JP2020022055A - Sound output device and sound output system - Google Patents

Abstract

To provide a sound output device and a sound output system capable of executing failure diagnosis about whether or not high-quality intended sound is outputted from sound information.SOLUTION: A sound output device 2 comprises: a serial audio interface 20 that acquires digital sound information; a digital/analog converter 24 that converts the digital sound information into analog sound information; an amplifier circuit 27; and a failure diagnosis unit 6. In the failure diagnosis unit 6, the analog sound information outputted from the amplifier circuit 27 is converted into digital sound information for diagnosis, and the digital sound information for diagnosis and the digital sound information are compared with each other to calculate a differential value, and when the differential value is larger than a threshold that is preliminarily set, a failure signal indicating a failure state is outputted.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a sound output device and a sound output system, and more particularly, to a technology effective when applied to a sound output device and a sound output system having a failure diagnosis function.

Patent Literature 1 below discloses a failure diagnosis device for audio equipment. A speaker is connected to the audio device through an amplifier, and the failure diagnosis device is connected to the speaker.
When a failure occurs in the audio device and the sound output is stopped, the failure diagnosis device performs a failure diagnosis as to whether or not the speaker has failed. When a failure has occurred in the speaker, an indicator such as an LED blinks, and the user is notified that the failure has occurred.

  By the way, the failure diagnosis device can perform a failure diagnosis as to whether or not there is a sound output and whether or not a speaker has failed. However, it is not possible to execute a failure diagnosis of an audio device or an amplifier based on sound information (sound source data) acquired by the audio device, as to whether or not a high-quality intended sound is output.

JP-A-1-176952

  The present invention provides a sound output device and a sound output system capable of performing a failure diagnosis on whether or not an intended sound with high quality is output from sound information in consideration of the above fact.

  In order to solve the above problems, a sound output device according to an embodiment of the present invention includes an interface unit that acquires digital sound information, and a digital-to-analog converter that converts digital sound information output from the interface unit into analog sound information. , An amplifier circuit that amplifies analog sound information output from the digital-to-analog converter, and converts the analog sound information output from the amplifier circuit to diagnostic digital sound information, and compares the diagnostic digital sound information with the digital sound information. And a failure diagnosis unit that outputs a failure signal in a failure state when the difference value exceeds a preset threshold value.

  A sound output system according to another embodiment of the present invention includes the sound output device and a microcontroller unit that outputs digital sound information to an interface unit and inputs a failure signal output from a failure diagnosis unit. Have.

  According to the present invention, it is possible to provide a sound output device and a sound output system capable of performing a failure diagnosis on whether or not an intended sound having high quality is output from sound information.

It is a block configuration diagram of a sound output device and a sound output system according to the first embodiment of the present invention. FIG. 2 is a detailed block diagram of a failure diagnosis unit provided in the sound output device shown in FIG. 1. (A) An output waveform diagram showing a normal state (non-failure state) in which sound information is output as intended sound in the failure diagnosis unit according to the first embodiment, and (B) is an output waveform as sound information intended as sound. FIG. 9 is an output waveform diagram showing an abnormal state (failure state) that has not been performed. It is a block configuration diagram corresponding to FIG. 1 of a sound output device and a sound output system according to a second embodiment of the present invention.

[First Embodiment]
Hereinafter, a sound output device and a sound output system according to the first embodiment of the present invention will be described with reference to FIGS.

(Configuration of the sound output system 1)
As shown in FIG. 1, a sound output system 1 according to the present embodiment includes a sound output device 2, a micro control unit (MCU) 3, a clock signal oscillator (CLK) 4, and a speaker 5. Is built on. That is, the sound output device 2 is incorporated in the sound output system 1 as one device that constructs the sound output system 1.

The micro control unit 3 selects a microcomputer (CPU) mounted on the sound output device 2 (not shown) to the sound output device 2 and outputs a control CSB signal, an SCLK signal, an SDATA signal, a RESET signal, and the like. Further, the micro control unit 3 outputs digital sound information to the sound output device 2 and outputs a SAI LRCK signal, a SAI BCK signal, a SAI DIN signal and the like for outputting a sound from the speaker 5. That is, the micro control unit 3 controls the operation of the sound output device 2.
The clock signal oscillator 4 outputs an MCLK signal necessary for controlling the operation of the sound output device 2 to the sound output device 2.

  The speaker 5 is connected to the sound output device 2 as an external element, and outputs analog sound information amplified and output from the sound output device 2 as sound (voice). Here, two (or more) speakers 5 are connected to the sound output device 2, and the sound output system 1 has a stereo configuration. Note that the sound output system 1 may have a monaural configuration.

(Configuration of the sound output device 2)
The sound output device 2 shown in FIG. 1 is configured as one semiconductor integrated circuit (one chip). The sound output device 2 includes a serial audio interface (SAI) 20, mixers (MIXER) 21, 26, a volume unit (VOL) 22, a filter (FILTER) 23, a digital-to-analog converter (DAC) 24, and an amplifier. And a circuit (AMP) 27. Since the mixer 26 and the amplifier circuit 27 have a stereo configuration here, two each are provided. The sound output device 2 includes a failure diagnosis unit 6.

The serial audio interface 20 is used as an interface unit of the sound output device 2. The serial audio interface 20 acquires digital sound information (SAI DIN signal) output from the micro control unit 3.
The serial audio interface 20 is connected to a mixer 21. The mixer 21 is connected to a decoder (not shown) connected to a storage medium that stores music information and audio information. The mixer 21 performs a mixing process of the digital sound information decoded by a decoder (not shown) and the digital sound information input from the serial audio interface 20.
The mixer 21 is connected to the volume unit 22. In the volume unit 22, volume processing is performed on the digital sound information output from the mixer 21.
The volume unit 22 is connected to the filter 23. The filter 23 is a block that applies sound processing to digital sound information output from the volume unit 22.

The filter 23 is connected to a digital / analog converter 24. The digital-to-analog converter 24 converts the digital sound information output from the filter 23 into analog sound information.
The digital / analog converter 24 is connected to each of the mixer 26 and the amplifier circuit 27. The mixer 26 performs a mixing process on the analog sound information.
The analog sound information output from the mixer 26 is input to an amplifier circuit 27, where the analog sound information is amplified. The speaker 5 is connected to the amplifier circuit 27, and the analog sound information amplified by the amplifier circuit 27 is output to the speaker 5, and the speaker 5 outputs a sound based on the analog sound information.

(Specific configuration of failure diagnosis unit 6)
As shown in FIG. 1, in the failure diagnosis unit 6, digital sound information output from the mixer 21 and analog sound information output from the amplifier circuit 27 are input. Based on the input sound information, the failure diagnosis unit 6 determines whether or not it is in a “failure state”, and outputs a “failure (ES) signal when in the failure state. Output to the control unit 3.

More specifically, as shown in FIG. 2, the failure diagnosis unit 6 includes a FIFO 60, an analog-to-digital converter 61, a diagnostic filter (NOISE FILTER) 62, a subtraction unit 63, and a determination unit 64. Have been.
The analog-to-digital converter 61 obtains analog sound information amplified and output from the amplifier circuit 27 between the amplifier circuit 27 and the speaker 5, and converts the analog sound information into diagnostic digital sound information.
The FIFO 60 is used as a memory unit, inputs digital sound information output from the mixer 21, and appropriately outputs digital sound information in the order of input. The FIFO 60 is configured to match the phase of the digital sound information output from the mixer 21 with the phase of the diagnostic digital sound information output from the analog-to-digital converter 61. In other words, the FIFO 60 is configured to eliminate the phase difference between the digital sound information and the diagnostic digital sound information.

  The analog-to-digital converter 61 is connected to a diagnostic filter 62. The diagnostic filter 62 removes noise from the diagnostic digital sound information output from the analog-to-digital converter 61. The diagnostic filter 62 may be provided between the amplifier circuit 27 and the analog-to-digital converter 61 to remove noise of analog sound information output from the amplifier circuit 27.

The diagnostic filter 62 is connected to the subtraction unit 63, and the FIFO 60 is similarly connected to the subtraction unit 63. The subtraction unit 63 compares the digital sound information with the diagnostic digital sound information to calculate a difference value.
The subtraction unit 63 is connected to the determination unit 64. A “threshold value” for determining whether or not a “failure state” is input to the determination unit 64. This threshold value is acquired from, for example, the micro control unit 3, and the user can appropriately adjust the threshold value. The determination unit 64 counts the number of times the difference value exceeds the threshold value within a predetermined sampling time. The determination unit 64 determines that a "failure state" has occurred when the predetermined number of times has been counted.
Here, the “threshold value” is set, for example, in an amplitude range of ± 20% to ± 30% with respect to the amplitude of the digital sound information. When the amplitude exceeds the set amplitude range, it exceeds the threshold.
Also, the number of times that the difference value exceeds the threshold value is the number of times that the difference value continuously exceeds the threshold value because the analog sound information includes a noise component and is erroneously detected when reacting to an instantaneous pulse. Used in a meaning. The number of times exceeding the threshold value is counted, and it is determined whether or not it is in a “failure state”.
Here, for example, when the threshold value is continuously exceeded 10 times or more, it is determined that the state is the “failure state”. The comparison between the digital sound information and the digital sound information for diagnosis is performed at intervals of a sampling frequency or more.

The determination unit 64 is connected to the micro control unit 3 as shown in FIGS. When the determination unit 64 determines that the state is “failure state”, the determination unit 64 outputs an ES signal indicating “failure state” to the microcontroller 3. When the microcontroller unit 3 receives the ES signal, it notifies the user of the "failure state".
For example, in the sound output system 1 mounted on an automobile, a “failure state” is displayed on an operation panel by an LED or the like. Further, the sound output system 1 may output a sound indicating that the state is “failure state”.

(Operation and effect of the present embodiment)
As shown in FIG. 1, the sound output device 2 according to the present embodiment includes a serial audio interface 20, a digital-to-analog converter 24, an amplifier circuit 27, and a failure diagnosis unit 6. The serial audio interface 20 acquires digital sound information. The digital-to-analog converter 24 converts digital sound information output from the serial audio interface 20 into analog sound information. The amplification circuit 27 amplifies analog sound information output from the digital-to-analog converter 24.

  Here, the sound output device 2 includes a failure diagnosis unit 6. The failure diagnosis unit 6 converts the analog sound information output from the amplifier circuit 27 into digital sound information for diagnosis, compares the digital sound information for diagnosis with the digital sound information to calculate a difference value, and calculates the difference value in advance. When the threshold value is exceeded, an ES signal in a “failure state” is output.

FIG. 3A shows an output waveform obtained by comparing the digital sound information output from the mixer 21 and the digital sound information for diagnosis obtained by converting the analog sound information output from the amplifier circuit 27 in the failure diagnosis unit 6. It is shown. The vertical axis is amplitude, and the horizontal axis is time.
In the output waveform shown in FIG. 3A, the digital sound information matches the diagnostic digital sound information within a range not exceeding a threshold set for the digital sound information. Although there is a pulse-like waveform exceeding the threshold value in the digital sound information for diagnosis, the analog sound information in the intended state with high quality for the digital sound information is output, so that it is in a normal state (non-failure state). If there is, the failure diagnosis unit 6 determines. Therefore, the failure diagnosis unit 6 does not output the ES signal.

  On the other hand, in the output waveform shown in FIG. 3B, the digital sound information for diagnosis exceeds the set threshold value with respect to the digital sound information. This output waveform is an example expressing the case where the volume unit 22 has failed. PCM (Plus Code Modulation) input to the volume unit 22 is represented by two's complement. If the most significant bit (bit) is fixed to 0 due to a circuit failure inside the volume unit 22, the output from the volume unit 22 will not be the expected value. The data output from the volume unit 22 is used as digital sound information for diagnosis. If the comparison between the digital sound information and the digital sound information for diagnosis is performed for each sampling frequency, the difference value clearly exceeds the threshold value more than 10 times, so that the abnormal state (failure state) The failure diagnosis unit 6 determines. As a result, the failure diagnosis unit 6 outputs an ES signal.

  Accordingly, in the failure diagnosis unit 6, the analog sound information output from the amplifier circuit 27 is converted into digital sound information for diagnosis, and the digital sound information for diagnosis is converted into the digital sound information before conversion into the analog sound information. Be compared. For this reason, the sound output device 2 can easily diagnose whether or not a high-quality intended sound is output.

Further, the sound output device 2 according to the present embodiment includes a FIFO 60 as a memory unit, as shown in FIG. The FIFO 60 receives the digital sound information, and outputs the digital sound information in accordance with the phase of the diagnostic digital sound information.
For this reason, it is possible to eliminate the phase difference between the digital sound information and the diagnostic digital sound information and improve the accuracy of diagnosis as to whether or not the intended sound is output.

Further, in the sound output device 2 according to the present embodiment, as shown in FIG. 2, the failure diagnosis unit 6 includes an analog-to-digital converter 61, a subtraction unit 63, and a determination unit 64. The analog-to-digital converter 61 converts analog sound information output from the amplifier circuit 27 into digital sound information for diagnosis. The subtraction unit 63 calculates a difference value by comparing the digital sound information for diagnosis output from the analog-to-digital converter 61 with the digital sound information output from the mixer 21. The determination unit 64 acquires a “threshold” for determining a “failure state”, and determines whether or not the “failure state” is present based on the threshold. That is, when the difference value exceeds the threshold value, the determination unit 64 outputs an ES signal in a “failure state”.
Therefore, the failure diagnosis unit 6 including the analog-to-digital converter 61, the subtraction unit 63, and the determination unit 64 can be easily constructed, and the failure diagnosis can be performed.

Further, in the sound output device 2 according to the present embodiment, the failure diagnosis unit 6 includes a diagnosis filter 62 as shown in FIG. The diagnostic filter 62 removes noise from the digital sound information for diagnosis.
For this reason, the noise of the digital sound information for diagnosis is removed, so that the accuracy of diagnosis as to whether or not the intended sound is output can be improved.

  Furthermore, the sound output device 2 according to the present embodiment includes a volume unit 22 and a filter 23 between the serial audio interface 20 and the digital-to-analog converter 24. The volume unit 22 performs volume processing of digital sound information. The filter 23 removes noise of digital sound information. The sound output device 2 can be constructed including the volume unit 22 and the filter 23.

In the sound output device 2 according to the present embodiment, as shown in FIGS. 1 and 2, digital sound information compared in the failure diagnosis unit 6 is digital sound information input to the volume unit 22. .
Therefore, the failure diagnosis unit 6 diagnoses whether or not an intended sound is output based on the digital sound information immediately after output from the serial audio interface 20, so that the diagnosis accuracy can be improved. .
Here, when the failure diagnosis unit 6 makes a diagnosis of “failure state”, it can be determined that the circuit after the volume unit 22 has a cause of failure.

Further, the sound output system 1 according to the present embodiment is constructed mainly by the sound output device 2 and the micro control unit 3, as shown in FIG. The micro control unit 3 outputs digital sound information to the serial audio interface 20 of the sound output device 2 and inputs an ES signal output from the failure diagnosis unit 6 of the sound output device 2.
For this reason, since the sound output device 2 can be developed and manufactured independently of the microcontroller 3, the sound output device 2 can be optimized and downsized.

  The sound output system 1 according to the present embodiment includes a speaker 5, as shown in FIG. The speaker 5 is connected to the amplifier circuit 27 of the sound output device 2, and outputs a sound based on analog sound information. Therefore, by simply connecting the speaker 5 to the amplifier circuit 27 of the sound output device 2, the sound output system 1 can be easily constructed.

[Second embodiment]
Next, a sound output device 2 and a sound output system 1 according to a second embodiment of the present invention will be described with reference to FIG. In this embodiment, the same reference numerals are given to the same or substantially the same components as those of the sound output device 2 and the sound output system 1 according to the above-described first embodiment. , And the description thereof will be omitted.

As shown in FIG. 4, the sound output device 2 according to the present embodiment includes a selector (SELECTOR) 7. The selector 7 receives digital sound information input from the mixer 21 to the volume unit 22, digital sound information input from the volume unit 22 to the filter 23, and digital sound information input from the filter 23 to the digital-to-analog converter 24. Is entered. The selector 7 selects any digital sound information based on the selection signal output from the micro control unit 3, and outputs the selected digital sound information to the failure diagnosis unit 6.
The failure diagnosis unit 6 diagnoses whether or not the intended sound is output based on the digital sound information selected by the selector 7.

  Except for having the selector 7, the configuration of the sound output device 2 is similar to the configuration of the sound output device 2 according to the above-described first embodiment. The configuration of the sound output system 1 is the same as the configuration of the sound output system 1 according to the first embodiment.

  According to the sound output device 2 and the sound output system 1 according to the present embodiment configured as described above, the same effects as those obtained by the sound output device 2 and the sound output system 1 according to the above-described first embodiment are obtained. The operation and effect of the present invention can be obtained.

In the sound output device 2 according to the present embodiment, a selector 7 is provided as shown in FIG. The selector 7 outputs any digital sound information input to the volume unit 22, the filter 23, and the digital-to-analog converter 24 to the failure diagnosis unit 6. Therefore, when the digital sound information selected by the selector 7 is output to the failure diagnosis unit 6, the failure circuit can be specified.
For example, when the digital sound information input to the volume unit 22 is output to the failure diagnosis unit 6, it is determined that the state is not the “failure state”. Subsequently, when the digital sound information output from the volume unit 22 is input to the failure diagnosis unit 6, it is determined that the state is "failure state". In this case, it can be specified that the volume unit 22 has a cause of failure.

[Other embodiments]
The present invention is not limited to the above embodiment, and can be variously modified without departing from the gist thereof. For example, the sound output device may include other circuits, specifically, a phase locked loop (PLL), a CPU interface, a decoder, and the like.

DESCRIPTION OF SYMBOLS 1 ... Sound output system, 2 ... Sound output device, 20 ... Serial audio interface (interface unit), 21, 26 ... Mixer, 22 ... Volume unit, 23 ... Filter, 24 ... Digital-analog converter, 27 ... Amplification circuit, 3 ... Micro control unit, 4 clock signal oscillator, 5 speaker, 6 failure diagnosis unit, 60 FIFO (memory unit), 61 analog-digital converter, 62 diagnostic filter, 63 subtraction unit, 64 determination unit, 7 ... Selector.

Claims (9)

An interface unit for acquiring digital sound information;
A digital-to-analog converter that converts digital sound information output from the interface unit into analog sound information,
An amplifier circuit for amplifying analog sound information output from the digital-to-analog converter,
The analog sound information output from the amplifier circuit is converted into digital sound information for diagnosis, the digital sound information for diagnosis is compared with the digital sound information to calculate a difference value, and the difference value is set in advance. A fault diagnostic unit that outputs a fault signal in a fault state when the threshold value is exceeded.
Sound output device provided with. The failure diagnosis unit includes:
The sound output device according to claim 1, further comprising: a memory unit that inputs the digital sound information and outputs a phase of the digital sound information in accordance with a phase of the diagnostic digital sound information. The failure diagnosis unit includes:
An analog-to-digital converter that converts the analog sound information into the diagnostic digital sound information,
A subtraction unit for calculating the difference value;
A determination unit that obtains the threshold value, and determines whether or not there is a failure state based on the threshold value;
The sound output device according to claim 1, wherein the sound output device is configured to include: The failure diagnosis unit includes:
The sound output device according to any one of claims 1 to 3, further comprising a diagnostic filter configured to remove noise of the analog sound information or the digital sound information for diagnosis. Between the interface unit and the digital-to-analog converter,
A volume unit that performs volume processing of the digital sound information;
A filter for removing noise of the digital sound information;
The sound output device according to any one of claims 1 to 4, further comprising: The digital sound information compared in the failure diagnosis unit is:
The sound output device according to claim 5, wherein the digital sound information is input to the volume unit, the digital sound information is input to the filter, or the digital sound information is input to the digital-to-analog converter. A selector unit for selecting any of the digital sound information input to the volume unit, the digital sound information input to the filter, or the digital sound information input to the digital-to-analog converter. Item 7. The sound output device according to Item 6. The sound output device according to any one of claims 1 to 7,
A microcontroller unit that outputs the digital sound information to the interface unit and that inputs the failure signal output from the failure diagnosis unit;
Sound output system. The sound output system according to claim 8, further comprising: a speaker connected to an output of the amplification circuit and outputting a sound based on analog sound information.