JPH07199966A - Adaptive active silencer for vehicle interior sound - Google Patents

Abstract

(57) [Summary] [Object] The present invention relates to an adaptive active noise suppression system for vehicle interior sound, which can generate an arbitrary reference signal from a signal that correlates with the engine speed, and can cope with various engine operating conditions. The purpose is to be able to mute. A sound wave signal output from the secondary sound source 3 so as to minimize the control point signal by receiving the reference signal from the reference signal generating means 1 and the control point signal from the control point signal detecting means 2-1. Control means 4 using an adaptive filter for controlling
Based on the signal frequency information calculation means 1A for calculating the signal frequency information from the signal correlated with the engine speed and the signal frequency information calculated by the signal frequency information calculation means 1A, The reference signal generating means 1B is configured to generate a reference signal having a plurality of frequencies including a frequency that is a non-integer multiple of the frequency of the signal that correlates with the engine speed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adaptive active silencer for vehicle interior sound. In general, in the indoor muffled noise of 200 Hz or less, which has a large effect on the occupant noise in the vehicle interior noise, the panel vibration radiation noise caused by the engine rotation vibration is dominant. , Is an important issue related to the strength problem.

[0002]

2. Description of the Related Art Conventionally, an active noise canceller using an adaptive filter has been proposed in order to reduce the muffled noise in the room. That is, in such an active noise canceller, a sound having an equal amplitude and a reverse phase to the vehicle interior noise is emitted from the secondary sound source by using an adaptive filter so that the signal at the control point in the vehicle interior is minimized. It is in control. In this case, the engine ignition signal itself is used as the reference signal.

[0003]

However, in such conventional means, since the engine ignition signal itself is used as the reference signal of the active noise canceller as described above, the fundamental order component (for example, in the case of a four cylinder engine) is used. , The crank rotation secondary frequency component C ₂ , the crank rotation 4th frequency component C ₄ , the crank rotation 6th frequency component C ₆ , the crank rotation 8th frequency component C ₈ , ... Half-order components (for example, crank rotation 0.25-order frequency component C _0.25 and crank rotation 0.5 are said to deteriorate sound quality during acceleration / deceleration.
It is not possible to mute the next frequency component C _0.5 etc.). Therefore, during acceleration / deceleration, there is a problem that a sufficient silencing effect and improvement in sound quality cannot be obtained.

The present invention was devised in view of the above problems, and in an adaptive active silencer using an adaptive filter, an arbitrary reference signal can be generated from a signal correlated with the engine speed, It is an object of the present invention to provide an adaptive active noise reduction system capable of muffling in response to various engine operating conditions.

[0005]

Therefore, the adaptive active noise canceling system for the vehicle interior sound according to the present invention includes a reference signal generating means for generating a reference signal correlating with the number of revolutions of the engine mounted in the vehicle, and the vehicle. The control point signal detecting means for detecting a signal at a control point in the room and the secondary sound source for outputting a sound wave signal to the vehicle interior are provided, and the reference signal from the reference signal generating means and the control point signal detection are provided. A control means using an adaptive filter for receiving the control point signal from the means and controlling the sound wave signal output from the secondary sound source so that the control point signal is minimized. In the adaptive sound silencer of sound, the reference signal generating means calculates signal frequency information from signal correlated with engine speed, and a signal frequency calculated by the signal frequency information calculating means. On the basis of the report, a reference signal generating means for generating a reference signal having a plurality of frequencies including a frequency that is a non-integer multiple of the frequency of the signal that correlates with the engine speed is provided. I am trying.

[0006]

In the above-mentioned adaptive active noise canceling system for vehicle interior sound of the present invention, the control means using the adaptive filter receives the reference signal from the reference signal generating means and the control point signal from the control point signal detecting means. 2 so that the control point signal is minimized.
The sound wave signal output from the next sound source is controlled. At this time, the reference signal is generated as follows. That is, the signal frequency information calculating means calculates the signal frequency information from the signal correlated with the engine speed, and the reference signal generating means changes the engine frequency of the engine based on the signal frequency information calculated by the signal frequency information calculating means. A reference signal having a plurality of frequencies including a non-integer multiple of the frequency of the signal correlated with the rotation speed is generated.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 9 show an adaptive active noise reduction system for vehicle interior sound as an embodiment of the present invention. FIG. 1 is a block diagram of its essential parts, FIG. 2 is its system block diagram, and FIG. 3 is system control. 4 is a block diagram showing details of the unit, FIG. 4 is a block diagram illustrating a control algorithm of the present apparatus, FIGS. 5 and 6 are flowcharts illustrating a control procedure thereof, and FIG. 7 is a flowchart illustrating a reference frequency calculation procedure. 8 is a time chart of FIG. 8, FIG. 8 is a main part block diagram showing a modification of the present embodiment, and FIG. 9 is a main part block diagram showing still another modification of the present embodiment.

In this embodiment, as shown in FIGS. 1 to 3, control point signal detecting means for detecting a signal at a control point (evaluation point) in the vehicle interior 200 is provided. The control point signal detection means is configured as a control microphone (for example, a simple condenser microphone) 2-1 provided on the headrest of the driver seat 201 in the vehicle interior 200. More specifically, the control microphone 2-1 is provided in a portion of the headrest near the center of the vehicle compartment via a rubber case. The reason why the control microphone 2-1 is provided in the portion of the headrest near the center of the vehicle compartment in this way is to reduce the influence of the reflection of the glass and the like and increase the effective area.

The control point signal detected by the control microphone 2-1 is amplified by a microphone amplifier (amplifier) provided in the seat back. Further, a sound wave signal (secondary source signal) directed into the passenger compartment 200
A speaker (cancelling speaker) 3 serving as a secondary sound source for outputting is provided. In this case, the speaker 3 is provided at the rear end of the rear seat 203 of the vehicle interior 200.
It is arranged at a position where the trunk room can be used as a back cavity. That is, the speaker 3 is attached to the partition wall (speaker mounting plywood) on the rear surface of the seat back of the rear seat 203 so that the vibrating surface faces the opening that opens when the armrest of the rear seat 203 is tilted.

Further, a reference signal generating means 1 for generating a reference signal correlating with the rotation speed of an engine (for example, a V6 engine) 100 mounted on a vehicle is provided. The reference signal generating means 1 has a signal frequency. It is configured as a synthesizer having the functions of the information calculation means 1A and the reference signal generation means 1B. Here, the signal frequency information calculation means 1
A is for calculating signal frequency information from an engine pulse (ignition pulse) as a signal correlating with the engine speed from the electronic control unit (ECU) 5. For this reason, as shown in FIG. Information computing means 1A
Is a counting means 1A-1 for counting the number of engine pulses.
And frequency calculating means 1A- for obtaining an engine pulse frequency from the number of engine pulses counted by the counting means 1A-1.
It has the function of 2.

The ECU 5 receives detection signals from an engine speed sensor, an engine load sensor, etc., and outputs a signal for controlling ignition timing of the engine 100 and a signal for controlling fuel supply (air-fuel ratio control). It is a well-known thing that consists of a microprocessor, memory, etc.
An engine pulse (ignition pulse) can be easily taken out from the ECU 5.

The counting means 1A-1 and the frequency calculating means 1A-2 are realized by software in order to maintain the causal relationship between the input engine pulse and the microphone signal. ing. That is, if the above means is realized by hardware instead of software, the causal relationship between the input engine pulse and the microphone signal disappears due to the non-linearization of the timing difference and the time delay.

Next, the calculation method by the above counting means 1A-1 and frequency calculating means 1A-2 will be described. First, the initial angular velocity and the reference frequency from the cycle of the engine ignition pulse (engine pulse) can be expressed as sin θ = sin (W · T _SAMPLE ) = sin (2πF _SIGNAL · T _SAMPLE ) ·· (A1).

Since F _SIGNAL = 1 / T _SIGNAL , assuming that the number of pulses counted in T _SIGNAL is n, sin θ = sin (2π (T _SAMPLE / (n / F _CLOCK ) )) = Sin (2π · (T _SAMPLE · F _CLOCK / n)) = sin (2π · (F _CLOCK / F _SAMPLE · n)) ··· (A2)

Thus, if the pulse number n (n is a natural number) counted during T _SIGNAL is measured, the known information F
_The frequency information sin θ can be obtained from _CLOCK and F _SAMPLE , and this calculation is performed by the signal frequency information calculation means 1A. The pulse counter clock F _CLOCK (cycle T _CLOCK ) and the A / D sampling clock F
_SAMPLE (cycle T _SAMPLE ), engine ignition pulse F _SIGNAL
FIG. 7 shows (cycle T _{SI GNAL} ) and timing generator timing, digital signal processor (DSP) timing.

The reference signal generating means 1B, based on the signal frequency information calculated by the signal frequency information calculating means 1A,
Although a reference signal having a plurality of frequencies including a frequency that is a non-integer multiple of the frequency of the engine pulse (a signal that correlates with the engine speed) is generated, in the present embodiment, the reference signal generating means 1B. Is mode 0 map 1B
-1 and mode 1 map 1B-2.

The mode 0 map 1B-1 is for generating a reference signal during engine steady operation and for outputting a reference signal (ΣA _i sin θ _i ) including a fundamental order component. Is for generating a reference signal during engine acceleration / deceleration operation, and is a frequency that is a non-integer multiple of the fundamental order components such as the 0.5th order frequency component of crank rotation and the 0.25th order frequency component of crank rotation. The reference signal (ΣB _i sin θ _i ) including the component is output, and each of the maps 1B-1 and 1B-2 is equivalently composed of a plurality of oscillators and an adder for adding the outputs of the respective oscillators. Will be configured.

The reference signal generating means 1B has a mode 0
It also has a function of switch means 1B-3 for selecting the output of the map 1B-1 or the output of the mode 1 map 1B-2. Then, the switch means 1B-3 receives the signal from the switching control means (CONT) 6, and during the steady operation,
The output of the mode 0 map 1B-1 is selected as a reference signal, and the output of the mode 1 map 1B-2 is selected as a reference signal during acceleration / deceleration operation.

Here, the switching control means 6 obtains the angle change gradient (Δsin θ) per unit time from the signal frequency information calculated by the signal frequency information calculation means 1A, and this angle change gradient (Δsin θ) is desired. If it exceeds the threshold value TH1 of, the acceleration / deceleration operation is determined, the mode 1 map selection signal is output, and the angle change gradient (Δsin θ) becomes equal to or less than the desired threshold value TH2 (TH2 <TH1). Then, it is determined that the operation is a steady operation, and the mode 0 map selection signal is output. The angle change gradient (Δsin θ) is obtained from the following equation.

Δsin θ = sin (θ _OLD + (2π · (F _CLOCK / F _SAMPLE · n))) ··· (A3) where θ _OLD is the signal frequency information obtained one time before. By the way, the system control unit 13
Is installed in the trunk room. Then, as shown in FIGS. 2 and 3, an engine pulse from the ECU 5 and a detection signal from the control microphone 2-1 are input to the system control unit 13, and the system control unit 13 outputs the signal to the speaker 3 via the speaker amplifier 7. The next source signal is output.

This system control unit 13
Is a numerical processor 40, ROM 41, RAM 4
2, digital signal processor (hereinafter referred to as DSP) 43, status control register (hereinafter referred to as S)
CR) 44, clock generator 45, pulse counter 51, low-pass filters 52 and 53, A / D converter 6
2, a D / A converter 63, a timing generator 8, a serial port 10, and a numerical operation processor 4
0, ROM41, RAM42, DSP43, SCR4
4, the pulse counter 51, the A / D converter 62, and the D / A converter 63 are connected via the optical fiber 15 with a photoelectric converter (O / E) and an electro-optical converter (E / O). .

Then, these numerical arithmetic processors 4
0, ROM41, RAM42, DSP43, SCR4
4, the clock generator 45 constitutes the main controller 4. Here, the numerical calculation processor 40 is a DSP used for calculation for silencing control (active noise cancellation).
On the bus of this numerical operation processor 40, ROM4
1, the RAM 42, the DSP 43, and the SCR 44 are arranged.

The ROM 41 stores the characteristic information of the muffler transmission system [the transmission system from the speaker (secondary sound source) 3 to the control point in the vehicle interior 200 (position where the control microphone 2-1 is installed), the speaker 3, the amplifier 7, the microphone. 2-1 including the frequency characteristic (time delay) of 2-1] and the like are stored. The RAM 42 stores a control program, the DSP 43 functions as a digital filter processor, and the SCR 44 is a D
It controls address allocation between the SP 43 and the numerical operation processor 40.

The clock generator 45 generates an operation clock for the numerical processor 40. The pulse counter 51 counts engine pulses,
It constitutes a part of the signal frequency information calculation means 1A. Low-pass filters 52, 53, A / D converter 62,
The D / A converter 63 is an interface between the control microphone 2-1 and the speaker 3 and the main control unit 4, and is the control microphone 2-.
The analog signal detected in 1 is the low-pass filter 52.
After being filtered, the signal is converted into a digital signal by the A / D converter 62 and input to the main control unit 4, while the secondary source signal from the main control unit 4 is converted into a D / A converter 63. After being converted into an analog signal by, the signal is filtered by the low-pass filter 53 and output to the speaker 3.

The low-pass filter used is one that cuts the band output above the maximum control frequency in order to prevent aliasing from the speaker 3. The timing generator 8 includes a pulse counter 51, an A / D converter 62,
It generates a timing pulse that determines the input / output timing of the D / A converter 63, and is started / stopped by the numerical arithmetic processor 40 writing a command in the control register.

The serial port 10 is an external terminal for connection with an external computer. It should be noted that the control program of this system is booted by the on-board ROM when the power is turned on, so that the system operates in a stand-alone manner. By the way, in the present embodiment, the main control section 4 of the system control unit 13 controls the engine pulse signal from the ECU 5 (a reference signal is generated based on this engine pulse signal) and the control detected by the control microphone 2-1. In response to the point signal, the control point signal is configured as a control means using an adaptive filter so as to control the sound wave signal output from the speaker 3 so that the control point signal becomes minimum (preferably 0). Further, in this example, the main control unit 4 is adapted to perform the muffling control using an adaptive filter using an algorithm based on the least square error estimation method (LMS method).

Further, in this embodiment, before the muffling control is performed, the characteristics of the muffling transmission system including the transmission system from the speaker 3 to the control point in the vehicle interior 200 (position where the control microphone 2-1 is installed) in advance ( Transfer function) D is measured. This measurement is performed as follows. That is, the M series random sound (white noise) is output from the speaker 3 and detected by the control microphone 2-1 to measure the characteristic D of the silence transmission system.

After that, the measured muffling characteristic information of the muffler transmission system is used as the correction information of the reference signal to perform the muffling control by the main control section 4. That is, the reference signal is filtered by a filter having the characteristic information D ′ of the measured muffler transmission system, and from this and the control point signal detected by the control microphone 2-1, a filter by the LMS method is used. The coefficient is updated.

Next, the basic algorithm of this system will be described in detail. First, the mute control (active noise control) of this system is Filtered-X LMS.
An adaptive FIR filter using an algorithm is used. A basic block diagram is shown in FIG. In this block diagram, T is the characteristic of the vehicle body transmission system (including the acoustic transmission characteristic from the noise source to the control point (control microphone 2-1 installation position)),
W is an adaptive FIR filter, D is a characteristic of a sound transmission system [including sound transmission characteristics from the secondary sound source (speaker 3) to the control point (installation position of control microphone 2-1)], D'is a model of D, LMS Is the LMS algorithm.

This system uses the reference signal X from the noise source.
(T) (this reference signal is different during steady operation and during acceleration / deceleration) is input and convolved by FIR to obtain the output Y (t). Y (t) = ΣW (i) X (t−i) ··· (1) In addition, regarding the formula (1), the summation is performed for i = 0 to N−1.

When the present system outputs -Y (t), the error signal E at the control point is obtained due to the transfer characteristic of the sound field. E (t) = T (z) X (z) -D (z) Y (z) (2) Further, in order to maintain the causal relationship between the reference signal X (t) and the error signal E (t). Filter X (t) and d
Find (t).

D (t) = ΣD ′ (i) X (t−i) ··· (3) It should be noted that the equation (3) is also adapted to take the total sum for i = 0 to N−1. . Then, the filter coefficient W (i) is updated using the LMS algorithm from the error signals E (t) and d (t). That is, Wn (i) = Wo (i) + kE (t) d (t-i)
(I = 0 to N−1) (4) where Wn (i) is the updated filter coefficient, Wo
(I) is a filter coefficient before updating, and k is an updating coefficient.

As a result, the filter converges on the optimum filter that minimizes the error signal. Further, the error E is determined by the reference signal X, the filter coefficient W, and the silence transmission system characteristic D. That is, it is necessary to consider D in the preceding stage of the LMS algorithm used to maintain the causal relationship between the input data and the error. For this reason, in this system, the adaptive algorithm is defined as the Filtered-X-LMS algorithm, and this D is identified before the adaptive control is started.

In this way, W will converge on the Wiener filter if a sufficient time elapses after the start of control, and if it is ideal, then W =-(T / D). That is,
W will perform forward modeling of T and inverse modeling of D at the same time. At this time, when the input noise signal is X, the output of T is TX, the output of W is represented by (-TX / D), and the output of D is (-TX /
D) .D = -TX.

That is, the error signal E becomes 0 at the addition point (see P) which is the evaluation point (control point). Here, when T and D are expressed in polar coordinates, they are expressed by W = (T / D) exp [-j (θt−θd)] ··· (5). Considering the actual machine model, the engine intake sound measured in the vehicle compartment is caused by the engine rotation (vibration), and is therefore always larger than the delay of T and (θt-θ
d) shows a positive value. In other words, W is considered to be controllable because it becomes a delay element.

Next, the control flow in this system is shown in FIGS. 5 and 6. First, the identification procedure of D performed before the start of adaptive control will be described with reference to FIG.
In step A1, A / D, D / A conversion, control register,
Initial settings are made for the counter and the like, A / D conversion is started, and an M-sequence signal is generated in step A2. After that, in step A3, adaptive filter calculation is performed, D / A conversion is started, and step A4
Then, by repeating the operation of updating the adaptive filter coefficient, the characteristics of the silence transmission system are identified.

After that, the operation as shown in FIG. 6 is performed. That is, first, as shown in step B1, the A / D, D / A conversion, the control register, the counter, etc. are initialized, and the characteristic information (initial impulse response) of the sound deadening transmission system measured in advance is added. After reading, a reference signal is generated. That is, step B2
, The engine pulse is counted, the initial angle θ is calculated in step B3, and the reference frequency (sin
θ) is calculated, and in step B5, the change gradient (Δsin
θ) is calculated, and in step B6, the gain mode is selected. If steady operation is performed, the mode 0 map is selected and a reference signal corresponding to this is generated (step B
7, B9), and during acceleration / deceleration operation, in step B6, the mode 1 map is selected and a reference signal corresponding thereto is generated (steps B8, B9).

After that, A / D and D / A conversion is started, adaptive filter calculation is performed, and adaptive filter coefficients are updated (steps B10 to B12). Further, by repeating the same processing operation, the convolution operation is performed by the adaptive FIR filter, the coefficient is updated by the LMS method until the error signal becomes equal to or lower than a predetermined level, and the output signal is output to the speaker 3.

Since the number of taps of the adaptive filter and the noise reduction amount are in a substantially linear proportional relationship,
The larger the number of taps, the greater the amount of effect, but D to use
Since it is necessary to determine the relationship between the SP performance, the number of SPs, and the cost, for example, the number of taps is 256.
Alternatively, 128 is set. Further, in the silencing control using the adaptive filter, it is necessary to control at the sampling frequency at which a waveform of at least ¼ wavelength exists between the number of taps used, and therefore the sampling frequency is determined accordingly.

As described above, since it is possible to input an arbitrary order component synchronized with an engine pulse at an arbitrary amplitude level to the adaptive filter as a reference signal according to the engine operating state, it is conventionally impossible to mute. Further, it is possible to muffle the 0.5th or 0.25th order component, etc. As a result, it is possible to reliably cancel the muffled sound in the vehicle not only during steady operation but also during acceleration / deceleration operation.

Further, the reference signal input power level can be manipulated, whereby the target silence level of any order component sound can be freely set. Furthermore, since the characteristic of the noise transmission system is measured in advance and the measured characteristic information of the noise transmission system is used as the correction information of the reference signal, the system control unit 13 performs the noise reduction control. Can be operated stably.

As shown in FIG. 8, during acceleration / deceleration,
The switch means 71 may be turned on to directly add two types of specific order components (for example, Asin θ ₁ and Bsin θ ₂ ) to the speaker 3. By doing so, in addition to the effects obtained in the above-described embodiment, it is possible to quickly respond to acceleration / deceleration. Note that 72A and 72B are specific order component generating means, 7
Reference numerals 3A and 73B are bandpass filters that filter only specific order frequencies, and 74A and 74B are amplifiers.

Further, instead of switching the reference signal generation mode according to the operating condition as in the above-mentioned embodiment, as shown in FIG. 9, in all operating conditions, the fundamental order component and the proximity order component (for example, near order component) A reference signal including a non-integer multiple frequency component of the fundamental order component such as a crank rotation 0.5th-order frequency component or a crank rotation 0.25th-order frequency component may be output. Also in this case, the reference signal generating means 1B is equivalently composed of a plurality of oscillators 81-1 to 81-N and an adder 82 for adding the outputs of the respective oscillators.
The signal frequency information calculating means 1A is composed of the counting means 1A-1 and the frequency calculating means 1A-2, as in the above-mentioned embodiment. With this configuration, it is possible to cancel the muffled sound in the vehicle in a wide range of driving modes with a simple control system.

Needless to say, the present invention can be similarly applied to a system in which the system control unit 13 performs the silencing control without measuring the characteristics of the silencing transmission system in advance. Further, the present invention can be applied to the case where the number of control points is plural, and in this case, the reference signal generated by the method of the present invention can be used as a common reference signal.

As the secondary sound source, the speaker 3 is arranged at the rear end of the rear seat 203 of the vehicle compartment 200 at a position where the trunk room can be used as a back cavity as described above, and a vibration exciter is provided on the roof panel. It is possible to install these by installing a vibrator on the floor panel.
It may be the next sound source. Further, the connecting lines of the A / D converter, the D / A converter, the ROM, the RAM, the DSP, etc. may of course be copper wires.

[0046]

As described above in detail, according to the adaptive noise canceling system for the vehicle interior sound of the present invention, the reference signal generating means for generating the reference signal correlating with the rotational speed of the engine mounted on the vehicle is provided. A control point signal detecting means for detecting a signal at a control point in the vehicle interior; and a secondary sound source for outputting a sound wave signal to the vehicle interior, and a reference signal from the reference signal generating means and the control point. The control means using an adaptive filter is provided to receive the control point signal from the signal detecting means and control the sound wave signal output from the secondary sound source so that the control point signal is minimized. In the adaptive active silencer for vehicle interior sound, the reference signal generating means is operated by the signal frequency information calculating means for calculating signal frequency information from the signal correlated with the engine speed and the signal frequency information calculating means. Signal frequency Based on the information, with respect to the frequency of the signal correlating with the engine speed, since it is configured with a reference signal generating means for generating a reference signal having a plurality of frequencies including non-integer multiple frequency, An arbitrary order component synchronized with a signal that correlates with the engine speed can be input as a reference signal to the adaptive filter according to the engine operating condition at any amplitude level, which has conventionally been impossible to mute. It is also possible to mute the 0.5th order or 0.25th order components, and as a result, there is an advantage that the muffling can be performed in accordance with various engine operating conditions.

[Brief description of drawings]

FIG. 1 is a block diagram of an essential part of an embodiment of the present invention.

FIG. 2 is a system block diagram showing an embodiment of the present invention.

FIG. 3 is a block diagram showing details of a system control unit according to an embodiment of the present invention.

FIG. 4 is a block diagram illustrating a control algorithm of this device.

FIG. 5 is a flowchart illustrating a control procedure of an embodiment of the present invention.

FIG. 6 is a flowchart illustrating a control procedure of an embodiment of the present invention.

FIG. 7 is a time chart for explaining how to calculate a reference frequency.

FIG. 8 is a principal block diagram showing a modified example of the embodiment of the present invention.

FIG. 9 is a principal block diagram showing still another modification of the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 reference signal detection means 1A signal frequency information calculation means 1A-1 counting means 1A-2 frequency calculation means 1B reference signal generation means 1B-1 mode 0 map 1B-2 mode 1 map 1B-3 switch means 2-1 control microphone ( Control point signal detecting means) 3 Speaker (secondary sound source) 4 Main control section 5 ECU 6 Switching control means 7 Amplifier 8 Timing generator 10 Serial port 13 System control unit 15 Optical fiber 40 Numerical arithmetic processor 41 ROM 42 RAM 43 DSP 44 SCR 45 Clock generator 51 Pulse counter 52,53 Low pass filter 62 A / D converter 63 D / A converter 71 Switch means 72A, 72B Specific order component generation means 73A, 73B Band pass filter 74A, 74B Amplifier 81-1 to 81- 81-N Oscillator 82 Adder 100 Engine 200 Cabin 201 Driver's seat 203 Rear seat

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location H03H 21/00 8842-5J

Claims (1)

[Claims] 1. A reference signal generating means for generating a reference signal that correlates with the number of revolutions of an engine mounted on a vehicle, a control point signal detecting means for detecting a signal at a control point in the vehicle interior, and a vehicle inside the vehicle interior. And a secondary sound source that outputs a directed sound wave signal, and receives a reference signal from the reference signal generating means and a control point signal from the control point signal detecting means to minimize the control point signal. An adaptive active silencer for vehicle interior sound, comprising control means using an adaptive filter for controlling a sound wave signal output from the secondary sound source, wherein the reference signal generating means is a rotation speed of an engine. Signal frequency information calculation means for calculating signal frequency information from the correlated signal, and based on the signal frequency information calculated by the signal frequency information calculation means, the frequency possessed by the signal correlated with the engine speed And, characterized in that it is configured to include a reference signal generating means for generating a reference signal having a plurality of frequencies including a frequency of the non-integer multiple, of the vehicle interior sound adaptive active silencer.