Audio output device and protection method therefor

Abstract

The present invention relates to an audio output device comprising: an audio amplifier for transmitting amplified audio signals to a plurality of speaker units for outputting audio signals; a reference signal generator for generating frequency-specific reference signals to be input into the audio amplifier; a digital filter disposed between the reference signal generator and the audio amplifier so as to modify a frequency; and a processor for determining a modification value to be input into the digital filter, wherein the processor calculates frequency-specific impedances corresponding to the frequency-specific reference signals through the audio amplifier, determines whether the frequency-specific impedances satisfy a preset condition, and, according to the determination result, uses the digital filter to modify a frequency that does not satisfy the preset condition.

Description

Audio output device and method for protecting the same

[0001] The present invention relates to an audio output device and a method for protecting the same. More specifically, the present invention relates to an audio output device capable of preventing damage to an audio amplifier or enhancing the sound quality of a speaker depending on impedance at different frequencies.

[0002] In general, a public address system is a system designed to broadcast to the entire area, each floor, or each section of a single building or adjacent buildings, such as a school, office building, apartment, or hotel.

[0003] The on-site public address system is used to inform people of various information related to the building during normal times, and to inform them of disaster situations and evacuation routes in the event of an emergency such as a fire or earthquake.

[0004] In this way, since the in-house broadcasting system functions as an emergency broadcasting system in an emergency situation, it is very important to prevent factors that may cause malfunctions or defects in advance and maintain the stability of the entire system.

[0005] Accordingly, technologies for monitoring abnormal conditions in conventional speakers or amplifiers connected to speakers have been disclosed. However, these technologies focus on minimizing damage caused by problems rather than fundamentally solving the problem. For example, when an abnormal condition is detected within the circuit of an audio output device included in a conventional in-house broadcasting system, a technology has been disclosed that detects an abnormal signal flowing into the amplifier (hereinafter referred to as an "audio amplifier") and blocks the entire signal. However, no technology has been disclosed for removing the abnormal signal.

[0006] Meanwhile, the background technology of the invention has been prepared to facilitate a better understanding of the present invention. It should not be construed as an admission that the matters described in the background technology of the invention exist as prior art.

[0007] Accordingly, a method is required to automatically resolve problems occurring in audio output devices included in an in-house broadcasting system without administrator intervention.

[0008] As a result, the inventors of the present invention sought to develop a method for measuring the impedance of speakers by frequency, diagnosing and resolving the cause of an abnormality based on the measured impedance value, and an audio output device that performs this.

[0009] The tasks of the present invention are not limited to the tasks mentioned above, and other tasks not mentioned will be clearly understood by those skilled in the art from the description below.

[0010] In order to solve the above-described problem, an audio output device according to an embodiment of the present invention is provided. The device includes an audio amplifier configured to transmit an amplified audio signal to a plurality of speaker units configured to output an audio signal, a reference signal generator configured to generate a frequency-specific reference signal input to the audio amplifier, a digital filter disposed between the reference signal generator and the audio amplifier and configured to correct a frequency, and a processor configured to determine a correction value to be input to the digital filter, wherein the processor is configured to calculate a frequency-specific impedance corresponding to the frequency-specific reference signal through the audio amplifier, determine whether the frequency-specific impedance satisfies a preset condition, and, based on a result of the determination, correct a frequency that does not satisfy the preset condition using the digital filter.

[0011] According to a feature of the present invention, the processor generates an arbitrary number (N) in the audible frequency band. f ) arranged so that the frequency points (f) increase at logarithmic intervals. x ) can be further configured to determine.

[0012] According to a feature of the present invention, the processor, the frequency point (f x ) based on each, the voltage (V) between the speaker unit connected to the audio amplifier fx ) and current (I fx ) and measure the measured voltage (V fx ) and current (I fx ) is calculated using the impedance (Z fx ) and can be configured to generate an impedance table using frequency points (fx) arranged to increase at the logarithmic scale interval.

[0013] According to a feature of the present invention, the processor, the frequency point (f x ) star impedance (Z fx ) can be configured to determine whether the maximum output condition of the audio amplifier is satisfied.

[0014] According to a feature of the present invention, the processor may be further configured to determine an attenuation amount (dB) to be applied to a frequency point that does not satisfy the maximum output condition based on an impedance difference value or a preset value.

[0015] According to a feature of the present invention, the processor has a frequency point (f) that satisfies the maximum output condition. x ) star impedance (Z fx ) can be further configured to determine whether the average impedance condition is satisfied.

[0016] According to a feature of the present invention, the processor applies an attenuation or amplification amount (G) to the corresponding frequency point according to the following [Mathematical Formula 1]. x ) can be further configured to determine.

[0017] [Mathematical Formula 1]

[0018]

[0019] Here, Z target is the average impedance, Z xis the impedance measured at the frequency point, V vol refers to the reference output voltage according to the volume of the audio amplifier.

[0020] According to a feature of the present invention, the processor can measure using a monitoring circuit disposed between the audio amplifier and the speaker unit.

[0021] According to a feature of the present invention, the reference signal may be a pilot signal related to the protection of a speaker unit connected to the output terminal of the audio amplifier.

[0022] In order to solve the problem described above, a method for protecting an audio output device according to another embodiment of the present invention is provided. The method is configured to include a step of generating a frequency-specific reference signal input to an audio amplifier connected to a plurality of speaker units, a step of calculating a frequency-specific impedance corresponding to the frequency-specific reference signal through the audio amplifier, a step of determining whether the frequency-specific impedance satisfies a preset condition, and a step of correcting a frequency that does not satisfy the preset condition using a digital filter disposed between the reference signal generator and the audio amplifier according to a result of the determination.

[0023] Specific details of other embodiments are included in the detailed description and drawings.

[0024] The present invention considers that impedance imbalance exists by frequency depending on the number of speakers included in an in-house broadcasting system and the cable layout environment, and thereby balances the impedance across the entire audible frequency band using a digital filter, thereby maintaining the sound quality of an audio output device without distortion across the entire audible frequency band. In particular, by resolving the frequency-specific impedance imbalance that frequently occurs in in-house broadcasting systems where the signal line length increases or speakers are connected in parallel due to a wide installation range, the present invention enables the stable operation of the in-house broadcasting system.

[0025] The present invention determines and corrects an imbalance in impedance using a frequency-specific impedance table configured in a logarithmic scale, as the arrangement of auditory nerves constituting the human cochlea is configured in a logarithmic scale according to frequency, thereby performing a correction more suitable for human hearing than using an impedance table configured in integer multiples, and can resolve the instability of the connection environment of an audio output device at a site where an in-house broadcasting system is installed.

[0026] The present invention can prevent damage to an audio amplifier and maintain audio quality by adjusting or removing an input signal in a frequency band that exceeds the maximum output impedance that can be output from an audio output device using a digital filter.

[0027] The present invention enables the stable operation of an in-house broadcasting system that serves as an emergency broadcast system 24 hours a day by enabling immediate resolution of problems occurring in an audio output device without the need for an administrator's operation.

[0028] The effects according to the present invention are not limited to those exemplified above, and more diverse effects are included within the present invention.

[0029] FIG. 1 is a schematic diagram illustrating an in-house broadcasting system according to one embodiment of the present invention.

[0030] FIG. 2 is a block diagram showing the configuration of an audio output device according to one embodiment of the present invention.

[0031] FIG. 3 is a flowchart of a method for protecting an audio output device according to an embodiment of the present invention.

[0032] Figure 4 is a flowchart illustrating steps S130 and S140 illustrated in Figure 3.

[0033] FIGS. 5A to 5C are graphs for explaining a method of calculating synthetic impedance according to one embodiment of the present invention.

[0034] FIG. 6a and FIG. 6b are graphs for explaining a compensation method for preventing damage to an audio amplifier according to one embodiment of the present invention.

[0035] FIGS. 7A and 7B are graphs for explaining a compensation method for maintaining the quality of a plurality of speaker units according to one embodiment of the present invention.

[0036] The advantages and features of the present invention, and the methods for achieving them, will become clearer with reference to the embodiments described in detail below together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms. These embodiments are provided only to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined only by the scope of the claims. In connection with the description of the drawings, similar reference numerals may be used for similar components.

[0037] In this document, the expressions "has," "may have," "includes," or "may include" indicate the presence of a feature (e.g., a number, function, operation, or component such as a part), but do not exclude the presence of additional features.

[0038] In this document, the expressions "A or B," "at least one of A and / or B," or "one or more of A or / and B" can include all possible combinations of the listed items. For example, "A or B," "at least one of A and B," or "at least one of A or B" can all refer to cases where (1) at least one A is included, (2) at least one B is included, or (3) at least one A and at least one B are included.

[0039] The terms "first," "second," "first," or "second," as used herein, may describe various components, regardless of order and / or importance, and are only used to distinguish one component from another, without limiting the components. For example, a first user device and a second user device may represent different user devices, regardless of order or importance. For example, without departing from the scope of the rights set forth in this document, a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component.

[0040] When it is said that a component (e.g., a first component) is "(operatively or communicatively) coupled with / to" or "connected to" another component (e.g., a second component), it should be understood that the component is directly coupled to the other component, or can be connected via another component (e.g., a third component). Conversely, when it is said that a component (e.g., a first component) is "directly coupled to" or "directly connected to" another component (e.g., a second component), it should be understood that no other component (e.g., a third component) exists between the first component and the other component.

[0041] The expression "configured to" as used herein can be used interchangeably with, for example, "suitable for," "having the capacity to," "designed to," "adapted to," "made to," or "capable of." The term "configured to" does not necessarily mean something that is "specifically designed to" in hardware. Instead, in some contexts, the expression "a device configured to" can mean that the device, together with other devices or components, is "capable of." For example, the phrase "a processor configured (or set) to perform A, B, and C" may mean a dedicated processor (e.g., an embedded processor) for performing those operations, or a general-purpose processor (e.g., a CPU or application processor) that can perform those operations by executing one or more software programs stored in a memory device.

[0042] The terms used in this document are used only to describe specific embodiments and may not be intended to limit the scope of other embodiments. The singular expression may include the plural expression unless the context clearly indicates otherwise. Terms used herein, including technical or scientific terms, may have the same meaning as commonly understood by those of ordinary skill in the art described in this document. Terms defined in general dictionaries among the terms used in this document may be interpreted as having the same or similar meaning in the context of the relevant technology, and shall not be interpreted in an idealized or overly formal sense unless explicitly defined in this document. In some cases, even if a term is defined in this document, it cannot be interpreted to exclude the embodiments of this document.

[0043] The individual features of the various embodiments of the present invention may be partially or wholly combined or combined with each other, and various technical connections and operations are possible, as can be fully understood by those skilled in the art, and each embodiment may be implemented independently of each other or may be implemented together in a related relationship.

[0044] For clarity in the interpretation of this specification, the terms used in this specification are defined below.

[0045] FIG. 1 is a schematic diagram illustrating an in-house broadcasting system according to one embodiment of the present invention.

[0046] Referring to FIG. 1, an in-house broadcasting system (1000) may include an audio output device (100) equipped with a protection function for maintaining broadcast quality, a speaker unit (200) connected thereto, and a central broadcasting device (300) that provides a broadcast to be transmitted to the speaker unit (200).

[0047] The audio output device (100) can perform frequency correction to secure broadcast quality when installing the speaker unit (200) so that the speaker units (200) installed in different locations can operate stably. Specifically, the audio output device (100) can correct the frequency in each frequency band of the speaker unit (200) by taking into account various installation environments, such as when the line (101) connected to the speaker unit (200) becomes longer, the number of speaker units (200) connected to a single broadcasting zone increases, or an impedance matching transformer is added to the front of the speaker unit (200).

[0048] The audio output device (100) can generate a reference signal in the entire audible frequency band (20 Hz to 20 kHz) to measure the impedance of the speaker unit (200), or can generate a reference signal swept in the entire audible frequency band. The audio output device (100) can measure the impedance of the speaker unit (200) based on the generated signal, and, based on the result, can perform various control operations to prevent damage to or maintain the quality of the speaker unit (200). For example, the audio output device (100) can prevent damage to an audio amplifier that can amplify an analog audio signal or a digital audio signal provided from a central broadcasting device (100) into a high-voltage analog signal suitable for an in-house broadcasting system, or can uniformly correct the sound quality of the speaker unit (200) that outputs a broadcast, and a more specific description will be given later.

[0049] In the in-house broadcasting system (1000), the audio output device (100) can be connected in parallel with speaker units (200) installed in different broadcasting zones via lines (101a), (101b), and (101c). For example, the different broadcasting zones can be divided by building, by floor within a building, or by multiple areas designated by an administrator within a single floor. The audio output device (100) can correct the frequency of the speaker unit (200) according to different reference values ​​for each broadcasting zone.

[0050] The speaker unit (200) is one of the broadcast output means provided in the in-house broadcasting system (1000), and can receive and output an amplified analog signal from the audio output device (100). According to an embodiment, the speaker unit (200) included in the in-house broadcasting system (1000) can have an impedance that is inversely proportional to the maximum output power that the speaker unit can produce. For example, when connecting an amplifier having an output voltage of 100 V and a speaker having a rated power of 50 W, the impedance of the speaker is (100). 2 / 50=200 ohm. However, depending on the installation environment, there are cases where the impedance of the speaker unit (200) is not uniform across all audible frequency bands, and this can be corrected through the audio output device (100).

[0051] The central broadcasting device (300) can provide long-distance broadcasting between buildings. The central broadcasting device (300) can provide various multimedia, such as individual broadcasting for each speaker unit (200), group broadcasting for each building, emergency broadcasting, scheduled broadcasting, remote broadcasting, and TTS (Text-To-Speech) broadcasting. For example, the central broadcasting device (300) can packetize multimedia implemented as audio and transmit it to the audio output device (100).

[0052] So far, a schematic configuration of an in-house broadcasting system (1000) according to one embodiment of the present invention has been described. Hereinafter, with reference to FIG. 2, an audio output device (100) that controls a speaker unit (200) to protect it will be described.

[0053] FIG. 2 is a block diagram showing the configuration of an audio output device according to one embodiment of the present invention.

[0054] Referring to FIG. 2, the audio output device (100) may include a reference signal generator (110), a digital filter (120), an audio amplifier (130), and a processor (140).

[0055] The reference signal generator (110) can generate a predefined constant signal, such as a pilot signal, to protect the speaker unit (200). The reference signal generator (110) can transmit the generated reference signal to the speaker unit (200). The reference signal transmitted to the speaker unit (200) by the reference signal generator (110) can be used to measure the voltage and current flowing to the speaker unit (200).

[0056] The digital filter (120) can correct the frequency band of the speaker unit (200). Specifically, the digital filter (120) can store an impedance table for each frequency point provided by the processor (140) and an attenuation or amplification amount for each frequency point, and can correct a newly input audio signal based on the table. Here, the newly input audio signal may correspond to a broadcast multimedia signal to be output from the in-house broadcasting system (1000), rather than a reference signal used to measure the impedance of the speaker unit (200).

[0057] In various embodiments, the audio output device (100) may further include a memory (not shown). The memory may store group information, broadcast zone information, and individual identification information of a single speaker unit (200) connected in parallel. In addition, the memory may store correction values ​​and an impedance table of a digital filter (120) assigned to each speaker unit (200).

[0058] Additionally, the correction value and impedance table of the digital filter (120) specified for each output group consisting of multiple speaker units (200) can be stored.

[0059] Meanwhile, the memory performing these functions may include a volatile or non-volatile storage medium capable of storing various data, commands, and information. For example, the memory may include at least one type of storage medium among flash memory type, hard disk type, multimedia card micro type, card type memory (e.g., SD or XD memory, etc.), RAM, SRAM, ROM, EEPROM, PROM, network storage, cloud, and blockchain database.

[0060] Additionally, the memory may have recorded therein commands for the operation of the audio output device (100). For example, the memory may have recorded therein an application (not shown) for correcting the frequency depending on whether the impedance for each frequency satisfies a preset condition.

[0061] The audio amplifier (130) can amplify an analog audio signal and transmit the amplified audio signal to the speaker unit (200). Specifically, the audio amplifier (130) can output voltage using an internal high voltage generator (not shown), and the speaker unit (200) can convert the voltage into kinetic energy through an internal coil to output sound.

[0062] The processor (140) is operably connected to a reference signal generator (110), a digital filter (120), and an audio amplifier (130) to control the overall operation of the audio output device (100). The processor (140) can drive an application or program stored in a memory and, depending on the synthetic impedance of the speaker unit (200), execute various commands to protect all components connected to the speaker unit (200) during the driving process of the in-house broadcasting system (1000).

[0063] Meanwhile, the composite impedance of the speaker unit (200) can be determined based on the capacitance (102) and inductance (103) of the line connected to the speaker unit (200). Accordingly, the processor (140) can determine whether to correct the frequency band of the plurality of speaker units (200) based on the composite impedance.

[0064] In various embodiments, the processor (140) may correspond to a computing device such as a Central Processing Unit (CPU) or an Application Processor (AP). Additionally, the processor (140) may be implemented in the form of an integrated chip (IC), such as a System on Chip (SoC) in which various computing devices are integrated.

[0065] Hereinafter, with reference to FIGS. 3 to 7b, a method for protecting the inside of the device and the speaker unit (200) connected thereto by the processor (140) of the audio output device (100) will be described.

[0066] FIG. 3 is a flowchart of a method for protecting an audio output device according to an embodiment of the present invention.

[0067] Referring to FIG. 3, the processor (140) can generate a frequency-specific reference signal input to an audio amplifier connected to a plurality of speaker units (S110). Here, the reference signal may be a pilot signal related to the protection of the speaker unit (200) connected to the output terminal of the audio amplifier (130). The processor (140) can generate an arbitrary number (N) of reference signals in an arbitrary frequency band predefined by an administrator in the audible frequency band. f ) as many frequency points (f x ) can be determined, and the frequency point (f) can be determined using a reference signal generator (110). x ) can generate a reference signal corresponding to the reference signal.

[0068] That is, the processor (140) can receive the frequency band and the number of frequency points to be monitored from the manager, and can generate multiple frequency points that can have a logarithmic scale interval within the frequency band using [Mathematical Formula 1] according to the number of inputs. The number of frequency points (N f ) is large, the protection range of the audio output device (100) can be expanded, and the number of frequency points (N f ) can protect the audio output device (100) through faster processing results.

[0069]

[0070] Here, f start is the minimum value of the preset frequency range, f span Silver f start Wow f stop It means the frequency band between, N f is the number of frequency points to be generated within the frequency band. For example, frequency points (f) based on the entire audible frequency band x ) is set, f start is 20Hz, f stop is 20KHz, f spancan be understood as 19980Hz.

[0071] After step S110, the processor (140) can calculate the impedance by frequency through the audio amplifier (120) (S120). Specifically, the processor (140) calculates a voltage (V) between the audio amplifier (110) and the speaker unit (200) based on each frequency point. fx ) and current (I fx ) can be measured. For example, the processor (140) may further include a monitoring circuit (not shown) between the audio amplifier (110) and the speaker (200) unit. The processor (140) may input a reference signal from the audio amplifier (110) and output an amplified output voltage (V fx ) and the current measured in the monitoring circuit (I fx ) can be measured, and the output voltage value (V fx ) as the current value (I fx ) is divided into impedance (Z) for frequency points f = (V fx / I fx )) can be calculated. The processor (140) calculates the impedance (Z) calculated for each frequency point f ) can create an impedance table combining values.

[0072] The processor (140) can generate a composite impedance by adding the impedances measured from each of the plurality of speaker units (200). The composite impedance is a value obtained by adding the impedances of the speaker units (200) grouped in one broadcast area, and can be understood as a comparison value for frequency correction.

[0073] In relation to this, FIGS. 5a to 5c are graphs for explaining a method of calculating synthetic impedance according to one embodiment of the present invention.

[0074] Referring to FIGS. 5A to 5C, the processor (140) inputs a reference signal corresponding to a frequency point in the audible frequency band to the audio amplifier (130), thereby obtaining a frequency-impedance graph, such as FIGS. 5A and 5B, from each of the plurality of speaker units (200). The processor (140) can add the impedances calculated from each of the plurality of speaker units (200), thereby obtaining a synthetic impedance graph made up of solid lines, as in FIG. 5C.

[0075] After step S120, the processor (140) can determine whether the impedance for each frequency satisfies a preset condition (S130). Based on the determination result, the processor (140) can correct a frequency that does not satisfy the preset condition using a digital filter (120) arranged between the reference signal generator (110) and the audio amplifier (130) (S140, No).

[0076] In relation to this, FIG. 4 is a flowchart specifying steps S130 and S140 illustrated in FIG. 3, and FIGS. 6a and 6b are graphs for explaining a compensation method for preventing damage to an audio amplifier according to one embodiment of the present invention.

[0077] Referring to FIG. 4, the processor (140) is a frequency point (f x ) star impedance (Z fx ) can determine whether the maximum output condition of the audio amplifier (130) is satisfied (S130-1). Specifically, the processor (140) determines whether the maximum output voltage (V) of the audio amplifier (130) is satisfied. max ) to the maximum output current (I max ) is divided into the lowest output impedance (Z min ) can calculate the value. The processor (240) calculates the frequency point (f x ) star impedance (Z fx ) value is the lowest output impedance (Z min) can be determined to be lower than the value. Since the output impedance is the lowest under the maximum output condition, if there is an impedance lower than the minimum output impedance, the audio amplifier will be damaged by exceeding the maximum output.

[0078] Referring to FIG. 6A, the processor (140) can obtain a composite impedance graph of N speaker units (200) tied to one broadcast zone as follows. The processor (140) obtains the lowest output impedance (Z) from the composite impedance graph. min )(Z') If A-band and B-band frequencies having lower values ​​are input, it can be judged that the audio amplifier (130) may be damaged.

[0079] Accordingly, the processor (140) determines, as a result of the judgment in step S130-1, one of the frequency points (f x ) impedance value (Z fx ) is the lowest output impedance (Z min ) value is lower than the value (S140-11, for example), the processor (140) can determine the attenuation applied to the frequency point or frequency band that does not satisfy the maximum output condition based on the impedance difference value or the preset value (S140-11). For example, under the condition that the lowest impedance of the audio amplifier (130) with specifications of 100 V and 500 W and the speaker unit (200) stably connected thereto is 20 ohm, if the impedance measured at the 1 kHz frequency point is 10 ohm, the audio amplifier (130) may be damaged due to the maximum input of 100 V output and 1 kHz audio signal, causing a current of 10 A (1000 W) to flow. Accordingly, the processor (140) may determine the attenuation applied to the frequency point or frequency band that does not satisfy the maximum output condition based on the impedance difference value (10 ohm = 20 ohm - 10 ohm) in the 1 kHz band. min) can be used as the attenuation ratio (50%) to determine the attenuation (6 dB). In other words, the processor (140) can compensate the frequency so that only a voltage of 50 V is output even if the maximum signal is input in the 1 kHz band. For another example, the processor (140) can apply a fixed value of attenuation (e.g., 10 dB) in a frequency band lower than 20 ohm regardless of the impedance difference value. For example, as shown in FIG. 6b, the processor (140) can apply a fixed value of attenuation (e.g., 10 dB) in a frequency band lower than 20 ohm. In this way, by applying a fixed, large value of attenuation and not using the frequency band, it is possible to prevent the audio amplifier from being damaged due to an accident in a situation where real-time monitoring by the manager is impossible.

[0080] After step S140-11, the processor (140) can apply a previously determined attenuation amount to the digital filter (120). For example, the processor (140) can input an attenuation amount for each frequency point to the digital filter (120), thereby allowing the audio amplifier (130) to operate only within an undamaged output range.

[0081] Again, referring to Figure 4, the judgment result at step S130-1 is that one of the frequency points (f x ) impedance value (Z fx ) is the lowest output impedance (Z min ) is not lower than the value of the frequency point (f x ) satisfies the maximum output condition, the corresponding frequency point (f x ) star impedance value (Z fx) can be calculated to determine whether the average impedance condition is satisfied (S130-2, example). Here, the average impedance may correspond to an impedance value determined according to the voltage (V) and output (W) of the audio amplifier (130). For example, if a 500W audio amplifier (130) can output a voltage of up to 100V, the average impedance may be 20ohm.

[0082] The processor (140) is a frequency point (f x ) star impedance value (Z fx ) can be judged whether it is included in the average range (S130-3). As a result of the judgment, any one frequency point (f x ) impedance value (Z fx ) is the average impedance (Z target ) is not included, the processor (140) calculates the frequency point (f) as in [Mathematical Formula 2] below. x ) by attenuation or amplification (G) x ) can be determined (S140-21).

[0083]

[0084] Here, Z target is the average impedance, Z x is the impedance measured at the frequency point, V vol may mean a reference output voltage according to the volume of the audio amplifier (130).

[0085] After step S140-21, the processor (140) can apply a previously determined attenuation or amplification amount to the digital filter (120). For example, the processor (140) can input an attenuation or amplification amount for each frequency point to the digital filter (120), thereby allowing the speaker unit (200) connected to the audio amplifier (130) to maintain a uniform sound quality across the entire audible frequency band.

[0086] In relation to this, FIGS. 7a and 7b are graphs for explaining a compensation method for maintaining the quality of a plurality of speaker units according to one embodiment of the present invention.

[0087] Referring to FIG. 7a, the processor (140) can obtain a composite impedance graph of N speaker units (200) tied to one broadcast zone as follows. The processor (140) obtains an average impedance (Z target ) based on the attenuation or amplification (G) x ) can be calculated, which can be represented as in Fig. 7b. In this way, the average impedance (Z target ) calculated based on the attenuation or amplification (G) x ) is applied, the audio output device (100) can obtain the impedance value for each frequency point.

[0088] So far, a method for protecting an audio output device (100) according to an embodiment of the present invention has been described. According to the present invention, the central broadcasting device (100) can prevent damage to an audio amplifier by resolving impedance non-uniformity and eliminating a frequency band lower than the lowest output impedance that can be output, and can maintain the sound quality of the audio output device without distortion across the entire audible frequency band.

[0089] Although the embodiments of the present invention have been described in more detail with reference to the attached drawings, the present invention is not necessarily limited to these embodiments, and various modifications may be implemented without departing from the technical spirit of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention, but to explain it, and the scope of the technical spirit of the present invention is not limited by these embodiments. Therefore, it should be understood that the embodiments described above are illustrative in all aspects and not restrictive. The protection scope of the present invention should be interpreted by the claims below, and all technical ideas within a scope equivalent thereto should be interpreted as being included in the scope of the rights of the present invention.

Claims

1. An audio amplifier configured to transmit an amplified audio signal to a plurality of speaker units configured to output an audio signal; A reference signal generator configured to generate a frequency-specific reference signal input to the audio amplifier; A digital filter arranged between the reference signal generator and the audio amplifier and configured to correct the frequency; and A processor configured to determine a correction value to be input to the digital filter; The above processor, An audio output device configured to calculate a frequency-specific impedance corresponding to the frequency-specific reference signal through the audio amplifier, determine whether the frequency-specific impedance satisfies a preset condition, and, based on the determination result, correct a frequency that does not satisfy the preset condition using the digital filter.

2. In paragraph 1, The above processor, Any number (N) in the audible frequency band f ) arranged so that the frequency points (f) increase at logarithmic intervals. x ) is further configured to determine the audio output device.

3. In paragraph 2, The above processor, The above frequency point (f x ) based on each, the voltage (V) between the speaker unit connected to the audio amplifier fx ) and current (I fx ) and measure it, The above measured voltage (V fx ) and current (I fx ) is calculated using the impedance (Z fx ) and an audio output device configured to generate an impedance table using frequency points (fx) arranged at the logarithmic scale intervals.

4. In paragraph 3, The above processor, The above frequency point (f x ) star impedance (Z fx ) is configured to determine whether the maximum output condition of the audio amplifier is satisfied.

5. In paragraph 4, The above processor, At any one frequency point (f x ) and the difference value between the impedance value and the lowest output impedance value of the audio amplifier or a preset value, and determines the attenuation amount (dB) to be applied to a frequency point that does not satisfy the maximum output condition.

6. In paragraph 4, The above processor, Frequency point (f) that satisfies the above maximum output condition x ) star impedance (Z fx ) is further configured to determine whether the average impedance condition is satisfied.

7. In paragraph 6, The above processor, According to the following [Mathematical Formula 1], the amount of attenuation or amplification (G) applied to the corresponding frequency point x ) is further configured to determine the audio output device. [Mathematical Formula 1] Here, Z target is the average impedance, Z x is the impedance measured at the frequency point, V vol refers to the reference output voltage according to the volume of the audio amplifier.

8. In paragraph 3, The above processor, An audio output device configured to measure the voltage and current using a monitoring circuit disposed between the audio amplifier and the speaker unit.

9. In paragraph 1, The above reference signal is, An audio output device, which is a pilot signal related to the protection of a speaker unit connected to the output terminal of the above audio amplifier.

10. A step of generating a frequency-specific reference signal input to an audio amplifier connected to a plurality of speaker units; A step of calculating a frequency-specific impedance corresponding to the frequency-specific reference signal through the audio amplifier; A step of determining whether the impedance for each frequency satisfies a preset condition; and A method for protecting an audio output device, comprising: a step of correcting a frequency that does not satisfy the preset condition using a digital filter disposed between a reference signal generator that generates the reference signal and the audio amplifier, based on the judgment result; 11. In paragraph 10, The step of generating the above reference signal is: Any number (N) in the audible frequency band f ) arranged so that the frequency points (f) increase at logarithmic intervals. x ) further comprising a step of determining an audio output device protection method.

12. In paragraph 11, The steps for calculating the impedance for each frequency are: The above frequency point (f x ) based on each, the voltage (V) between the speaker unit connected to the audio amplifier fx ) and current (I fx ) measuring step, The above measured voltage (V fx ) and current (I fx ) is calculated using the impedance (Z fx ) and a step of generating an impedance table using frequency points (fx) arranged to increase at the logarithmic scale interval, a method for protecting an audio output device, comprising:

13. In paragraph 12, The step of determining whether the above-mentioned conditions are satisfied is: The above frequency point (f x ) star impedance (Z fx ) is a step of determining whether the maximum output condition of the audio amplifier is satisfied, and is a method for protecting an audio output device.

14. In paragraph 13, The step of correcting the above frequency is: At any one frequency point (f x ) and the minimum output impedance value of the audio amplifier, or a preset value, based on the difference value, or a step of determining the attenuation amount (dB) to be applied to a frequency point that does not satisfy the maximum output condition, a method for protecting an audio output device further comprising.

15. In paragraph 13, The step of determining whether the above-mentioned conditions are satisfied is: Frequency point (f) that satisfies the above maximum output condition x ) star impedance (Z fx ) further comprising a step of determining whether the average impedance condition is satisfied.

16. In paragraph 15, The step of correcting the above frequency is: According to the following [Mathematical Formula 1], the amount of attenuation or amplification (G) applied to the corresponding frequency point x ) further comprising a step of determining an audio output device protection method. [Mathematical Formula 1] Here, Z target is the average impedance, Z x is the impedance measured at the frequency point, V vol refers to the reference output voltage according to the volume of the audio amplifier.

17. In paragraph 12, The steps of measuring the voltage and current are as follows: A method for protecting an audio output device, comprising a step of measuring the voltage and current using a monitoring circuit disposed between the audio amplifier and the speaker unit.

18. In paragraph 10, The above reference signal is, A method for protecting an audio output device, the method comprising: a pilot signal related to the protection of a speaker unit connected to the output terminal of the above audio amplifier.

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