CN107438221B

CN107438221B - Online loudspeaker sound pressure detector and detection method

Info

Publication number: CN107438221B
Application number: CN201610352116.0A
Authority: CN
Inventors: 徐燕春; 管海敏
Original assignee: Baoshan Iron and Steel Co Ltd
Current assignee: Baoshan Iron and Steel Co Ltd
Priority date: 2016-05-25
Filing date: 2016-05-25
Publication date: 2020-03-27
Anticipated expiration: 2036-05-25
Also published as: CN107438221A

Abstract

The invention discloses an online loudspeaker sound pressure detector and a detection method, which relate to the technical field of wired communication and comprise a CPU (1), an on-site loudspeaker (2), a detection result display (3), a simulation ear (4), an input amplification circuit (5), a frequency selection circuit (6), an adaptive frequency selection switch circuit (7), a test baseband signal generation circuit (8), an audio pulse amplification circuit (9), a V/F conversion circuit (10), a test setting control circuit (11), a working state control circuit (12), a power amplifier (13) and an input matching circuit (14). The invention can accurately and quickly carry out on-line detection on the loudspeaker, can quantitatively judge the sound pressure performance of the detected loudspeaker and improve the maintenance efficiency of equipment; the method can scientifically judge the sound pressure performance of the loudspeaker in various strong noise environments, and provides a new scientific measurement way for rapidly and accurately judging the output loudness of various sounding devices in high-risk audio complex environments.

Description

Online loudspeaker sound pressure detector and detection method

Technical Field

The invention relates to the technical field of wired communication, in particular to a sound pressure detector and a sound pressure detection method for an online loudspeaker.

Background

The existing broadcasting loudspeaker installed in an industrial field is divided into a low-impedance loudspeaker and a high-impedance loudspeaker, a universal meter is usually adopted for measuring the state of the online loudspeaker, and the online loudspeaker is qualitatively judged and quantitatively detected in two modes, wherein the two modes have the following defects: firstly, the qualitative mode of judging, adopt pointer multimeter to judge through the sense organ whether normal the speaker promptly, need be with the speaker off-line this moment, the multimeter adjusts to the resistance and keeps off low gear, beats speaker both sides wiring end constantly gently with two table sticks, can hear this moment that the speaker sends slight "click" sound, just judges that the speaker is normal, and can not send slight "click" sound, judges its damage. However, the ambient noise around the speakers installed in the production field is quite noisy, and some speakers are installed far away from the communication terminal, so that it is difficult to hear a slight "click" sound from the speakers during measurement. The other is a quantitative judgment mode, namely detecting the impedance of the loudspeaker, and when the line is long or the contact resistance of a terminal is large when detecting the low-impedance loudspeaker, the impedance and the contact resistance of the line exceed normal values; when measuring a high-impedance loudspeaker, it is often difficult to correctly measure the approximate impedance of each loudspeaker because of different loudspeaker powers or differences in the design parameters of an internal impedance matcher, various faults cannot be correctly determined, and the sound pressure performance of the loudspeaker cannot be detected, so that a universal meter has difficulty in detecting the loudspeaker and a high misjudgment rate.

The loudspeaker fault positioning detection system (patent number: CN01278343.9) comprises a detection host, a detection bus and a detection module, can be used for manually and automatically positioning and detecting three states of open circuit, short circuit and normal of an impedance converter connected with a loudspeaker, and can also be used for detecting the communication state of the module. The limitation of the patent is that only three states of open circuit, short circuit and normal of the tested loudspeaker and the connected impedance converter can be detected, and the sound pressure performance of the loudspeaker cannot be judged.

The patent 'a loudspeaker on-line detector' (patent number: CN202150939U) comprises a main control circuit, a test signal generating circuit, a power amplifying circuit, a sampling circuit, an impedance range adjusting circuit, an A/D conversion circuit, a display circuit and the like, and can carry out rapid and accurate on-line detection on a loudspeaker loop on line, carry out quantitative judgment on alternating current impedance of the loudspeaker loop (including a cable and an impedance matcher), and simultaneously, detect personnel qualitatively judge the loudspeaker effect of the loudspeaker by hearing on site. The patent is limited in that only the impedance of the speaker circuit can be quantitatively determined, but the speaker effect of the speaker can be qualitatively determined only by the auditory sense of human ears, and the misjudgment rate is high. Meanwhile, under high noise and remote environment, the human ear is hard to hear the loudspeaker to send out the test loud-speaking signal, and the loud-speaking condition of the loudspeaker cannot be judged qualitatively.

Disclosure of Invention

The invention provides an online loudspeaker sound pressure detector and a detection method for overcoming the defects of online loudspeaker detection by simple methods such as a universal meter, and the like.

The technical problem to be solved by the invention can be realized by the following technical scheme:

an online loudspeaker sound pressure detector comprises a CPU (1), a field loudspeaker (2), a detection result display (3), a simulation ear (4), an input amplification circuit (5), a frequency selection circuit (6), a self-adaptive frequency selection switch circuit (7), a test baseband signal generation circuit (8), an audio pulse amplification circuit (9), a V/F conversion circuit (10), a test setting control circuit (11), a working state control circuit (12), a power amplifier (13) and an input matching circuit (14), wherein the detection result display (3), the self-adaptive frequency selection switch circuit (7), the audio pulse amplification circuit (9), the V/F conversion circuit (10), the test setting control circuit (11) and the working state control circuit (12) are peripheral circuits of the CPU (1) and are respectively connected with the CPU (1); the working state control circuit (12) is connected with the field loudspeaker (2) through a test baseband signal generating circuit (8) and a power amplifier (13), and the working state control circuit (12) is also connected with the field loudspeaker (2) through an audio pulse amplifying circuit (9); the simulation ear (4) is connected with the V/F conversion circuit (10) sequentially through the input amplification circuit (5), the frequency selection circuit (6) and the input matching circuit (14), and the frequency selection circuit (6) is also connected with the self-adaptive frequency selection switch circuit (7).

An on-line loudspeaker sound pressure detection method comprises the following detection steps,

s1, pressing a test button in the test setting control circuit (11), outputting a control signal to enable the working state control circuit (12) to work after the CPU (1) receives a test instruction, starting the test baseband signal generating circuit (8) and the audio pulse amplifying circuit (9), enabling the test baseband signal generating circuit (8) to work, generating a fundamental frequency constant amplitude pulse signal, sending the fundamental frequency constant amplitude pulse signal to the power amplifier (13), amplifying the fundamental frequency constant amplitude pulse signal, and outputting the amplified fundamental frequency constant amplitude pulse signal to the field loudspeaker (2);

s2, a CPU (1) generates a group of fixed-frequency audio pulse signals, the fixed-frequency audio pulse signals are input into an audio pulse amplifying circuit (9) for power amplification, output signals are modulated by a base-frequency constant-amplitude signal generated by a test base-band signal generating circuit (8) and then input into a field loudspeaker (2), and the field loudspeaker outputs a modulated and synthesized signal to be sent to the space of an area needing to be measured;

s3, the artificial ear (4) receives the modulation synthesis signal in the area, amplifies the received modulation synthesis signal through the input amplifying circuit (5), decomposes the high frequency component of the signal through the frequency selecting circuit (6), detects the fixed frequency audio signal and decomposes and confirms the base frequency spectrum, the CPU (1) controls the self-adaptive frequency selecting switch circuit (7) to automatically adapt to the audio signal and the base frequency signal of the frequency selecting circuit (6);

and S4, inputting the audio signal and the fundamental frequency signal output by the frequency selection circuit (6) into the CPU (1) through the input matching circuit (14) and the V/F conversion circuit (10), distinguishing and interpreting various signals by the CPU (1) according to respective frequency characteristics of the received signals, controlling the test process, and displaying sound pressure level data of the loudspeaker on the detection result display (3).

Further, the frequency of the fundamental frequency signal is 15 KHZ.

Furthermore, the frequency of the audio signal is 300-3 KHZ.

Further, the frequency selection circuit (6) is composed of a first-order band-pass filter and a fourth-order adaptive filter.

The invention has the beneficial effects that: an online loudspeaker sound pressure detector and a detection method can accurately and quickly perform online detection on a loudspeaker, can quantitatively judge the sound pressure performance of the detected loudspeaker, and improve the maintenance efficiency of equipment; the double-frequency amplitude modulation signal in the audio frequency range is adopted, so that the interference of various strong noises and broadband sound fields on the site can be effectively removed, the signal receiving of a simulation ear in a required monitoring range is effectively ensured, the frequency response characteristic of an original site loudspeaker and the accuracy and the authenticity of the test are ensured; the adaptive frequency-selecting filter circuit is adopted, 1 band-pass filter is used, 1 four-order electronic switch controlled by a CPU is added to form the adaptive filter, the high-frequency component of the signal is decomposed, the fixed-frequency audio signal is detected, the fundamental frequency spectrum is decomposed and confirmed, various frequencies can be intelligently detected, the adaptive frequency-selecting filter circuit is applicable to industrial communication terminal equipment used in various complex environments, and a new technical approach for testing audio sounding equipment in a strong noise environment is developed.

Drawings

FIG. 1 is a schematic block diagram of a detector of the present invention;

FIG. 2 is a flowchart of a main process of the present invention;

FIG. 3 is a flow chart of the functional procedure of the present invention.

Detailed Description

In order to make the technical means, the creation characteristics, the achievement purposes and the effects of the invention easy to understand, the invention is further explained below by combining the specific drawings.

In specific implementation, referring to fig. 1, an online speaker sound pressure detector includes a CPU (1), a field speaker (2), a detection result display (3), a dummy ear (4), an input amplification circuit (5), a frequency selection circuit (6), an adaptive frequency selection switch circuit (7), a test baseband signal generation circuit (8), an audio pulse amplification circuit (9), a V/F conversion circuit (10), a test setting control circuit (11), a working state control circuit (12), a power amplifier (13), and an input matching circuit (14). The detection result display (3), the self-adaptive frequency-selecting switch circuit (7), the audio pulse amplification circuit (9), the V/F conversion circuit (10), the test setting control circuit (11) and the working state control circuit (12) are peripheral circuits of the CPU (1) and are respectively connected with the CPU (1). The working state control circuit (12) is connected with the field loudspeaker (2) through the test baseband signal generating circuit (8) and the power amplifier (13), and the working state control circuit (12) is also connected with the field loudspeaker (2) through the audio pulse amplifying circuit (9). The simulation ear (4) is connected with the V/F conversion circuit (10) sequentially through the input amplification circuit (5), the frequency selection circuit (6) and the input matching circuit (14), and the frequency selection circuit (6) is also connected with the self-adaptive frequency selection switch circuit (7).

The function of each module circuit is described as follows: (1) a processor CPU; controlling the working time sequence of each circuit, synthesizing and outputting audio pulse signals, detecting, calculating and inputting and outputting the level of the related circuit, synthesizing and displaying the final result. (2) A live speaker; and outputting the modulation composite signal and sending the signal to the area to be measured. (3) Displaying the detection result; and displaying the test result and setting process data by using a nixie tube. (4) Simulating a real ear; receiving a modulation synthesis signal (5) sent by a field loudspeaker in the area, and inputting the modulation synthesis signal into an amplifying circuit; amplifying the received modulated composite signal. (6) A frequency selecting circuit; a band-pass filter and 1 fourth-order adaptive filter are used to decompose the high-frequency component of signal and detect out the fixed-frequency audio signal. (7) A self-adaptive frequency-selecting switch circuit; the frequency through the filter passband is automatically adapted by the CPU selecting the electronic switch. (8) Generating a test baseband signal; a function signal generating circuit is used to generate a sine wave high frequency signal (range of frequencies that can be broadcast by a loudspeaker). (9) An audio pulse amplifying circuit; the power amplification CPU synthesizes the fixed frequency audio signal. (10) A V/F conversion circuit; the sampled dc level is converted to a linear frequency signal. (11) A test setup control circuit; and sending an instruction to the GPU by using the tact switch, and setting the working time sequence of each circuit. (12) A working state control circuit; and the relay driving circuit executes the instruction sent by the CPU and controls the test process. (13) A power amplifier; the sine wave high-frequency signal generated by the test baseband signal circuit is amplified to push the simulation mouth to send a modulation signal in a specific space domain for receiving by the simulation ear. (14) An input matching circuit; and the impedance matching between the frequency selection circuit and the V/F conversion circuit is realized.

s1, pressing a test button in a test setting control circuit (11), outputting a control signal to enable a working state control circuit (12) to work after a CPU (1) receives a test instruction, starting a test baseband signal generating circuit (8) and an audio pulse amplifying circuit (9), enabling the test baseband signal generating circuit (8) to work, generating a 15KHZ fundamental frequency constant amplitude pulse signal (the frequency is adjustable according to the signal frequency of the field condition), sending the signal to a power amplifier (13), amplifying the signal and outputting the signal to a field loudspeaker (2);

s2, a CPU (1) generates a group of fixed-frequency audio pulse signals according to a certain time sequence in a frequency range of 300-3 KHZ, the fixed-frequency audio pulse signals are input into an audio pulse amplifying circuit (9) for power amplification, output signals are input into a field loudspeaker (2) after being modulated by fundamental frequency constant amplitude signals generated by a test baseband signal generating circuit (8), and the output modulated and synthesized signals are output by the field loudspeaker and are sent to a space of an area to be measured;

s3, a simulation ear (4) receives the modulation synthesis signal of the area, amplifies the received modulation synthesis signal through an input amplifying circuit (5), decomposes the high-frequency component of the signal through a frequency selecting circuit (6) (composed of a first-order band-pass filter and 1 fourth-order self-adaptive filter), detects a fixed-frequency audio signal and decomposes a confirmed fundamental frequency spectrum, controls a self-adaptive frequency selecting switch circuit (7) through a CPU (1), selects a corresponding electronic switch, and automatically adapts to 300-3 KHZ audio signals and 15KHZ fundamental frequency signals passing through the pass band of the filter;

FIG. 2 is a flow chart of the main program of the sound pressure detector of the on-line speaker, wherein the CPU executes the main program in a specific flow, which is started first, the detection result display (3) is cleared, and the interrupts T0 and T1 are set to a 16-bit counting mode; then, allowing T0 interruption and T1 interruption, starting an analog-to-digital converter A/D650, and allowing an A/D end of a CPU to acquire signals; calling a display subroutine to test whether the voltage across the port is normal? If not, the display subroutine is continuously called, and if normal, it is judged whether or not the test button in the test setting control circuit (11) is pressed? If the test button is not pressed, the display subprogram is called again, if the test button is pressed, the functional program is executed, after the functional program is executed, the calling display subprogram is returned to for testing the voltage outside the port again, whether the test button is pressed or not is judged, the functional program is executed, and the process is circulated.

As shown in fig. 3, the functional program is a T0 interrupt subroutine, and when a T0 interrupt occurs, the CPU responds to the T0 interrupt, and calls the T0 interrupt subroutine, and the specific process is as follows: start calling, set the interrupt parameter of T0, then start the test function signal generator, read the measurement port information, determine if it is within the preset measurement range? If not in the preset measurement range, re-reading the measurement port information after performing range adjustment, and if in the preset measurement range, determining whether the measurement port information is within the preset normal use data range? If not in the predetermined normal use data range, the detection result display (3) displays a fault code, if in the predetermined normal use data range, the detection result display (3) displays measurement data, and the T0 subroutine call is interrupted to complete, returning to the main routine.

The detector is connected to a loudspeaker to be detected on line, a detection button is pressed, a circuit generates a fundamental frequency signal of about 15KHZ (the frequency is matched with the upper limit frequency response range of a field loudspeaker) and an audio pulse signal (300HZ-6KHZ) synthesized by a modulation CPU (central processing unit), a modulation composite signal is formed and is sent to the loudspeaker to be output after power amplification, the signal output by the loudspeaker is monitored intelligently by a simulated ear, the characteristics of 2 signals are restored through an adaptive filter, and the output sound pressure level is displayed at a display end through the identification of the CPU. The on-line loudspeaker sound pressure detection method is characterized in that a modulation composite signal synthesized by a fundamental frequency and a fixed frequency pulse signal is sent out, the signal is received by an artificial ear, and the two signal characteristics are restored by wave detection and filtering through a self-adaptive frequency-selecting filter circuit, so that the on-line loudspeaker sound pressure detection method has good isolation capability on various external interference noises and audio signals, provides a good technical method for on-line loudspeaker detection in high-risk environment, and provides good guarantee for measurement accuracy.

The foregoing shows and describes the general principles, essential features, and advantages of the invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are given by way of illustration of the principles of the present invention, and that various changes and modifications may be made without departing from the spirit and scope of the invention as defined by the appended claims. The scope of the invention is defined by the appended claims and equivalents thereof.

Claims

1. An on-line speaker sound pressure detector, comprising: the device comprises a CPU (1), a field loudspeaker (2), a detection result display (3), a simulation ear (4), an input amplification circuit (5), a frequency selection circuit (6), a self-adaptive frequency selection switch circuit (7), a test baseband signal generation circuit (8), an audio pulse amplification circuit (9), a V/F conversion circuit (10), a test setting control circuit (11), a working state control circuit (12), a power amplifier (13) and an input matching circuit (14), wherein the detection result display (3), the self-adaptive frequency selection switch circuit (7), the audio pulse amplification circuit (9), the V/F conversion circuit (10), the test setting control circuit (11) and the working state control circuit (12) are respectively connected with the CPU (1) as peripheral circuits of the CPU (1); the working state control circuit (12) is connected with the field loudspeaker (2) through a test baseband signal generating circuit (8) and a power amplifier (13), and the working state control circuit (12) is also connected with the field loudspeaker (2) through an audio pulse amplifying circuit (9); the simulation ear (4) is connected with the V/F conversion circuit (10) through the input amplification circuit (5), the frequency selection circuit (6) and the input matching circuit (14) in sequence, the frequency selection circuit (6) is also connected with the self-adaptive frequency selection switch circuit (7),

the frequency of the base frequency signal generated by the test baseband signal generating circuit (8) and the audio frequency of the signal generated by the audio pulse amplifying circuit (9) are in an audio frequency range, the frequencies of the two signals are different, and the frequency of the base frequency signal generated by the test baseband signal generating circuit (8) is higher than the frequency of the audio signal generated by the audio pulse amplifying circuit (9).

2. The on-line speaker sound pressure detector as claimed in claim 1, wherein: the frequency selection circuit (6) is composed of a first-order band-pass filter and a fourth-order adaptive filter.

3. A detection method for the sound pressure detector of the on-line speaker according to claim 1, wherein: the detection steps are as follows,

s3, the artificial ear (4) receives the modulation synthesis signal in the area, amplifies the received modulation synthesis signal through the input amplifying circuit (5), decomposes the high frequency component of the signal through the frequency selecting circuit (6), detects the fixed frequency audio signal and decomposes and confirms the base frequency spectrum, the CPU (1) controls the self-adapting frequency selecting switch circuit (7), selects the corresponding electronic switch, and automatically adapts to the audio signal and the base frequency signal through the frequency selecting circuit (6);

4. A detection method according to claim 3, characterized in that: the frequency of the fundamental frequency signal is 15 KHZ.

5. A detection method according to claim 3, characterized in that: the frequency of the audio signal is 300-3 KHZ.