CN103414440A - Signal amplification circuit with time-varying gain - Google Patents
Signal amplification circuit with time-varying gain Download PDFInfo
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- CN103414440A CN103414440A CN2013103517053A CN201310351705A CN103414440A CN 103414440 A CN103414440 A CN 103414440A CN 2013103517053 A CN2013103517053 A CN 2013103517053A CN 201310351705 A CN201310351705 A CN 201310351705A CN 103414440 A CN103414440 A CN 103414440A
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Abstract
The invention discloses a signal amplification circuit with a time-varying gain. A variable resistor is connected to an input link or a feedback link of an amplifier, the resistance of the variable resistor is controlled by the voltage of a charging and discharging capacitor, the variable resistor can be achieved by a field-effect transistor or other semi-conductor devices with features of the variable resistor, the field-effect transistor has a variable resistor region, equivalent resistances between the drain and the source of the field-effect transistor working in the variable resistor region are controlled by a gate-source voltage, the charging and discharging of the charging and discharging capacitor are controlled by external signals, and during charging or discharging, voltages at two ends of the capacitor increase or decrease over time, so that the resistance of the variable resistor controlled by the voltages varies accordingly. The variable resistor is connected to the input link or the feedback link of the amplifier, so that the gain of the amplifier increases or decreases over time. The signal amplification circuit is simple in structure, easy to implement and capable of meeting the requirement for the time-varying gain required by detection.
Description
Technical field
The present invention relates to the electronic circuit technology field, relate in particular to a kind of variable-gain amplification circuit that carrys out amplification input signal by variable gain.
Background technology
In some input fields, the prolongation in time of measured signal, its signal amplitude is decay or increase fast.As adopt microwave signal, the ultrasonic signal of time difference method measuring distance, signal outwards sends and is reflected back transducer by dielectric surface from transducer, electronic unit carries out timing to signal from being issued to again the received time, then calculates tested distance according to the propagation velocity of signal in space.For determining transmitting of energy, tested distance is nearer, and the time of propagation is shorter, and the signal be reflected back is stronger; Distance is far away, and the time of propagation is longer, and the signal be reflected back is more weak, and is the exponential manner decay.Adopt the fixing signal amplification circuit of multiplication factor can not adapt to the variation of sort signal.Need gain in time variable amplifying circuit adapt to this in time prolongation and amplitude changes the signal of (decay or increase).
This time dependent signal amplification circuit of known amplification, its gain is controlled and is normally adopted AGC automatic gain control mode, or adopts the digital programmable gain amplifier to realize the variable gain amplification of signal.Adopt its theory diagram of amplifying circuit of AGC automatic gain control as shown in Figure 1.According to Fig. 1, the agc circuit component links is more, realizes the circuit more complicated of corresponding function, if while requiring it to have larger gain variation range simultaneously, needing increases number of stages of amplification, thereby circuit is more complicated, and other performance index also there will be variation.
Another kind of adoptable mode is to use the digital programmable gain-controlled amplifier, and its circuit forms simple, and it is convenient to control.But weak point is that the gain ranging of sort circuit is little, its operating frequency, switching rate often can not meet the needs of actual detection simultaneously.The signal that detection is sent as time difference method is pulse-modulated signal normally, requires amplifier to have higher signal switching rate, and common digital programmable gain-controlled amplifier is difficult to satisfy the demand on this index.
Summary of the invention
For solving existing signal amplification circuit above shortcomings, the invention provides a kind of time dependent variable gain signal amplification circuit of gain of simple in structure, the satisfied detection needs that are easy to realize.
The technical scheme that the present invention adopts for achieving the above object is:
Scheme one, the time dependent signal amplification circuit of a kind of gain, include amplifier (A1), charge and discharge capacitance (C1) and variable resistor (RT1), the feedback element of variable resistor (RT1) access amplifier (A1), the resistance size of variable resistor (RT1) is by the voltage control on charge and discharge capacitance (C1).
Described variable resistor (RT1) can be realized by the semiconductor device with variable resistance characteristics.
Described semiconductor device with variable resistance characteristics can be realized by field effect transistor, and the grid of field effect transistor directly is connected with an end of charge and discharge capacitance (C1) or indirectly is connected by devices such as resistance, realizes controlling variable-resistance function.
Described charge and discharge capacitance (C1) can it discharges and recharges by outside high-low level signal controlling.
Described amplifier (A1), charge and discharge capacitance (C1) and variable resistor (RT1) can adopt following connected mode to realize the technical program: charge and discharge capacitance (C1) end ground connection or by device ground connection such as resistance, the control end of the other end and variable resistor (RT1) directly joins or indirectly joins by devices such as resistance; Charge and discharge capacitance (C1) is gone back contact resistance (R3) and resistance (R4), the other end of resistance (R3) connects external control voltage Vctrl, another termination negative voltage of resistance (R4), the feedback element of the amplifier A1 that variable resistor (RT1) series resistor (R2) forms is parallel between the input and output of amplifier A1.
Scheme two, the time dependent signal amplification circuit of a kind of gain, include amplifier (A2), charge and discharge capacitance (C2) and variable resistor, the input element of variable resistor access amplifier (A2), variable-resistance resistance size is by the voltage control on charge and discharge capacitance (C2).
Described variable resistor can be realized by the semiconductor device with variable resistance characteristics.
Described semiconductor device with variable resistance characteristics can be by field effect transistor (T2) realization, and the grid of field effect transistor (T2) directly is connected with an end of charge and discharge capacitance (C2) or indirectly is connected by devices such as resistance.
Described charge and discharge capacitance (C2) can it discharges and recharges by outside high-low level signal controlling.
Described amplifier (A2), charge and discharge capacitance (C2) and can adopt following connected mode to realize the technical program as variable-resistance field effect transistor (T2): charge and discharge capacitance (C2) end ground connection or by device ground connection such as resistance, the grid of the other end and field effect transistor (T2) directly joins or indirectly joins by devices such as resistance, the source ground of field effect transistor (T2) or pass through grounding through resistance, the drain electrode of field effect transistor (T2) and resistance (R6), resistance (R7) joins, the other end of resistance (R6) is connected with the input signal end, the reverse input end of the other end access amplifier (A2) of resistance (R7), resistance (R8) is the feedback resistance of amplifier (A2), the one end while and resistance (R9) of charge and discharge capacitance (C2), resistance (R10) and resistance (R11) join, resistance (R9) other end connects external control voltage Vctrl, one end of resistance (R10) and resistance (R9), resistance (R11), charge and discharge capacitance (C2) joins, another termination negative voltage of resistance (R10).In this programme, as variable-resistance field effect transistor (T2), be linked into the input element of amplifier (A2).
The time dependent signal amplification circuit of gain of the present invention, feedback element or the input element of variable resistor access amplifier, variable-resistance resistance size is controlled by the voltage on charge and discharge capacitance, charge and discharge capacitance is controlled it by external signal and is discharged and recharged, when its charge or discharge, the voltage at electric capacity two ends can increase or reduce over time, the resistance that is controlled by like this variable resistor of this voltage can change thereupon, due to variable resistor, be connected to input element or the feedback element of amplifier, therefore the gain of amplifier also can increase over time or reduce, the present invention is simple in structure, be easy to realize, can meet the time dependent demand of gain of detection needs.
The accompanying drawing explanation
Fig. 1 is AGC amplifying electric circuit with auto-gain-controlling function theory diagram.
Fig. 2 is voltage and the control signal oscillogram on specific embodiment of the invention charge and discharge capacitance.
Fig. 3 is the circuit diagram of the specific embodiment of the invention one.
Fig. 4 is the circuit diagram of the specific embodiment of the invention two.
Embodiment
According to foregoing the solution of the present invention one and scheme two, 2 preferred specific embodiments (infinite) are proposed, specifically details are as follows.
Specific embodiment one, as shown in Figure 3, include amplifier A1, input resistance R1, charge and discharge capacitance C1, by R2 and variable resistor RT1, formed the feedback element of amplifier A1, impulse electricity capacitor C 1 one end ground connection, the other end joins with resistance R 3, R4, R5 respectively, and the control end of the other end of resistance R 5 and variable resistor RT1 joins; Another termination external control voltage Vctrl of resistance R 3, another termination of resistance R 4-5v voltage.In the present embodiment, establish C1=1uF, R3=R4=100k Ω, R5=50k Ω.As shown in Figure 2, the height of controlling voltage Vctrl changes will make capacitor C 1 be in charging and discharging state, and the voltage on C1 can occur from high to low, variation from low to high.Voltage on C1 is applied to the control end of variable resistor RT1 by resistance R 5, thereby the resistance of variable resistor RT1 is changed, and the functional relation of its variation can be expressed as RT1=f (CU1), and CU1 is the voltage at C1 two ends.The gain of the present embodiment amplifying circuit is
AV=VO/Vi=-(R2+?RT1)/R1
Variable resistor in Fig. 3 can be by the realization of N channel junction field-effect pipe, and the drain electrode of field effect transistor is connected with resistance R 2, and the source electrode of field effect transistor is received the output of amplifier A1, and the grid of field effect transistor is connected with resistance R 5.
Hence one can see that, the gain of the present embodiment amplifying circuit is affected by variable-resistance resistance, and variable-resistance resistance is controlled by the voltage on capacitor C 1, voltage on C1 is temporal evolution due to discharging and recharging of C1, so this circuit is a signal amplification circuit that the gain temporal evolution increases or reduces.Change in voltage speed on capacitor C 1 is determined by the resistance of C1 capacity and resistance R 3, R4.
In the present embodiment, amplifier A1 should suitably choose according to the characteristics (as bandwidth) of input signal.
In the present embodiment, only in basic amplifying circuit, increased variable resistor, charge and discharge capacitance etc. a small amount of, base components, by discharging and recharging of external control electric capacity, the gain that has namely realized amplifier variable functional requirement in time.
Specific embodiment two, the amplifying circuit of the present embodiment as shown in Figure 4, include amplifier A2, charge and discharge capacitance C2, with the variable resistor of being realized by N channel junction field-effect pipe T2, by the variable resistor of field effect transistor realization, be connected on the input element of amplifier, the source ground of field effect transistor T2 (also can pass through grounding through resistance), the drain electrode of T2 and resistance R 6, R7 join, input signal accesses by R6, the other end access amplifier A2 end of oppisite phase of resistance R 7, and R8 is the feedback resistance of amplifier A2; Charge and discharge capacitance C2 mono-end ground connection, the other end joins with resistance R 9, R10, R11 simultaneously, voltage on capacitor C 2 is applied to the grid of field effect transistor T2 by resistance R 11, external control voltage Vctrl is entered by resistance R 9, one end and R9, R11, the C2 of resistance R 10 join, resistance R 10 another terminations-5v voltage.In the present embodiment, establish C1=470nF, R3=R4=82k Ω, R5=50k Ω.
As shown in Figure 2, the height of controlling voltage Vctrl changes will make capacitor C 2 be in charging and discharging state, and the voltage on C2 can occur from high to low, variation from low to high.Equivalent resistance RT2 between field effect transistor drain electrode and source electrode also changes thereupon.The gain of the present embodiment amplifying circuit is
AV=VO/Vi=-（R8/R7）·RT2/?(R6+?RT2)
As can be known by top gain formula, variable resistor RT2 is larger, and the gain of amplifier is larger, and variable resistor RT2 is subjected to the temporal evolution that voltage is controlled on capacitor C 2, so also temporal evolution of the gain of amplifier.
By above two embodiment, the implementation of summary of the invention has been carried out to careful description, those skilled in the art know, without departing from the spirit and scope of the present invention, can carry out various changes or equivalence replacement to these features and embodiment.In addition, under instruction of the present invention, can modify to adapt to concrete situation and material and can not break away from the spirit and scope of the present invention these features and embodiment.Therefore, the present invention is not subjected to the restriction of specific embodiment disclosed herein, and the embodiment in all the application's of falling into claim scope belongs to protection scope of the present invention.
Claims (10)
- One kind the gain time dependent signal amplification circuit, it is characterized in that: include amplifier (A1), charge and discharge capacitance (C1) and variable resistor (RT1), the feedback element of variable resistor (RT1) access amplifier (A1), the resistance size of variable resistor (RT1) is by the voltage control on charge and discharge capacitance (C1).
- 2. the time dependent signal amplification circuit of a kind of gain according to claim 1 is characterized in that: described variable resistor (RT1) is for having the semiconductor device of variable resistance characteristics.
- 3. the time dependent signal amplification circuit of a kind of gain according to claim 2, it is characterized in that: described semiconductor device is field effect transistor, and the grid of field effect transistor directly is connected with an end of charge and discharge capacitance (C1) or indirectly is connected by devices such as resistance.
- 4.. the time dependent signal amplification circuit of a kind of gain according to claim 1 is characterized in that: the discharging and recharging by outside high-low level signal controlling of described charge and discharge capacitance (C1).
- 5. the time dependent signal amplification circuit of a kind of gain according to claim 1, it is characterized in that: charge and discharge capacitance (C1) end ground connection or by device ground connection such as resistance, the control end of the other end and variable resistor (RT1) directly joins or indirectly joins by devices such as resistance; Charge and discharge capacitance (C1) is gone back contact resistance (R3) and resistance (R4), the other end of resistance (R3) connects external control voltage Vctrl, another termination negative voltage of resistance (R4), the feedback element of the amplifier (A1) that variable resistor (RT1) series resistor (R2) forms is parallel between the input and output of amplifier (A1).
- One kind the gain time dependent signal amplification circuit, it is characterized in that: include amplifier (A2), charge and discharge capacitance (C2) and variable resistor, the input element of variable resistor access amplifier (A2), variable-resistance resistance size is by the voltage control on charge and discharge capacitance (C2).
- 7. the time dependent signal amplification circuit of a kind of gain according to claim 6, it is characterized in that: described variable resistor is the semiconductor device with variable resistance characteristics.
- 8. the time dependent signal amplification circuit of a kind of gain according to claim 7, it is characterized in that: described semiconductor device is field effect transistor (T2), and the grid of field effect transistor (T2) directly is connected with an end of charge and discharge capacitance (C2) or indirectly is connected by devices such as resistance.
- 9. the time dependent signal amplification circuit of a kind of gain according to claim 6 is characterized in that: the discharging and recharging by outside high-low level signal controlling of described charge and discharge capacitance (C2).
- 10. the time dependent signal amplification circuit of a kind of gain according to claim 6, it is characterized in that: charge and discharge capacitance (C2) end ground connection or by device ground connection such as resistance, the grid of the other end and field effect transistor (T2) directly joins or indirectly joins by devices such as resistance, the source ground of field effect transistor (T2) or pass through grounding through resistance, the drain electrode of field effect transistor (T2) and resistance (R6), resistance (R7) joins, the other end of resistance (R6) is connected with the input signal end, the reverse input end of the other end access amplifier (A2) of resistance (R7), resistance (R8) is the feedback resistance of amplifier (A2), the one end while and resistance (R9) of charge and discharge capacitance (C2), resistance (R10) and resistance (R11) join, resistance (R9) other end connects external control voltage Vctrl, one end of resistance (R10) and resistance (R9), resistance (R11), charge and discharge capacitance (C2) joins, another termination negative voltage of resistance (R10).
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| Application Number | Priority Date | Filing Date | Title |
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| CN2013103517053A CN103414440A (en) | 2013-08-14 | 2013-08-14 | Signal amplification circuit with time-varying gain |
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| Application Number | Priority Date | Filing Date | Title |
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| CN2013103517053A CN103414440A (en) | 2013-08-14 | 2013-08-14 | Signal amplification circuit with time-varying gain |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112187203A (en) * | 2020-09-14 | 2021-01-05 | 北京航空航天大学 | Automatic gain control circuit and gain adjusting method thereof |
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| US3798559A (en) * | 1971-04-20 | 1974-03-19 | Matsushita Electric Ind Co Ltd | Noise reduction system |
| JPS58154909A (en) * | 1982-03-10 | 1983-09-14 | Hitachi Ltd | Amplifying circuit possible for variable gain control |
| JP2002100944A (en) * | 2000-09-21 | 2002-04-05 | Nec Microsystems Ltd | Automatic gain controller |
| CN101154930A (en) * | 2006-09-27 | 2008-04-02 | 普诚科技股份有限公司 | Automatic gain control circuit |
| CN102427328A (en) * | 2011-09-28 | 2012-04-25 | 北京经纬恒润科技有限公司 | Sine wave oscillating circuit |
| CN203387474U (en) * | 2013-08-14 | 2014-01-08 | 董志伟 | Signal amplification circuit with gain changing along with time |
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2013
- 2013-08-14 CN CN2013103517053A patent/CN103414440A/en active Pending
Patent Citations (6)
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|---|---|---|---|---|
| US3798559A (en) * | 1971-04-20 | 1974-03-19 | Matsushita Electric Ind Co Ltd | Noise reduction system |
| JPS58154909A (en) * | 1982-03-10 | 1983-09-14 | Hitachi Ltd | Amplifying circuit possible for variable gain control |
| JP2002100944A (en) * | 2000-09-21 | 2002-04-05 | Nec Microsystems Ltd | Automatic gain controller |
| CN101154930A (en) * | 2006-09-27 | 2008-04-02 | 普诚科技股份有限公司 | Automatic gain control circuit |
| CN102427328A (en) * | 2011-09-28 | 2012-04-25 | 北京经纬恒润科技有限公司 | Sine wave oscillating circuit |
| CN203387474U (en) * | 2013-08-14 | 2014-01-08 | 董志伟 | Signal amplification circuit with gain changing along with time |
Non-Patent Citations (3)
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112187203A (en) * | 2020-09-14 | 2021-01-05 | 北京航空航天大学 | Automatic gain control circuit and gain adjusting method thereof |
| CN112187203B (en) * | 2020-09-14 | 2022-06-21 | 北京航空航天大学 | Automatic gain control circuit and gain adjusting method thereof |
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