JPS5815126A - Noise measuring device - Google Patents

Abstract

PURPOSE:To facilitate the arrangement, analysis and printing and illustrating of the result of measured data by means of an electronic calculator, by providing an auto ranging circuit of a measuring level and recording the measured data after digital conversion together with a measured time. CONSTITUTION:Gain of a noise inputted in a microphone 8 is converted by s signal from a gain converter 25 of a range converter 2 through an amplifier 9, a frequency characteristic correcting device 10 and an amplifier 11, and this is inputted to a varialble gain amplifier 12. Then, this is detected by a linear detector 13 and is applied to an A/D converter 17 through an integrating circuit 14, a logarithmic compressor 15 and an adder 16 and its inputting signal is digital converted by getting a signal of a controlling part 3 and transferred to a level display device 6a of a display part 6 and displayed. While the noise is inputted to a recording register 19 through a conversion inputting register 18 and receives the control from a timing circuit 23 of a controlling part 3 and is outputted from a measurement output terminal 27. On the other hand, a time signal of a time circuit 5 is outputted through a recording register 19 by a signal from a timing circuit 23.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a noise measuring device, and more particularly to a noise measuring device that records measurement data as a digital signal on a magnetic recording/reproducing medium. usually requires about 20 to 100 observation points, and
Since there is no constancy like seismic observation, wired or wireless telemetering methods cannot be used, and portable noise measuring devices are in practical use, but methods that record measurement data directly on recording paper have a dynamic tendency. It has the disadvantage that it is small and requires a large number of operating personnel and time to replenish ink and recording paper used for recording, to install it, and to organize and analyze measurement data.

SUMMARY OF THE INVENTION An object of the present invention is to provide a portable noise measuring device that constantly digitally displays noise level measurement data, records measurement time, measurement conditions, and measurement data, and facilitates collection and analysis of measurement data.

In order to accurately display the noise level digitally, the present invention is equipped with an auto-rende circuit that changes the measurement level range when the noise level is high, and the measured data is converted into analog and
The data is converted into binary numbers using a digital converter and recorded on a magnetic recording/reproducing medium along with the measurement time, making it easy to organize and analyze the measurement data, and print and draw the results, which is typically done on an electronic computer.

Hereinafter, one embodiment of the noise measuring device according to the present invention will be described in detail with reference to the accompanying drawings.

In Figure 1, 1 is a digital sound level meter, 2 is a measurement range switch, 3 is a control section, 4 is a magnetic recording section, 5 is a clock circuit, 6 is a display section, 7 is an operation switch, and P is a power supply section. be. The power supply part P requires approximately 2VA/h of power at 100V AC, and 1
It has a built-in 2V lead-acid battery (40A/h, capacity for 8 days of continuous use), and is powered by a float method.

The digital sound level meter 1 is composed of a microphone 8, a frequency characteristic corrector 10, a variable gain amplifier 12, a linear detector 13, an integrating circuit 14, a logarithmic compressor 15, an A/D converter 17, a conversion output register 18, and a recording register 19. has been done.

The microphone 8 is made entirely of stainless steel, the height at which the microphone is installed is approximately 1.2 m, and the sensitivity is -53 dBldB. Noise input to the microphone 8 is input to a frequency characteristic corrector 10 via an amplifier 9. The frequency characteristic corrector 10 has a frequency range of 31.5H
The response characteristic for the frequency range of 8000 Hz to 8000 Hz is corrected by the A/C control signal sent from the control circuit 20 of the control unit 3 so that it becomes better than the A characteristic or the C characteristic. When the A/C control signal is rOJ, it is corrected to A characteristics. A-weighting is -40dB at low frequencies.

It exhibits a characteristic of approximately OdB at 1000 Hz, and is used for noise that affects humans. C characteristic is almost O
It shows a flat characteristic in dB. The corrected output is input to the amplifier 11. The amplifier 11 is provided with a calibrator 11a, and the calibrator 11& is operated to perform "0" level adjustment. Note that TP is the test point, and amplifier 1
Test the output level of 1. Further, the output of the amplifier 11 can be drawn out via the AC output terminal 'Ilb' and used by connecting it to an external measuring device. The output impedance is 600Ω. Variable gain amplifier 12 is supplied with the output signal of amplifier 11. The variable gain amplifier 12 switches the gain from OdB to 40 dBK in response to a switching signal from the gain switch 25 of the measurement range switch 2. Due to this gain switching operation, the measurement range of the digital sound level meter 1 is [30
dB~75dBJ range to r75dB~130dBJ
Can be switched to microwave. The linear detector 13' linearly detects the output signal from the variable gain amplifier 12. The detection output is applied to the integrating circuit 14. The integrating circuit 14 integrates the dynamic characteristics of the digital sound level meter 1 using an F/S control signal that instructs the measurement conditions sent from the control circuit 20 of the control unit 3 so that the dynamic characteristics of the digital sound level meter 1 become either "fast" or "slow" characteristics. Change the constant.

Also, the integral constant of this integrating circuit 14 is determined by the measuring range switch 2.
It also changes depending on the F/S switching signal from the dynamic characteristic switching device 26.

The logarithmic compressor 15 obtains the integral output from the integrating circuit 14,
Adder 1 converts this voltage to correspond to a decibel value.
6. The adder 16 samples and holds the voltage converted to the decibel value. This sample holding constant is changed by an addition constant switching signal from the adder constant switching device 27 of the measurement range switching device 2. Output signal FiA/ of adder 16
The signal is applied to the D converter 17 and analog-to-digital conversion is performed. The analog/digital conversion speed is 300 m5, and 175 sample signals are obtained from the 1/5 second circuit 21 of the control unit 3, and the input signal is converted from analog to digital at a cycle of 1 c/sec or once every 5 seconds. .

The conversion accuracy is 0.1 dB, and the output signal is sent to the level indicator 6a of the display section 6 and displayed in 4 decimal digits and 0.1 dB units by a light emitting element at a sampling period of 0.1 seconds.

Also, the binary number 1 is input to the conversion output register 18.

The recording register 19 records the measurement level in 8 binary digits, 1 dB.
Accumulate in steps. The recording register 19 receives control from the timing circuit 23 of the control unit 3 and has a measurement output terminal 27 (
Output in parallel 8 bits via 8 parallel terminals). The output is TTL positive logic, the latch time of level signal output and time signal output is 100 m5, and the measurement condition signal output is 15
It is 0m5.

Depending on the output control signal from the timing circuit 23, the time signal output converted into an binary code by the hour and nine minute register 25 of the clock circuit 5 is sent to the recording register 19 at the beginning of one block (64 words) of recording data. Output via . Further, the contents of the measurement condition output device 22 are inputted in parallel in the order of No. 21 to No. 28 VC "AC15FS11", respectively.
It is output via the recording register 19. The corresponding position is 10
'', the measurement is being performed under the conditions of use. Therefore, hexa "57" (01010111) is A curve, 1 second,
The dynamic characteristic is F.

Note that 2.2 bits are not used. The magnetic recording section 4 includes a recording control circuit 28, a tape drive section 29, and an operation section 30.

This magnetic recording section 4 has two tracks and a recording density of 615B.
PI, the driving motor uses a stepping motor, the storage capacity is 2,214,0 OObit/volume, and the writing speed is 80-120 steps/sec. Continuous writing time is 56 hours when sampling is 1 second. Further, when the sampling period is 5 seconds, there is a capacity of 240 hours. The level discriminator 24 of the measurement range switch 2 has an output of 75d from the adder 10.
B and 90 dB, a hysteresis operation is performed according to the fluctuation, and a control signal is sent to the gain switch 25, operating characteristic switch 26, and adder constant switch 27.

The clock circuit 5 includes a clock 24, an hour/0 minute register 25, and a second/minute register 25.
and a pulse circuit 26. The time setting section 24b of the clock 24 allows setting of the current time 0 minute 1 second, month of August, and day of the week.

The time display 6b of the display section 6 displays the hour 0 minute 6 seconds or the year, month, day, and day of the week by operating the time setting section 24b.

The operation switch 7 sets the measurement condition rA to the control circuit 201C.
/C, 115, F/SJ: A switch is provided to determine i.

The magnetic recording and reproducing medium on which the above data is recorded is an ordinary cassette chip, and the length of one volume is 300 feet. The reading speed is approximately 2.7 IPS, and it takes approximately 20 minutes to read one volume, but this varies depending on the capabilities of the small computer, printer, etc.

1st Table 23131557 9494949494949494949494949
4949494949494949494949494
9494949494949494949494949
4949494949494949494949494
9494949494949494949423131
657 9494949494949494949494949
4949494949494949494949494
9494949.19494949494949494
9494949494949494949494949
494949494949494949494 Table 1 is the printout format when the sample is 1 second, A characteristic, and the data format is F. 23 13 15 57 on the top row
"94..." indicates the date 0:00 and the measurement conditions described above.
is the measured value every second.

2nd Table 64 DATA 23132857 6866666664646464656866686
9697373737370717576787581
8383848487879091929696979
7959087848380787777797574
727270706'L 6867676765231
32957 6666646161616160625960585
9606160585857η67171605558
5859616164646670656671686
9726766717476798483848585
90909093939395959387 Table 2 shows aircraft noise data, and the measurement conditions are the same as in Table 1.

In Figure 2 (Shu) is the measurement data of the noise measuring device according to the present invention, (B) in Figure 2 is the pen-written output obtained by connecting the noise meter of the conventional unmanned sound stand to the AC output terminal 11B. Second
Figure (Q is the output of a normal sound level meter.

The noise measuring device according to the present invention has a configuration including a measurement range changing means for changing the range for measuring the noise level according to the noise level, and a means for digitizing the measurement data and recording it on a magnetic recording/reproducing medium. Therefore, the measurement accuracy is excellent even against large fluctuations in the measurement data, and since the measurement data is recorded on the magnetic recording and reproducing medium as 8-bit parallel signals, it is easy to reproduce, organize, analyze the measurement data, and print and draw the results. It has the advantage of being able to use electronic computers.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the noise measuring device according to the present invention, and FIGS. 2 (A), (B), and (C5 are printed graphs of measurement data. In the figure, 1 is a digital sound level meter; 2 is a measurement range switch, 3
1 is a control unit, 4 is a magnetic recording unit, 5 is a clock circuit, 6 is a display unit, 7 is an operation switch, 8 is a microphone, 9.11 is an amplifier, 10 is a frequency characteristic corrector, 12 is a variable gain amplifier, and 13 is a Linear detector, 14 is an integrator, 15 is a logarithmic compressor, 16 is an adder, 17 is an A/D converter, 18 is a conversion output register, 19 is a recording register xp, 20 is a control circuit, 21
rI'11 seconds 5 seconds circuit, 22 is a measurement condition output device, 23 is a timing circuit, 24 is a clock, 25Fi is a date, hour and minute register, 26 is a second pulse circuit, and 27 is a measurement output terminal. Patent Applicant Ishikawajima Soundproofing Industry Co., Ltd. Agent Patent Attorney Nobuo Kinutani

Claims (1)

[Claims] In a noise measuring device having a measuring means for measuring a noise level and a recording means for recording the measured noise level, a measuring range changing means for changing the range for measuring the noise level according to the noise level, and a measuring range changing means for changing the range for measuring the noise level according to the noise level, 1. A noise measuring device comprising a recording means for digitizing and recording on a magnetic recording/reproducing medium, and processing the measured data of the magnetic recording/reproducing medium via an input/output device of a computer.