CN103905959A - Active noise control device based on pilot headset - Google Patents
Active noise control device based on pilot headset Download PDFInfo
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- CN103905959A CN103905959A CN201210573027.0A CN201210573027A CN103905959A CN 103905959 A CN103905959 A CN 103905959A CN 201210573027 A CN201210573027 A CN 201210573027A CN 103905959 A CN103905959 A CN 103905959A
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Abstract
The invention discloses an active noise control device based on a pilot headset. The active noise control device is characterized in that the active noise control device comprises a secondary sound source for cancelling the external noise; a reference sensor for acquiring the external noise; an error sensor for acquiring the residual error after the secondary sound source and the external noise are superimposed; and a controller for receiving electrical signals sent by the reference sensor and the error sensor and sending a control signal to the secondary sound source. The active noise control device of the invention has the following advantages that control parameters can be adjusted according to a specific noise environment so as to make the noise control be targeted and selective, the successful transmission of a voice signal can be ensured while performing noise reduction, and the masking effect of low-frequency noise is reduced, so the voice or music clarity can be improved.
Description
Technical field
The present invention relates to the control device of active noise, this control device is applied in aircraft, tank, the contour noise of automobile cabin place.
Background technology
Noise pollution, as one of three large public hazards of environmental pollution, is more and more subject to people's attention.Noise pollution has become a kind of very important environmental problem.Long term exposure, under noise, can have a strong impact on people's physical and mental health, reduces operating efficiency.
The principle of active noise controlling (also can be described as Active noise control using) is application electric technology and electro-acoustic element, introducing one equates and the secondary sound wave of single spin-echo with former noise sound wave (primary sound wave) amplitude, the noise of its generation and original noise are cancelled out each other in certain area, thereby reach the object of noise reduction.At present, Active noise control using has all obtained considerable progress at aspects such as mechanism research, system realization and engineering application, but for those strong noise places, such as, in aircraft cockpit, its effect is not still very desirable.
Summary of the invention
The present invention seeks to solve the not good problem of noise reduction in prior art, by the research of active noise reduction technology, a kind of novel active noise controller based on pilot's earphone is proposed, realize the object that reduces noise on aircraft, sense of hearing pressure that so not only can ease pilot, increase work efficiency, but also can guarantee the voice signal transmission of " totally ".
To achieve these goals, the present invention is achieved in that the active noise controller based on pilot's earphone, it is characterized in that, comprises, secondary sound source, for offsetting outside noise; Reference sensor, for gathering outside noise; Error pick-up, for gathering the residual error after secondary sound source and outside noise stack; And controller, for receiving the signal of telecommunication that reference sensor and error pick-up send and sending control signal to secondary sound source.
Described controller comprises,
One first operational amplification circuit, has an input, for being connected with error pick-up and reference sensor; One output;
One second operational amplification circuit, has an input, for being connected with error pick-up and reference sensor; One output;
One first frequency overlapped-resistable filter, has an input, for being connected with the output of described the first operational amplification circuit; One output;
One second frequency overlapped-resistable filter, has an input, for being connected with the output of described the second operational amplification circuit; One output;
One multipath conversion and data holding circuit have a first input end, for being connected with the output of described the first frequency overlapped-resistable filter; One second input, for being connected with the output of described the second frequency overlapped-resistable filter; One the 3rd input; One output;
One A/D converter, has a first input end, for being connected with the output of described multipath conversion and data holding circuit; One second input; One output;
One logic controller, has one first output, for being connected with the 3rd input of described multipath conversion and data holding circuit; One second output, for being connected with the second input of described A/D converter; One the 3rd output; One two-way input/output terminal;
One SDRAM, has an input, for being connected with the output of described A/D converter; One two-way input/output terminal;
One digital signal processor, has one first two-way input/output terminal, for being connected with the two-way input/output terminal of described SDRAM; One second two-way input/output terminal, for being connected with the two-way input/output terminal of described logic controller; One the 3rd two-way input/output terminal, for being connected with computer; One output;
One D/A change-over circuit, has a first input end, for being connected with the output of described digital signal processor; One second input, for being connected with the 3rd output of described logic controller; One output;
One smoothed filter circuit, has an input, for being connected with the output of described D/A change-over circuit; One output; And,
One power amplifier, has an input, for being connected with the output of described smoothed filter circuit; One output, for being connected with described secondary sound source.
Preferably, the loud speaker that described secondary sound source is unidirectivity.
Preferably, described frequency overlapped-resistable filter be more than or equal to the half of its sample frequency by frequency.
Preferably, the word length of described A/D converter, more than 12, and adopts parallel model.
Preferably, described digital signal processor adopts TMS320C6000 DSP series, for example, and TMS320C6713.
Preferably, the input impedance of described power amplifier is 5000-15000 Ω, and the distortion factor is below 0.05%.
Accompanying drawing explanation
Fig. 1 is structural representation of the present invention.
Fig. 2 is the structural representation of middle controller of the present invention.
Embodiment
Below in conjunction with drawings and Examples, the present invention is elaborated.
Refer to Fig. 1, shown in Fig. 1 is a kind of active noise controller based on pilot's earphone, comprises, secondary sound source 1, is positioned at earmuff, and being one is the loud speaker adding for offsetting outside noise people; Error pick-up 2, in earmuff between secondary sound source and elementary sound source, for gathering the residual error after sound field stack, to upgrade the weight coefficient of the following controller of iteration; Be positioned at the reference sensor 3 on headband top, for gathering outside noise the primary signal as following controller; And controller 4, for receiving the signal that reference sensor and error pick-up send and sending control signal to secondary sound source.
Described secondary sound source is the loud speaker (direction is contrary with elementary sound source) of unidirectivity, avoids bringing acoustic feedback to error pick-up and reference sensor, affects system stability; Reference sensor and error pick-up adopt highly sensitive microphone, and its amplitude-frequency characteristic is as far as possible steady in audiorange.
Described controller, as the vitals of this control device, complete the adjustment of the external input signal of active control, and be converted into digital signal, complete adaptive control algorithm for digital signal processor, it is adjusted and is converted into analog signal to the digital signal of output simultaneously.Generally speaking, controller has been mainly mould/number, the adjustment of D/A switch and signal thereof.Its structure is specially: comprises,
One first operational amplification circuit 5, has an input; One output;
One second operational amplification circuit 5, has an input; One output;
One first frequency overlapped-resistable filter 6, has an input, for being connected with the output of described the first operational amplification circuit; One output;
One second frequency overlapped-resistable filter 6, has an input, for being connected with the output of described the second operational amplification circuit; One output;
One multipath conversion and data holding circuit 7, have a first input end, for being connected with the output of described the first frequency overlapped-resistable filter; One second input, for being connected with the output of described the second frequency overlapped-resistable filter; One the 3rd input; One output;
One A/D converter 8, has a first input end, for being connected with the output of described multipath conversion and data holding circuit; One second input; One output;
One logic controller 10, has one first output, for being connected with the 3rd input of described multipath conversion and data holding circuit; One second output, for being connected with the second input of described A/D converter; One the 3rd output; One two-way input/output terminal;
One SDRAM9, has an input, for being connected with the output of described A/D converter; One two-way input/output terminal;
One digital signal processor 11, has one first two-way input/output terminal, for being connected with the two-way input/output terminal of described SDRAM; One second two-way input/output terminal, for being connected with the two-way input/output terminal of described logic controller; One the 3rd two-way input/output terminal, for being connected with computer; One output;
One D/A change-over circuit 12, has a first input end, for being connected with the output of described digital signal processor; One second input, for being connected with the 3rd output of described logic controller; One output;
One smoothed filter circuit 13, has an input, for being connected with the output of described D/A change-over circuit; One output; And,
One power amplifier 14, has an input, for being connected with the output of described smoothed filter circuit; One output, for being connected with described secondary sound source.
The external input signal of controller, concerning feedforward control system, comprises reference signal and error signal; For feedback control system, only there is error signal.From theory, should be noted that the requirement of sampling thheorem to A/D conversion.Sampling thheorem explanation: if the upper limiting frequency of an analog signal is f
k, keeping the distortionless necessary condition of frequency content after this signal sampling is sample frequency f
s>=2f
k.In order to meet sampling thheorem and to keep certain reference input amplitude, before A/D conversion, need to carry out the preposition amplification of voltage and anti-aliasing filter.If systematic sampling frequency is f
s, (be in fact a low pass filter, its cut-off frequency is f to frequency overlapped-resistable filter
s/ 2.) be exactly to leach f in analog signal
smore than/2 frequency contents, to guarantee that aliasing does not occur the discrete-time signal after A/D conversion on frequency spectrum.
A/D converter is exactly that analog signal is sampled in time, in amplitude, quantizes.In Active noise control using, the performance index of the A/D converter of being concerned about most have: quantizing noise and conversion speed.Quantizing noise is relevant with the word length of A/D converter.In general the word length that needs only A/D converter is more than 12, and the impact that quantizing noise causes active controller performance is just negligible.The conversion speed of A/D converter is main relevant with the type of transducer.From operation principle point, A/D converter divides parallel model, the long-pending formula of diclinic, ramp type, successive approximation etc.Comparatively speaking, the conversion speed of parallel model A/D converter is the fastest, and still, along with the raising of resolution, cost can increase sharply.For multichannel active control system, it is considerable selecting A/D converter fast.The present embodiment selects parallel model.
As can be seen from the figure, active controller output is secondary signal.Secondary signal is carried out needing to insert smothing filtering after D/A conversion, and its object is the stairstep signal after level and smooth D/A conversion.D/A converter is conventionally with a zero-order holder, and it is output as analog signal.The frequency response of zero-order holder is " step " of the lowpass function composition of constantly decay, and smoothing filter is exactly to want first lowpass response of filtering signal frequency composition in addition.
D/A converter is converted to analog quantity by digital quantity exactly, by power amplification rear drive secondary sound source.In active noise control system, needing the performance index of the D/A converter of being concerned about is mainly settling time, and it is relevant with element used, special relevant with some switching devices and amplifier.Generally speaking, the settling time of D/A converter is all very short, can not cause large impact to the performance of active controller.
In the time of design frequency overlapped-resistable filter and smoothing filter, except paying close attention to their cut-off frequency and amplitude response, also should pay special attention to their time delay.Because these time delays are as a part for secondary channel delay character, to the stability important of system.If the phase-frequency response of frequency overlapped-resistable filter and reconstruction filter is
, their delay character can be used group delay
represent, have
.
Filter phase-frequency response is relevant with type, parameter and the purposes (as anti-aliasing filter, still as smothing filtering) of filter.
Power amplifier, in the time of design, be considered the resistance matching problem of pilot's earmuff, with the conversion efficiency of guaranteed output amplifier, avoids overload to cause power amplifier to damage; Should be noted that in addition to such an extent that be: (1) input impedance: the size of the antijamming capability of ordinary representation power amplifier, generally can be at 5000-15000 Ω, the larger expression antijamming capability of numerical value is stronger; (2) distortion factor: refer to the distortion level that output signal is compared with input signal, the less quality of numerical value is better, generally below 0.05%; (3) signal to noise ratio: refer to the ratio between the central music signal of output signal and noise signal, the larger representative voice of numerical value is cleaner.
Digital signal processor is in the time of design, and the selection of dsp chip is a very important link.In general, choice criteria is mainly: arithmetic speed (mainly comprises instruction cycle and MAC, the former refers to carry out the time that instruction is required, and the latter has referred to multiplication and required time of a sub-addition), complete and convenience, the power consumption of chip etc. of price, hardware resource, operational precision, development environment.In active noise control system, general dsp chip can meet the demands aspect hardware resource, operational precision, power consumption at present, and price is also in continuous decline.Therefore, selecting the main standard of dsp chip is to see that its operational capability can guarantee the real-time of adaptive active control algolithm, this point particular importance that just seems concerning multichannel active control system.Take LMS algorithm as example, if a multichannel active control system is by J road reference signal, M road error signal and K secondary path, be respectively L and I as the filter length of controller and modeling filter, realize required the taking advantage of of this algorithm and add number of times and be
.
According to comprehensive analysis, the dsp chip that the present embodiment adopts is that TMS320C6713 is best, and TMS320C6713 is TMS320C6000 DSP series.TMS320C6000 series digit signal processor (DSP) is the important series of TMS320DSP family.This series DSP chip has fixed point and two kinds of floating-points, and wherein TMS320C62 series and TMS320C64 series are serial for fixing a point, and TMS320C67 series is floating-point series.
The DSP of C6000 series all adopts VelociTI structure, and this structure is the command word that a kind of high performance, advanced VLIW(grows very much) structure, make C6000 series DSP become the optimal selection of multichannel and multifunctional application.
In C6000 DSP sheet, there are 8 parallel processing units, are divided into identical two groups.The architecture of DSP adopts very long command word (VLIW) structure.Single instrction word length is 32, an instruction bag of 8 instruction compositions, and total word length is 256.Chip internal is provided with special instruction distribution module, each 256 bit instructions can be assigned to 8 processing units simultaneously, and be moved by 8 unit simultaneously, therefore can within the single cycle, carry out many instructions.In the time that 8 processing units of chip internal move simultaneously, it is million instructions per second that its maximum processing capability can reach 6000MIPS(MIPS).The key property of C6713 can be summarized as follows:
The compatible DSP of fixed point/floating-point series, dominant frequency 200MHz.
Internal storage space is 264K × 16bit.
There is the advanced VLIW CPU of 8 functional units, comprise 2 multipliers and 6 arithmetic logic unit (ALU).
Each cycle can be carried out nearly 8 instructions, is 10 times of typical dsp chip.
Allow designer to develop efficient class RISC(reduced instruction code), to improve development efficiency.
Instruction packing.
8 instructions carrying out for serial or parallel provide code length equivalent process.
Reduce code length and reduce power consumption.
All instructions can be carried out by realization condition.
Reduce the branch transition of high expense.
Effective run time version in functional unit independently.
Be applied to the most effective C compiler of DSP.
For fast Development with improve the Assembly Optimizer that concurrent working efficiency is used.
8/16/32 bit data support, for various application provide efficient memory support.
Saturated and normalization technology provide support for crucial algorithm operating.
Territory operation and instruction fetch, setting, removing and position counting are supported in the general operation in control and data manipulation application.
For the IEEE floating-point operation of single precision (32) and double precision (64) provides hardware supports.
32 integer multiplication can obtain 32 or 64 results.
When active noise controller work, pick up control signal by microphone, send into controller, produce continuous secondary signal, through power amplification rear drive secondary sound source, produce secondary signal identical with elementary acoustical signal frequency, single spin-echo, realize the decay of noise.
Below only expressed embodiments of the present invention, it describes comparatively concrete and detailed, but can not therefore be construed as limiting the scope of the patent.It should be pointed out that for the person of ordinary skill of the art, without departing from the inventive concept of the premise, can also make some distortion and improvement, these all belong to protection scope of the present invention.Therefore, the protection range of patent of the present invention should be as the criterion with claims.
Claims (7)
1. the active noise controller based on pilot's earphone, is characterized in that, comprises, secondary sound source, for offsetting outside noise; Reference sensor, for gathering outside noise; Error pick-up, for gathering the residual error after secondary sound source and outside noise stack; And controller, for receiving the signal of telecommunication that reference sensor and error pick-up send and sending control signal to secondary sound source.
2. the active noise controller based on pilot's earphone according to claim 1, is characterized in that: described controller comprises,
One first operational amplification circuit, has an input, for being connected with error pick-up and reference sensor; One output;
One second operational amplification circuit, has an input, for being connected with error pick-up and reference sensor; One output;
One first frequency overlapped-resistable filter, has an input, for being connected with the output of described the first operational amplification circuit; One output;
One second frequency overlapped-resistable filter, has an input, for being connected with the output of described the second operational amplification circuit; One output;
One multipath conversion and data holding circuit have a first input end, for being connected with the output of described the first frequency overlapped-resistable filter; One second input, for being connected with the output of described the second frequency overlapped-resistable filter; One the 3rd input; One output;
One A/D converter, has a first input end, for being connected with the output of described multipath conversion and data holding circuit; One second input; One output;
One logic controller, has one first output, for being connected with the 3rd input of described multipath conversion and data holding circuit; One second output, for being connected with the second input of described A/D converter; One the 3rd output; One two-way input/output terminal;
One SDRAM, has an input, for being connected with the output of described A/D converter; One two-way input/output terminal;
One digital signal processor, has one first two-way input/output terminal, for being connected with the two-way input/output terminal of described SDRAM; One second two-way input/output terminal, for being connected with the two-way input/output terminal of described logic controller; One the 3rd two-way input/output terminal, for being connected with computer; One output;
One D/A change-over circuit, has a first input end, for being connected with the output of described digital signal processor; One second input, for being connected with the 3rd output of described logic controller; One output;
One smoothed filter circuit, has an input, for being connected with the output of described D/A change-over circuit; One output; And,
One power amplifier, has an input, for being connected with the output of described smoothed filter circuit; One output, for being connected with described secondary sound source.
3. the active noise controller based on pilot's earphone according to claim 1, is characterized in that: the loud speaker that described secondary sound source is unidirectivity.
4. the active noise controller based on pilot's earphone according to claim 1, is characterized in that: described frequency overlapped-resistable filter be more than or equal to the half of its sample frequency by frequency.
, the active noise controller based on pilot's earphone according to claim 1, it is characterized in that: the word length of described A/D converter, more than 12, and adopts parallel model.
6. the active noise controller based on pilot's earphone according to claim 1, is characterized in that: described digital signal processor adopts TMS320C6000 DSP series, for example, and TMS320C6713.
7. the active noise controller based on pilot's earphone according to claim 1, is characterized in that: the input impedance of described power amplifier is 5000-15000 Ω, and the distortion factor is below 0.05%.
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| CN105913836A (en) * | 2016-04-07 | 2016-08-31 | 虞安波 | Fixed-point real time noise reduction method based on DSP |
| CN106098053A (en) * | 2016-06-01 | 2016-11-09 | 安瑞装甲材料（芜湖）科技有限公司 | Active noise reducing device |
| CN106292138A (en) * | 2015-05-20 | 2017-01-04 | 江苏宜清光电科技有限公司 | A kind of system using active noise to reduce scialyscope noise |
| CN107882487A (en) * | 2017-11-23 | 2018-04-06 | 四川三元环境治理股份有限公司 | A kind of ventilating sound-proof device |
| CN108600894A (en) * | 2018-07-11 | 2018-09-28 | 重庆传乐音响科技有限公司 | A kind of earphone adaptive active noise control system and method |
| CN109379652A (en) * | 2018-08-29 | 2019-02-22 | 四川长虹电器股份有限公司 | A kind of the secondary channel offline identification method and system of earphone Active noise control |
| CN110521215A (en) * | 2017-04-20 | 2019-11-29 | 伯斯有限公司 | The earphone system and method that pressure adaptive active noise is eliminated |
| CN112869946A (en) * | 2021-03-23 | 2021-06-01 | 吉林大学 | Underslung active noise reduction earmuff |
| CN113183707A (en) * | 2021-05-21 | 2021-07-30 | 辽宁工业大学 | Design method and system of whole-vehicle active suspension self-adaptive fixed-period sampling controller |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN106292138A (en) * | 2015-05-20 | 2017-01-04 | 江苏宜清光电科技有限公司 | A kind of system using active noise to reduce scialyscope noise |
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| CN110521215A (en) * | 2017-04-20 | 2019-11-29 | 伯斯有限公司 | The earphone system and method that pressure adaptive active noise is eliminated |
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| CN112869946A (en) * | 2021-03-23 | 2021-06-01 | 吉林大学 | Underslung active noise reduction earmuff |
| CN113183707A (en) * | 2021-05-21 | 2021-07-30 | 辽宁工业大学 | Design method and system of whole-vehicle active suspension self-adaptive fixed-period sampling controller |
| CN113183707B (en) * | 2021-05-21 | 2024-04-02 | 辽宁工业大学 | Design method and system of self-adaptive fixed-period sampling controller of full-vehicle active suspension |
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