JP4031588B2 - Method and apparatus for measuring floor impact sound level - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a floor impact sound level measurement method and apparatus for examining the sound insulation performance of a room in a detached house or an apartment house.
[0002]
[Prior art]
Conventionally, measurement of a floor impact sound level at a building site is performed by a method stipulated in a certain industrial standard defined by law. FIG. 5 is a diagram showing a configuration and a measuring method of a floor impact sound level measuring apparatus used in the conventional measurement, and the floor impact sound level measuring apparatus is installed in the sound source room A and generates a floor impact sound. The sound receiving chamber B through the floor impact sound generator 20 to be measured and the measurement target floor (including the ceiling portion of the sound receiving chamber B) C installed in the sound receiving chamber B immediately below the sound source chamber A. A microphone 21 that collects the impact sound propagated inside and a sound receiving device 22 that measures the floor impact sound level of the sound pressure signal collected by the microphone 21 are provided. The sound receiving device 22 includes a low noise amplifier 23 that amplifies the sound pressure signal collected by the microphone 21 and a frequency of 1 octave width with the sound pressure signal amplified by the low noise amplifier 23 as a center frequency. An octave band filter 24 for band limiting to the band, a floor impact sound level detecting means 25 for detecting a floor impact sound level (dB) of the sound pressure signal band-limited by the octave band filter 24, and the floor impact sound level ( The sound level meter 27 is provided with a level indicator 26 for analog display of dB).
[0003]
The floor impact sound generator 20 uses a lightweight impact source composed of five hammers of a predetermined weight aligned in a straight line as an impact source for hitting the floor, and the hammers are sequentially dropped vertically to collide with the floor surface. Using a lightweight floor impact sound generator that generates a continuous impact sound generated by this collision and one heavy impact source such as an automobile tire, the floor surface is hit vertically to generate an impact sound. There are two types, heavy floor impact sound generators, and the floor impact level is determined by detecting floor impact sounds from the two types of light and heavy floor impact sound generators. The details of the impact sound generation by the light and heavy floor impact sound generators are well known and will not be described.
[0004]
The sound level meter 27 includes a square law rectifying means 28, a rectifying circuit 31 comprising an averaging means 29 comprising an RC integrating circuit and an effective value computing means 30, as shown in FIG. In this case, a Fast or Slow time correction is applied to the sound pressure signal thus converted and converted to an effective dB value. The time constant of the RC integration circuit is set so as to obtain characteristics.
Also, the floor impact sound level is measured with a frequency of f₁= 7 Hz with a fundamental frequency of 63 Hz and increasing by one octave (f₁= 63Hz, f₂= 125Hz, f_Three= 250Hz, f_Four= 500Hz, f_Five= 1000Hz, f₆= 2000Hz, f₇= 4000 Hz) for each frequency band with a center frequency.
[0005]
Normally, there are five locations (A) in the sound source room A where impact sound is generated (hereinafter referred to as impact points).₁~ A_Five) And five locations (B) for collecting the impact sound (hereinafter referred to as measurement points) in the sound receiving chamber B.₁~ B_Five(See FIG. 5). In FIG. 5, the operator S who performs the measurement₁~ S_FourOmitted.
First, calibration is performed by inputting a calibration signal to the sound receiving device 22 before measurement, and a voltage value V in which the maximum quantization value when the calibration signal is A / D converted is set in advance.₀The voltage value is V₀If V₀Is the reference value of the calibration sound pressure signal.
The floor impact sound level is measured when the impact of the sound source room A is A_iThe impact sound is generated by the floor impact sound generator 20 and the measurement point B of the sound receiving chamber B is_jThe microphone 21 is set upward and the impact sound is collected, and each frequency band (center frequency f_k) Sound pressure level (floor impact sound level) L_ijk(DB) is read from the level indicator 26 of the sound level meter 27 and recorded on a recording sheet. The floor impact sound level L_ijkIs the measured sound pressure signal V_ijkAnd the reference value V of the calibration sound pressure signal described above₀RMS value V_CAnd the calculation formula L_ijk= 20log_Ten(V_ijk/ V_C) Is the dB value obtained by
[0006]
Next, the procedure for measuring the floor impact sound level will be described.
In the sound source room A, the worker S₁Is impact point A₁The floor impact sound generator 20 is operated to generate an impact sound. In the receiving room B, the worker S₂Is measuring point B₁Set the microphone 21 to the measurement point B₁Collect sound pressure signal at. Also, worker S_ThreeOperates the sound receiving device 22 to set the center frequency of the octave band filter 24 to f₁= Measurement point B according to 63Hz₁Floor impact sound level L of sound pressure signal at₁₁₁(DB) is read from the level indicator 26 of the sound level meter 27 and recorded on a recording sheet. Center frequency f₁== When the measurement in the frequency band of 63 Hz is completed, the worker S₁Is the impact point A above.₁The impact sound is generated again at₃Operates the sound receiver 22 to set the center frequency of the octave band filter 24 to f₂= Workers S in line with 125Hz₂Is the same measurement point B as before₁The center frequency is f from the sound pressure signal measured in₂Floor impact sound level L in the frequency band of₁₁₂(DB) is read from the level indicator 26 of the sound level meter 27 and recorded on a recording sheet.
By repeating such work, the impact point becomes A₁And the measurement point is B₁Floor impact sound level L for each frequency band₁₁₁~ L₁₁₇(DB) is measured. Thereafter, the microphone 21 is moved to the next measurement point B in the sound receiving chamber B.₂~ B_FiveThe impact point is A₁And the measurement point is B₂~ B_FiveFloor impact sound level L for each frequency band_1j1~ L_1j7(J = 2 to 7) are measured.
Impact point A₁When the measurement of the floor impact sound level is completed, the worker S₁The floor impact sound generator 20 is the next measurement point A₂~ A_FiveThe impact point is A_i, The measurement point is B_jFloor impact sound level L for each frequency_ij1~ L_ij7(I = 2 to 5, j = 1 to 5) are measured and recorded on recording paper or the like.
[0007]
After the measurement, each frequency band (the center frequency is f_k) Impact point A every time_iAverage floor impact sound level at L_jk(DB) is calculated using a power average calculation formula represented by the following formula (1).
L_jk= (1 / n) · Σ10^{( Lijk / Ten )}            (1)
Where n is the number of measurement points (n = 5) and Σ is the measurement point B_jThe sum about (j = 1-5) is shown.
Each frequency band (the center frequency is f_k) Average value L of floor impact sound level for each_kIs calculated using an arithmetic average calculation formula represented by the following formula (2).
L_k= (1 / m) ・ ΣL_jk                    (2)
Where m is the number of impact points = 5 and Σ is the impact point A_iThe sum about (i = 1-5) is shown.
The average value of the floor impact sound level by the lightweight floor impact sound generator is L_LkThe average value of the floor impact sound level by the heavy floor impact sound generator is represented by L_HkThe measurement result clearly indicates the type of the impact source and is shown in a graph and a table, respectively. In the case of the graph, the horizontal axis represents the frequency, the vertical axis represents the floor impact sound level, the floor impact sound level for each center frequency is indicated by a point, and the lines are sequentially connected by a straight line.
Also, the floor impact sound level L at each measurement point in the sound receiving chamber B_ijkWhen the difference between the maximum value and the minimum value of (dB) is 5 dB or less, the impact point A is used instead of the above equation (1) in order to save the calculation work._iEach frequency f_kAverage L of floor impact sound level for each_jkYou may approximate (dB) with the arithmetic mean represented by the following formula | equation (3).
L_jk= (1 / n) · ΣL_ijk                  (3)
The floor impact sound level L at each measurement point in the sound receiving chamber B_ijkWhen the level difference between the maximum value and the minimum value of (dB) exceeds 10 dB, the average floor impact sound level for that frequency band is not calculated.
[0008]
[Problems to be solved by the invention]
However, the conventional method for measuring the floor impact sound level has been required to measure the floor impact sound level (dB) by performing the band limitation by the octave band filter 24 for each frequency band, and therefore it takes a huge amount of time for the measurement. There was a problem that it was. Further, since the data is read by the level indicator 26, an error in reading by humans occurs, and an accurate floor impact sound level may not be obtained. Furthermore, average floor impact sound level L_kIs calculated, each measured value L entered on the recording sheet after the measurement_ijk(DB) 7 (frequency) × 5 (measurement point) × 5 total 175 pieces of data are used to calculate the power average or arithmetic average, so there is a problem that it takes time to calculate the measurement result. It was.
[0009]
The present invention has been made in view of the conventional problems, and a floor impact sound level measuring method capable of obtaining a floor impact sound level for each frequency in a frequency band necessary for measurement by a single measurement, and An object is to provide such a device.
[0010]
[Means for Solving the Problems]
  BookWishAccording to claim 1inventionCollects the sound pressure signal of the impact sound emitted from the floor impact sound generator in the sound source room in the sound receiving room directly below the sound source room.As well asThe sound pressure signal collected aboveA / D conversion is performed, and the A / D converted quantized data is passed through the digital low-pass filter and then passed through the digital high-pass filter to limit the band, and a plurality of preset frequencies are set as the center frequency. A floor impact sound level measuring method for measuring a floor impact sound level in a frequency band,When calculating the floor impact sound level in order from the higher frequency band of the center frequency, and calculating the floor impact sound level of the lower frequency band of the center frequency.IsWhen calculating the floor impact sound level in the high frequency band of the center frequencyPassed the digital low-pass filter to limit the bandwidthFrom the quantized data, Using quantized data selected based on the ratio of the center frequency of the high frequency band to the center frequency of the low frequency bandIt is characterized by thatIs a thing.
[0013]
  Claim2Described ininventionThe floor impact sound generator installed in the sound source room and the sound source roomstraightSound receiving means for collecting the sound pressure signal of the impact sound generated in the sound source room installed in the lower sound receiving roomAnd a floor impact sound level measuring device for measuring a floor impact sound level in a frequency band having a plurality of frequencies set in advance as center frequencies from the collected sound pressure signal.An A / D converter for A / D converting the collected sound pressure signal, initial data storage means for storing the A / D converted quantized data, a digital low-pass filter for band limiting the quantized data, and A digital high-pass filter, and passage data storage means for storing quantized data that has passed through the digital low-pass filter;Switching means for switching quantized data input to the digital low-pass filter from quantized data stored in the initial data storage means to quantized data stored in the passing data storage means, and a center of a frequency band to be processed Center frequency setting means for setting the frequency and instructing the extraction of the quantized data and the setting of the cutoff frequency;The floor impact sound level for each frequency band is calculated from the above band-limited quantized data.In order from the highest frequency band of the center frequencyWith floor impact sound level calculation means to calculateWhen the quantized data input to the digital low-pass filter is switched to the quantized data stored in the passing data storage means, the switching means selects from among the quantized data stored in the passing data storage means. The quantized data selected based on the ratio between the center frequency of the high frequency band and the center frequency of the low frequency band is sent to the digital low-pass filter.It is what I did.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram showing a configuration and a measuring method of a floor impact sound level measuring apparatus according to an embodiment of the present invention. The floor impact sound level measuring device includes a floor impact sound generator 20 for generating a floor impact sound installed in the sound source room A, and a measurement target of the sound source room A installed in the sound receiving room B immediately below the sound source room A. The microphone 21 that collects the impact sound propagated in the sound receiving chamber B through the floor (including the ceiling of the sound receiving chamber B) C, and the floor impact sound level of the sound pressure signal collected by the microphone 21 are measured. Sound receiving device 10. The sound receiving device 10 includes a low noise amplifier 1 that amplifies the output of the microphone 21, an A / D converter 2 that A / D converts the sound pressure signal amplified by the low noise amplifier 1 at a predetermined sampling frequency, and The initial data storage means 3 for storing the quantized data (hereinafter referred to as initial sound pressure data) A / D converted by the A / D converter 2 and the quantized data that has passed through the digital low-pass filter 5 described later are stored. And the quantized data stored in the initial data storage means 3 or the passage data storage means 4, the seven frequencies f₁~ F₇Is the center frequency, and the upper limit of one octave band of the center frequency is the cutoff frequency f._c1The digital low-pass filter 5 and the switching means 6 for switching the quantized data input to the digital low-pass filter 5 from the initial sound pressure data to the passing sound pressure data, and the lower limit of one octave band of the center frequency as the cutoff frequency f_c2The digital high-pass filter 7 and the center frequency of the frequency band to be processed are set, and this is notified to the passing data storage means 5, the digital low-pass filter 5 and the digital high-pass filter 7, and the quantized data extraction and cutoff frequency f_c1, F_c2From the center-frequency setting means 8 for instructing the setting of the signal and the band-limited quantized data output from the digital high-pass filter 7_i, Measuring point B_j, Center frequency f_kFloor impact sound level L_ijk(DB) is calculated and the above L_ijkTo the frequency band (center frequency f_k) Average floor impact sound level L_kFloor impact sound level calculation means 9 for calculating (dB). The initial data storage means 3 and the passage data storage means 4 are constituted by a RAM, and the data stored in the passage data storage means 4 can be rewritten sequentially.
[0015]
Floor impact sound level L_ijkIn calculating (dB), when a light floor impact sound generator is used as an impact source, the measurement is performed a plurality of times, and L obtained from the maximum value of the dynamic characteristic Fast is obtained._ijkIs obtained by arithmetic averaging. On the other hand, when a heavy floor impact sound generator is used, for example, as shown in FIG._SL obtained from the dynamic characteristic Fast maximum value at_ijkIs obtained by arithmetic averaging. At this time, as shown in FIG._ijkThreshold L_SBy providing the above, it is possible to reliably suppress the secondary noise generated accompanying the impact sound.
In addition, as the measurement frequency band, the frequency is f.₁= 7 Hz with a fundamental frequency of 63 Hz and increasing by one octave (f₁= 63Hz, f₂= 125Hz, f_Three= 250Hz, f_Four= 500Hz, f_Five= 1000Hz, f₆= 2000Hz, f₇= Floor impact sound level in a frequency band of one octave width with 4000 Hz as the center frequency is measured for each center frequency.
[0016]
Next, a method for measuring the floor impact sound level will be described with reference to the block diagram of FIG. 1 and the flowchart of FIG.
In the sound source room A, the worker S₁Operates the floor impact sound generator 20 and each impact point A_iAn impact sound is generated at (i = 1 to 5). In the sound receiving room B, the direction of the microphone 21 is set upward, and each of the impact points A_iThe impact sound generated at the measurement point B_j(J = 1 to 5), respectively. In addition, as shown in FIG.₁~ A_Five), 5 measurement points (B₁~ B_Five). In addition, the apparatus is calibrated before measurement, and the maximum quantization value when the calibration signal is A / D converted is a preset voltage value V.₀And confirm that V₀Is the reference value. Impact point A_i, Measuring point B_j, Center frequency is f_kFloor impact sound level L_ijk(DB) is the effective value V of the measured sound pressure signal, as will be described later._ijkAnd the reference value V of the calibration sound pressure signal described above₀RMS value V_CAnd the calculation formula L_ijk= 20log_Ten(V_ijk/ V_C)
[0017]
The impact point collected by the microphone 21 is A._iAnd the measurement point is B_jAre amplified by the low noise amplifier 1 and then output to the A / D converter 2. The A / D converter 2 converts the amplified sound pressure signal into, for example, a sampling frequency F_S0= Sampling at 44.1 kHz, and converted into quantized data (initial sound pressure data) having a quantization bit number of 16 bits (step S1) The quantized data is stored in the initial data storage means 3. Next, the center frequency is set to f by the center frequency setting means 8.₇= 4 kHz is set (step S2). Thereafter, the quantized data is read from the initial data storage means 3 and sent to the digital low-pass filter 5, and the cutoff frequency of the digital low-pass filter 5 is set to the center frequency f.₇= Upper limit of 1 octave band at 4kHz f_c1To give instructions. The sampling frequency F of the digital low-pass filter 5_SIs the center frequency f_k11.025 times greater than f₇= 4kHz above for F_SIs the sampling frequency F in the A / D converter 2_S0Therefore, filtering is performed using the data in the initial data storage means (step S3). The filtered quantized data is sent to and stored in the passage data storage means 4, and the center frequency f₇The lower limit of one octave band is the cutoff frequency f_c2To the digital high-pass filter 7. In the digital high-pass filter 7, the above F_SSampling frequency F equal to_SAnd the center frequency f from the quantized data is filtered.₇= Quantized data of one octave band at 4 kHz is extracted (step S4), and this data is sent to the floor impact sound level calculation means 9.
[0018]
The floor impact sound level calculation means 9 squares the band-limited quantized data (step S5), and then a dynamic characteristic Fast digital filter (not shown) provided in the floor impact sound level calculation means 9 After the time correction by (step S6), as described above, the impact point A_i, Measuring point B_j, Center frequency f_k= RMS value of 4kHz V_ijkAnd the reference value V₀RMS value V_C= V₀/ √2 and formula L_ijk= 20log_Ten(V_ijk/ V_C) Floor impact sound level L_ijk(k = 7) is obtained (step S7). Note that L_ijkWhen a lightweight floor impact sound generator is used as the impact source, as described above, the measurement time is divided by time intervals, and L obtained from the maximum value of the dynamic characteristics Fast is obtained._ijkL is the arithmetic average of_ijkWhen a heavy floor impact sound generator is used, the interval T at which three falls occur T_SL obtained from the dynamic characteristic Fast maximum value at_ijkL is the arithmetic average of_ijk(Step S8).
Impact point A_i, Measuring point B_j, Center frequency f_kFloor impact sound level L_ijkWhen the measurement of the center frequency f is completed_kIs the lowest frequency used for measuring the floor impact sound level f₁It is determined whether or not = 63 Hz (step S9). Here, the center frequency is f₇= 4 kHz, so that data thinned out every other data from the data sent to the passage data storage means 4 is sent as quantized data to the low-pass filter 5 (step S10), and the set center frequency f_k(1/2) f₇F₆= 2 kHz (step S11), and then the process returns to step S3 to use the quantized data to obtain the center frequency f.₆= Average sound pressure level L at 2kHz_ij6Is calculated.
Thus, the center frequency f_kIs reduced by one octave and f₇= 4kHz to f₁= Average sound pressure level L up to 63Hz_ij7~ L_ij1Are calculated sequentially. Note that the quantized data stored in the passage data storage unit 4 is sequentially rewritten for each process at one center frequency. In step S9, the center frequency f_kIs f₁= 63Hz, floor impact sound level L at seven frequencies used for measurement_ijkSince all (k = 1 to 7) are obtained, the processing is completed, and the average floor impact sound level L_k(K = 1 to 7) is calculated.
[0019]
Impact point A_i, Center frequency f_kAt measurement point B₁~ B_FiveAverage floor impact sound level at L_ikIs the floor impact sound level L_ijkIs calculated using the power average represented by the following formula.
L_ik= (1 / n) · Σ10^{( Lijk / Ten )}
Where n is the number of measurement points (n = 5) and Σ is the measurement point B_jThe sum about (j = 1-5) is shown.
Each frequency band (center frequency f_k) Average value L_kIs calculated using the arithmetic average represented by the following formula.
L_k= (1 / m) ・ ΣL_jk
Where m is the number of impact points = 5 and Σ is the impact point A_iThe sum about (i = 1-5) is shown.
Calculated by
Finally, this measurement result is represented by a graph in which the horizontal axis represents the frequency, the vertical axis represents the floor impact sound level, and the floor impact sound level for each center frequency is sequentially connected by a straight line, thereby completing the measurement of the floor impact sound level.
[0020]
Thus, according to this embodiment, the initial data storage means 3 for storing the quantized data obtained by A / D converting the sound pressure signal collected by the microphone 1 by the A / D converter 2 and the digital low-pass filter are provided. A passage data storage means 4 for storing sound pressure data of a sound pressure signal that has passed, and a floor for calculating a floor impact sound level for each frequency band from sound pressure signals band-limited by the digital low-pass filter 5 and the digital high-pass filter 7. And an impact sound level calculation means 9 for calculating the floor impact sound level in order from the frequency band having the higher center frequency, and the center frequency is (1/2) f._kFloor impact sound level L in the frequency band_ijk, The data stored in the initial data storage means 3 is not used again as quantized data to be used, and the center frequency that has passed through the digital low-pass filter 5 stored in the passage data storage means 4 is f._kSince the data obtained by thinning out every other frequency band data is used, all frequency bands necessary for measurement can be performed in one measurement, and the calculation time is reduced because the number of data to be processed is small. It can be greatly shortened. In addition, the sampling frequency F in the digital low-pass filter 5 and the digital high-pass filter 7_SIs the center frequency f_kTherefore, if filtering is performed using all of the thinned data, the data satisfies the sampling theorem, so that no alias phenomenon occurs.
[0021]
In the above embodiment, the initial data storage unit 3 and the passage data storage unit 4 are configured using separate RAMs. However, the data storage unit is configured by one RAM, and the stored data is rewritten sequentially. It may be.
In the above example, the case of measuring the impact sound level in the frequency band having a plurality of frequencies whose frequency increases by one octave as the center frequency has been described. However, the floor impact sound level of the plurality of center frequencies to be measured is described. If the ratio is large to some extent (for example, 1.5 times or more), the quantized data used when calculating the floor impact sound level at a low frequency based on the ratio of the center frequencies and satisfying the sampling theorem If is selected, the floor impact sound level can be accurately obtained without generating alias noise.
In addition, the floor impact sound level measuring device can be easily manufactured by using a personal computer with a built-in sound board and a sound level meter. That is, the AC output of the sound level meter is used as the audio frequency signal input from the microphone as the sampling frequency F._S0By connecting to a sound board that performs A / D conversion at 44.1 kHz, the sound pressure signal collected by the microphone is easily A / D converted, and this sound pressure data is processed by software on a personal computer.
Further, the sound receiving chamber B may be the lower side displaced in the lateral direction, not directly below the sound source chamber A.
[0022]
【The invention's effect】
  As described above, according to the first aspect of the present invention, the sound pressure signal of the impact sound emitted from the floor impact sound generator in the sound source room is collected in the sound receiving room immediately below the sound source room.As well as, A / D conversion of the collected sound pressure signalThen, the A / D converted quantized data is passed through the digital low-pass filter and then passed through the digital high-pass filter to limit the band, and floor impact in a frequency band having a plurality of preset frequencies as the center frequency. When measuring the sound level,When calculating the floor impact sound level in order from the higher frequency band of the center frequency, and calculating the floor impact sound level of the lower frequency band of the center frequency.IsWhen calculating the floor impact sound level in the high frequency band of the center frequencyPassed the digital low-pass filter to limit the bandwidthFrom the quantized data, Using quantized data selected based on the ratio of the center frequency of the high frequency band to the center frequency of the low frequency bandAs a result, the floor impact sound level for each frequency in the frequency band required for measurement can be obtained in one measurement.Butit can. Also,Since the number of data to be processed is small, the calculation time can be greatly reduced.At the same time, alias noise can be prevented.
[0025]
  Claim2According to the invention described in the above, the floor impact sound generator installed in the sound source roomAnd a sound receiving means that is installed in a sound receiving room immediately below the sound source room and collects a sound pressure signal of an impact sound generated in the sound source room;An A / D converter for A / D converting a sound pressure signal of an impact sound, initial data storage means for storing the A / D converted quantized data, a digital low-pass filter for band-limiting the quantized data, and A digital high-pass filter, and passage data storage means for storing quantized data that has passed through the digital low-pass filter;Switching means for switching quantized data input to the digital low-pass filter from quantized data stored in the initial data storage means to quantized data stored in the passing data storage means, and a center of a frequency band to be processed Center frequency setting means for setting the frequency and instructing the extraction of the quantized data and the setting of the cutoff frequency;The floor impact sound level for each frequency band is obtained from the quantized data band-limited by the above filter.In order from the highest frequency band of the center frequencyWith floor impact sound level calculation means to calculateWhen the quantized data input to the digital low-pass filter is switched to the quantized data stored in the passing data storage means, the switching means selects from among the quantized data stored in the passing data storage means. The quantized data selected based on the ratio between the center frequency of the high frequency band and the center frequency of the low frequency band is sent to the digital low-pass filter.Because of floor impact sound levelCalculationTime can be significantly reduced.
[Brief description of the drawings]
FIG. 1 is a diagram showing a floor impact sound level measuring method and measuring apparatus according to an embodiment of the present invention.
FIG. 2 is a diagram illustrating the timing of capturing an impact sound.
FIG. 3 is a diagram illustrating an example of how to capture sound pressure data of an impact sound.
FIG. 4 is a flowchart showing a sound pressure data processing method according to the present embodiment.
FIG. 5 is a diagram showing a conventional floor impact sound level measuring method and measuring apparatus.
FIG. 6 is a diagram showing a configuration of a rectifier circuit in a conventional sound level meter.
[Explanation of symbols]
A sound source room, B sound receiving room, C measurement object floor, 1 low noise amplifier, 2 A / D converter, 3 initial data storage means, 4 passing data storage means, 5 digital low pass filter, 6 switching means, 7 digital high pass Filter, 8 center frequency setting means, 9 floor impact sound level calculation means, 10 sound receiving device, 20 floor impact sound generator, 21 microphone.

Claims (2)

The sound pressure signal of the impact sound emitted from the floor impact sound generator in the sound source room is sampled in the sound receiving room below the sound source room, and the sampled sound pressure signal is A / D converted, and this A / D The D-converted quantized data is passed through the digital low-pass filter and then passed through the digital high-pass filter to limit the band, and the floor impact sound level in the frequency band with each of a plurality of preset frequencies as the center frequency is measured. in the method of floor impact sound level, the operation of the floor impact sound level from a high frequency band center frequency performs in order, when calculating the floor impact sound level of low frequency band center frequency, the center frequency from among the quantized data that has passed through the digital low-pass filter that band-limits when calculating the floor impact sound level of high frequency band, the center frequency of the high frequency band And the low frequency band center frequency and the ratio measurement method for floor impact sound level, characterized in that the so that with the selected quantized data based on the of. A floor impact sound generator installed in the sound source room, and a sound receiving means that is installed in the sound receiving room directly below the sound source room and collects the sound pressure signal of the impact sound generated in the sound source room. In a floor impact sound level measuring device for measuring a floor impact sound level in a frequency band having a plurality of frequencies set in advance as center frequencies from the sound pressure signal, the A / D conversion is performed on the collected sound pressure signal. / D converter, initial data storage means for storing the A / D converted quantized data, a digital low pass filter and a digital high pass filter for band limiting the quantized data, and a quantum that has passed through the digital low pass filter passing data storage means and, quantized data quantized data to be input to the digital low-pass filter is stored in the initial data storage means for storing the data Switching means for switching to quantized data stored in the passing data storage means, and center frequency setting means for setting the center frequency of the frequency band to be processed and instructing the extraction of the quantized data and the setting of the cutoff frequency If, Rutotomoni a floor impact sound level calculating means for calculating from said band-limited quantized data floor impact sound level for each frequency band, in order from the higher frequency band of the center frequency, the switching means of the digital low-pass When the quantized data input to the filter is switched to the quantized data stored in the passing data storage means, the center frequency of the high frequency band is selected from the quantized data stored in the passing data storage means. The quantized data selected based on the ratio to the center frequency of the low frequency band is transferred to the digital low-pass filter. Floor impact sound level measuring device being characterized in that the send to filter.

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