CN108417191B - Electric piano impromptu accompaniment allocation management system suitable for music score recognition - Google Patents
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- G10H1/00—Details of electrophonic musical instruments
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- G10H1/344—Structural association with individual keys
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- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10H—ELECTROPHONIC MUSICAL INSTRUMENTS; INSTRUMENTS IN WHICH THE TONES ARE GENERATED BY ELECTROMECHANICAL MEANS OR ELECTRONIC GENERATORS, OR IN WHICH THE TONES ARE SYNTHESISED FROM A DATA STORE
- G10H1/00—Details of electrophonic musical instruments
- G10H1/36—Accompaniment arrangements
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- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10H—ELECTROPHONIC MUSICAL INSTRUMENTS; INSTRUMENTS IN WHICH THE TONES ARE GENERATED BY ELECTROMECHANICAL MEANS OR ELECTRONIC GENERATORS, OR IN WHICH THE TONES ARE SYNTHESISED FROM A DATA STORE
- G10H1/00—Details of electrophonic musical instruments
- G10H1/44—Tuning means
Abstract
The invention belongs to the technical field of electric pianos, and discloses an electric piano impromptu accompaniment allocation management system suitable for music score identification, which comprises the following components: the device comprises a power supply module, a sensing module, a main control module, a tone color library module, a light-emitting module, a judging module and a display module. The induction module replaces a contact switch of conductive rubber, so that the defects of poor contact, misoperation and inconvenient cleaning and maintenance caused by humid environment, contact abrasion, crack dust and conductive rubber aging are avoided; simultaneously through the automatic judgement that contrasts of tone quality in the tone quality of judging the learner exercise piano and the tone quality library module, the learner of being convenient for differentiates the difference in two kinds of tone qualities to reach the effect of distinguishing the sound, improve the learning level of piano.
Description
Technical Field
The invention belongs to the technical field of electric pianos, and particularly relates to an impromptu accompaniment allocation management system of an electric piano, which is suitable for music score identification.
Background
Currently, the current state of the art commonly used in the industry is such that:
the sound production principle of the electric piano is that a keyboard is used as an on-off switch to form electrophoresis, once a key is pressed down, an internal crystal oscillator starts to work to form a pulse to generate a waveform with a certain frequency, and then the waveform is amplified by a frequency divider and sent to a loudspeaker to produce sound. The whole sounding process depends on a simple frequency division analog circuit, so the keyboard has no dynamics and string hitting feeling, and the sound is mechanical and monotonous. However, the existing electric piano using physical keys (e.g., keys made of silicone rubber) for a long time may have a problem of damage in case of contact abrasion; the conductive rubber has the problems that poor contact or misoperation can be caused by the aging of the rubber along with the passage of time or in a humid environment; meanwhile, the existing electric piano does not support the sound distinguishing training and can not cultivate the judgment of the learner on the pitch.
Short term frequency of signalStability is an important factor for measuring signal quality, which directly affects system performance, and phase noise is an important index for describing signal short-term frequency stability. Particularly, in the application fields of radar, communication, navigation and the like, reducing phase noise becomes one of the key technologies for improving system performance. For example, in a doppler radar, phase noise directly affects the moving target detection performance of the radar; in digital communications, particularly in the phase modulation communication regime, phase noise is of great significance to both the system bit error rate and the isolation of adjacent channels. Therefore, the phase noise measurement has an important application in modern electronic technology, and has become one of the research hotspots in the current electronic measurement field. According to different methods for extracting phase noise signals, the current phase noise measurement methods are mainly divided into methods such as a direct spectrometer measurement method, a time difference measurement method, a frequency discrimination method and a phase discrimination method. The direct frequency spectrograph method is a simple and easy phase noise measuring method, which directly inputs the source signal to be measured to the input end of the frequency spectrograph, tunes the carrier frequency of the frequency spectrograph, and calculates the phase noise of the measured signal by measuring the frequency spectrum of the measured signal and carrying out necessary correction according to the ratio of the noise power to the carrier power. The spectrometer measurement method is limited in application by the following factors: the measurement result is restricted by the local vibration source phase noise of the frequency spectrograph, the phase noise and the amplitude noise cannot be distinguished, and the phase noise at the position close to a carrier wave is not easy to measure. In the time difference measurement method, the signals of the measured source and the reference source are sent to a time difference counter after being subjected to frequency division through a frequency divider for measuring the time difference between zero-crossing points of the two signals, and the phase noise of the measured source relative to the reference source is calculated by using a measured time difference sequence. In the method, the frequency divider is used for reducing the signal frequency of the measured source and the reference source, and the resolution of the time difference measured by the time interval counter is improved. The method has the main advantages of low system construction cost and easy realization; the method has the limitations that the method is limited by the bandwidth of the system, the phase noise of the local oscillator inside the time interval counter limits the measurement effect, and in addition, the length of the cable and the impedance matching must be paid attention to. The frequency discrimination method, also called reference source-free method, converts the frequency fluctuation delta f of the source to be measured into voltage fluctuation delta v by some kind of microwave frequency discriminator and then uses baseband frequencyThe spectrum analyzer measures the fluctuation amount of the voltage, thereby realizing phase noise measurement. Commonly used frequency discriminators include delay line/mixer discriminator, RF bridge/delay line discriminator, cavity discriminator, dual delay line discriminator, etc. The working principle is as follows: the measured source signal is divided into two paths by a power divider, and one path is delayed by a time delay tau through a broadband delay linedChanging the frequency fluctuation into a phase fluctuation of 2 pi f0τdThe other path of signal passes through a bandwidth-variable phase shifter, the phase shifter is adjusted to enable two input signals to be orthogonal, the two input signals are sent to a phase discriminator to carry out orthogonal phase discrimination, the phase discriminator converts phase noise into voltage noise, the voltage noise is converted into a digital signal through A/D (analog to digital) and then signal processing such as FFT (fast Fourier transform) and power spectrum estimation is carried out, and the phase noise power spectrum S of the measured signal is measuredφ(f) And single sideband phase noise l (f). The frequency discrimination measurement method has the main advantages that a reference signal source is not needed, and the frequency discrimination measurement method has good measurement effect on a measured source with large phase fluctuation; the defect is that the frequency discriminator needs to be adjusted according to the measured sources with different frequencies, and the phase noise at the position close to the carrier wave is not easy to measure. The phase detection measurement method is also called a dual source measurement method or a phase-locked loop measurement method. The method uses a double-balanced mixer as a phase discriminator, uses a measured signal and a high-stability orthogonal reference source signal with the same frequency as the two input signals of the phase discriminator, outputs a low-frequency noise voltage proportional to the phase fluctuation of the measured signal, passes through a low-pass filter and a low-noise amplifier, and is added to a frequency spectrograph to measure different fmThe S of the signal source to be measured is calculated according to the noise levelφ(f) Or sampling the output signal of the phase discriminator after low-pass filtering and low-noise amplification, converting the sampled output signal into a digital domain, and obtaining the single-sideband power spectrum of the detected signal by using a digital signal processing method. The phase discrimination method has the main advantages of high measurement sensitivity, high frequency resolution, wide output frequency range and better inhibition capability on amplitude noise; the disadvantage is that the reference source signal must be equal in frequency to the signal under test. The common feature of the above-mentioned phase noise measurement methods is that a special hardware circuit is used to extract the phase information of the source signal to be measured, and the single-sideband phase noise of the source signal to be measured is analyzed accordingly.
The existing phase noise measuring method utilizes a special hardware circuit to extract the phase information of a measured signal source and analyzes the single-sideband phase noise of the measured signal source, so that the extraction performance of the phase extraction circuit determines the performance of phase noise measurement to a great extent, and the frequency response of the phase extraction circuit can also be used for measuring the result.
The rapid development of wireless communications and ultra-wideband technology requires very wide frequency bands, which makes the spectrum more and more crowded. In order to fully utilize limited frequency spectrum resources, various applications must exist within a certain frequency bandwidth, and the requirement of a microwave circuit system on multi-band multi-channel frequency selection is met. Accordingly, techniques such as frequency hopping, spread spectrum, dynamic frequency allocation, etc. have been developed, and tunable filters have been highly regarded as important components of these techniques. According to research reports, the structures of the tunable filter mainly include microstrip, suspension line, dielectric resonator, Substrate Integrated Waveguide (SIW) and the like. The adjustable implementation modes mainly comprise variable capacitance diodes, PIN diodes, RF MEMS technology and the like. According to the tuning method, the method can be divided into: 1. mechanically tuning; 2. electrically tuning; 3. and (4) acousto-optic tuning. According to the tuning content, the following can be classified: 1. a center frequency tunable filter; 2. a bandwidth adjustable filter; 3. the center frequency and bandwidth are simultaneously adjustable filters.
At present, a series of research works are carried out on tunable filters at home and abroad, and some achievements are obtained. However, the reported filters generally suffer from the following drawbacks:
(1) the tunable filter generally tunes the bandwidth by controlling the coupling between the multi-order resonators, so that the bandwidth tuning range is very small, and the requirement on the bandwidth tuning range in practical application cannot be met.
(2) The tunable filter generally adopts a multi-order resonator structure and uses a coupling input/output method, so that the insertion loss of the filter is large.
(3) The absolute bandwidth of the passband changes in the process of tuning the center frequency, and the requirement that the absolute bandwidth is kept constant during frequency electric tuning in practical application cannot be met.
(4) In the process of tuning the center frequency or bandwidth, stable filtering performance cannot be maintained, which mainly shows that the stability of the overall response of the system is influenced in the aspects of large and small echo loss and insertion loss, uneven passband ripple and the like.
The existing adjustable band-pass filter has the problems of large insertion loss, change of absolute bandwidth and unstable filtering characteristic in the adjustable process.
In summary, the problems of the prior art are as follows:
the existing electric piano uses physical keys (such as keys made of silica gel) for a long time, and the problem of damage can be caused under the condition that contacts are worn; the conductive rubber has the problems that poor contact or misoperation can be caused by the aging of the rubber along with the passage of time or in a humid environment; meanwhile, the existing piano does not support the sound distinguishing training and can not cultivate the judgment of the learner on the pitch;
the existing phase noise measurement method adopts the measurement result with the frequency response of the phase extraction circuit, and has lower accuracy;
the existing adjustable band-pass filter has the defects of large insertion loss, change of absolute bandwidth and unstable filtering characteristic in the adjustable process.
Disclosure of Invention
Aiming at the problems in the prior art, the invention provides an electronic piano improvised accompaniment allocation management system suitable for music score identification.
The invention is realized in this way, a piano improvised accompaniment allocation management system suitable for music score identification, which comprises:
the sensing module is connected with the main control module and used for receiving touch signals generated on the piano keyboard and sending the signals to the main control module for processing and analysis;
the induction module utilizes signal power spectrum measurement data through a power spectrum model of an oscillator signal, adopts a nonlinear least square method to perform curve fitting to obtain a parameter initial value in the power spectrum model, writes a regular equation set to correct the parameter, and finally obtains a parameter meeting the set requirement; substituting the obtained parameters into the phase noise power law model according to the relation between the signal power spectrum and the phase noise power law model thereof, and further obtaining a phase noise measurement result of the measured signal;
the master control module is connected with the power supply module, the induction module, the tone color library module, the light-emitting module, the judgment module and the display module and is used for controlling and scheduling each module to work;
the tone library module is connected with the main control module and used for storing tone data;
the judging module is connected with the main control module and is used for comparing the pitch selected by the learner with the pitch selected by the controller, if the pitch corresponds to the controller, the judging module displays the pitch correctly through the output device, otherwise, if the pitch does not correspond to the controller, the judging module displays the error through the display module;
the oscillator is provided with an upper-layer microstrip structure which is formed by sequentially connecting an input microstrip line, an input matching tuning network, a resonator, an output matching tuning network and an output microstrip line;
the input microstrip line and the output microstrip line feed electricity to the resonator, the input matching tuning network and the output matching tuning network realize matching with the resonator, the required external Q value is met, and the invariable absolute bandwidth and the stable filter characteristic are ensured in the adjustable process; the input matching tuning network and the output matching tuning network are composed of variable capacitance diodes and are respectively connected with the input and output microstrip lines and the resonator;
the microstrip resonator, the input microstrip line and the output microstrip line are printed on the dielectric substrate of the middle layer of the band-pass filter.
Further, the input microstrip line and the output microstrip line are both 50 Ω microstrip lines;
the resonator is loaded with T-shaped open-circuit branches by a half-wavelength microstrip line, wherein a first variable capacitance diode and a second variable capacitance diode are respectively loaded at two ends of the half-wavelength microstrip line; a third variable capacitance diode and a fourth variable capacitance diode are respectively loaded at two ends of a horizontal microstrip line of the T-shaped open-circuit branch section;
an input matching tuning network is arranged between the input microstrip line and the resonator, and the input matching tuning network consists of a first variable capacitance diode and a fifth variable capacitance diode;
an output matching tuning network is arranged between the resonator and the output microstrip line, and the output matching tuning network consists of a second variable capacitance diode and a sixth variable capacitance diode;
the first variable capacitance diode, the second variable capacitance diode, the third variable capacitance diode, the fourth variable capacitance diode, the fifth variable capacitance diode and the sixth variable capacitance diode are all provided with a bias circuit;
a first blocking capacitor and a fifth variable capacitance diode are respectively loaded between the input microstrip line and the resonator; a sixth varactor and a second blocking capacitor are respectively loaded between the resonator and the output microstrip line; the fifth variable capacitance diode and the first blocking capacitor, and the sixth variable capacitance diode and the second blocking capacitor are formed by cascading square microstrip patches with the side length of 0.7 mm;
the one-half wavelength microstrip line and the T-shaped open-circuit branch of the resonator are bent to a certain degree so as to reduce the size, and the whole resonator is in an axisymmetric structure.
Further, the method for determining the initial parameter value by using the nonlinear least square method specifically comprises the following steps:
according to the formula
Determining initial values of parameters by using nonlinear least square method, and taking
(β ═ 0,1,2,3,4), i.e. a needs to be selectedβInitial value of (1), will
Expressed in matrix form as follows:
FA＝S；
wherein:
A＝[a0 a1 … a4]T S＝[S0 S1 … S4]T；
the data points to be used in the matrix F are from N { (F)i,Si) Selecting five frequency points from 1,2, …, and ensuring that the matrix F is reversible;
thereby obtaining the expression parameter aβThe initial values of the matrix a of initial values are:
to be provided with
Iteration is carried out for the initial value to estimate the value of the matrix A, wherein l represents the iteration number, and the value of the matrix A is 0;
error of parameter estimation
β＝0,1,…,4，
Estimated by the following equation:
wherein the coefficients
And
comprises the following steps:
wherein SkRepresenting the frequency fkThe measured value of the power spectrum of (b),
representing the frequency fkThe ith iteration value of the corresponding power spectrum, namely:
the noise model parameter estimation judging method comprises the following steps:
judgment of
If the error requirement is not met, let:
l＝l+1；
and will be corrected
And corresponding power spectrum measurement data
Substituting the regular equation set for solving to obtain the correction value of each parameter
β is 0,1, … 4, and re-judged
Until error occurs
Meet the measurement requirements orAnd reaching the set iteration number.
If the error requirement is met, the parameter value is added
As
The value of (β ═ 0,1,2,3,4) is substituted into the formula
And obtaining the phase noise of the detected signal, and drawing a phase noise curve.
Further, the sensing module includes:
the power spectrum data acquisition module has the main functions of completing the acquisition of the power spectrum data of the input signal and providing a data source for the subsequent parameter estimation.
And the parameter calculation module has the main function of estimating parameters in the input signal power spectrum model to finally obtain parameter values meeting the error requirements.
And the phase noise measurement result generation module is mainly used for calculating the phase noise measurement result of the measured oscillator signal by substituting the finally obtained parameters into the signal phase noise power law model.
Further, the system for managing the allocation of the improvised accompaniment of the electric piano suitable for music score recognition comprises:
the power supply module is connected with the main control module and used for supplying power to the electric piano;
the light-emitting module is connected with the main control module and used for calling the corresponding tone according to the decoded touch signal of the main control module, sending out a corresponding low-level signal and prompting the currently selected tone;
and the display module is connected with the main control module and is used for displaying the data information of the judgment result of the judgment module.
Further, the sensing method of the sensing module is as follows:
firstly, the induction module receives a touch signal generated on a piano keyboard and sends the signal to the main control module;
then, the main control module decodes the received touch signal and calls the corresponding tone,
and finally, the master control module dispatches the light-emitting module to send out a corresponding low level signal to prompt the currently selected tone.
The invention has the advantages and positive effects that:
the induction module replaces a contact switch of conductive rubber, so that the defects of poor contact, misoperation and inconvenient cleaning and maintenance caused by humid environment, contact abrasion, crack dust and conductive rubber aging are avoided; simultaneously through the automatic judgement that contrasts of tone quality in the tone quality of judging the learner exercise piano and the tone quality library module, the learner of being convenient for differentiates the difference in two kinds of tone qualities to reach the effect of distinguishing the sound, improve the learning level of piano.
The invention does not adopt a hardware phase noise extraction circuit to extract the phase information of the measured signal, but utilizes the relation between the power spectrum of the oscillator signal and the phase noise power law spectrum model thereof to realize parameter calculation by a nonlinear least square method, thereby realizing the measurement of the phase noise of the oscillator signal based on a phase noise mathematical model. Compared with the existing phase noise measurement method, the method has the main advantage that the influence of a hardware phase noise extraction circuit on the measurement performance is avoided. Compared with the existing phase noise measurement method, the method has the main advantage that the influence of a hardware phase noise extraction circuit on the measurement performance is avoided.
The upper layer of the oscillator of the induction module adopts a micro-strip structure; the variable capacitance diodes at two ends of the T-shaped open-circuit branch are symmetrically arranged, and a grounding hole and a bias circuit are shared, so that a direct current control circuit is reduced, and the control is simple; the constant value capacitor between the resonator and the input/output line plays a role of blocking; the one-half wavelength microstrip line and the T-shaped branch of the resonator are bent properly, so that the size is reduced, and the whole resonator is of a symmetrical structure; the frequency and bandwidth can be fully adjusted, the absolute bandwidth can be kept constant in the process of adjusting the frequency in a wider range, the central frequency can be kept constant in the process of adjusting the bandwidth in the wider range, and the stability of the filtering characteristic in the process of adjusting the frequency can be ensured.
Compared with the prior art, the invention has the following advantages:
1. the invention adopts a micro-strip structure, has compact design, simple processing, low cost and easy integration.
2. In the bandwidth tuning process, the center frequency is kept unchanged, the absolute bandwidth adjusting range is 150MHz-460MHz, and the wide-range bandwidth adjustment is realized.
3. The electrically tunable filter has very stable filter characteristics within a relatively wide central frequency tuning range, the insertion loss is kept about 0.85dB, and the return loss is kept about 25 dB.
4. The electrically tunable filter can keep the absolute bandwidth basically constant within a wider central frequency tuning range, and meets the requirement of invariable absolute bandwidth.
5. The invention adopts the input and output matching tuning network loaded between the resonator and the input and output ends, facilitates the flexible impedance matching between the tuning feed network and the resonator, provides tunable external Q value, and meets the matching requirements when the frequency and the bandwidth are adjustable.
6. The self-adaptive improvement can be carried out according to actual requirements, the resonant working frequency band is adjusted by changing the length of the resonator and the type of the variable capacitance diode, and the requirements of different frequency band communication standards are met.
Drawings
Fig. 1 is a block diagram of an electronic piano improvised accompaniment schedule management system suitable for score recognition according to an embodiment of the present invention.
In the figure: 1. a power supply module; 2. a sensing module; 3. a main control module; 4. a tone color library module; 5. a light emitting module; 6. a judgment module; 7. and a display module.
Fig. 2 is a schematic diagram of a measurement curve and a fitted curve of a power spectrum of a measured signal in an embodiment provided in the present invention.
Fig. 3 is a schematic diagram of the measurement result of the method of the present invention in the embodiment provided in the present invention compared with the measurement result of AV 4036F.
Fig. 4 is a schematic structural diagram provided in an embodiment of the present invention.
Fig. 5 is a schematic diagram of a matching tuning network according to an embodiment of the present invention.
Fig. 6 is a schematic diagram of an equivalent circuit of a matching tuning network according to an embodiment of the present invention.
Detailed Description
In order to further understand the contents, features and effects of the present invention, the following embodiments are illustrated and described in detail with reference to the accompanying drawings.
The existing electric piano uses physical keys (such as keys made of silica gel) for a long time, and the problem of damage can be caused under the condition that contacts are worn; the conductive rubber has the problems that poor contact or misoperation can be caused by the aging of the rubber along with the passage of time or in a humid environment; meanwhile, the existing electric piano does not support the sound distinguishing training and can not cultivate the judgment of the learner on the pitch.
As shown in fig. 1, an electronic piano improvised accompaniment schedule management system suitable for score recognition according to an embodiment of the present invention includes: the device comprises a power module 1, a sensing module 2, a main control module 3, a tone library module 4, a light-emitting module 5, a judgment module 6 and a display module 7.
The power supply module 1 is connected with the main control module 3 and used for supplying power to the electric piano;
the sensing module 2 is connected with the main control module 3 and used for receiving touch signals generated on the piano keyboard and sending the signals to the main control module 3 for processing and analysis;
the main control module 3 is connected with the power module 1, the induction module 2, the tone library module 4, the light-emitting module 5, the judgment module 6 and the display module 7 and is used for controlling and scheduling the work of each module;
the tone library module 4 is connected with the main control module 3 and used for storing tone data;
the light-emitting module 5 is connected with the main control module 3 and used for calling the corresponding tone according to the decoded touch signal of the main control module 3, sending out a corresponding low level signal and prompting the currently selected tone;
the judging module 6 is connected with the main control module 3 and is used for comparing the pitch selected by the learner with the pitch selected by the controller, if the pitch corresponds to the controller, the judging module displays the correct pitch through the output device, otherwise, if the pitch does not correspond to the controller, the judging module displays the error through the display module 7;
and the display module 7 is connected with the main control module 3 and is used for displaying the data information of the judgment result of the judgment module 6.
The induction method of the induction module 2 provided by the invention comprises the following steps:
firstly, the induction module receives a touch signal generated on a piano keyboard and sends the signal to the main control module;
then, the main control module decodes the received touch signal and calls the corresponding tone,
and finally, the master control module dispatches the light-emitting module to send out a corresponding low level signal to prompt the currently selected tone.
When the piano electric power supply device is used, the power module 1 supplies power to the electric piano; then, receiving a touch signal generated on the piano keyboard through the induction module 2, and sending the signal to the main control module 3 for processing and analysis; the main control module 3 calls the corresponding tone after decoding the touch signal from the tone library module 4; a corresponding low level signal is sent out through the light-emitting module 5 to prompt the currently selected tone; the pitch selected by the learner is compared with the pitch selected by the controller through the judging module 6, if the pitch corresponds to the controller, the judging module displays the tone correctly through the output device, otherwise, if the pitch does not correspond to the controller, the judging module displays the tone incorrectly through the display module 7.
The induction module utilizes signal power spectrum measurement data through a power spectrum model of an oscillator signal, adopts a nonlinear least square method to perform curve fitting to obtain a parameter initial value in the power spectrum model, writes a regular equation set to correct the parameter, and finally obtains a parameter meeting the set requirement; substituting the obtained parameters into the phase noise power law model according to the relation between the signal power spectrum and the phase noise power law model thereof, and further obtaining a phase noise measurement result of the measured signal;
the oscillator is provided with an upper-layer microstrip structure which is formed by sequentially connecting an input microstrip line, an input matching tuning network, a resonator, an output matching tuning network and an output microstrip line;
the input microstrip line and the output microstrip line feed electricity to the resonator, the input matching tuning network and the output matching tuning network realize matching with the resonator, the required external Q value is met, and the invariable absolute bandwidth and the stable filter characteristic are ensured in the adjustable process; the input matching tuning network and the output matching tuning network are composed of variable capacitance diodes and are respectively connected with the input and output microstrip lines and the resonator;
the microstrip resonator, the input microstrip line and the output microstrip line are printed on the dielectric substrate of the middle layer of the band-pass filter.
The input microstrip line and the output microstrip line are both 50 omega microstrip lines;
the resonator is loaded with T-shaped open-circuit branches by a half-wavelength microstrip line, wherein a first variable capacitance diode and a second variable capacitance diode are respectively loaded at two ends of the half-wavelength microstrip line; a third variable capacitance diode and a fourth variable capacitance diode are respectively loaded at two ends of a horizontal microstrip line of the T-shaped open-circuit branch section;
an input matching tuning network is arranged between the input microstrip line and the resonator, and the input matching tuning network consists of a first variable capacitance diode and a fifth variable capacitance diode;
an output matching tuning network is arranged between the resonator and the output microstrip line, and the output matching tuning network consists of a second variable capacitance diode and a sixth variable capacitance diode;
the first variable capacitance diode, the second variable capacitance diode, the third variable capacitance diode, the fourth variable capacitance diode, the fifth variable capacitance diode and the sixth variable capacitance diode are all provided with a bias circuit;
a first blocking capacitor and a fifth variable capacitance diode are respectively loaded between the input microstrip line and the resonator; a sixth varactor and a second blocking capacitor are respectively loaded between the resonator and the output microstrip line; the fifth variable capacitance diode and the first blocking capacitor, and the sixth variable capacitance diode and the second blocking capacitor are formed by cascading square microstrip patches with the side length of 0.7 mm;
the one-half wavelength microstrip line and the T-shaped open-circuit branch of the resonator are bent to a certain degree so as to reduce the size, and the whole resonator is in an axisymmetric structure.
The method for determining the initial parameter value by adopting the nonlinear least square method specifically comprises the following steps:
according to the formula
Determining initial values of parameters by using nonlinear least square method, and taking
(β ═ 0,1,2,3,4), i.e. a needs to be selectedβInitial value of (1), will
Expressed in matrix form as follows:
FA＝S；
wherein:
A＝[a0 a1 … a4]T S＝[S0 S1 … S4]T；
the data points to be used in the matrix F are from N { (F)i,Si) Selecting five frequency points from 1,2, …, and ensuring that the matrix F is reversible;
thereby obtaining the expression parameter aβThe initial values of the matrix a of initial values are:
to be provided with
Iteration is carried out for the initial value to estimate the value of the matrix A, wherein l represents the iteration number, and the value of the matrix A is 0;
of parameter estimationError of the measurement
β＝0,1,…,4，
Estimated by the following equation:
wherein the coefficients
And
comprises the following steps:
wherein SkRepresenting the frequency fkThe measured value of the power spectrum of (b),
representing the frequency fkThe ith iteration value of the corresponding power spectrum, namely:
the noise model parameter estimation judging method comprises the following steps:
judgment of
If the error requirement is not met, let:
l＝l+1；
and will be corrected
And corresponding power spectrum measurement data
Substituting the regular equation set for solving to obtain the correction value of each parameter
β is 0,1, … 4, and re-judged
Until error occurs
The measurement requirements are met or the set iteration number is reached.
If the error requirement is met, the parameter value is added
As
The value of (β ═ 0,1,2,3,4) is substituted into the formula
And obtaining the phase noise of the detected signal, and drawing a phase noise curve.
The invention is further described with reference to specific examples.
In the embodiment, the carrier frequency of the measured signal is 800 MHz. The power spectrum of the measured signal is measured by the spectrum analyzer AV4036F, and the phase noise of the measured signal is calculated according to the method of the invention by using the measured power spectrum data, so that the measurement result of the phase noise is given. And compares the phase noise measurement of the inventive algorithm with the results directly measured using the phase noise measurement module of AV4036F to illustrate the implementation and effectiveness of the inventive method.
Fig. 2 shows the measured signal power spectrum curve measured by the spectrum analyzer AV4036F and the result of the non-linear least squares fitting using the power spectrum measurement data. The measured signal phase noise coefficient obtained from the fitting result is:
and obtaining the single sideband phase noise of the measured signal according to the parameter values obtained by fitting. Figure 3 shows a comparison of the measured signal phase noise measured using the method of the present invention with the measured signal phase noise measured by the phase noise measurement module of AV 4036F. Table 1 lists the numerical comparison and error of the phase noise measured by the method of the present invention at some frequency offsets in this example with the phase noise measured by the phase noise measurement module of spectrum analyzer AV 4036F.
The following table illustrates the data comparison of the measurements obtained by the method of the invention with the AV4036F measurements
As shown in fig. 4, the resonator of the present invention is a half-wavelength microstrip loaded T-type open stub. Y is1，L1The admittance and the physical length of a one-half wavelength microstrip line are expressed, and a variable capacitance diode C is loaded at two endsv1；Y2，L2The admittance and the physical length of the loaded T-shaped branch section longitudinal microstrip line are represented; y is3，L3The admittance and the physical length of the loaded T-shaped branch-node transverse microstrip line are shown, and a variable capacitance diode C is loaded at two endsv2. The resonator is in an axisymmetric structure, and parity mode analysis is carried out to obtain parity mode admittances which are respectively as follows:
Yin_odd，Yin_evenrespectively, representing odd-even mode admittances, wherein:
Ys＝Y1tan(βL1){Y2[Y3-ωeventan(βL3)]-2Y3tan(βL2)[ωCv2+Y3tan(βL3)]} (4)
depending on the resonance condition, the odd-even mode resonance frequency can be expressed as:
from the equations (5) and (6), foddDependent on Cv1Variation of (a) fevenDependent on Cv1And Cv2Change of, i.e. tuning Cv1Both frequency and bandwidth variations can be induced. If fixed Cv1Then foddWill also be fixed, fevenTuning of (2) is dependent only on Cv2. This property is applied to achieve tuning of the bandwidth.
θ1＝-tan-1[(2Y2/B')/(Y1/Y2-Y2/Y1-Y1Y2/B'2)] (9)
θ2＝-tan-1[(2Y1/B')/(Y2/Y1-Y1/Y2-Y1Y2/B'2)] (10)
B'＝(B-1/X) (11)
Qe＝b/(J01 2/Y0) (12)
Where b is the slope parameter of the resonator.
From (7), it is possible: to achieve a constant absolute bandwidth, the external quality factor increases with increasing center frequency. As shown in FIG. 5, the input/output matching tuning network between the input/output microstrip line and the resonator is implemented by a varactor diode Cv1、CeTo be realized, the equivalent circuit diagram is as the figure6, varactor diode CeEquivalent admittance being Y1Electrical length of theta1One microstrip line is connected in series with a variable susceptance jB and a variable capacitance diode Cv1Equivalent to a variable reactance jX connected in parallel with an admittance of Y2Electrical length of theta2A microstrip line of (a); the variable susceptance jB ' and the variable reactance jX form a variable susceptance jB ', which can be derived from equations (8) (12) by which varying jB ' corresponds to varying J01Thereby obtaining a varying QeTo meet the need for an external figure of merit during the tuning process. Theta can be obtained by combining the formulas (9) and (10)1And theta2Is taken to be a value of1And theta2The two sections of microstrip lines are respectively absorbed by the input/output microstrip line and the resonator. When the frequency tuning range of the resonator is determined, an appropriate capacitance value can be selected, and the tunable network can realize the external quality factor Q required by a given bandwidthe。
The above description is only for the preferred embodiment of the present invention, and is not intended to limit the present invention in any way, and all simple modifications, equivalent changes and modifications made to the above embodiment according to the technical spirit of the present invention are within the scope of the technical solution of the present invention.
Claims (5)
1. An electronic piano improvised accompaniment allocation management system suitable for music score recognition, characterized in that the electronic piano improvised accompaniment allocation management system suitable for music score recognition comprises:
the sensing module is connected with the main control module and used for receiving touch signals generated on the piano keyboard and sending the signals to the main control module for processing and analysis;
the induction module utilizes signal power spectrum measurement data through a power spectrum model of an oscillator signal, adopts a nonlinear least square method to perform curve fitting to obtain a parameter initial value in the power spectrum model, writes a regular equation set to correct the parameter, and finally obtains a parameter meeting the set requirement; substituting the obtained parameters into the phase noise power law model according to the relation between the signal power spectrum and the phase noise power law model thereof, and further obtaining a phase noise measurement result of the measured signal;
the master control module is connected with the power supply module, the induction module, the tone color library module, the light-emitting module, the judgment module and the display module and is used for controlling and scheduling each module to work;
the tone library module is connected with the main control module and used for storing tone data;
the judging module is connected with the main control module and is used for comparing the pitch selected by the learner with the pitch selected by the controller, if the pitch corresponds to the controller, the judging module displays the pitch correctly through the output device, otherwise, if the pitch does not correspond to the controller, the judging module displays the error through the display module;
the oscillator is provided with an upper-layer microstrip structure which is formed by sequentially connecting an input microstrip line, an input matching tuning network, a resonator, an output matching tuning network and an output microstrip line;
the input microstrip line and the output microstrip line feed electricity to the resonator, the input matching tuning network and the output matching tuning network realize matching with the resonator, the required external Q value is met, and the invariable absolute bandwidth and the stable filter characteristic are ensured in the adjustable process; the input matching tuning network and the output matching tuning network are composed of variable capacitance diodes, an input microstrip line is connected with the input matching tuning network, the input matching tuning network is connected with a resonator, the resonator is connected with the output matching tuning network, and the output matching tuning network is connected with an output microstrip line;
the microstrip resonator, the input microstrip line and the output microstrip line are printed on the dielectric substrate of the middle layer of the band-pass filter;
the input microstrip line and the output microstrip line are both 50 omega microstrip lines;
the resonator is loaded with T-shaped open-circuit branches by a half-wavelength microstrip line, wherein a first variable capacitance diode and a second variable capacitance diode are respectively loaded at two ends of the half-wavelength microstrip line; a third variable capacitance diode and a fourth variable capacitance diode are respectively loaded at two ends of a horizontal microstrip line of the T-shaped open-circuit branch section;
an input matching tuning network is arranged between the input microstrip line and the resonator, and the input matching tuning network consists of a first variable capacitance diode and a fifth variable capacitance diode;
an output matching tuning network is arranged between the resonator and the output microstrip line, and the output matching tuning network consists of a second variable capacitance diode and a sixth variable capacitance diode;
the first variable capacitance diode, the second variable capacitance diode, the third variable capacitance diode, the fourth variable capacitance diode, the fifth variable capacitance diode and the sixth variable capacitance diode are all provided with a bias circuit;
a first blocking capacitor and a fifth variable capacitance diode are respectively loaded between the input microstrip line and the resonator; a sixth varactor and a second blocking capacitor are respectively loaded between the resonator and the output microstrip line; the fifth variable capacitance diode and the first blocking capacitor, and the sixth variable capacitance diode and the second blocking capacitor are formed by cascading square microstrip patches with the side length of 0.7 mm;
the one-half wavelength microstrip line and the T-shaped open-circuit branch of the resonator are bent to reduce the size, and the whole resonator is in an axisymmetric structure.
2. The system for managing improvised accompaniment for an electric piano adapted for score recognition as set forth in claim 1, wherein the method for determining the initial value of the parameter by using the non-linear least square method specifically comprises:
according to the formula
Determining initial values of parameters by using nonlinear least square method, and taking
(β ═ 0,1,2,3,4), i.e. a needs to be selectedβInitial value of (1), will
Expressed in matrix form as follows:
FA＝S；
wherein:
A＝[a0 a1…a4]T S＝[S0 S1…S4]T；
the data points to be used in the matrix F are from N { (F)i,Si) Selecting five frequency points from 1,2, …, and ensuring that the matrix F is reversible;
thereby obtaining the expression parameter aβThe initial values of the matrix a of initial values are:
to be provided with
Iteration is carried out for the initial value to estimate the value of the matrix A, wherein l represents the iteration number, and the value of the matrix A is 0;
error of parameter estimation
β＝0,1,…,4，
Estimated by the following equation:
wherein the coefficients
And
comprises the following steps:
wherein SkRepresenting the frequency fkThe measured value of the power spectrum of (b),
representing the frequency fkThe ith iteration value of the corresponding power spectrum, namely:
the noise model parameter estimation judging method comprises the following steps:
judgment of
If the error requirement is not met, let:
l＝l+1；
and will be corrected
And corresponding power spectrum measurement data
Substituting into a regular equation set to solve to obtain parametersCorrection value
β is 0,1, … 4, and re-judged
Until error occurs
The measurement requirements are met or the set iteration times are reached;
if the error requirement is met, the parameter value is added
As
The value of (β ═ 0,1,2,3,4) is substituted into the formula
And obtaining the phase noise of the detected signal, and drawing a phase noise curve.
3. The system for managing an improvised accompaniment for an electric piano adapted for score recognition as set forth in claim 1, wherein said sensing module comprises:
the power spectrum data acquisition module is mainly used for completing the acquisition of power spectrum data of input signals and providing a data source for subsequent parameter estimation;
the parameter calculation module is mainly used for estimating parameters in the input signal power spectrum model to finally obtain parameter values meeting the error requirements;
and the phase noise measurement result generation module is mainly used for calculating the phase noise measurement result of the measured oscillator signal by substituting the finally obtained parameters into the signal phase noise power law model.
4. The system for managing an improvised accompaniment for electric piano adapted for score recognition according to claim 1, wherein said system for managing an improvised accompaniment for electric piano adapted for score recognition comprises:
the power supply module is connected with the main control module and used for supplying power to the electric piano;
the light-emitting module is connected with the main control module and used for calling the corresponding tone according to the decoded touch signal of the main control module, sending out a corresponding low-level signal and prompting the currently selected tone;
and the display module is connected with the main control module and is used for displaying the data information of the judgment result of the judgment module.
5. The system for managing an improvised accompaniment for an electric piano adapted for score recognition as set forth in claim 1, wherein the sensing means comprises:
firstly, the induction module receives a touch signal generated on a piano keyboard and sends the signal to the main control module;
then, the main control module decodes the received touch signal and calls the corresponding tone,
and finally, the master control module dispatches the light-emitting module to send out a corresponding low level signal to prompt the currently selected tone.
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Application publication date: 20180817 Assignee: Yiyang Sunshine Music Center Assignor: Hunan City University Contract record no.: X2023980043236 Denomination of invention: An impromptu accompaniment allocation management system for electric piano suitable for music score recognition Granted publication date: 20220405 License type: Exclusive License Record date: 20231016 |