RU170962U1 - RC-AUTO GENERATOR OPERATED AMPLIFIER MANIPULATED BY FREQUENCY OF HARMONIOUS OSCILLATIONS - Google Patents

Abstract

A useful model of an RC oscillator based on an operational amplifier of frequency-manipulated harmonic oscillations belongs to the field of electronics and can be used in radio transmitting devices, as well as in measuring equipment, as a source of harmonic frequency-manipulated oscillations. The RC-oscillator contains an operational amplifier (OA), two power supplies, three MOS transistors with induced n-type channels, a rectangular pulse generator, eleven constant resistance resistors, three constant capacitors. With sudden changes, drops 01 and 10 of the control voltage of the rectangular pulse generator, the frequency-manipulated low-frequency harmonic oscillations with frequencies f and f, respectively, are generated without phase disruption, while f> f The declared generator is implemented in the integral version.

Description

The utility model “RC-oscillator on an operational amplifier (OA) manipulated by the frequency of harmonic oscillations” (hereinafter for brevity, “The claimed generator”) relates to the field of radio engineering and can be used in radio transmitting devices, in measuring equipment as a source of low-frequency harmonic frequency manipulated vibrations.

The known structure of a common interpolation (heterodyne) device for implementing frequency manipulation. The structure of a known interpolation (heterodyne) device for implementing frequency manipulation is shown in FIG. 1 [1, p. 438]. The device contains a quartz master oscillator (21) with a frequency of f _square , a so-called interpolation oscillator, a generator (22) with a frequency of generation f _d , a mixer (23) (frequency converter), a high-pass selective filter (24), a frequency manipulator (25) telegraph signal source (26). Oscillations with frequencies f _q and f _d are fed to a mixer (23) operating in a nonlinear mode. As a result, in the current spectrum of the mixer, in particular, combinational components of the form f _pr1 = f _sq -f _d and f _pr2 = f _sq + f _{d are formed} . One of the conversion frequencies is allocated by the filter (24) and is output to the device. Frequency manipulation is carried out using a reactive lamp (or reactive transistor, or diode), which (which) is switched on in parallel with the contour of the range master oscillator [1, p. 439]. It should be noted that the generators (21) and (22), the selective filter (24) contain inductances, so the device (Fig. 1) is completely unattractive for integral implementation. In addition, "a reaction lamp is controlled by a special electronic manipulator." The structure of a special electronic manipulator is shown in FIG. 2 [1, p. 439]. It is energy-intensive, it cannot be implemented in an integrated version.

Closest to the claimed generator is the well-known "RC generator of low-frequency harmonic oscillations on an operational amplifier with phase-shifting RC circuit" (Fig. 3) [2, p. 123]. A three-link RC filter is used here as a phase-shifting chain of positive feedback.

The disadvantage of this known RC-oscillator of low-frequency harmonic oscillations on an operational amplifier with a three-link RC filter is that it cannot generate frequency-manipulated electrical oscillations.

The purpose of the claimed technical solution is to expand the functionality of an RC-oscillator of low-frequency harmonic oscillations on an operational amplifier with a three-link RC filter by improving its design.

The technical result achieved by the claimed generator is to expand the functionality of the RC-oscillator of low-frequency harmonic oscillations on an operational amplifier with a three-link RC filter, which consists in the generation of low-frequency harmonic oscillations, frequency-manipulated.

The block diagram of the claimed generator shown in FIG. 4, comprises: an operational amplifier (OA) (19), a first power source (18), a second power source (20), equal in value of constant capacitance to the first capacitor (1), the second capacitor (2), the third capacitor (3), equal in value of constant resistances to the first resistor (15), the second resistor (16), the third resistor (17), the constant resistance resistors: the fourth resistor (4) and the fifth resistor (5), while the first output of the fifth resistor (5) is connected to the output of the op-amp (19), the second output of the fifth resistor (5) is connected to the first output of the fourth resistor (4) and invert the op amp input, the first output of the first capacitor (1) is connected to the op amp output (19), the second output of the fifth resistor (5) is connected to the first output of the fourth resistor (4) and the inverting input of the op amp (19), the first output of the first capacitor (1) connected to the output of the op-amp (19), the second terminal of the first capacitor (1) is connected to the first terminal of the second capacitor (2) and the first terminal of the first resistor (15), the second terminal of the second capacitor (2) is connected to the first terminal of the third capacitor (3) and the first output of the second resistor (3), the second output of the fourth resistor soy Inonii to a first terminal of the third resistor (17) and the second terminal of the third capacitor (3). The claimed generator is characterized in that the second terminals of the first (15), second (16) and third resistors (17) are disconnected from the common bus of the device power supply, the first MOS transistor (12) with an n-type channel Q1 is induced, the second MOS transistor ( 13) with an induced channel of the n-type Q2, a third MOS transistor (13) with an induced channel of the n-type Q3, a rectangular pulse generator VI (21), equal in value of the constant resistance resistors: the sixth resistor (6), the seventh resistor (7) and the eighth resistor (8), which eliminate the short circuit of the source VCC power supply (18) when the first, second, and third nMOS transistors Q1, Q2, and Q3 are open, the resistors are equal in value of the constant resistances: the ninth resistor (9), the tenth resistor (10), the eleventh resistor (11), while the first the conclusions of the ninth, tenth, eleventh resistors (9), (10), (11) are connected to the second conclusions of the first, second, third resistors (1), (2), (3), respectively, the first conclusions of the sixth, seventh and eighth resistors ( 6), (7), (8) are connected to the potential output of the power source (18), the second conclusions of the sixth, seventh and eighth of resistors (6), (7), (8) are connected to the drains of the first, second, and third nMOS transistors (12), (13), (14), respectively, as well as with the first terminals of the eleventh, tenth, and ninth resistors (11) , (10), (9), respectively, the second terminals of the eleventh, tenth and ninth resistors (11), (10), (9), the sources and substrates of the first, second, third nMOS transistors are connected to a common bus of the power supply, the gates of the first , the second, third nMOS transistors (12), (13), (14) are connected to the potential output of the rectangular pulse generator VI.

To simplify the presentation, the connection nodes of the resistors R1 (15) and R9 (9), R2 (16) and R10 (10), R3 (17) and R11 (11) are indicated by the letters “a”, “b” and “c”, respectively, and without quotes.

The claimed generator operates as follows.

We introduce the notation: R ₁ = R1 (15) + R9 (9), R ₂ = R2 (16) + R10 (10), R ₃ = R3 (17) + R11 (11), C ₁ = C1 (1), C ₂ = C2 (2), C ₃ = C3 (3). “A three-link RC filter, consisting of R ₁ C ₁ , R ₂ C ₂ , R ₃ C ₃ links, is a positive feedback circuit. It rotates the phase of the output wave 180 °. The number of links is chosen equal to three, since each link simply provides a phase shift of 60 °. To improve the shape of the generated oscillations, which is achieved by reducing non-linear distortions, a negative feedback is introduced, formed by resistors R ₃ , R ₄ , R ₅ "(in our case, resistors R ₃ (17) + R11 (11), R4 (4), R5 (5), respectively). “The output of the positive feedback circuit is connected to the inverting input of the operational amplifier. Therefore, in a closed system consisting of an operational amplifier and a positive feedback circuit, the phase shift will be equal to 2π, i.e. phase balance ... it runs. To ensure the generation mode, it is also necessary to balance the amplitudes ”[2, p. 124]. In FIG. 5. (in the literature [2, p. 125, Fig. 4.6]) are given "the dependence of the module and the transmission coefficient of the three-link chain of the positive OS on the frequency." From FIG. 5 it follows, “that oscillation generation in the analyzed RC generator will occur at an op-amp gain of 29” [2, p. 124]. “Operational amplifiers have a very large gain (of the order of 10 ⁵ ... 10 ⁶ )” [4, p. 352]. Therefore, the balance of the amplitudes in the analyzed generator is performed.

“The generation frequency for a circuit with an ideal opamp is determined by the dependence

where C is the capacitance of the filter condensates; R is the resistance of the filter resistors.

As follows from this formula, the generation frequency depends only on the parameters of the positive feedback circuit R and C (ie, external elements) ”[2. p. 125].

∞)» [3, стр. 410]. Поэтому эквивалентное сопротивление участка цепи между узлами «а», «общая шина устройства питания» практически определяется величиной сопротивления девятого резистора (9). Аналогично эквивалентные сопротивления участков цепи между узлами «b», «общая шина устройства питания» и между узлами «с», «общая шина устройства питания» практически определяются величинами сопротивлений десятого и одиннадцатого резисторов (10), (11) соответственно. В этом случае структурная схема Заявленного генератора (фиг. 4) вырождается в структурную схему (фиг. 3) классического RC-автогенератора с трехзвенной RC-цепью. Обозначим частоту генерации гармонических низкочастотных колебаний при напряжении на выходе генератора прямоугольных импульсов (21), равном уровню логического нуля, через f₀,When the voltage at the output of the rectangular pulse generator (21) is equal to a logic-zero level, nMOS transistor Q1 (14) with an induced n-type channel is locked, so the channel resistance induced nMOS transistor channel tends to infinity «(R _vT = R _app

∞) ”[3, p. 410]. Therefore, the equivalent resistance of the circuit section between nodes “a”, “common bus of the power supply device” is practically determined by the resistance value of the ninth resistor (9). Similarly, the equivalent resistances of the circuit sections between nodes “b”, “common bus of the power supply device” and between nodes “c”, “common bus of the power supply device” are practically determined by the resistance values of the tenth and eleventh resistors (10), (11), respectively. In this case, the structural diagram of the claimed generator (Fig. 4) degenerates into a structural diagram (Fig. 3) of a classic RC autogenerator with a three-link RC circuit. Denote the frequency of generation of harmonic low-frequency oscillations at a voltage at the output of the rectangular pulse generator (21), equal to the level of logical zero, through f ₀ ,

In this case, the first link of the RC filter rotates the phase of the signal from the output of the control generator (21) to the input of the first link of the RC filter (Fig. 6, a) by the angle BCA = J0 (Fig. 6, b). Similarly, the second and third links of the RC filter also rotate the phase of the oscillation arriving at their inputs by an angle J0. As a result, the resulting phase shift of the signal when passing through a three-link RC filter at the generation frequency (1) is 180 ° (Fig. 5).

1 управляющего напряжения генератора прямоугольных импульсов (21) сопротивление канала МОП транзистора скачком уменьшается, стремится к нулю «(R_vT=R_нас

0)» [3, стр. 410].With abrupt change, differential 0

1 of the control voltage of the square-wave pulse generator (21), the resistance of the MOSFET channel abruptly decreases, tends to zero "(R _vT = R _us

0) ”[3, p. 410].

1 управляющего напряжения генератора (21) сопротивления резисторов звеньев RC-цепи скачком уменьшаются и практически определяются величинами сопротивлений первого, второго и третьего резисторов (15), (16) и (17) соответственно. В итоге, трехзвенный фильтр сдвигает фазу на угол ψ, превышающий π. Поэтому колебания с частотой f_ген=f₀ прекращаются. Из фиг. 5 следует, что уменьшение фазового сдвига имеет место только при увеличении частоты. Фазовый сдвиг, равный 180°, наступает на частоте f₁, которая превышает значение частоты f₀, баланс фаз выполняется на более высокой частоте f₁, поэтомуThe resistance of the nMOS transistor Q1 in saturation mode (14) shunts the resistance of the ninth resistor (9). Therefore, the equivalent resistance of the circuit section between nodes “a”, “the common bus of the power supply device”, drops abruptly, tends to zero. The equivalent circuit of the first (in the general case of the ith filter link) takes the form of FIG. 6, c. A sharp decrease in the active component of the filter link leads to a sharp decrease in the voltage at the active resistance of the filter link, vector A1B1 <vector AB, therefore, the phase shift angle of one link increases, the angle C1A1B1 jumps larger than the angle CAB (Fig. 6, b and Fig. 6, d ) Similarly, the equivalent resistances of the circuit sections between nodes “b”, “common bus of the power supply device” and between nodes “c”, “common bus of the power supply device” also tend to zero. So, with an abrupt change, a difference of 0

1 of the control voltage of the generator (21) of the resistance of the resistors of the links of the RC circuit jumpwise decrease and are practically determined by the resistance values of the first, second and third resistors (15), (16) and (17), respectively. As a result, the three-link filter shifts the phase by an angle ψ exceeding π. Therefore, oscillations with a frequency f _gene = f ₀ cease. From FIG. 5 it follows that a decrease in the phase shift takes place only with increasing frequency. A phase shift of 180 ° occurs at a frequency f ₁ that exceeds the value of the frequency f ₀ , the phase balance is performed at a higher frequency f ₁ , therefore

moreover, f ₁ > f ₀ . The change in the frequency f ₀ to the frequency f ₁ occurs without breaking the oscillation phase.

1 и 1

0 управляющего напряжения генерируется без разрыва фазы сигнала последовательность манипулированных по частоте низкочастотных гармонических колебаний с частотами f₁ и f₀ соответственно, при это f₁>f₀, генерация гармонических сигналов с частотами f₁ и f₀ обусловлена резкими изменениями сопротивлений каналов nМОП транзисторов, приводящими к значительному изменению сопротивлений звеньев трехзвенного RC-фильтра (цепи положительной обратной связи автогенератора), а значит, и величины фазового сдвига сигнала с выхода операционного усилителя на его инвертирующий вход при поступлении каждого из перепадов 0

1 и 1

0 соответственно напряжения управляющего генератора на затворы nМОП транзисторов с индуцированными каналами.Thus, with spasmodic changes, differences 0

1 and 1

0 control voltage is generated without breaking the phase of the signal, a sequence of low-frequency harmonic oscillations manipulated in frequency with frequencies f ₁ and f _0, respectively, while f ₁ > f ₀ , the generation of harmonic signals with frequencies f ₁ and f ₀ is due to sharp changes in the channel resistances of nMOS transistors, leading to a significant change in the resistances of the links of a three-link RC filter (positive feedback circuit of the oscillator), and hence the magnitude of the phase shift of the signal from the output of the operational amplifier at its inverting input at receipt of each of the differences 0

1 and 1

0, respectively, the voltage of the control generator to the gates of nMOS transistors with induced channels.

The simulation of the claimed generator. Used: nMOS transistors Q1 (14), Q2 (13), Q3 (12) with induced channels with channel parameters: 1 (channel length) 0.18u, w (channel width) 3.0u; a rectangular control pulse generator V1 (21) with parameters: pulse amplitude 3V, pulse repetition rate 25 Hz; operational amplifier OPAMP_5T_VIRTUAL, operational amplifier power supplies: U1 VCC 5V, VSS-5V; resistors and capacitors in terms of number and ratings according to FIG. 4. In FIG. Figure 7 shows the rectangular control signal of generator VI (21) and the output signal of an RC oscillator on an operational amplifier of frequency-manipulated harmonic oscillations. The output of the RC oscillator is frequency-manipulated. When the voltage at the output of the control generator is equal to the voltage of logical zero, the generation frequency f _gene = 768 Hz. When the voltage at the output of the control generator is equal to the voltage of a logical unit, the generation frequency f _gene = 1872 Hz. Frequency manipulation of the generated low-frequency harmonic components of the output signal is carried out without phase discontinuity.

The claimed RC-oscillator on an operational amplifier of frequency-manipulated harmonic oscillations is implemented in an integrated version, expanding the functionality of an RC-oscillator of low-frequency harmonic oscillations on an operational amplifier with a three-link RC filter. The extension of the functionality of the claimed generator is to generate low-frequency harmonic oscillations, frequency-manipulated.

Literature

1. Pakhlavyan A.N. Radio transmitting devices. - M .: Communication, 1967 .-- 567 p.

2. Mushta A.I. Information technology analysis of analog electronic devices in CAD OrCAD. - Voronezh: GOUVPO "Voronezh State Technical University", 2011. - 215 p.

3. Opadchiy Yu.F. Analog and Digital Electronics / Yu.F. Opadchiy, O.P. Gludkin, A.I. Gurov. Ed. O.P. Gludkina. - M .: Radio and communication. 1996 .-- 768 p.

4. Novozhilov O.P. Electrical and Electronics. Textbook. - M .: Gardariki. 2008 .-- 654 p.

Claims (1)

An RC oscillator based on an operational amplifier manipulated by the frequency of harmonic oscillations contains: an operational amplifier (op amp), a first power source, a second power source, equal in value of constant capacitance to the first capacitor, second capacitor, third capacitor, equal in value of constant resistances to the first resistor, second a resistor, a third resistor, constant resistance resistors: a fourth resistor and a fifth resistor, with the first output of the fifth resistor connected to the op-amp output, the second output of the fifth resistor and connected to the first output of the fourth resistor and the inverting input of the op-amp, the first output of the first capacitor is connected to the output of the op-amp, the second output of the first capacitor is connected to the first output of the second capacitor and the first output of the first resistor, the second output of the second capacitor is connected to the first output of the third capacitor and the first output the second resistor, the second terminal of the fourth resistor is connected to the first terminal of the third resistor and the second terminal of the third capacitor, characterized in that the first MOS transistor is introduced with an induced channel n-type Q1, a second MOS transistor with an induced channel n-type Q2, a third MOS transistor with an induced channel n-type Q3, a square-wave generator V1, equal in value of constant resistance resistors: the sixth resistor, the seventh resistor and the eighth resistor that exclude a short circuit of the first power source when the first, second, and third nMOS transistors Q1, Q2, and Q3 are open, resistors of equal constant resistances are introduced: the ninth resistor, the tenth resistor, eleven the first resistor, the presence of which increases the active resistance of the links of the RC filter, while the first terminals of the ninth, tenth, eleventh resistors are connected to the second terminals of the first, second, third resistors, respectively, the first terminals of the sixth, seventh and eighth resistors are connected to the potential output of the first power source , the second conclusions of the eighth, seventh and sixth resistors are connected to the drains of the first, second and third nMOS transistors, respectively, as well as with the first conclusions of the eleventh, ten of the ninth and ninth resistors, respectively, the second terminals of the eleventh, tenth and ninth resistors, the sources and substrates of the first, second, third nMOS transistors are connected to the common bus of the power source, the gates of the first, second, third nMOS transistors are connected to the potential output of the square-wave generator V1, at spasmodic changes, drops 0 → 1 and 1 → 0 of the control voltage of the rectangular pulse generator V1 are generated without phase discontinuity, frequency-manipulated low-frequency harmonic oscillations frequencies f ₁ and f _0, respectively, with f ₁ > f ₀ , the frequency manipulation of the generated low-frequency harmonic signals with frequencies f ₁ and f ₀ is due to sharp changes in the resistances of the channels of nMOS transistors, leading to a significant change in the active resistances of the links of a three-link RC filter and, therefore, the magnitude of the phase shift of the signal from the output of the operational amplifier to its inverting input upon receipt of each of the differences 0 → 1 and 1 → 0, respectively, of the voltage of the control generator to the gates of the first, second of the third and third nMOS transistors to ensure a change in the frequency of the generated oscillations.

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