients of the comparison circuit 7, respectively, at the first and second inputs.

Provided that the coefficients k ₃ = k ₄ = β are equal, at the output of the comparison circuit 7, symmetrical oscillations of the triangular shape N ₁ (t) are formed, the amplitude values of which N _1m will depend on the coefficient β, i.e.

The symmetric signal of a triangular shape N ₁ (t) is supplied to the first input of the output driver 8, which operates as follows.

When a constant voltage E _{02 of} negative polarity is applied to the first input of the third inverting controlled integrator 13, a linearly increasing voltage L ₃ (t) of positive polarity begins to form at its output (Fig. 2), which is supplied to the first input of the sample-storage device 14.

The signal L ₃ (t) is reset to zero at the moment of applying a pulse D ₂ to the second input of the controlled integrator 13, then the process of generating the signal L ₃ (t) is repeated.

The memory voltage, that is, the formation of the signal Ν ₂ , occurs at the moment of supply of the gate pulse D ₁ to the second input of the sample-storage device 14. The value of the constant voltage N ₂ generated at the output of the sample-storage device 14 will be half (Fig. 2) the maximum voltage L _{3max of the} signal L ₃ (t).

Find the maximum value of L _3max signal L ₃ (t)

where τ ₃ is the time constant of the third controlled integrator 13.

Therefore, the constant voltage Ν ₂ at the output of the sample-storage device 14 will be

From the analysis of formulas (2), (3) and (7) it follows that when the frequency f of the input signal S ₁ (t) changes, the maximum values L _m1 , L _m2 and L _{3max of the} corresponding signals L ₁ (t), L ₂ will change (t) and L ₃ (t).

The divider 15 performs amplitude stabilization of the signal S ₃ (t), which is formed at the output of the output driver 8

where m is the scale factor of the divider 15.

The amplitude values of S _3m signal S ₃ (t)

Substituting in (10) the value of N _1m from (6) and the value of N ₂ from (8), we obtain

, то есть не будет зависеть от частоты f входного сигнала S₁(t).For m = 1, β = 1, τ ₃ = τ and E ₀₂ = U _{m2, the} amplitude S _{3m of the} signal S ₃ (t) will be equal to the normalized value $$S_{3m}^{*}=\mathrm{one}$$

that is, it will not depend on the frequency f of the input signal S ₁ (t).

The present invention can be used in measurement technology and automation as a functional generator that generates stable sine, triangular waveforms as well as rectangular bipolar waveforms at its outputs.

Information sources

1. Shustov M. Functional generator. - Radiomir, 2010, No. 7, p. 26-27.

2. Lozitsky S. Circuit engineering CAD: opportunities and problems of effective use. - Circuitry, 2007, No. 3, p. 38-40.

3. Titze U., Schenk K. Semiconductor circuitry: a reference guide. - M .: Mir, 1982, p. 307, fig. 18.25.

4. Dubrovin V.S., Nikulin V.V. A method of constructing controlled functional generators. T-comm, 2013, p. 22.

5. A.S. USSR No. 828366, Η03В 19/06. Zakletskaya J.Ya. Signal frequency doubler. - Declared. 07/18/1979, publ. 05/07/1981. Bull. No. 17 (prototype).

Claims (4)

1. A functional generator containing a bipolar pulse shaper, first and second short pulse shapers, an inverter, first and second controlled integrators, a comparison circuit and an output driver, while the first and second inputs of the comparison circuit are connected to the outputs of the first and second controlled integrators, inverter is connected between the output of the bipolar signal shaper and the first input of the first controlled integrator, the second input of which is connected to the output of the first short importer xs, the input of which is connected to the input of the bipolar pulse generator and the input of the second short pulse generator, to the output of which the second input of the second controlled integrator is connected, the first input of which is connected to the output of the bipolar pulse generator, and the first input of the output driver is connected to the output of the comparison circuit connected to the third output of the functional generator, the second output of which is connected to the output of the bipolar pulse shaper, characterized in that in it A harmonic signal source and a comparator whose output is connected to the input of the bipolar pulse generator are introduced, one output of the harmonic signal source is connected to the first output of the functional generator and the non-inverting input of the comparator, the inverting input of which is connected to the common bus, the second and third inputs of the output former are connected to the outputs of the second and first shapers of short pulses, respectively, and the free output of the harmonic signal source is connected to a common bus. 2. The functional generator according to claim 1, characterized in that the bipolar pulse generator is made of an adder and a reference voltage source, the positive terminal of which is connected to a common bus, and the negative terminal is connected to the second input of the adder, the first input of which is connected to the input of the bipolar pulse generator and the output of which is connected to the output of the adder. 3. The functional generator according to claim 1, characterized in that the output driver is made of a third controlled integrator, a sampling-storage device, a divider and a constant voltage source, the positive terminal of which is connected to a common bus, and the negative terminal is connected to the first input of the third controlled integrator, the second input of which is connected to the second input of the output driver, the first input of which is connected to the first input of the divider, the second input of which is connected to the output of the sampling-storage device, the first and second inputs of which connected respectively to the output of the third integrator and managed third input of the output driver, the output of which is connected to the divider output. 4. The functional generator according to claim 1, characterized in that the first and second short-pulse shapers are made of single vibrators.

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