CN105827206A - Phase shift complementation-type oscillator - Google Patents

Abstract

The invention relates to the field of oscillators and discloses a phase shift complementation-type oscillator, which is composed of an amplifier and a phase shift complementation unit, wherein the phase shift complementation unit is a two-stage phase shift network. The phase shift complementation-type oscillator has the beneficial effects that as a typical RC phase shift oscillator replacement circuit, phase shift of the amplifier and the phase shift complementation unit in the entire circuit is zero, the entire circuit is thus ensured to become a positive feedback amplifier, the circuit combination mode meets general requirements of an oscillator structure, and thus, the phase shift complementation-type oscillator of the invention is a brand new formation mode for the phase shift oscillator. As the phase shift network structure is changed into a two-stage structure from a three-stage structure, the numbers of resistors and reactance elements participating in voltage dividing and current dividing are reduced, the sizes of signals in each step inside are good in consistency. Two similar circuit structures are involved, and the number of derivative specific circuits (AC channels) is thus four.

Description

The complementary agitator of phase shift

[technical field]

The present invention relates to field of oscillators, particularly relate to a kind of complementary agitator of phase shift.

[background technology]

Sine-wave oscillator, as the basic element circuit of electronic circuit, realizes having basic status and effect to the allomeric function of circuit.Classical RC phaseshift oscillator is made up of with anti-phase RC phase-shift network antiphase voltage amplifier, and these two parts produce the phase shift of 180 ° respectively, finally make whole circuit become positive feedback amplifier, obtain sine-wave oscillation.The phase shift object of classical RC phaseshift oscillator can only be voltage, and meanwhile, the structure of classical RC phaseshift oscillator phase-shift network has three grades.

Owing to the structure of this phase-shift network has three grades, the resistance capacitor device wherein participating in dividing potential drop and shunting is too much, and signal after phase-shift network can be caused to have bigger decay.Therefore, the signal magnitude of the internal each link of classical RC phaseshift oscillator is lack of consistency.But, in addition to the RC phaseshift oscillator of this classics, about phaseshift oscillator, there is no the proposition of other implementation so far.

[summary of the invention]

In order to solve the problems of the prior art, the present invention constructs a kind of complementary agitator of brand-new phase shift.

The present invention is a kind of new implementation of phaseshift oscillator, and compared with classical RC agitator implementation, amplifier therein both can be voltage amplifier, it is also possible to be current amplifier；Wherein the structure of phase-shift network only has two-stage, and the reactance component in phase-shift network both can be electric capacity, it is also possible to be inductance.

The invention provides a kind of complementary agitator of phase shift, be made up of an amplifier and a phase shift complementation unit；Described phase shift complementation unit is two-stage phase-shift network.

As a further improvement on the present invention: described two-stage phase-shift network is made up of the reactance component that a resistance and two impedance properties are identical；The reactance component that said two impedance property is identical is all electric capacity or is all inductance.

As a further improvement on the present invention: in the embodiment of Fig. 1 and Fig. 2, described amplifier is current amplifier, and when the alternating current direction of input is to flow into amplifier, this current amplifier alternating current direction obtained by outfan is to flow out amplifier.

As a further improvement on the present invention: in the embodiment of Fig. 3 and Fig. 4, described amplifier is voltage amplifier, and this voltage amplifier is in-phase amplifier.

As a further improvement on the present invention: described two-stage phase-shift network has complementarity to the impact of curtage phase place.

As a further improvement on the present invention: before and after in described two-stage phase-shift network, phase shift produced by two-layer configuration is contrary, one-level is advanced, and additionally one-level is delayed, the purpose complementary to reach phase shift.

As a further improvement on the present invention: in the embodiment of Fig. 1 and Fig. 2, the reactance component that said two impedance property is identical is the first reactance component and the second reactance component；The outfan of described amplifier is simultaneously connected with the first end and first end of described first reactance component of described resistance；The input of described amplifier is simultaneously connected with the second end and first end of described second reactance component of described first reactance component；Second end of described resistance and the second equal ground connection of end of described second reactance component.

As a further improvement on the present invention: in the embodiment of Fig. 3 and Fig. 4, the reactance component that said two impedance property is identical is the first reactance component and the second reactance component；The outfan of described amplifier is connected with described first reactance component with after described resistant series again；Second end of described first reactance component is simultaneously connected with the first end and the input of described amplifier of described second reactance component；Second end ground connection of described second reactance component.

The invention has the beneficial effects as follows: as the replacement circuit of classical RC phaseshift oscillator, in the whole circuit of the present invention, the phase shift of amplifier and phase shift complementation unit is zero, ensure that whole circuit becomes positive feedback amplifier with this, the building form of this circuit meets the general requirement of oscillator structure, thus the present invention is the brand-new constituted mode of phaseshift oscillator.Owing to the structure of phase-shift network becomes two-stage from three grades, wherein participating in dividing potential drop and the resistance of shunting and reactance component number reduces, therefore the signal magnitude of internal each link has preferable concordance.It relates to two kinds of similar circuit structures, and thus derivative physical circuit (referring to alternating current path) has four.

[accompanying drawing explanation]

Fig. 1 is one embodiment of the invention schematic diagram, for the complementary agitator of current mode RC phase shift；

Fig. 2 is further embodiment of this invention schematic diagram, for the complementary agitator of current mode RL phase shift；

Fig. 3 is another embodiment of the present invention schematic diagram, for the voltage-type complementary agitator of RC phase shift；

Fig. 4 is yet another embodiment of the invention schematic diagram, for the voltage-type complementary agitator of RL phase shift.

[detailed description of the invention]

Below in conjunction with the accompanying drawings and detailed description of the invention the invention will be further described.

The invention provides a kind of complementary agitator of phase shift, be made up of an amplifier and a phase shift complementation unit；Described phase shift complementation unit is two-stage phase-shift network.

Described two-stage phase-shift network is made up of the reactance component that a resistance and two impedance properties are identical；The reactance component that said two impedance property is identical is all electric capacity or is all inductance.

In the embodiment of Fig. 1 and Fig. 2, described amplifier is current amplifier, and when the alternating current direction of input is to flow into amplifier, this current amplifier alternating current direction obtained by outfan is to flow out amplifier.

In the embodiment of Fig. 3 and Fig. 4, described amplifier is voltage amplifier, and this voltage amplifier is in-phase amplifier.

Described two-stage phase-shift network has complementarity to the impact of curtage phase place.

Before and after in described two-stage phase-shift network, phase shift produced by two-layer configuration is contrary, and one-level is advanced, and additionally one-level is delayed, the purpose complementary to reach phase shift.

In the embodiment of Fig. 1 and Fig. 2, the reactance component that said two impedance property is identical is the first reactance component and the second reactance component；The outfan of described amplifier is simultaneously connected with the first end and first end of described first reactance component of described resistance；The input of described amplifier is simultaneously connected with the second end and first end of described second reactance component of described first reactance component；Second end of described resistance and the second equal ground connection of end of described second reactance component.

In the embodiment of Fig. 3 and Fig. 4, the reactance component that said two impedance property is identical is the first reactance component and the second reactance component；The outfan of described amplifier is connected with described first reactance component with after described resistant series again；Second end of described first reactance component is simultaneously connected with the first end and the input of described amplifier of described second reactance component；Second end ground connection of described second reactance component.

The present invention gives the brand-new constituted mode of phaseshift oscillator, be properly termed as the complementary agitator of phase shift.Its circuit structure has two kinds of similar forms, is the complementary agitator of current mode phase shift and the complementary agitator of voltage-type phase shift respectively.Thus derivative physical circuit has four (refer to alternating current path, and the side circuit realizing alternating current path is the most various).This is a technological improvement about sine-wave oscillator basic structure, can build abundant practical circuit on this basis.

The constituted mode of phase shift complementation unit (i.e. two-stage phase-shift network): phase shift complementation unit has two kinds of constituted modes, i.e. current mode phase shift complementation unit is (see the phase shift complementation unit in Fig. 1 and Fig. 2, the difference of two figures is that reactance component is electric capacity and inductance respectively) and voltage-type phase shift complementation unit (see the phase shift complementation unit in Fig. 3 and Fig. 4, the difference of two figures is that reactance component is electric capacity and inductance respectively).

Current amplifier constitutes the complementary agitator of current mode phase shift with current mode phase shift complementation unit, and it has the complementary agitator of current mode RC phase shift (Fig. 1) and two kinds of concrete forms of the complementary agitator of current mode RL phase shift (Fig. 2)；Voltage amplifier constitutes the complementary agitator of voltage-type phase shift with voltage-type phase shift complementation unit, and it has the complementary agitator of voltage-type RC phase shift (Fig. 3) and two kinds of concrete forms of the complementary agitator of voltage-type RL phase shift (Fig. 4).

Qualitative analysis:

For meeting the current amplifier that aforementioned currents direction requires, if output electric current is fed back to input without phase shift, whole circuit just becomes positive feedback amplifier, it is possible to realize sine-wave oscillation.And output electric current is fed back to input without phase shift by the function of current mode phase shift complementation unit exactly.In FIG, it is considered to phase shift complementation unit two ends electric current i_iWith i_oPhase relation.Due to R_iWith C₂Parallel connection, therefore phase shift complementation unit also includes R_i, it is made up of two-stage RC phase-shift network.R_iWith C₂Parallel connection, constitutes first order phase-shift network, total current i of this one-level_AIt is ahead of resistance branch electric current i_i.If not considering R_iWith C₂Impact, R and C₁Constitute second level phase-shift network, total current i of this one-level_oLag behind capacitive branch electric current；Even if considering R_iWith C₂Impact, this branch road is still capacitive branch, total current i_oLag behind capacitive branch electric current i_AQualitative conclusions also will not change.Generally speaking, the two-stage RC phase-shift network in Fig. 1 serves, on the impact of current phase, the effect cancelled out each other, and the most therefore it be named as current mode phase shift complementation unit.In general, the situation of change of phase shift is relevant with frequency.Under certain frequency, the total phase shift of electric current produced by phase shift complementation unit will be zero, make whole circuit become positive feedback amplifier, obtain sine-wave oscillation；Therefore this frequency the most just becomes frequency of oscillation.

In like manner, in fig. 2, two-stage RL phase-shift network serves the effect cancelled out each other to the impact of current phase, and simply first order phase-shift network produces hysteresis, and second level phase-shift network produces anticipation.

For in-phase voltage amplifier, if output voltage is fed back to input without phase shift, whole circuit just becomes positive feedback amplifier, it is possible to realize sine-wave oscillation.And output voltage is fed back to input without phase shift by the function of phase shift complementation unit exactly.In figure 3, it is considered to phase shift complementation unit both end voltage V_iWith V_oPhase relation.Due to R_iWith C₂Parallel connection, therefore phase shift complementation unit also includes R_i, it is made up of two-stage RC phase-shift network.R_iWith C₂Parallel connection, constitutes first order phase-shift network, the electric current i of this one-level_AIt is ahead of voltage V_i.If not considering R_iWith C₂Impact, R and C₁Constitute second level phase-shift network, due to resistance and capacitance partial pressure, total voltage V of this one-level_oLag behind the electric current i of this branch road_A；Even if considering R_iWith C₂Impact, resistance will not change with the feature of capacitive device dividing potential drop, total voltage V of this one-level_oLag behind the electric current i of this branch road_AQualitative conclusions also will not change.Generally speaking, the two-stage RC phase-shift network in Fig. 3 serves the effect cancelled out each other to the change of voltage-phase, and therefore it is just named as voltage-type phase shift complementation unit.Under certain frequency, the total phase shift of voltage produced by phase shift complementation unit will be zero, make whole circuit become positive feedback amplifier, obtain sine-wave oscillation；Therefore this frequency the most just becomes frequency of oscillation.

In like manner, in the diagram, two-stage RL phase-shift network serves the effect cancelled out each other to the change of voltage-phase, and simply first order phase-shift network produces hysteresis, and second level phase-shift network produces anticipation.

Quantitative analysis:

Consider to be easy to because form is simple application, thus have the situation of bigger using value.Here it is the situation that the component parameters of two reactance components is identical (i.e. identical or two inductance the inductance value of the capacitance of two electric capacity in phase shift complementation unit is identical).

1. work as C₁=C₂During=C, analyze the complementary agitator of current mode RC phase shift (Fig. 1)

The gain of basic amplifier is

$A=\frac{i_o}{i_i}=A_i$

The feedback factor of feedback network (i.e. current mode phase shift complementation unit) is

$F=\frac{i_i}{i_o}=\frac{i_A}{i_o}\·\frac{i_i}{i_A}=\frac{R}{{\left(j\mathrm{\ω}C\right)}^{-1}+\frac{{\left(j\mathrm{\ω}C\right)}^{-1}\·R_i}{{\left(j\mathrm{\ω}C\right)}^{-1}+R_i}+R}\·\frac{{\left(j\mathrm{\ω}C\right)}^{-1}}{{\left(j\mathrm{\ω}C\right)}^{-1}+R_i}$

It can be reduced to

$F=\frac{R}{R+2R_i+j({\mathrm{\ωCRR}}_i-1/\mathrm{\ω}C)}$

Thus obtain loop gain

$T\left(j\mathrm{\ω}\right)=A\·F=A_i\·\frac{1}{1+2R_i/R+j({\mathrm{\ωCR}}_i-1/\mathrm{\ω}CR)}$

It is said that in general, circuit starting condition for oscillation is T (j ω) ＞ 1.?Time, loop gain is just, illustrates that now the impact of phase place is just cancelled out each other by current mode two-stage RC phase-shift network, and output electric current feeds back to input without phase shift, and whole circuit becomes positive feedback amplifier.More precisely, A is worked as_i＞ 1+2R_iDuring/R, loop gain is more than 1.It follows that the starting condition for oscillation of the complementary agitator of current mode RC phase shift (Fig. 1) can be embodied as

A_i＞ 1+2R_i/R

Corresponding hunting angle frequency is

${\mathrm{\ω}}_0={\left(C\sqrt{R_{i}R}\right)}^{-1}$

Frequency of oscillation is

$f_0=\frac{1}{2\mathrm{\π}C\sqrt{R_{i}R}}$

2. work as L₁=L₂During=L, analyze the complementary agitator of current mode RL phase shift (Fig. 2)

This situation is exactly that in Fig. 1 two electric capacity all replace to the circuit that the inductance that size is L obtains, the therefore impedance (j ω C) of electric capacity in formula^-1Also the impedance j ω L of inductance should be replaced with, so loop gain is correspondingly written as

$T\left(j\mathrm{\ω}\right)=A_i\·\frac{1}{1+2R_i/R+j(\mathrm{\ω}L/R-R_i/\mathrm{\ω}L)}$

Thus obtaining, starting condition for oscillation is

A_i＞ 1+2R_i/R

Corresponding hunting angle frequency is

${\mathrm{\ω}}_0=\frac{\sqrt{R_{i}R}}{L}$

Frequency of oscillation is

$f_0=\frac{\sqrt{R_{i}R}}{2\mathrm{\π}L}$

3. work as C₁=C₂During=C, analyze the complementary agitator of voltage-type RC phase shift (Fig. 3)

The gain of basic amplifier is

$A=\frac{V_o}{V_i}=A_v$

The feedback factor of feedback network (i.e. voltage-type phase shift complementation unit) is

$F=\frac{V_i}{V_o}=\frac{i_A}{V_o}\·\frac{V_i}{i_A}=\frac{1}{R+{\left(j\mathrm{\ω}C\right)}^{-1}+\frac{1}{j\mathrm{\ω}C+R_i^{-1}}}\·\frac{1}{j\mathrm{\ω}C+R_i^{-1}}$

It can be reduced to

$F=\frac{1}{2+R/R_i+j(\mathrm{\ω}CR-1/{\mathrm{\ωCR}}_i)}$

Loop gain is

$T\left(j\mathrm{\ω}\right)=A\·F=A_v\·\frac{1}{2+R/R_i+j(\mathrm{\ω}CR-1/{\mathrm{\ωCR}}_i)}$

?Time, loop gain is just, illustrates that now the impact of phase place is just cancelled out each other by voltage-type two-stage RC phase-shift network, and output voltage feeds back to input without phase shift, and whole circuit becomes positive feedback amplifier.More precisely, A is worked as_v＞ 2+R/R_iTime, loop gain is more than 1.It follows that the starting condition for oscillation of the complementary agitator of voltage-type RC phase shift (Fig. 3) can be embodied as

A_v＞ 2+R/R_i

Corresponding hunting angle frequency is

${\mathrm{\ω}}_0={\left(C\sqrt{R_{i}R}\right)}^{-1}$

Frequency of oscillation is

$f_0=\frac{1}{2\mathrm{\π}C\sqrt{R_{i}R}}$

4. work as L₁=L₂During=L, analyze the complementary agitator of voltage-type RL phase shift (Fig. 4)

This situation is exactly that in Fig. 3 two electric capacity all replace to the circuit that the inductance that size is L obtains, the therefore impedance (j ω C) of electric capacity in formula^-1Also the impedance j ω L of inductance should be replaced with, so loop gain is correspondingly written as

$T\left(j\mathrm{\ω}\right)=A\·F=A_v\·\frac{1}{2+R/R_i+j(\mathrm{\ω}L/R_i-R/\mathrm{\ω}L)}$

Thus obtaining, starting condition for oscillation is

A_v＞ 2+R/R_i

Corresponding hunting angle frequency is

${\mathrm{\ω}}_0=\frac{\sqrt{R_{i}R}}{L}$

Frequency of oscillation is

$f_0=\frac{\sqrt{R_{i}R}}{2\mathrm{\π}L}.$

Special instruction:

According to above qualitative analysis and quantitative analysis, by the multiple practical circuit built according to the complementary agitator of phase shift shown in Fig. 1 Fig. 4 (alternating current path) are carried out Experiment of Electrical Circuits, have proven to this kind of circuit can vibrate, and starting condition for oscillation and frequency of oscillation are consistent with the conclusion of aforementioned theory analysis, this demonstrates the imagination of the present invention is feasible with design, and analysis is correct.

When two reactance component parameters of Such analysis are identical, can circuit the determiner of frequency of oscillation all have simple and clear and be prone to the feature judged after starting of oscillation and starting of oscillation, that is: can circuit starting of oscillation be solely dependent upon simply comparing of amplifier gain and resistance, and the expression formula of frequency of oscillation is a simple formula the most relevant with reactance component and resistance.

Above content is to combine concrete preferred implementation further description made for the present invention, it is impossible to assert the present invention be embodied as be confined to these explanations.For general technical staff of the technical field of the invention, without departing from the inventive concept of the premise, it is also possible to make some simple deduction or replace, all should be considered as belonging to protection scope of the present invention.

Claims (8)

1. the complementary agitator of phase shift, it is characterised in that: it is made up of an amplifier and a phase shift complementation unit；Described phase shift complementation unit is two-stage phase-shift network.

The complementary agitator of phase shift the most according to claim 1, it is characterised in that: described two-stage phase-shift network is made up of the reactance component that a resistance and two impedance properties are identical；The reactance component that said two impedance property is identical is all electric capacity or is all inductance.

The complementary agitator of phase shift the most according to claim 1, it is characterized in that: described amplifier is current amplifier, when the alternating current direction of input is to flow into amplifier, this current amplifier alternating current direction obtained by outfan is to flow out amplifier.

The complementary agitator of phase shift the most according to claim 1, it is characterised in that: described amplifier is voltage amplifier, and this voltage amplifier is in-phase amplifier.

The complementary agitator of phase shift the most according to claim 1, it is characterised in that: described two-stage phase-shift network has complementarity to the impact of curtage phase place.

The complementary agitator of phase shift the most according to claim 1, it is characterised in that: before and after in described two-stage phase-shift network, phase shift produced by two-layer configuration is contrary, and one-level is advanced, and additionally one-level is delayed, the purpose complementary to reach phase shift.

7. according to the complementary agitator of phase shift described in claim 2 and 3, it is characterised in that: the reactance component that said two impedance property is identical is the first reactance component and the second reactance component；The outfan of described amplifier is simultaneously connected with the first end and first end of described first reactance component of described resistance；The input of described amplifier is simultaneously connected with the second end and first end of described second reactance component of described first reactance component；Second end of described resistance and the second equal ground connection of end of described second reactance component.

8. according to the complementary agitator of phase shift described in claim 2 and 4, it is characterised in that: the reactance component that said two impedance property is identical is the first reactance component and the second reactance component；The outfan of described amplifier is connected with described first reactance component with after described resistant series again；Second end of described first reactance component is simultaneously connected with the first end and the input of described amplifier of described second reactance component；Second end ground connection of described second reactance component.