CN108347231B - Broadband 90-degree phase shifter - Google Patents
Broadband 90-degree phase shifter Download PDFInfo
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- CN108347231B CN108347231B CN201810085250.8A CN201810085250A CN108347231B CN 108347231 B CN108347231 B CN 108347231B CN 201810085250 A CN201810085250 A CN 201810085250A CN 108347231 B CN108347231 B CN 108347231B
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- 230000010363 phase shift Effects 0.000 claims abstract description 29
- 238000006243 chemical reaction Methods 0.000 claims abstract description 24
- 239000003990 capacitor Substances 0.000 claims abstract description 19
- 230000003321 amplification Effects 0.000 claims description 4
- 238000003199 nucleic acid amplification method Methods 0.000 claims description 4
- 238000001914 filtration Methods 0.000 claims description 3
- 238000000034 method Methods 0.000 claims description 2
- 230000003287 optical effect Effects 0.000 description 9
- 229910052792 caesium Inorganic materials 0.000 description 4
- TVFDJXOCXUVLDH-UHFFFAOYSA-N caesium atom Chemical compound [Cs] TVFDJXOCXUVLDH-UHFFFAOYSA-N 0.000 description 4
- 238000010521 absorption reaction Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 2
- 230000005358 geomagnetic field Effects 0.000 description 2
- 230000010354 integration Effects 0.000 description 2
- 230000010355 oscillation Effects 0.000 description 2
- 150000001340 alkali metals Chemical group 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H11/00—Networks using active elements
- H03H11/02—Multiple-port networks
- H03H11/16—Networks for phase shifting
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
- Y02D30/00—Reducing energy consumption in communication networks
- Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks
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Abstract
A broadband 90 DEG phase shifter comprises a resistor R5, a resistor R3, a capacitor C2, an operational amplifier A1, a current controllable resistance unit and a phase difference/current conversion unit. The resistor R5, the resistor R3, the capacitor C2, the operational amplifier A1 and the current controllable resistance unit form a phase-shifting circuit. The phase difference/current conversion unit receives an input signal Uin and an output signal Uo of the operational amplifier A1, and converts the phase difference of two paths of signals into current output. The current controllable resistance unit receives the output current of the phase difference/current conversion unit, converts the current change into resistance change, controls the phase of the output signal of the phase shift circuit, and ensures that the phase difference between the input signal and the output signal of the phase shift circuit is 90 degrees. The phase shifter can adaptively track frequency change to input sinusoidal signals with frequency change in a wider frequency range to realize 90-degree phase shift under different frequencies.
Description
Technical Field
The invention relates to a broadband 90-degree phase shifter which is used for accurately shifting 90-degree phase of an alternating current sinusoidal signal.
Background
An optical pump magnetometer is a weak magnetic measuring instrument, which takes the Zeeman effect of some gaseous alkali metal atoms (39K, 87Rb, 133Cs, etc.) or some inert gas (3He, 4He) atoms in an external magnetic field as the basis, under the combined action of optical pumping and a radio frequency magnetic field, the atoms generate an optical magnetic resonance phenomenon, the size of the external magnetic field can be determined according to the frequency of the radio frequency magnetic field, and the optical pump magnetometer can be divided into a tracking type and a self-excited oscillation type according to different working modes. The two structures of magnetometers need to shift the phase of an output signal by 90 degrees and then feed back the phase to the sensor absorption chamber, so that the intensity of light is modulated by working substances in the absorption chamber in an absorption mode, the intensity change frequency of the modulated light is detected by the photosensitive diode, and the frequency is in direct proportion to an external magnetic field, and then a magnetic field value to be measured can be obtained. The phase shift error can cause the magnetic field measurement error, so the design of the high-precision broadband 90-degree phase shift network is one of the key technologies of the optical pump magnetometer.
A cesium optical pump magnetometer for measuring the geomagnetic field needs an accurate 90-degree phase shift circuit capable of self-adapting to frequency change in the range of 50KHz-350KHz, namely, when the input frequency of the circuit is required to be randomly changed in the range of 50KHz-350KHz, the phase difference of the output signal of the cesium optical pump magnetometer is always lagged behind the phase difference of the input signal by 90 degrees. Most of the current phase shifting circuits shift the phase of a signal with a narrow frequency range or a fixed frequency. For example, the' 201410411245.3 patent describes a phase shift circuit using the integration and comparator principle, which cannot perform a precise 90 ° phase shift on signals with frequencies higher than 10KHz due to the time required for the charging and discharging process of the integration. In addition, a phase shift circuit realized by using an RLC network is provided, and the phase shift network can accurately perform 90-degree phase shift on a fixed frequency point by adjusting R, L, C three parameters, and once the frequency changes, the phase shift angle deviates from 90 degrees, so that the 90-degree phase shift of self-adaptive frequency change in a broadband range cannot be realized. In addition, 90 ° phase shifters in a wide frequency band are also required in other engineering applications.
Disclosure of Invention
The invention aims to overcome the defects in the prior art, and provides a broadband 90-degree phase shifter which can adaptively track frequency change to sinusoidal signals with changed input frequency and realize 90-degree phase shift under different frequencies in a wider frequency range.
The technical scheme adopted by the invention is as follows:
a broadband 90 DEG phase shifter comprises a resistor R5, a resistor R3, a capacitor C2, an operational amplifier A1, a current controllable resistance unit and a phase difference/current conversion unit.
One end of the resistor R5 is connected with the phase difference/current conversion unit, the other end of the resistor R5 is connected with one end of a resistor R3 and the reverse input end of an operational amplifier A1, and the other end of the resistor R3 is connected with the output end of an operational amplifier A1;
one end of the capacitor C2 is connected with one end of the resistor R5, and the other end of the capacitor C2 is connected with the current controllable resistance unit and the equidirectional input end of the operational amplifier A1;
the output end of the operational amplifier A1 is connected with the phase difference/current conversion unit, and the phase difference/current conversion unit is connected with the current controllable resistance unit;
the resistor R5, the resistor R3, the capacitor C2, the operational amplifier A1 and the current controllable resistance unit form a phase-shifting circuit;
the phase difference/current conversion unit receives an input signal Uin and an output signal Uo of an operational amplifier A1, and converts the phase difference of two paths of signals into current output;
the current controllable resistance unit receives the output current of the phase difference/current conversion unit, converts the current change into resistance change, controls the phase of the output signal of the phase shift circuit, and ensures that the phase difference between the input signal and the output signal of the phase shift circuit is 90 degrees.
The current controllable resistance unit comprises a photoresistor R and a light emitting diode D1, wherein the light emitting diode D1 is bonded with a transparent window of the photoresistor R and is packaged by a heat shrinkable tube to form a 4-port element;
wherein, the port I and the port II are respectively: an anode of the light emitting diode D1, a cathode of the light emitting diode D1;
a port I is connected with a current output end Iout of the phase difference/current conversion unit;
the port is grounded;
the port (c) and the port (c) are output pins of the photoresistor R, wherein the port (c) is connected with the homodromous input end of the operational amplifier A1, and the port (c) is grounded.
The phase difference/current conversion unit includes:
the first comparator consists of a resistor R1, a resistor R4 and a comparator A2;
the second comparator is composed of a resistor R9, a resistor R6 and a comparator A3;
the output end of the first path of comparator is connected with two input ends of a two-input AND gate U1A;
the output ends of the first path of comparator and the second path of comparator are respectively connected with two input ends of a two-input AND gate U1B;
the resistor R2 is connected with the capacitor C1 to form a low-pass filter of the first and gate output;
the resistor R10 is connected with the capacitor C3 to form a low-pass filter of the output of the second AND gate;
two paths of output signals after low-pass filtering are respectively connected into two paths of voltage followers formed by an operational amplifier A4 and an operational amplifier A5: the first path of voltage follower and the second path of voltage follower are connected;
the output voltage of the first path of voltage follower passes through a voltage division network formed by resistors R8 and R7 and then is connected to an operational amplifier A6 together with the output voltage of the second path of voltage follower;
the output end of the operational amplifier A6 is connected with a current amplification circuit which is composed of a resistor R11, a resistor R13 and a PNP triode Q1, and Iout of the current amplification circuit is connected with a port (R) of the current controllable resistance unit.
Compared with the existing 90-degree phase shifter or phase shift circuit, the broadband 90-degree phase shifter has the following technical effects: 1. the phase shift precision is high: the phase shift precision of the circuit is determined by whether the voltage difference of the positive input end and the negative input end of the amplifier is zero, if the voltage difference is zero, the phase difference is 90 degrees, the positive input end and the negative input end of the circuit are required to be consistent according to the virtual break principle of the operational amplifier, otherwise, the output of larger voltage is generated under the condition of extremely large gain, so that the phase shift circuit is controlled to carry out phase adjustment, the input voltage difference of the amplifier can be adjusted according to the phase adjustment result, and finally, the input voltage difference is zero, so that the phase shift precision.
2. The phase shift range is wide: under the condition of the selected capacitance, the 90-degree accurate phase shift can be realized on the input sinusoidal signal with any frequency within the working limit range of the selected electronic component.
3. The response tracking speed is high: once the frequency of the input sinusoidal signal changes, the phase difference between the input signal and the output signal deviates from 90 degrees, and because the operational amplifier works in an open loop state and the open loop gain is extremely large, the control speed of the phase difference adjustment is very high, and the phase difference can quickly return to 90 degrees.
Drawings
Fig. 1 is a block diagram of a wideband 90 ° phase shifter according to the present invention.
Fig. 2 is a schematic diagram of the current controllable resistance unit according to the present invention.
Fig. 3 is a circuit diagram of the phase difference/current conversion unit according to the present invention.
Detailed Description
As shown in fig. 1, in order to achieve the above object, the present invention adopts the following technical solutions: a wide-band 90 DEG phase shifter includes resistors R5, R3, a capacitor C2, an operational amplifier A1, a current controllable resistance unit and a phase difference/current conversion unit. The resistors R5 and R3, the capacitor C2, the operational amplifier a1, and the current controllable resistance unit constitute a phase shift circuit, and the phase difference between the input signal and the output signal of the phase shift circuit is controlled by the output current of the phase difference/current conversion unit.
The resistors R5 and R3, the capacitor C2, the operational amplifier A1 and the current controllable resistance unit form a phase-shifting network, according to the virtual short and virtual break principle of the operational amplifier, R5 is taken as R3, and the phase-shifting network needs to meet the following conditions for realizing 90-degree phase shifting:
in the formula: f is the frequency of the input sinusoidal signal, and R is the resistance value of the current controllable resistance unit. Once capacitance C2After selection, R must be adjusted according to different input frequencies to maintain the input signal 90 ° out of phase with the output signal for different input frequencies f.
The current controllable resistance unit is composed of a photoresistor R and a light-emitting diode D1, the light-emitting diode and a transparent window of the photoresistor are bonded together and packaged by a heat-shrinkable tube to form a 4-port element, wherein ports (i) and (ii) are an anode and a cathode of the light-emitting diode, the port (i) is connected with a current output Iout of the phase difference/current conversion unit, and the port (ii) is grounded; ports (c) and (c) are photoresistor output pins, wherein the port (c) is connected with the negative input end of the amplifier A1, and the port (c) is grounded. Because the whole device is in a sealed state, the photoresistor is not illuminated, and the ports (c) and (d) have extremely large output resistors. After the current is injected into the port I and the port II is grounded, the light emitting diode emits light to irradiate the photoresistor, so that the resistance value of the photoresistor changes along with the change of the luminous intensity of the light emitting diode, the luminous intensity of the light emitting diode can be changed by changing the current of the injection port I, and the purpose of changing the output resistors of the port III and the port IV is achieved.
The phase difference/current conversion unit includes: the resistors R1 and R4 and the comparator A2 form a first comparator, and the resistors R9 and R6 and the comparator A3 form a second comparator; the output of the first path of comparator is connected with two input ends of a two-input AND gate U1A, and the outputs of the first path of comparator and the second path of comparator are respectively connected with two input ends of a two-input AND gate U1B; the resistor R2 and the capacitor C1 form a low-pass filter of the output of the first AND gate, and the resistor R10 and the capacitor C3 form a low-pass filter of the output of the second AND gate; the two paths of output signals after low-pass filtering are respectively connected into two paths of voltage followers formed by operational amplifiers A4 and A5; the output voltage of the first follower passes through a voltage division network formed by resistors R8 and R7 and then is connected into an operational amplifier A6 together with the output voltage of the second follower; the output of the operational amplifier A6 is connected with a current amplifying circuit composed of resistors R11 and R13 and a PNP triode Q1, and the Iout of the current amplifying circuit is connected with the port (R) of the current controllable resistance unit.
Resistors R1 and R4 and a comparator A2 form a first comparator, the first comparator changes an input sine signal Uin into a TTL square wave signal with a duty ratio of 50%, the output square wave signal is respectively connected to pins 1 and 2 of a two-input AND gate U1A and pin 4 of the two-input AND gate U1B, and the waveform of an output pin 3 of the U1A is completely consistent with the waveform of input pins 1 and 2 and is a square wave with a duty ratio of 50%. After the square wave with 50% duty ratio output by the pin 3 of the U1A is low-pass filtered by R1 and C1, a dc voltage of VCC/2 is generated at the pin 3 of the positive input terminal of the amplifier a4, and when the dc voltage is taken as R8 ═ R7, the dc voltage passes through a voltage follower formed by an amplifier a4 and a voltage division network formed by R8 and R7, and then a dc voltage of VCC/4 is generated at the pin 3 of the negative input terminal of the amplifier a 6.
Resistors R9 and R6 and a comparator A3 form a second comparator which converts a sinusoidal signal Uo output by the phase-shift circuit into a TTL square waveThe outgoing square wave signal is connected into the 5 pins of the two-input AND gate U1B, and the phase difference between Uin and Uo is assumed to beThen a duty cycle of "d" is generated at output pin 6 of U1BThe square wave of (2). 6 pin output duty cycle of U1BAfter being low-pass filtered by R10 and C3, the square wave of the amplifier A5 is generated at the positive input end 3 pinsThe dc voltage is inputted to the positive input terminal of the amplifier a6 after passing through a voltage follower constituted by the amplifier a 5.
The amplifier A6 is used as an error amplifier for combining the DC voltage VCC/4 output from the first path with the DC voltage output from the second pathThe amplified voltage signal acts on a current amplifier formed by R11 and Q1, and a current signal is output and injected into the port (R) of the current controllable resistor to control the resistance value between the port (R) and the port (R) of the current controllable resistor. Because the amplifier A6 is in open-loop working state, if and only if the DC voltage VCC/4 outputted by the first path and the DC voltage outputted by the second path areWhen they are equal, the output voltage of the amplifier A6 no longer changes, and the calculation can be madeI.e. Uin and Uo are 90 out of phase.
When the frequency of the input signal Uin changes, the phase difference between the input signal Uin and the output signal Uo of the phase shift circuit is not 90Then the DC voltage VCC/4 output by the first path and the DC voltage output by the second path of the amplifier A6 are setWhen the voltage drop of the output of the amplifier A6 is not equal to that of the current amplifier composed of R11 and Q1, the current is generated to adjust the output resistance of the current controllable resistor, so as to change the phase difference between Uin and Uo until the phase difference is 90 degrees, namely, the DC voltage VCC/4 output by the first path of the amplifier A6 and the DC voltage VCC/4 output by the second path of the amplifier A6 are equal to each otherUntil equal.
As the cesium optical pump magnetometer for measuring the geomagnetic field needs to shift the phase of an output signal by 90 degrees within the range of 50KHz to 350KHz and feed back the phase to a sensor, a self-oscillation system is formed, and the oscillation output frequency is in direct proportion to an external magnetic field. The broadband 90-degree phase shifter can be used for a broadband phase shifting network of a cesium optical pump magnetometer.
Claims (2)
1. A broadband 90 DEG phase shifter comprises a resistor R5, a resistor R3, a capacitor C2, an operational amplifier A1, a current controllable resistance unit and a phase difference/current conversion unit; the method is characterized in that:
one end of the resistor R5 is connected with the phase difference/current conversion unit, the other end of the resistor R5 is connected with one end of a resistor R3 and the reverse input end of an operational amplifier A1, and the other end of the resistor R3 is connected with the output end of an operational amplifier A1;
one end of the capacitor C2 is connected with one end of the resistor R5, and the other end of the capacitor C2 is connected with the current controllable resistance unit and the equidirectional input end of the operational amplifier A1;
the output end of the operational amplifier A1 is connected with the phase difference/current conversion unit, and the phase difference/current conversion unit is connected with the current controllable resistance unit;
the resistor R5, the resistor R3, the capacitor C2, the operational amplifier A1 and the current controllable resistance unit form a phase-shifting circuit;
the phase difference/current conversion unit receives an input signal Uin and an output signal Uo of an operational amplifier A1, and converts the phase difference of two paths of signals into current output;
the current controllable resistance unit receives the output current of the phase difference/current conversion unit, converts the current change into resistance change, controls the phase of the output signal of the phase shift circuit and ensures that the phase difference between the input signal and the output signal of the phase shift circuit is 90 degrees;
the phase difference/current conversion unit includes:
the first comparator consists of a resistor R1, a resistor R4 and an operational amplifier A2;
the second path of comparator consists of a resistor R9, a resistor R6 and an operational amplifier A3;
the output end of the first path of comparator is connected with two input ends of a two-input AND gate U1A;
the output ends of the first path of comparator and the second path of comparator are respectively connected with two input ends of a two-input AND gate U1B;
the resistor R2 is connected with the capacitor C1 to form a low-pass filter of the first and gate output;
the resistor R10 is connected with the capacitor C3 to form a low-pass filter of the output of the second AND gate;
two paths of output signals after low-pass filtering are respectively connected into two paths of voltage followers formed by an operational amplifier A4 and an operational amplifier A5: the first path of voltage follower and the second path of voltage follower are connected;
the output voltage of the first path of voltage follower passes through a voltage division network formed by resistors R8 and R7 and then is connected to an operational amplifier A6 together with the output voltage of the second path of voltage follower;
the output end of the operational amplifier A6 is connected with a current amplification circuit which is composed of a resistor R11, a resistor R13 and a PNP triode Q1, and Iout of the current amplification circuit is connected with a port (R) of the current controllable resistance unit.
2. A wideband 90 ° phase shifter according to claim 1, wherein: the current controllable resistance unit comprises a photoresistor R and a light emitting diode D1, wherein the light emitting diode D1 is bonded with a transparent window of the photoresistor R and is packaged by a heat shrinkable tube to form a 4-port element;
wherein, the port I and the port II are respectively: an anode of the light emitting diode D1, a cathode of the light emitting diode D1;
a port I is connected with a current output end Iout of the phase difference/current conversion unit;
the port is grounded;
the port (c) and the port (c) are output pins of the photoresistor R, wherein the port (c) is connected with the homodromous input end of the operational amplifier A1, and the port (c) is grounded.
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CN201810085250.8A CN108347231B (en) | 2018-01-29 | 2018-01-29 | Broadband 90-degree phase shifter |
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