CN107589690B - Harmonic signal phase adjusting method and device for piezoelectric micro-fluidic system - Google Patents
Harmonic signal phase adjusting method and device for piezoelectric micro-fluidic system Download PDFInfo
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Abstract
The invention discloses a harmonic signal phase adjusting method and a device for a piezoelectric micro-fluidic system, which are characterized by comprising the following steps: a main control chip,A structural circuit,The circuit comprises a construction circuit, a conditioning circuit, a key circuit and a display circuit; during phase adjustment, harmonic signals are input in the form of two lines of orthogonal signals, and the main control chip sends digital control quantity k to the T-shaped resistance network I and the T-shaped resistance network II1、k2Meridian/channelA structural circuit,After the structural circuit and the conditioning circuit are processed, the structure circuit and the conditioning circuit are obtainedAnalog quantity, which realizes the phase adjustment of harmonic signals; the digital control quantity is stored in the main control chip in a table form; the phase adjusting range is 0-360 degrees; by setting ntabThe value, phase resolution may be of any precision.
Description
Technical Field
The invention relates to the technical field of harmonic signal phase adjustment, in particular to a harmonic signal phase adjustment method and device for a piezoelectric micro-fluidic system. The adjustment range of the harmonic phase is 0-360 degrees, and the resolution can be any precision.
Background
Complex piezoelectric microfluid control systems (such as a double-active-valve piezoelectric micropump and a double-cavity series piezoelectric micropump) are often driven by multiple harmonic signals, the phase difference between the harmonic signals is precisely adjusted, and parameters such as the output pressure and the flow of the micropump can be accurately controlled. For voltage control, frequency control mode, be favorable to piezoelectricity micropump life-span, control process is steady, but also can realize micropump function extension: for example, for a double-active piezoelectric micropump, the phase difference between harmonic signals is adjusted, and when the phase difference is continuously changed between 0 degrees and 360 degrees, the conveying direction and the output flow of the fluid can be changed, so that the micropump has the function of bidirectionally conveying the fluid. In addition, the harmonic signal phase adjustment technology plays an important role in piezoelectric miniature precision drivers, micro-grid parallel systems, power system relay protection devices, communication and laser technologies.
In the past, an RC circuit is often adopted for harmonic signal phase adjustment, the RC circuit is simple in form, but the phase adjustment range is narrow, and parameters such as signal frequency and amplitude are easy to change in the adjustment process; the other method is to adopt a direct digital frequency synthesis (DDS) technology, but for a specific type of DDS chip, the phase resolution is fixed and cannot be arbitrarily improved according to needs. The method is characterized in that waveform data are stored in a storage unit, the content or address of the storage unit is modified by a microcontroller according to the phase adjustment requirement, so that the output phase is changed, and the method has high requirement on the processing speed of the microcontroller due to the continuous sampling and reconstruction, and is not suitable for occasions with high working frequency.
Therefore, it is an object of the present invention to provide a method and an apparatus for adjusting the phase of a harmonic signal with as high resolution and as wide an adjustment range as possible.
Disclosure of Invention
The invention aims to solve the technical problem of overcoming the defects of the prior art, and provides a harmonic signal phase adjusting method for a piezoelectric micro-fluidic system, which is scientific and reasonable, strong in applicability, good in effect, capable of meeting the driving control requirements of the complex piezoelectric micro-fluidic system, has an adjusting range of 0-360 degrees and a resolution ratio of any precision, and a device thereof.
One of the solutions to solve the technical problem is a method for adjusting the phase of a harmonic signal for a piezoelectric micro-fluidic system, which is characterized by comprising the following steps:
(1) The harmonic signal sinx to be phase-modulated is input into the circuit in the form of two columns of quadrature signals sinx, cosx, wherein the sinx signal is input into the circuitIn the construction circuit, cosx signal is input toConstructing a circuit;
(2) In thatIn the structure circuit, the main control chip sends digital control quantity k to the first T-shaped resistance network1After being processed by the voltage converter I and the bipolar converter I, the voltage expression is constructed and obtainedThe analog signal of (1); in thatin the structure circuit, the main control chip sends digital control quantity k to the T-shaped resistance network II2after being processed by the voltage converter II and the bipolar converter II, the voltage expression is constructed and obtainedThe analog signal of (1); digital control quantity k1The value is obtained by inquiring a cosine construction table tab _ cos, and the numerical control quantity k2The values are obtained from the sine construction table tab _ sin;
(3)Voltage u for constructing circuit structure12Output andvoltage u for constructing circuit structure22The output is simultaneously input into a conditioning circuit to form a voltage u12and the constructed voltage u22Adding and amplitude processing are carried out to obtain voltageAmplitude modulation tofinally obtaining the analog quantityi.e. a phase difference ofThereby achieving phase adjustment.
Phase difference of phase adjustmentDigital control quantity k sent by main control chip1，k2Determining, digitally controlling quantity k1Constructing table tab _ cos and digital control quantity k by cosine2The sine structure table tab _ sin is stored in the main control chip, and the phase adjusting process comprises the following steps:
(1) Firstly, i is assigned with 0 and points to the 0 th element of the tab _ cos table and the tab _ sin table;
(2) Judging whether a key is pressed or not, if the key is pressed and is a key 1 'phase +', adding 1 to the value of i, and further judging whether the value of i is more than or equal to n at the momenttabIf yes, i is reset; if the key is pressed to be 2 'phase-', subtracting 1 from the value of i, further judging whether i is less than 0, and if the value of i is less than 0, assigning the value of i to be ntab-1; if no key is pressed, jumping to the step (4);
(3) The main control chip sends digital control quantity k to the T-shaped resistance network I1＝tab_cos[i](ii) a Sending digital control quantity k to T-shaped resistance network two 512＝tab_sin[i]；
(4) Display phase difference
(5) And (4) returning to the step (2).
The second solution to solve the technical problem is to provide a harmonic signal phase adjusting device for a piezoelectric micro-fluidic system, which is characterized by comprising:A structural circuit,the device comprises a construction circuit, a conditioning circuit, a main control chip, a key, a display circuit, and a cosine construction table tab _ cos and a sine construction table tab _ sin in a main control chip storage unit; the harmonic signals to be phase-modulated are fed into the circuit in the form of two quadrature signals sinx, cosx, the sinx signals being fed into the circuitIn the construction circuit, cosx signal is input toconstructing a circuit; the above-mentionedThe construction circuit comprises a T-shaped resistance network I, a voltage converter I and a bipolar converter I, and is used for constructing and obtaining a voltage expressionin an analog quantity ofIn the structure circuit, the main control chip sends n-bit digital control quantity k to a first T-type resistance network1The switching state of an electronic switch in the first T-shaped resistance network is controlled, the output of the first T-shaped resistance network is connected with the first voltage converter, and the output of the first voltage converter is connected with the first bipolar converter; the above-mentionedThe construction circuit comprises a T-shaped resistance network II, a voltage converter II and a bipolar converter II, and is used for constructing and obtaining a voltage expressionIn an analog quantity ofIn the structure circuit, the main control chip sends n-bit digital control quantity k to the T-type resistance network II2the switching state of an electronic switch in the T-shaped resistance network II is controlled, the output of the T-shaped resistance network II is connected with the voltage converter II, and the output of the voltage converter II is connected with the bipolar converter II;Output of the structure circuit andConstructing the output of the circuit and inputting the output into the conditioning circuit; the conditioning circuit comprises an adding circuit and a proportional amplifying circuit, and the function of the adding circuit is to add the addition signal to the proportional amplifying circuitStructural circuit andAdding the analog quantities generated by the structural circuit, adjusting the voltage amplitude to obtain the analog quantityI.e. a phase difference ofThereby achieving phase adjustment.
the third solution to solve the technical problem is a harmonic signal phase adjusting device for a piezoelectric micro-fluidic system, characterized in that k is1constructing table tab _ cos, k by cosine2The form of the sine configuration table tab _ sin is stored in the memory unit of the main control chip,
The analytical formula of the tab _ cos table element is as follows:
The analytical formula of the tab _ sin table elements is as follows:
i ranges from 0 to ntab-1。
The invention realizes the phase adjustment by inputting the harmonic signal sinx to be processed into a circuit in the form of orthogonal signal sinx, cosx, pertinently constructing a main control chip, a T-shaped resistance network, a voltage converter and a bipolar converterA structural circuit,Constructing the circuit to fit the analog quantityThen obtaining the product after summation and amplitude modulationNamely, it isBy this method, the harmonic signal is converted from sinx to sinxA phase difference between the two isThereby achieving an adjustment of the phase of the harmonics, wherein,The value size and the resolution can be freely and flexibly set through software.
The invention has the further advantages that:
(1) when i is from 0 to ntabWhen the phase position is changed to-1, the phase position adjusting range is 0-360 degrees, and the phase position adjusting range is wide;
(2) The phase resolution may be of any precision. The phase adjustment resolution of the invention isThe resolution of the phase adjustment is determined by the number n of table elementstabDetermination of ntabThe larger the value, the higher the resolution. E.g. ntabAt a value of 360, the phase difference resolution is 1 °; if higher resolution is required, e.g. 0.1 °, 0.01 °, … …, it is only necessary to create a solution with a higher number of elements ntabThe phase resolution precision can be passed through as requiredthe software is flexibly set, and the resolution can be any precision;
(3) The main control chip sends k to the T-shaped resistance network only when the phase difference needs to be changed1，k2The circuit has low requirement on the processing speed of the main control chip, good frequency adaptability and low circuit cost;
(4) The phase difference parameter is digitally controlled, can be continuously and linearly adjusted, and is convenient to use;
(5) The method is scientific and reasonable, has strong applicability and good effect, and can meet the driving control requirement of a complex piezoelectric microfluid system.
The present invention will be described in detail with reference to the attached drawings and specific embodiments so that the features and advantages of the invention can be more fully understood.
Drawings
FIG. 1 is a schematic block diagram of harmonic signal phase adjustment;
FIG. 2 is a view of the view shown in FIG. 1Constructing a circuit schematic diagram;
FIG. 3 is a schematic diagram of the conditioning circuit shown in FIG. 1;
FIG. 4 is a block flow diagram of a process;
FIG. 5 is a schematic diagram of an embodiment of a harmonic signal phase adjustment apparatus according to the present invention;
FIG. 6 is a schematic diagram of a quadrature harmonic signal generation circuit;
Fig. 7 is a waveform diagram obtained in the harmonic signal phase adjustment experiment.
Detailed Description
fig. 1 is a schematic block diagram of harmonic signal phase adjustment. The phase adjusting device consists of a main control chip 1,A structural circuit 4,A structure circuit 5, a conditioning circuit 6, a key circuit 2 and a display circuit 3.
To realize a phasePotential differenceThe harmonic signal needs to be input into the circuit in the form of two columns of orthogonal signals sinx, cosx (the orthogonal signals can be generated by a differentiating circuit, an integrating circuit or a DDS circuit, etc.), wherein the sinx signal is input into the circuitIn the configuration circuit 4, a cosx signal is inputted toThe circuit 5 is constructed.
The construction circuit 4 is used for constructing a voltage expressionThe circuit comprises a T-shaped resistor network I41, a voltage converter I42 and a bipolar converter I43.The construction circuit 5 is used for constructing a voltage expressionThe circuit comprises a second T-type resistor network 51, a second voltage converter 52 and a second bipolar converter 54.
During phase adjustment, the main control chip is in the direction of 1The construction circuit 4 sends a digital control quantityTo the direction ofThe construction circuit 5 sends a digital control quantity output signal of the configuration circuit 4 Output signal of the configuration circuit 5
Output u of the construction circuit 412andOutput u of the construction circuit 522and simultaneously to the conditioning circuit 6. The conditioning circuit 6 firstly combines and adds the two analog quantities to obtainThen adjusting the amplitude to obtainThe output of the conditioning circuit 6 is thusTo obtain a phase difference ofthereby realizing the adjustment of the phase.
in the harmonic signal phase adjusting device, a key circuit 2 and a display circuit 3 are connected with a main control chip 1 and used for setting and displaying a phase difference parameter in real time and realizing the digital control of the phase difference parameter.
FIG. 2 is a view of the view shown in FIG. 1A schematic diagram of the circuit is constructed. TheThe configuration circuit 4 comprises a first T-shaped resistor network 41, a voltage converter 42 and a bipolar converter 43.
The first T-shaped resistor network 41 comprises a plurality of resistors and electronic switches, the resistance values of the resistors are R and 2R, the number of the electronic switches is equal to the processing digit of the main control chip 1, and the electronic switches are set as n. The on-off state of the electronic switch is controlled by n-bit digital quantity sent by the main control chip 1, and each bit in the digital quantity respectively controls one electronic switch. When the control bit is '1', the corresponding electronic switch is connected with the first signal wire, and the current flows to the first signal wire; when the control bit is '0', the electronic switch is connected with the second signal wire, and the current flows to 'ground'. In a practical circuit, the first T-type resistor network 41 may be formed by discrete components, and in addition, the first T-type resistor network is widely present in various D/a converters and can be directly selected.
the first signal line of the first T-type resistor network 41 is connected to the non-inverting input terminal of the first voltage converter 42 (operational amplifier), and the second signal line is connected to the inverting input terminal of the first voltage converter 42. The output end of the first voltage converter 42 and the feedback resistor Rfb(RfbR) and the other end of the feedback resistor is connected to the inverting input of the first voltage converter 42.
Under the control of the electronic switch, the current signals of the resistance branches are weighted by the resistance network, and then are summed and converted into unipolar voltage signals by the voltage converter I42 to be output. Can determine the output u of the first voltage converter 4211Digital quantity k transmitted with main control chip 11The relationship between them is:
Here, let k1Has a value range of [1,2 ]n-1]Then the voltage expression u11Inpart of the range of values is Is a negative variable (unipolar) not consistent with the polarity distribution of the cos function, and therefore requires the signal u to be applied11Further sent to a bipolar converter 43 for conversion into bipolar signals.
The first bipolar converter 43 is essentially a summing circuit consisting of an operational amplifier and a resistor R41、R42、R43And (4) forming. In the converter, R41One terminal of (A) is connected to a sinx signal, R42Is connected to the output of the voltage converter one 42, R43One end of which is connected to the output of the operational amplifier, R41、R42、R43the other end of the operational amplifier is connected with the inverting input end of the operational amplifier, and the non-inverting input end of the operational amplifier is grounded.
It can be found that the output of the first bipolar converter 43 is: u. of12＝-(sinx+2u11) Into u11And simplifying to obtain:when k is1From 1 to 2nwhen the number of the terminal units is changed from-1,Has a value range ofThe positive and negative intervals are symmetrical. Order toNamely, it is
The output of the first bipolar converter 43 is:Thereby constructingAn item.
In the same way, inIn the structural circuit 5, the digital quantity sent by the main control chip 1 to the T-type resistor network two 51 is:
Make the output of the bipolar converter two 53Thereby constructingAn item.
fig. 3 is a schematic diagram of the conditioning circuit shown in fig. 1. The function of the conditioning circuit 6 is to convert two analog quantities u12、u22And combining and adding, and adjusting the amplitude. The conditioning circuit 6 is composed of an adder circuit and a proportional amplifier circuit. The addition circuit comprises an operational amplifier and a resistor R61、R62、R63Formed by adding the circuit output u3And u12、u22the relationship of (1) is: u. of3＝-(u12+u22). Substitution of u12、u22Further, it can be obtainedSignal u3Then sent into a proportional amplifying circuit which is composed of an operational amplifier and a resistor R64And a variable resistor R65Is formed with an output ofAdjusting the variable resistance R65To makethe conditioning circuit 6 outputs uocomprises the following steps:
uoI.e. the output of the whole harmonic signal phase adjusting device. It can be seen that the original signal sinx to be processed is obtained through a series of processingThe phase difference is generated between the signal and sinxThereby achieving phase adjustment of the harmonic signal.
Fig. 4 is a flow chart of a harmonic signal phase adjustment routine. In the phase adjustment process, the invention adopts a mode of combining hardware and software. In phase modulation circuits, phase differenceControl quantity k sent by the master control chip 11，k2To determine so as to be able to fit correctlyterm, thereby producing a phase shift ofThe harmonic signal of (2), and the digital quantity k sent to the first T-shaped resistance network 41 and the second T-shaped resistance network 511，k2Can be calculated in advance, is stored in a storage unit of the main control chip 1 in a table form, and can be directly taken out by looking up the table when needed, namely k1＝tab_cos[i]，k2＝tab_sin[i]。
For the present embodiment, according to the resolutionand (3) establishing a cosine structure table tab _ cos and a sine structure table tab _ sin, wherein when the electronic switching bit number of the T-type resistor network is n, the element analytic expression in the tab _ cos table obtained by the expressions (1) and (2) is as follows:
the element analytic formula in the tab _ sin table is as follows:
i ranges from 0 to ntab-1, when i varies by 1, the output phasea variation amount ofWhen the cosine structure table tab _ cos and the sine structure table tab _ sin are established, the resolution ratio is firstly determinedRequest to calculate ntabThe value is obtained.
The program flow comprises the following steps:
(1) firstly, i is assigned with 0 to point to the 0 th element of the tab _ cos table and the tab _ sin table;
(2) Judging whether a key is pressed or not, if the key is pressed and is a key 1 (phase +'), adding 1 to the value i, and further judging whether the value i is more than or equal to n at the momenttabif yes, i is reset; if the key is pressed to be a key 2 (phase-), subtracting 1 from the value of i, further judging whether i is less than 0, and if the value of i is less than 0, assigning the value of i to be ntab-1; if no key is pressed, jumping to the step (4);
(3) The main control chip 1 sends a digital control quantity k to the T-shaped resistance network I411＝tab_cos[i](ii) a Sending digital control quantity k to T-shaped resistance network two 512＝tab_sin[i]。
(4) Display phase difference
(5) Returning to the step (2);
By adjusting and explaining the working principle of the harmonic signal phase circuit, the circuit has the following characteristics
(1) When i is from 0 to ntabWhen the phase position is changed to-1, the phase position adjusting range is 0-360 degrees, and the full phase position range is adjustable;
(2) The phase resolution may be of any precision. The phase adjustment resolution of the invention isby this expression, the phase adjustment resolution is defined by the number n of table elementstabDetermination of ntabThe larger the value, the higher the resolution. For example, the number of table elements ntabwhen the phase difference resolution is 360 degrees, the phase difference resolution is 1 degree; if higher resolution is required, e.g. 0.1 °, 0.01 °, … …, it is only necessary to create a solution with a higher number of elements ntabThe table of (2) is required, and the phase resolution precision can be flexibly set through software according to the requirement;
(3) The main control chip sends k to the T-shaped resistance network only when the phase difference needs to be changed1，k2the circuit has low requirement on the processing speed of the main control chip, low circuit cost and good frequency adaptability.
(4) The phase difference parameter is digitally controlled, can be continuously and linearly adjusted, and is convenient to use.
Fig. 5 shows an embodiment of the phase adjustment apparatus for harmonic signals according to the present invention. The functions of all components and the circuit connection form completely correspond to the divided modules in the figure 1.
The circuit conforming to the method can be in various forms, and for expression concreteness, the main control chip and the T-shaped resistor network in the circuit are 8-bit without loss of generality. The main control chip is AT89S51 and is used for sending digital control quantity k1、k2And identifying the key action and calling a processing program. The T-shaped resistor network can be composed ofThe discrete component is formed, and in addition, a T-shaped resistance network is also widely existed in various D/A converters, and the T-shaped resistance network comes from a D/A converter DAC0832 in the embodiment. In addition, the circuit includes an operational amplifier of type LM324 and a resistor R41、R42、R43、R51、R52、R53、R61、R62、R63、R64、R65。
for a main control chip with higher digit n and a T-shaped resistance network, the design method and the working principle of the harmonic signal phase adjusting circuit are similar.
The corresponding relationship between the first T-shaped resistance network 41, the second T-shaped resistance network 51 signal nodes and the pins of the DAC0832 chip is as follows:
(1) Vref pin of DAC0832_1 and V in T-shaped resistor network one 41refThe ends are corresponding to the same signal node, and pins Iout1 and Iout2 of DAC0832_1 are respectively connected with I in the T-type resistor network I41out1、Iout2The ends are the same signal node; (2) the corresponding relationship between the DAC0832_2 pin and the signal node of the T-type resistor network one 51 is similar to (1).
In the circuit, the P0 port of the main control chip AT89S51 is connected with the DAC0832_1 and the data ports DI 0-DI 7 of the DAC0832_2 AT the same time, and the P2.5 pin is connected with the DAC0832_1With pin, P2.6 pin, DAC0832_2Pin P2.7 is connected to both DAC0832_1 and to Xfer from DAC0832_2,of pin and DAC0832_1Of pins and DAC0832_2The pins are connected simultaneously.
The sinx signal is connected to the Vref pin of DAC0832_1 and the cosx signal is connected to the Vref pin of DAC0832_ 2. Iout1, Iout2 and R of DAC0832_1fbthe pins are respectively connected with the inverting input end, the non-inverting input end and the output end of the first voltage converter 42; similarly, Iout1, Iout2 and R of DAC0832_2fbthe pins are respectively connected with the inverting input end, the non-inverting input end and the output end of the second voltage converter 52.
Through the circuit connection form, the main control chip AT89S51 can control the digital control quantity k through the port P01、k2Respectively sent to the electronic switches of the DAC0832_1 chip and the T-type resistance network module in the DAC0832_2 chip. In this embodiment, the number of table elements ntabThe selection is 360, and since AT89S51 has a processing bit number of 8, that is, n is 8, the transmitted digital control quantity is obtained from equations (3) and (4), and its specific expression isafter being processed by the first voltage converter 42 and the second voltage converter 52, the signals are generatedAnd
The output of voltage converter one 42 (pin 1) and the sinx signal are simultaneously connected to bipolar converter one 43. The output of the second voltage converter 52 is connected to the second bipolar converter 53 along with the cosx signal.
The first bipolar converter 43 is composed of an operational amplifier chip LM324(U21C), a resistor R41、R42、R43And (4) forming. R41One terminal of (A) is connected to a sinx signal, R42Is connected to the output of the voltage converter one 42, R43One end of which is connected to the output of the operational amplifier, R41、R42、R43The other end of the operational amplifier is connected with the inverting input end of the operational amplifier, and the non-inverting input end of the operational amplifier is grounded. The operation of the first bipolar converter 43 is illustrated in detail in FIG. 2, the output of which is
Similarly, the second bipolar converter 53 is composed of an operational amplifier chip LM324(U22D), a resistor R51、R52、R53and (4) forming. R51One terminal of (a) is connected to a cosx signal, R52One end of the first voltage converter is connected with the output of the second voltage converter 52, R53One end of which is connected to the output of the operational amplifier, R51、R52、R53the other end of the operational amplifier is connected with the inverting input end of the operational amplifier, and the non-inverting input end of the operational amplifier is grounded. Similar to the output of the first bipolar converter 43, the output of the second bipolar converter 53 is
the outputs of the first bipolar converter 43 and the second bipolar converter 53 are simultaneously input to the conditioning circuit 6. The conditioning circuit 6 is used for combining and adding the two analog quantities and adjusting the amplitude. The conditioning circuit 6 is composed of an adder circuit and a proportional amplifier circuit. The adder circuit comprises an operational amplifier LM324 and a resistor R61、R62、R63Is used for adding two analog signals, and the obtained signals areThe signal output by the adder circuit is then fed to a proportional amplifier circuit. The proportional amplifying circuit comprises LM324 and resistor R64Potentiometer R65Is formed in an input-output relationship ofProportional amplifying circuit for eliminating uo1The negative sign in the expression and the coefficient is adjusted to 1, so that the phase modulation circuit output is equal to the amplitude of the signal to be phase modulated. The input-output relationship of the whole conditioning circuit 6 is:to obtain the phase difference ofThereby realizing the adjustment of the phase.
examples of the present invention ntabThe value is chosen to be 360 and the phase adjustment resolution is 1, which can meet the control requirements of most piezoelectric microfluidic systems. For the application with higher requirement on phase adjustment precision, the program is changed and the proper n is settabBy recalculating the tab _ cos and tab _ sin tables, the desired, higher resolution phase difference output can be achieved.
Fig. 6 is a schematic diagram of a quadrature harmonic signal generating circuit. As a prerequisite for the operation of the embodiment shown in fig. 5, the harmonic signal to be phase modulated needs to be input into the circuit in the form of two columns of quadrature signals (sinx, cosx). The quadrature harmonic signal may be generated using a differentiating circuit, an integrating circuit, or a DDS circuit. A practical DDS quadrature harmonic signal generating circuit is presented below which is not part of the invention itself but which is helpful in understanding the principles of operation of the circuit of the invention.
The circuit comprises a main control chip AT89S51 (distinguished from AT89S51 in FIG. 5 and marked as AT89S51_2), two DDS chips AD9850(AD9850_1 and AD9850_2), a clock crystal oscillator (125MHz), a D flip-flop 74HC74 and a resistor R71、R72、R73、R72。
The AD9850 employs a "direct digital frequency synthesis" technique to generate harmonic signals whose frequency and initial phase are set by AT89S51_2 with a frequency resolution of 0.291Hz and an initial phase resolution of 11.25 °. To obtain a phase resolution of less than 11.25 °, the chip itself cannot be realized.
in the circuit, a P2 port of a main control chip AT89S51_2 is connected with D0-D7 of AD9850_1 and is simultaneously connected with D0-D7 of AD9850_2, the AD9850_1 and the AD9850_2 adopt a common clock signal, and an output end of a clock crystal Y2 is connected with a pin 9 of the AD9850_1 and a pin 9 of the AD9850_ 2. The P3.0 pin of AT89S51 is connected to the W _ CLK terminal (pin 7) of AD9850_1, and the P3.1 pin of AT89S51_2 is connected to the W _ CLK terminal (pin 7) of AD9850_ 2. The output of the clock oscillator is connected to the input CLK (pin 3) of the D flip-flop 74HC 74. Pin P3.2 of AT89S51_2 is connected to the input terminal, terminal D (pin 2) of 74HC74, and the output terminal Q (pin 5) of D trigger 74HC74 is connected to terminal FQ _ UD (pin 8) of AD9850_1 and AD9850_ 2.
AT89S51_2 writes a control word into the control function register of AD9850 by a pulse AT the W _ CLK end, and after the writing is finished, FQ _ UD has a rising edge to make the frequency parameters and initial phase values of AD9850_1 and AD9850_2 effective AT the same time, and generates a harmonic signal with a constant phase difference of 90 °. In the circuit, AD9850_1 outputs a sinx signal, and AD9850_2 outputs a cosx signal.
Fig. 7 is a waveform diagram obtained in the harmonic signal phase adjustment experiment. In each sub-graph, the waveform curve passing through the central point is an original harmonic waveform, and the other waveform curve is a harmonic waveform after phase modulation.
It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications therefrom are within the scope of the invention.
Claims (3)
1. a method for phase adjusting a harmonic signal for a piezoelectric microfluidic system, comprising the steps of:
(1) The harmonic signal sinx to be phase-modulated is input into the circuit in the form of two columns of quadrature signals sinx, cosx, wherein the sinx signal is input into the circuitIn the construction circuit, cosx signal is input toConstructing a circuit;
(2) In thatIn the structure circuit, the main control coreSending digital control quantity k to T-shaped resistance network one chip1after being processed by the voltage converter I and the bipolar converter I, the voltage expression is constructed asN is the number of bits of the digital control quantity; in thatIn the structure circuit, the main control chip sends digital control quantity k to the T-shaped resistance network II2After being processed by the voltage converter II and the bipolar converter II, the voltage expression is constructed asThe analog signal of (1); digital control quantity k1the value is obtained by inquiring a cosine construction table tab _ cos, and the numerical control quantity k2The values are obtained from the sine construction table tab _ sin; cosine structure table tab _ cos and sine structure table tab _ sin, adjusting resolution according to phaseIt is required to establish that,
The analytic formula of the tab _ cos element of the cosine structure table is as follows:
The analytic formula of the tab _ sin elements of the sine structure table is as follows:
Wherein i ranges from 0 to ntab-1，ntabThe number of elements, n, of the cosine or sine configuration table tab _ cos or Tab _ sintabAndHave a relationship with
(3)Voltage u for constructing circuit structure12Output andVoltage u for constructing circuit structure22The output is simultaneously input into a conditioning circuit to form a voltage u12And the constructed voltage u22Adding and amplitude processing are carried out to obtainAmplitude modulation toFinally obtaining the analog quantityI.e. a phase difference ofThereby achieving phase adjustment.
2. A method of harmonic signal phase adjustment for a piezoelectric microfluidic system as in claim 1, wherein: phase difference of phase adjustmentDigital control quantity k sent by main control chip1，k2Determining, digitally controlling quantity k1Constructing table tab _ cos and digital control quantity k by cosine2The sine structure table tab _ sin is stored in the main control chip, and the phase adjusting process comprises the following steps:
(1) Firstly, i is assigned with 0 and points to the 0 th element of the tab _ cos table and the tab _ sin table;
(2) Judging whether a key is pressed or not, if the key is pressed and is a key 1 'phase +', adding 1 to the value of i, and further judging whether the value of i is more than or equal to n at the momenttabif yes, i is reset; if the key is pressed to be 2 'phase-', subtracting 1 from the value of i, further judging whether i is less than 0, and if the value of i is less than 0, assigning the value of i to be ntab-1; if no key is pressed, jumping to the step (4);
(3) The main control chip sends digital control quantity k to the T-shaped resistance network I1＝tab_cos[i](ii) a Sending digital control quantity k to T-shaped resistance network two 512＝tab_sin[i]；
(4) Display phase difference
(5) And (4) returning to the step (2).
3. A harmonic signal phase adjustment device for a piezoelectric microfluidic system, comprising:A structural circuit,The device comprises a construction circuit, a conditioning circuit, a main control chip, a key, a display circuit, and a cosine construction table tab _ cos and a sine construction table tab _ sin in a main control chip storage unit; the harmonic signals to be phase-modulated are fed into the circuit in the form of two quadrature signals sinx, cosx, the sinx signals being fed into the circuitIn the construction circuit, cosx signal is input toConstructing a circuit; the above-mentionedThe construction circuit comprises a T-shaped resistance network I, a voltage converter I and a bipolar converter I, and is used for constructing and obtaining a voltage expressionin an analog quantity ofIn the structure circuit, the main control chip sends n-bit digital control quantity k to a first T-type resistance network1The switching state of an electronic switch in the first T-shaped resistance network is controlled, the output of the first T-shaped resistance network is connected with the first voltage converter, and the output of the first voltage converter is connected with the first bipolar converter; the above-mentionedThe construction circuit comprises a T-shaped resistance network II, a voltage converter II and a bipolar converter II, and is used for constructing and obtaining a voltage expressionIn an analog quantity ofIn the structure circuit, the main control chip sends n-bit digital control quantity k to the T-type resistance network II2The switching state of an electronic switch in the T-shaped resistance network II is controlled, the output of the T-shaped resistance network II is connected with the voltage converter II, and the output of the voltage converter II is connected with the bipolar converter II;Output of the structure circuit andConstructing the output of the circuit and inputting the output into the conditioning circuit; the conditioning circuit comprises an adding circuit and a proportional amplifying circuit, and the function of the adding circuit is to add the addition signal to the proportional amplifying circuitStructural circuit andAdding the analog quantities generated by the structural circuit, adjusting the voltage amplitude to obtain the analog quantityI.e. a phase difference ofThereby achieving phase adjustment.
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| RU2103698C1 (en) * | 1996-05-20 | 1998-01-27 | Акционерное общество открытого типа ЦКБ-связь" | Device for measurement of harmonic signal phase shift |
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