CN208026684U - A kind of difference frequency continuation sinusoidal radiating circuit - Google Patents
A kind of difference frequency continuation sinusoidal radiating circuit Download PDFInfo
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- CN208026684U CN208026684U CN201820163689.3U CN201820163689U CN208026684U CN 208026684 U CN208026684 U CN 208026684U CN 201820163689 U CN201820163689 U CN 201820163689U CN 208026684 U CN208026684 U CN 208026684U
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Abstract
The utility model is a kind of difference frequency continuation sinusoidal radiating circuit, including radiating circuit, is used to generate transmitting signal on the transmitting output end of radiating circuit；DDS frequency synthesizers are used to generate continuous sine voltage signal that is multiple, having different frequency；Seven rank Low-pass Elliptic Filters, are used for filtering clutter, obtain continuous sine voltage signal pure, that output is regular；Voltage amplifier is used to amplify voltage signal magnitude, adjusts filtered voltage value；Power amplifier is used to adjust the power in circuit；Clock circuit, for realizing the synchronization of binary channels DDS frequency synthesizers；Peak detector, for realizing the balance between binary channels radiating circuit；Net mate is used to carry out dynamic impedance matching with energy converter, and driving energy converter generates the continuous sound wave signal of required frequency.The utility model can be used as the independent ultrasonic signal driving source in Ultrasonic Nondestructive field, and circuit is stable, and reliability is high, and application value is high.
Description
Technical field
The utility model is related to the confocal sonac of line focus, ultrasonic excitation sound emission, chatter technical field of imaging,
More particularly to a kind of difference frequency continuation sinusoidal radiating circuit.
Background technology
Ultrasonic excitation sound emission（USAE）It is exactly by confocal focusing ultrasonic wave of two beams with small frequency difference Δ f in object,
Generate the alternation radiant force that frequency is Δ f.Under the action of radiant force, object does of reciprocating vibration, outside spoke along acoustic axis direction
Penetrate acoustic signals.According to radiative acoustic wave signal, Regulation Mechanism of the double frequency alternation compressing force to cartilage mechanical property is disclosed.For this purpose,
Ultrasonic wave transmitting circuit allows for excitation energy converter and emits stable, continuous, the regulatable ultrasonic wave of frequency.
Energy converter emits ultrasonic wave, needs electric excitation.Motivational techniques are often：Sheet metal is coated at the both ends of piezoelectric material
Then electrode adds alternating voltage, make its internal generation electric field.There are two types of forms for electric excitation：Continuous wave excitation and impulse wave swash
It encourages.General pulse wave excitation is for accurately telling object and its position.With the transducing of pulse wave excitation and relatively low quality value
Device, the shorter ping of energy emission duration, to improve distance resolution.The ultrasonic transduction of continuous wave excitation high quality value
The loss of device, energy converter is smaller, can launch the stronger continuous ultrasonic of frequency stabilization, power.
It is to regulate and control the frequency difference of transmitting ultrasonic wave to regulate and control alternation radiant force frequency, needs frequency synthesizer.Frequency synthesizer
It is based on the basis of one or more reference sources, in a certain frequency range, comprehensive generation simultaneously exports multiple working frequency points and grinds
The frequency source of system.Direct digital synthesis technique（DDS）It is looked into using digital form accumulated phase, then using the sum of phase as address
Table of natural sines is ask, the discrete numerical sequences of sinusoidal amplitude are obtained, is most obtained afterwards through digital analog converter (DAC) transformation
Analog sine exports.Direct Digital Frequency Synthesizers are the frequency synthesis cores from the required waveform of phase concept directly synthesis
Piece.This frequency combining method of direct digital synthesis technique can obtain very high frequency accuracy and phase resolution, Rapid Frequency
The frequency signal of rate conversion time and low phase noise, and integrated level simple in structure is high, is easy to Function Extension and total digitalization
The advantages that convenient for integrating, it can be used for synthesizing continuous sine voltage signal.
In order to improve the frequency resolution of system when signal Analysis frequency spectrum, the analog filter that design performance is excellent is needed.
In all analog filters, elliptic filter has high performance.Frequency range is very for passive filter (LC filters)
Width, elliptic filters stopband characteristic are better than other filters.Therefore according to design requirement, according to ellipse lowpass filter theory
Filter is normalized to primarily determine the exponent number of filter and component value by design method.
In ultrasonic transmitter, the high-frequency ac voltage signal for being used as transmitting signal is generated by radiating circuit.It is sending out
It penetrates in the stage, the ac voltage signal is applied on ultrasonic tr-ansducer, for sending out ultrasonic wave.Because ultrasonic transmitter
The effective range of transmission power is critically depend on the electric voltage frequency and amplitude of transmitting signal, so in being fed into ultrasonic tr-ansducer
The electric voltage frequency of the signal of control transmitting before, the voltage amplitude for amplifying transmitting signal by voltage amplifier.Realize that transmitting is higher
Frequency stability, high frequency resolution, and the sine wave that frequency can easily be adjusted in the larger context.
In ultrasonic transmitter, dynamic impedance matching is carried out to it in the working condition of ultrasonic transducer, is effectively driven
Energy converter generates ultrasonic wave that is continuous, stablizing.Resistance trimming is carried out to circuit simultaneously, keeps the active resistance of entire circuit and signal source defeated
Go out impedance to be close, to reach best power output.
If observing circuit it can be found that circuit uses the two independent channels DDS.When in use, it needs to ensure interchannel
Frequency difference is stable, circuit balancing.To realize above-mentioned function, need to introduce feedback circuit.It is and front and back by convention peak detector
Circuit resistance value matches, and realizes the balance of two channel powers.It is inputted end to connect with power amplifier output, to output electricity
Pressure carries out whole peak processing.It outputs it end to connect with microcontroller pin, output signal send microcontroller to sample after amplifier is amplified.
The output amplitude in two channels of microcontroller pair samples respectively, more afterwards by changing the amplitude of AD9851 and changing AD8330
Amplification factor come to output adjust so that their amplitude is close, reach the balance of circuit power.
Utility model content
The purpose of the utility model is to overcome problems of the existing technology, provide a kind of difference frequency continuation sinusoidal hair
Transmit-receive radio road.
To realize above-mentioned technical purpose and the technique effect, the utility model is achieved through the following technical solutions：
A kind of difference frequency continuation sinusoidal radiating circuit, including：
Microcontroller is used for comparison signal, output gain signal parameter；
Radiating circuit, for generating transmitting signal on the transmitting output end of the radiating circuit；
DDS frequency synthesizers, integrate the radiating circuit, and the input terminal of the DDS frequency synthesizers connects radiating circuit
Transmitting output end, for generating continuous sine voltage signal that is multiple, having different frequency；
Voltage amplifier, the output end of the voltage input end connection DDS frequency synthesizers of the voltage amplifier, for putting
The gain input of big sine voltage signal amplitude, the voltage amplifier connects microcontroller, for adjusting the voltage amplification
The yield value of device；
Power amplifier, the output end of the input terminal connection voltage amplifier of the power amplifier, for amplifying sine
The power of voltage signal；
Peak detector, the output end of the input terminal connection power amplifier of the peak detector, peak detector
Output end connects microcontroller, and microcontroller is fed back to behind the whole peak of sine voltage signal for the output end to power amplifier, protects
Hold the balance between multichannel radiating circuit；
Net mate, the output end of the input terminal connection power amplifier of the net mate, the output end of net mate
An energy converter is connected, for carrying out dynamic impedance matching with energy converter, driving energy converter generates the continuous sound wave letter of required frequency
Number；
Clock circuit, the clock signal input terminal of the clock circuit connection DDS frequency synthesizers, for keeping multichannel
Synchronization between DDS frequency synthesizers.
Further, seven are equipped between the output end and the voltage input end of voltage amplifier of the DDS frequency synthesizers
Rank low-pass elliptic filter is used for filtering clutter, obtains continuous sine voltage signal pure, that output is regular.
Further, both-end clock signal difference is exported on the transmitting output end of the radiating circuit be input to DDS frequencies
Synthesizer.
Further, it is equipped with an impedance matching circuit in the radiating circuit and carries out dynamic impedance matching with energy converter.
Further, it is quiet to be equivalent to a dynamic electric resistor, dynamic inductance, the series circuit of dynamic capacity and one for the energy converter
The circuit of state capacitance parallel connection.
Further, the impedance matching circuit be equivalent to one with series inductance value and in capacitive or be pure resistance value
Resistance.
Further, the DDS frequency synthesizers include phase accumulator, first adder, sine look up table, digital-to-analogue turn
Parallel operation DAC and low-pass filter LPF, the phase accumulator do cumulative, the positions N of output with step-length K under the control of clock fc
Binary code is used as the address of sine look up table after being added by first adder with phase control words P, to sine look up table into
Row addressing, sine look up table export digital sinusoidal signal, become analog sinus signals through digital analog converter DAC, using low pass
Filter LPF smoothly after composite signal waveform.
Further, the phase accumulator is made of second adder and phase register, before the second adder
Input has frequency control word F, to control step-length K, changes synthesis by changing the amplitude code stored in the sine look up table
The shape of signal waveform changes the output frequency of DDS frequency synthesizers by changing frequency control word F and phase control words P.
Further, the power amplifier constitutes push-pull type structure, AB class power amplifications using NPN, PNP power to pipe
Device electricity routing power builds pipe, and in a cycle of input signal, the pipe half period is connected in turn.In AB generic operations
In, even if occurring without input signal, this level-one of recommending of amplifier is also to be biased into the state be slightly connected.Pass through two
Indirect two diode in the same direction of transistor base, the configuration of divider and diode are biased, and the friendship of anti-stop signal is more lost
Very.
Further, the level-one of recommending of the power amplifier circuit of AB classes is biased into the state be slightly connected,
And it is biased by the configuration of two indirect two diodes in the same direction of transistor base, divider and diode.
The utility model has the beneficial effects that:
The utility model realizes the circuit design of ultrasonic signal excitation, control, and especially ultrasonic signal is continuous
Excitation, the design of sinusoidal signal electronic circuit meet the basic demand of ultrasonic wave transmitting signal；It can be used as the lossless inspection of ultrasonic wave
The independent ultrasonic signal driving source in survey field；The circuit is stable, and reliability is high, there is very high application value.
Description of the drawings
Fig. 1 is the single-frequency emission system structure diagram of the utility model embodiment；
Fig. 2 is the double frequency emission system structure diagram of the utility model embodiment；
Fig. 3 is the improvement double frequency emission system structure diagram of the utility model embodiment；
Fig. 4 is the DDS frequency synthesizer circuit figures of the utility model；
Fig. 5 is the low-pass filtering module of the utility model；
Fig. 6 is the voltage amplifier and power amplifier circuit of the utility model；
Fig. 7 is the dynamic impedance matching module of the utility model；
Fig. 8 is the logic diagram of the DDS frequency synthesizers of the utility model.
Figure label explanation：Label 1,2,3 indication circuit channel positions in figure, are not offered as component names.
Specific implementation mode
Below with reference to the accompanying drawings and in conjunction with the embodiments, the utility model is described in detail.
Shown in referring to Fig.1, a kind of difference frequency continuation sinusoidal radiating circuit, including：
Microcontroller is used for comparison signal, and output gain signal parameter, microcontroller is using CF80518005F microcontrollers and often
The peripheral circuit of rule；
Radiating circuit is used for generating transmitting signal on the transmitting output end of the radiating circuit
MC100LVEL16D differential signal driving chips export both-end clock signal；
DDS frequency synthesizers, integrate the radiating circuit, and the input terminal of the DDS frequency synthesizers connects radiating circuit
Transmitting output end, for generating continuous sine voltage signal that is multiple, having different frequency, DDS frequency synthesizers use two
The identical AD9851 chips of piece, AD9851 built-in chip type reference clock chips directly can use internal reference clock chip to synthesize
The clock signal of certain frequency, without quoting external timing signal；6 times of clocks multiply again can external input one such as compared with small frequency
The clock signal of 30MHz reaches the signal of 180MHz frequencies, resolution ratio about 0.04Hz after internal 6 times multiply again；AD9851 chips
Inside includes a high-speed comparator, and high-speed comparator, which can be configured as, receives the filtering output of digital analog converter DAC to produce
The output pulse of a low jitter is given birth to, this function module is not used in the present embodiment；The digital pin and monolithic of AD9851 chips
Machine Parallel Interface Communication, PGND are that 6 times of reference clock multipliers are grounded, and PVCC is 6 times of reference clock multiplier feeder ears for 8V voltages,
AGND analogue ground pins correspond to the analogue ground port of digital analog converter DAC and comparator, and AVDD is the mould of positive voltage
Quasi- circuit and band-gap reference；
Voltage amplifier, the output end of the voltage input end connection DDS frequency synthesizers of the voltage amplifier, for putting
The gain input of big sine voltage signal amplitude, the voltage amplifier connects microcontroller, for adjusting the voltage amplification
The yield value of device, it is linear adjustable gain voltage amplifier, input that voltage amplifier, which uses AD8330 chips, AD8330 chips,
End is connected with seven rank low-pass elliptic filter output ends, microcontroller pin, and output is connect with power amplifier；Specially AD8330
The INT0 pin input voltage range 0.3mV to 1V of chip, differential output impedance are 75 Ω, and linear gain can make output voltage
Peak value reaches 10V, and enabled pin meets reference voltage 6V；AD8330 chips are mainly by VGA nucleus modules, deviation and reference voltage mould
Block compensates control module, output stage module, output signal control and gain regulation module composition, wherein passes through control and list
The basic gain of the voltage control AD8330 chips of the VDBS pins of piece machine connection；
Power amplifier, the output end of the input terminal connection voltage amplifier of the power amplifier, for amplifying sine
The power of voltage signal；
Peak detector, the output end of the input terminal connection power amplifier of the peak detector, peak detector
Output end connects microcontroller, and microcontroller is fed back to behind the whole peak of sine voltage signal for the output end to power amplifier, protects
Hold the balance between multichannel radiating circuit；
Net mate, the output end of the input terminal connection power amplifier of the net mate, the output end of net mate
An energy converter is connected, for carrying out dynamic impedance matching with energy converter, driving energy converter generates the continuous sound wave letter of required frequency
Number；
Clock circuit, the clock signal input terminal of the clock circuit connection DDS frequency synthesizers, for keeping multichannel
Synchronization between DDS frequency synthesizers, clock circuit include clock difference chip and have source crystal oscillator, have source crystal oscillator to use SIT8103
Chip, clock difference chip also use MC100LVEL16D differential signal driving chips, have source crystal oscillator SIT8103 anodes pin with
3.3V voltages are connected, and negative pin ground connection, N/C pin zero setting, fuction output pin passes through protective resistance R3 and clock difference core
Digital input pins D0, D1 of piece MC100LVEL16D is connected, while accessing pin VEE, by chip VCC pin access 3.3V electricity
Pressure,WithPin is by resistance eutral grounding, simultaneouslyWithPin is that output pin accesses subordinate's circuit, and VBB and N/C pins are set
Zero.
It is oval that seven rank low passes are equipped between the output end and the voltage input end of voltage amplifier of the DDS frequency synthesizers
Filter is used for filtering clutter, obtains continuous sine voltage signal pure, that output is regular, the seven ranks low pass ellipse filtering
75 Ω of input and output resistance of device is matched with AD9851 chips, by three shunt circuits, inductance and has electrode capacitance parallel circuit
There is electrode capacitance to be connected in series with one again, is in series with and holds another pole ground connection of electrode, each component values are first according to standard ellipse type low pass
Filter theory design method value, then each parameter is by normalized, then carry out circuit simulation and obtain cutoff frequency be
72MHz is less than the elliptic filter of 0.1dB with interior ripple.
Both-end clock signal difference is exported on the transmitting output end of the radiating circuit is input to DDS frequency synthesizers.
It is equipped with an impedance matching circuit in the radiating circuit and carries out dynamic impedance matching with energy converter.
The energy converter is equivalent to a dynamic electric resistor, dynamic inductance, the series circuit of dynamic capacity and a direct capacitance simultaneously
The circuit of connection.
The impedance matching circuit be equivalent to one with series inductance value and in capacitive or for the resistance of pure resistance value.
Fig. 8 shows the logic diagram of DDS frequency synthesizers, the DDS frequency synthesizers include phase accumulator, first plus
Musical instruments used in a Buddhist or Taoist mass, sine look up table, digital analog converter DAC and low-pass filter LPF, the phase accumulator under the control of clock fc,
Done with step-length K cumulative, the N position binary codes of output are used as sinusoidal inquiry after being added by first adder with phase control words P
The address of table, is addressed sine look up table, and sine look up table exports digital sinusoidal signal, becomes through digital analog converter DAC
Analog sinus signals, using low-pass filter LPF smoothly after composite signal waveform.
The phase accumulator is made of second adder and phase register, and being inputted before the second adder has frequency
Control word F changes composite signal waveform to control step-length K by changing the amplitude code stored in the sine look up table
Shape changes the output frequency of DDS frequency synthesizers by changing frequency control word F and phase control words P.
The power amplifier using NPN, PNP power to pipe constitute push-pull type structure, AB power-like amplifiers circuit by
Power builds pipe, and in a cycle of input signal, the pipe half period is connected in turn.In AB generic operations, even if
There is no input signal appearance, this level-one of recommending of amplifier is also to be biased into the state be slightly connected.Pass through two triodes
Indirect two diode in the same direction of base stage, the configuration of divider and diode are biased, the intermodulation distortion of anti-stop signal.
The level-one of recommending of the power amplifier circuit of AB classes is biased into the state be slightly connected, and passes through two
The configuration of indirect two diode in the same direction of transistor base, divider and diode is biased, and is calculated through design and simulation, work(
Rate is after power amplifier amplifies, and power is more than 2.3W, and the distortion factor is smaller, can effectively avoid distorted signals, the power amplification
Device input termination voltage amplifier output pin, output termination match circuit and peak detector.
Each embodiment is illustrated one by one below in conjunction with the accompanying drawings：
Fig. 1 shows to be used for according to the structure diagram radiating circuit of the ultrasonic transmitter of the utility model first embodiment
1 sinusoidal signal is exported in signal output end.In this embodiment, switch S1, S2 is disconnected, and only DDS signals synthesis channel 2 connects
Circuit is accessed, the continuation sinusoidal of single frequency is generated.In this embodiment, pass through the frequency control of write-in AD9851 chips
The break-make in word control DDS frequency synthesizers processed channel.In addition, the switch S1 for disconnecting DDS frequency synthesizers channel 1 ensures in circuit
Only DDS signals synthesis channel 2 emits signal, avoids the interference of clock signal in channel 1.In the embodiment, differential clocks
Driving chipWithOutput end exports clock signal, respectively input clock signal to DDS frequency synthesizers channel 1,2
The ports REFCLOCK i.e. 9 pins.I.e. 11 pins in the ports AVDD of AD9851 chips access 5V voltages, and the D0-D7 pins of chip are logical
It crosses piece latch with microcontroller to be connected, control generates the frequency of sinusoidal signal.The AD9851 chips in DDS frequency synthesizers channel 2
The ends VOUTP i.e. 14 pin output voltage signals connect the seven rank low-pass elliptic filters into channel 1.Again through voltage amplifier and work(
Rate amplifier amplification, peak detector feedback, the voltage signal after adjustment respectively drive phase after corresponding dynamic impedance matching
The ultrasonic wave of the energy converter transmitting answered continuously, stable.
Fig. 2 shows the structure diagrams of the ultrasonic transmitter of the utility model second embodiment.Radiating circuit is used for
Signal output end exports two continuation sinusoidals, and the frequency control word by the way that two channel of DDS frequency synthesizers is written controls defeated
Go out the frequency of sinusoidal signal and the small frequency difference of two signals.In this embodiment, switch S1 is closed, and switch S2 is disconnected, and is generated
Two have different frequency continuation sinusoidal.In this embodiment, it is logical to be respectively written into DDS frequency synthesizers for frequency control word
The pin in road 1,2.Differential clocks driving chip is input to DDS frequency synthesizers channel 1,2 with output clock signal difference
The clock input pin of AD9851 chips controls the synchronous of continuation sinusoidal and generates.Distinguish in DDS frequency synthesizers channel 1 and 2
Export sinusoidal signal by build-out resistor access corresponding channel seven rank low-pass elliptic filters, it is filtered after voltage signal by
Respective voltage amplifier amplification.The input terminal of amplified signal access power amplifier.Wherein voltage is put in channel 1
The amplified voltage signal of big device, connects the power amplifier in channel 1, and the power amplifier 3 in channel 1 is in and opens at this time
Line state.Voltage signal in channel 1, through voltage amplifier 1,1 amplified voltage signal of power amplifier through peak detector 1
Microcontroller is fed back to behind whole peak.Meanwhile the voltage signal in channel 2, through peak after voltage amplifier 2, power amplifier 2 amplify
Value detector feeds back to microcontroller behind 2 whole peak.According to peak detector 1,2 feed back voltage signal, microcontroller adjust channel 1 with
The balance in two channel of ultrasonic signal emission circuit is realized in the linear gain of the DDS frequency synthesizers and voltage amplifier in channel 2.It adjusts
Voltage signal after whole respectively drives the ultrasound that corresponding energy converter transmitting is continuous, stablizes after corresponding dynamic impedance matching
Wave.
Fig. 3 shows the structure diagram of the ultrasonic transmitter of the utility model third embodiment.Radiating circuit is used for
Signal output end exports three continuation sinusoidals, and the frequency control word by the way that two channel of DDS frequency synthesizers is written controls defeated
Go out the frequency of sinusoidal signal and the small frequency difference of three signals.In this embodiment, switch S1 is closed, and switch S2 is closed, and is generated
Three have different frequency continuation sinusoidal.In this embodiment, it is logical to be respectively written into DDS frequency synthesizers for frequency control word
The pin in road 1,2.Differential clocks driving chip is input to DDS frequency synthesizers channel 1,2 with output clock signal difference
The clock input pin of AD9851 chips controls the synchronous of continuation sinusoidal and generates.DDS frequency synthesizers 1 and 2 export respectively
Sinusoidal signal by build-out resistor access corresponding channel seven rank low-pass elliptic filters, it is filtered after voltage signal by respective
Corresponding voltage amplifier amplification.The input terminal of amplified signal access power amplifier.Wherein voltage amplifier in channel 1
Amplified voltage signal connects the power amplifier in channel 1, and the power amplifier 3 in channel 1 is in closed form at this time
State.Voltage signal in channel 1, through voltage amplifier 1,1 amplified voltage signal of power amplifier through 1 whole peak of peak detector
After feed back to microcontroller.Meanwhile the voltage signal in channel 2, respectively after voltage amplifier 2, voltage amplifier 2 amplify voltage
Corresponding power amplifier 2 is inputted respectively, power amplifier 3 feeds back to microcontroller after amplifying behind 2 whole peak of peak detector.According to
The voltage signal that peak detector 1,2 is fed back, microcontroller adjust the DDS frequency synthesizers and voltage amplifier in channel 1 and channel 2
Linear gain realize the balance in two channel of ultrasonic signal emission circuit.Voltage signal after adjustment is through corresponding motional impedance
After matching, the ultrasonic wave that corresponding energy converter transmitting is continuous, stablizes is respectively driven.
Fig. 4 shows that the utility model DDS frequency synthesizer circuit figures, 2 pin function of AD9851 chips are distributed such as Fig. 4 institutes
Show.Its AGND pin, that is, pin 10 is grounded, and AVCC pins connect 5V power supplys and provide chip operating voltage.Clock signal is through differential clocks
Clock input REFCLOCK pins, that is, pin 9 of driving chip Differential Input AD9851, makes each Channel Synchronous act.AD9851's
IOUTB pins, that is, pin 20 exports the transformed alternating current of DAC converter.Output pin and the resistance that a resistance value is 100 Ω
It is connected, output current is converted into alternating voltage output.RESET pins, that is, pin 12 of AD9851 is 3.9K Ω by a resistance value
Protective resistance connect with microcontroller, for microcontroller control AD9851 reset operation.VOUTN and VOUTP pins are not connected into
Circuit.The pin of AD9851 is connected with microcontroller output, and the corresponding command is written to AD9851 for microcontroller, realizes corresponding operating
Function.
Fig. 5 shows seven rank low-pass elliptic filter circuit diagram of the utility model.Since seven rank low pass ellipse of each channel filters
It the structure of device, cutoff frequency and realizes that function is identical, therefore entirety can be analyzed by making a concrete analysis of the filter in one channel
Three filters of radiating circuit.Because the frequency range of LC filters is very wide, and elliptic filters stopband characteristic is than other
Filter is good, therefore the utility model uses passive elliptic filters.First according to elliptic filter Theoretical Design scheme, design
Go out the circuit that the parallel circuit of its structure i.e. inductance and active capacitor is connected in series with an active capacitor again to be in parallel.Further according to setting
Meter requires：AD9851 output signal frequencies are up to 72MHz, and resistance value is 75 Ω, are less than 0.1dB with interior maximum ripple, really
The exponent number for determining elliptic filter is seven ranks, and input and output resistance value is 50 Ω.Then use the ratio of stop-band frequency and cutoff frequency true
Determine steepness factor, to search filter according to the steepness factor and cutoff frequency normalize table, determines that each inductance, capacitance are returned
One changes design parameter.A parameter M is obtained with the cutoff frequency 72MHz divided by normalization cutoff frequency 1/ (2* π) of filter to be synthesized,
M divided by each component is used to normalize design parameter again.Finally, gained inductance value is multiplied by resistance value up to filter inductance value, gained
Capacitance divided by resistance value are up to filter capacitance.
Fig. 6 shows that the utility model voltage amplifier and power amplifier circuit figure, VPSO, VPSI of AD8330 chips draw
Foot is connected by resistance with pull-up 3.3V voltages, is connected with ground signalling using capacitance.CNTR, COMP, COMM, MODE pin
Signal ground is connect, VMAG pins do not access vacantly.INLO pins are connected with filter output, amplify DDS composite signal frequencies.INLI
Pin is connect with microcontroller, for directly controlling composite signal.
Fig. 7 shows the utility model dynamic impedance match circuit figure, and the match circuit is for driving ultrasonic transducer to send out
Penetrate stable, continuous acoustic signals.It is continuation sinusoidal that the utility model, which emits signal, and radiating circuit will always be in work
Make state.Therefore need to carry out Dynamic Matching to the ultrasonic transducer under working condition, make the energy converter after matching in dynamic branch
Resonant frequency point working efficiency highest.And output impedance also reduces, with best power driving ultrasonic transducer in its resonance frequency
Continuous work near rate.According to the characteristic of ultrasonic transducer, a direct capacitance can be equivalent to and be parallel to a dynamic electric resistor, move
The series circuit of state capacitance, dynamic inductance.The utility model selects dynamic branch resonant frequency for the best work of ultrasonic transducer
The matching principle for making resonant frequency carries out electricity matching to ultrasonic transducer.Dynamic electric resistor, dynamic capacity and dynamic inductance value
With frequencyCorrelation is the function of frequency.Branch dynamic resonance frequency is determined by equivalent circuit first, then the parallel circuit of direct capacitance and dynamic electric resistor is equivalent to a resistanceWith capacitanceSeries circuit.Last root
Serial inductance is determined according to resonant frequency and equivalent capacity C, note：Above-mentioned five formulas
In, the content in bracket is the value definition indicated to reference numerals outside bracket, rather than is multiplied.Further according to admittance circle, admittance circle
Whether formula and admittance circle Eigenvalue Theory inspection institute take resonant frequency reasonable.According to analysis of experimental results, whole system at this time
It is rendered as a pure resistor element circuit, set match circuit can maximal efficiency driving sonac transmitting continuous sound wave signal.To string
Join inductance, the input impedance of system at this time is：。
Furthermore, it is necessary to explanation, unless stated otherwise or is pointed out, the otherwise term in specification " first ", " the
The descriptions such as two " are used only for distinguishing various components, element, step etc. in specification, without being intended to indicate that various components, member
Logical relation or ordinal relation between element, step etc..
The above descriptions are merely preferred embodiments of the present invention, is not intended to limit the utility model, for this
For the technical staff in field, various modifications and changes may be made to the present invention.It is all in the spirit and principles of the utility model
Within, any modification, equivalent replacement, improvement and so on should be included within the scope of protection of this utility model.
Claims (10)
1. a kind of difference frequency continuation sinusoidal radiating circuit, which is characterized in that including：
Microcontroller is used for comparison signal, output gain signal parameter；
Radiating circuit, for generating transmitting signal on the transmitting output end of the radiating circuit；
DDS frequency synthesizers integrate the radiating circuit, the hair of the input terminal connection radiating circuit of the DDS frequency synthesizers
Output end is penetrated, for generating continuous sine voltage signal that is multiple, having different frequency；
Voltage amplifier, the output end of the voltage input end connection DDS frequency synthesizers of the voltage amplifier, for amplifying just
The gain input of string voltage signal magnitude, the voltage amplifier connects microcontroller, for adjusting the voltage amplifier
Yield value；
Power amplifier, the output end of the input terminal connection voltage amplifier of the power amplifier, for amplifying sinusoidal voltage
The power of signal；
Peak detector, the output end of the input terminal connection power amplifier of the peak detector, the output of peak detector
End connects microcontroller, and microcontroller is fed back to behind the whole peak of sine voltage signal for the output end to power amplifier, keeps more
Balance between channel emission circuit；
Net mate, the output end of the input terminal connection power amplifier of the net mate, the output end connection of net mate
One energy converter, for carrying out dynamic impedance matching with energy converter, driving energy converter generates the continuous sound wave signal of required frequency；
Clock circuit, the clock signal input terminal of the clock circuit connection DDS frequency synthesizers, for keeping multichannel DDS
Synchronization between frequency synthesizer.
2. difference frequency continuation sinusoidal radiating circuit according to claim 1, which is characterized in that the DDS frequency synthesis
It is equipped with seven rank low-pass elliptic filters between the output end of device and the voltage input end of voltage amplifier, is used for filtering clutter, obtains
To continuous sine voltage signal pure, that output is regular.
3. difference frequency continuation sinusoidal radiating circuit according to claim 1, which is characterized in that the hair of the radiating circuit
It penetrates output both-end clock signal difference on output end and is input to DDS frequency synthesizers.
4. difference frequency continuation sinusoidal radiating circuit according to claim 1, which is characterized in that set in the radiating circuit
There is an impedance matching circuit to carry out dynamic impedance matching with energy converter.
5. difference frequency continuation sinusoidal radiating circuit according to claim 4, which is characterized in that the energy converter is equivalent to
The series circuit circuit in parallel with a direct capacitance of one dynamic electric resistor, dynamic inductance, dynamic capacity.
6. difference frequency continuation sinusoidal radiating circuit according to claim 5, which is characterized in that the impedance matching circuit
One is equivalent to series inductance value and in capacitive or for the resistance of pure resistance value.
7. difference frequency continuation sinusoidal radiating circuit according to claim 1, which is characterized in that the DDS frequency synthesis
Device includes phase accumulator, first adder, sine look up table, digital analog converter DAC and low-pass filter LPF, the phase
Accumulator under the control of clock fc, done with step-length K it is cumulative, the N position binary codes of output and phase control words P by first plus
Address after musical instruments used in a Buddhist or Taoist mass addition as sine look up table, is addressed sine look up table, and sine look up table exports digital sine letter
Number, become analog sinus signals through digital analog converter DAC, using low-pass filter LPF smoothly after composite signal waveform.
8. difference frequency continuation sinusoidal radiating circuit according to claim 7, which is characterized in that the phase accumulator by
Second adder and phase register form, and being inputted before the second adder has frequency control word F, to control step-length K, lead to
The shape that the amplitude code for changing and being stored in the sine look up table changes composite signal waveform is crossed, by changing frequency control word F
With phase control words P, change the output frequency of DDS frequency synthesizers.
9. difference frequency continuation sinusoidal radiating circuit according to claim 1, which is characterized in that the power amplifier is adopted
Push-pull type structure is constituted to pipe with NPN, PNP power, AB power-like amplifier electricity routing powers build pipe, believe in input
Number a cycle in, the pipe half period is connected in turn.
10. difference frequency continuation sinusoidal radiating circuit according to claim 9, which is characterized in that the power of AB classes
The level-one of recommending of amplifier circuit is biased into the state be slightly connected, and passes through two transistor bases indirect two in the same direction two
The configuration of pole pipe, divider and diode is biased.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109802566A (en) * | 2019-01-03 | 2019-05-24 | 杭州电子科技大学 | A kind of direct current biasing module for Medical Devices cloud system |
| CN111208374A (en) * | 2020-02-28 | 2020-05-29 | 中国电力科学研究院有限公司 | Device and method for injecting sinusoidal excitation signal into transformer winding |
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2018
- 2018-01-31 CN CN201820163689.3U patent/CN208026684U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109802566A (en) * | 2019-01-03 | 2019-05-24 | 杭州电子科技大学 | A kind of direct current biasing module for Medical Devices cloud system |
| CN111208374A (en) * | 2020-02-28 | 2020-05-29 | 中国电力科学研究院有限公司 | Device and method for injecting sinusoidal excitation signal into transformer winding |
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