CN102684624A - Inphase amplifying circuit based on input branch switch modulation and implementation method thereof - Google Patents

Abstract

The invention discloses an inphase amplifying circuit based on input branch switch modulation and an implementation method of the inphase amplifying circuit. The inphase amplifying circuit comprises a resistor and an inphase amplifier, and further comprises an analog electronic switch connected in series with a circuit signal input end; the switching on-off of the analog electronic switch is controlled by a control signal input from a control end; the amplification factor of the inphase amplifying circuit based on input branch switch modulation is provided in the specification, wherein D=T0/0.1ms is duty cycle; when T0=0.09ms, i.e., D=90%, the C end in Figure3 is connected with a logic high level all the time, the amplification factor of the circuit is 10; when T0=0ms, i.e., D=0, the amplification factor of the circuit is 1; and when T0 is variable in the range of 0-0.09ms, i.e., D=0-90%, the amplification of the circuit varies in the range of 1-10. Based on the inphase amplifying circuit based on input branch switch modulation and the implementation method of the inphase amplifying circuit, continuously controllable amplification factor of the circuit is guaranteed, and the defect that the amplification factor of the prior circuit is intermittently controllable is avoided; and as just one analog switch is used, the design of the factor control circuit is simplified.

Description

In-phase amplification circuit and its implementation based on the modulation of input branch switch

Technical field

The present invention relates to electronic technology field, specifically is a kind of in-phase amplification circuit and its implementation based on the modulation of input branch switch.

Background technology

In the design of electronic circuit and using, the signal of telecommunication is amplified or decay is one of modal treatment technology, and it is as shown in Figure 1 wherein voltage signal to be carried out the typical circuit of homophase amplification.On the basis of Fig. 1, can constitute the in-phase amplification circuit of multi-stage programmable control as shown in Figure 2.For simplicity, 4 grades of multiplication factors in Fig. 2, have only been represented.Can distinguish control switch 1,2,3 or 4 through decoding circuit and connect, be respectively 1+R thereby obtain 4 kinds of multiplication factors ₂₁/ R ₁, 1+R ₂₂/ R ₁, 1+R ₂₃/ R ₁, 1+R ₂₄/ R ₁Circuit design scheme shown in Figure 2 has following shortcoming: (1) this circuit includes decoding circuit, and circuit constitutes comparatively complicated, has increased the production cost of circuit; If the cancellation decoding circuit, then the control signal number of control switch break-make will increase, and the progression of multiplication factor is identical with the switch controlling signal number.(2) progression of multiplication factor is limited, and along with the increase of multiplication factor progression, the switch number should increase thereupon, and corresponding decoding circuit is complicated more.

Summary of the invention

The present invention is directed to the above-mentioned deficiency that exists in the prior art, a kind of in-phase amplification circuit and its implementation based on the modulation of input branch switch is provided.

The present invention realizes through following technical scheme.

A kind of in-phase amplification circuit based on the modulation of input branch switch; Comprise resistance and in-phase amplifier; Also comprise the simulant electronic switch that is serially connected in the circuit signal input, said simulant electronic switch is opened or closure through controlling it in the control signal of control end input.

The feedback resistance of said in-phase amplifier adopts the T network form.

The simulant electronic switch on the said signal input branch road and the position of resistance can exchange.

A kind of implementation method based on the in-phase amplification circuit of importing the branch switch modulation may further comprise the steps:

The first step is the control signal of T in the control end C input cycle, and the time of switch closure is T in one-period ₀, must be at the equivalent mean value of cycle T internal feedback resistance:

$R_{1\mathrm{eq}}=\frac{T}{T_0}{R}_1,$

Wherein, R ₁Be the input resistance on the signal input branch road;

Second step, take away the frequency of closing control signal and be exaggerated signal frequency n doubly;

In the 3rd step, the frequency range that requires signal to amplify is 0～f _H, C is held in power taking ₂≤1/ (2 π f _HR ₂), capacitor C ₅≤1/ (2 π f _HR ₅), must be at frequency 0～f _HMultiplication factor in the scope is:

$A=\frac{u_o}{u_i}=-(1+\frac{R_2}{R_{1\mathrm{eq}}})\×\frac{R_5}{R_4}=-(1+\frac{R_2}{R_1}\×\frac{T_0}{T})\×\frac{R_5}{R_4},$

Wherein, U _iBe the amplitude of input signal, U _oBe the amplitude of output signal, R ₂And R ₅Be respectively the feedback resistance of in-phase amplifier, R ₄Be the connection resistance between the in-phase amplifier.

Said n>100.

Said R ₄=10k Ω, R ₅=10k Ω, R ₁=2k Ω, R ₂=20k Ω, said f _H=100Hz, said C ₂=22nF, C ₅=10nF, the frequency of said switch controlling signal is 10kHz, said T=0.1ms, said multiplication factor based on the in-phase amplification circuit of importing the branch switch modulation is:

$A=\frac{U_o}{U_i}=(1+\frac{R_2}{R_1}\&times;\frac{{\mathrm{<figure-callout\; id="0"\; label="T"\; filenames="HDA00001709299700022.png"\; state="\{\{state\}\}">T</figure-callout>}}_0}{0.1\mathrm{ms}})\&times;\frac{R_5}{R_4}=1+10D,$

Wherein, D=T ₀/ 0.1ms is a duty ratio.

The present invention compared with prior art has following characteristics:

1, the present invention can guarantee the multiplication factor continuous controllable of circuit, has overcome the interrupted controlled shortcoming of multiplication factor of available circuit;

2, the present invention only uses an analog switch, has simplified the design of multiple control circuit.

Description of drawings

Fig. 1 is for carrying out the typical circuit that homophase amplifies to voltage signal;

Fig. 2 is the in-phase amplification circuit of multi-stage programmable control;

Fig. 3 is the in-phase amplification circuit of the embodiment of the invention 1;

Fig. 4 is the in-phase amplification circuit of the embodiment of the invention 2;

Fig. 5 is the in-phase amplification circuit of the embodiment of the invention 3.

Embodiment

Elaborate in the face of embodiments of the invention down: present embodiment provided detailed execution mode and concrete operating process, but protection scope of the present invention is not limited to following embodiment being to implement under the prerequisite with technical scheme of the present invention.

Embodiment 1

Present embodiment comprises resistance and in-phase amplifier, also comprises the simulant electronic switch S that is serially connected in the circuit signal input, and simulant electronic switch S opens or closure through controlling it in the control signal of control end C input.

The control signal cycle of control end C input is T, and the time of switch closure is T in one-period ₀, then the equivalent mean value at cycle T internal feedback resistance is: Said R ₁Be the input resistance on the signal input branch road.

The frequency of the control signal of control end C input be exaggerated signal frequency n doubly, wherein, n>100.

Embodiment 2

Embodiment 2 is the variant of embodiment 1.

In the present embodiment, input resistance R on simulant electronic switch S and the signal input branch road ₁The position exchanges, and is as shown in Figure 4.

Embodiment 3

Embodiment 3 is the variant of embodiment 1 and/or embodiment 2.

In the present embodiment, simulant electronic switch S and the resistance R on the input branch road ₂And/or R ₅Can also adopt the form of T network, Fig. 5 has provided resistance R ₂Circuit structure when adopting T network, wherein simulant electronic switch S and resistance R ₁The position can exchange.

Embodiment 4

Present embodiment is the implementation method based on the in-phase amplification circuit of importing the branch switch modulation that the foregoing description provides.

Below the in-phase amplification circuit that provides according to embodiment 1 based on input branch switch modulation design an amplifying circuit, requiring passband frequency range is 0～100Hz, multiplication factor is in 1～10 continuous controllable.

Present embodiment may further comprise the steps:

The first step is the control signal of T in the control end C input cycle, and the time of switch closure is T in one-period ₀, must be at the equivalent mean value of cycle T internal feedback resistance:

$R_{1\mathrm{eq}}=\frac{T}{T_0}{R}_1,$

Wherein, R ₁Be the input resistance on the signal input branch road;

Through at the suitable pulse-width signal of control end C input, control the break-make of simulant electronic switch S, change input resistance R ₁Equivalence value, thereby change the amplification characteristic of circuit.As shown in Figure 3, be the control signal of T in the C end input cycle, the time of switch closure is T in one-period ₀, then at the equivalent mean value of cycle T internal feedback resistance

$R_{1\mathrm{eq}}=\frac{T}{T_0}{R}_1---\left(1\right).$

Second step, take away the frequency of closing control signal and be exaggerated signal frequency n doubly;

For making that the equivalence value of input resistance is constant as far as possible in one-period, the frequency of desirable switch controlling signal be exaggerated signal frequency n doubly, according to result of the test, generally get n>100.For example, the frequency range that requires amplifying circuit is 0～100Hz, and then the frequency of desirable switch controlling signal is greater than 100 * 100Hz=10kHz.

In the 3rd step, the frequency range that requires signal to amplify is 0～f _H, C is held in power taking ₂≤1/ (2 π f _HR ₂), capacitor C ₅≤1/ (2 π f _HR ₅), must be at frequency 0～f _HMultiplication factor in the scope is:

$A=\frac{u_o}{u_i}=-(1+\frac{R_2}{R_{1\mathrm{eq}}})\&times;\frac{R_5}{R_4}=-(1+\frac{R_2}{R_1}\&times;\frac{T_0}{T})\&times;\frac{R_5}{R_4},$

Wherein, U _iBe the amplitude of input signal, U _oBe the amplitude of output signal, R ₂And R ₅Be respectively the feedback resistance of in-phase amplifier, R ₄Be the connection resistance between the in-phase amplifier;

Capacitor C among Fig. 3 ₂And C ₅Be used for smooth signal waveform, suppress High-frequency Interference simultaneously.If the frequency range that requires signal to amplify is 0～f _H, desirable C ₂≤1/ (2 π f _HR ₂), C ₅≤1/ (2 π f _HR ₅), this moment based on the in-phase amplification circuit of input branch switch modulation at frequency 0～f _HMultiplication factor in the scope is:

$A=\frac{u_o}{u_i}=-(1+\frac{R_2}{R_{1\mathrm{eq}}})\&times;\frac{R_5}{R_4}=-(1+\frac{R_2}{R_1}\&times;\frac{T_0}{T})\&times;\frac{R_5}{R_4}---\left(2\right),$

Through control T ₀, perhaps T, perhaps duty ratio T ₀The size of/T just can be controlled the size of multiplication factor A.

Can know by formula (2),, work as T if T fixes ₀During=T, the multiplication factor of circuit maximum (disregarding phase place), for

$\left|A\right|=\left|\frac{u_o}{u_i}\right|=(1+\frac{R_2}{R_1})\&times;\frac{R_5}{R_4}---\left(3\right)$

If T fixes, work as T ₀=0 o'clock, the multiplication factor of circuit maximum (disregarding phase place), for

$\left|A\right|=\left|\frac{u_o}{u_i}\right|=\frac{R_5}{R_4}---\left(4\right)$

Therefore, scope is

to the multiplication factor of circuit of the present invention (disregarding phase place)

In the present embodiment, get R ₄=10k Ω, R ₅=10k Ω, R ₁=2k Ω, R ₂=20k Ω; Because f _H=100Hz, desirable C ₂≤1/ (2 π f _HR ₂)=0.16 μ F gets C here ₂=22nF; In like manner get C ₅=10nF; The frequency of switch controlling signal is got 100 * 100Hz=10kHz, then T=0.1ms.Multiplication factor based on the in-phase amplification circuit of importing the branch switch modulation is:

$A=\frac{U_o}{U_i}=(1+\frac{R_2}{R_1}\&times;\frac{{\mathrm{<figure-callout\; id="0"\; label="T"\; filenames="HDA00001709299700022.png"\; state="\{\{state\}\}">T</figure-callout>}}_0}{0.1\mathrm{ms}})\&times;\frac{R_5}{R_4}=1+10D---\left(5\right)$

U in the formula _i, U _oBe respectively the amplitude of input, output signal; D=T ₀/ 0.1ms is a duty ratio.Can know by formula (5), when getting T ₀=0.09ms, when promptly the C end connect logic high all the time among Fig. 3 during D=90%, the multiplication factor of circuit was 10; When getting T ₀=0ms, promptly during D=0, the multiplication factor of circuit is 1; Work as T ₀In 0～0.09ms scope, change, i.e. D=0～90% o'clock, the multiplication factor of circuit changes between 1～10.

It is 100Hz at frequency input signal that table 1 has provided above-mentioned design example, the measured result when amplitude is 1V, wherein, and ui=sin (200 π t) V, the frequency of switch controlling signal is got 10kHz.

Table 1 measured result

Claims (6)

1. in-phase amplification circuit based on input branch switch modulation; Comprise resistance and in-phase amplifier; It is characterized in that, also comprise the simulant electronic switch that is serially connected in the circuit signal input, said simulant electronic switch is opened or closure through controlling it in the control signal of control end input.

2. the in-phase amplification circuit based on the modulation of input branch switch according to claim 1 is characterized in that the feedback resistance of said in-phase amplifier adopts the T network form.

3. the in-phase amplification circuit based on the modulation of input branch switch according to claim 1 and 2 is characterized in that, the simulant electronic switch on the said signal input branch road and the position of resistance can exchange.

4. one kind as require the implementation method of 1 described in-phase amplification circuit based on input branch switch modulation, it is characterized in that, may further comprise the steps:

The first step is the control signal of T in the control end C input cycle, and the time of switch closure is T in one-period ₀, must be at the equivalent mean value of cycle T internal feedback resistance:

$R_{1\mathrm{eq}}=\frac{T}{T_0}{R}_1,$

Wherein, R ₁Be the input resistance on the signal input branch road;

Second step, take away the frequency of closing control signal and be exaggerated signal frequency n doubly;

In the 3rd step, the frequency range that requires signal to amplify is 0～f _H, C is held in power taking ₂≤1/ (2 π f _HR ₂), capacitor C ₅≤1/ (2 π f _HR ₅), must be at frequency 0～f _HMultiplication factor in the scope is:

$A=\frac{u_o}{u_i}=-(1+\frac{R_2}{R_{1\mathrm{eq}}})\&times;\frac{R_5}{R_4}=-(1+\frac{R_2}{R_1}\&times;\frac{T_0}{T})\&times;\frac{R_5}{R_4},$

Wherein, U _iBe the amplitude of input signal, U _oBe the amplitude of output signal, R2 and R5 are respectively the feedback resistance of in-phase amplifier, R ₄Be the connection resistance between the in-phase amplifier.

5. the in-phase amplification circuit based on the modulation of input branch switch according to claim 4 is characterized in that said n>100.

6. the in-phase amplification circuit based on the modulation of input branch switch according to claim 4 is characterized in that said R ₄=10k Ω, R ₅=10k Ω, R ₁=2k Ω, R ₂=20k Ω, said f _H=100Hz, said C ₂=22nF, C ₅=10nF, the frequency of said switch controlling signal is 10kHz, said T=0.1ms, said multiplication factor based on the in-phase amplification circuit of importing the branch switch modulation is:

$A=\frac{U_o}{U_i}=(1+\frac{R_2}{R_1}\&times;\frac{T_0}{0.1\mathrm{ms}})\&times;\frac{R_5}{R_4}=1+10D,$

Wherein, D=T ₀/ 0.1ms is a duty ratio.

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