Audio digital-to-analog conversion circuit and electronic equipment

Abstract

The invention relates to the technical field of electronic circuits, and provides an audio digital-to-analog conversion circuit and electronic equipment. The audio digital-to-analog conversion circuit comprises a filtering unit, a modulation unit and a digital-to-analog conversion unit. The end audio data of the digital audio signal is subjected to up-sampling to obtain the target audio data, the filtering unit is utilized to perform filtering operation based on the target audio data according to the preset filtering frequency, and when the voltage amplitude of the filtered target audio data is smaller than the preset threshold value, the target audio data is subjected to filtering operation according to the preset filtering frequency. According to the embodiment of the invention, the filtering completion signal used for indicating the completion of the filtering operation on the target audio data is output, so that when digital-to-analog conversion is carried out on the new digital audio signal according to the filtering completion signal, the voltage amplitude difference between two adjacent groups of target analog signals can be reduced, explosion sound is avoided, the use experience of a user is improved, and the user experience is improved. And the application range of the audio conversion circuit is widened.

Description

Technical Field

[0001] The present application belongs to the technical field of electronic circuits, and in particular, relates to an audio digital-to-analog conversion circuit and an electronic device. Background Art

[0002] As electronic devices become more intelligent, most electronic devices have audio transceiver functions. When playing or listening to audio using an electronic device, the electronic device needs to convert the audio into digital-to-analog format through an audio conversion circuit, and then output a sound signal that can be heard by the human ear, that is, output a target analog signal.

[0003] However, in some scenarios, such as when using a headset connected to a mobile phone terminal to make a call, if the headset is suddenly disconnected from the mobile phone terminal or the call is hung up, the sound source data suddenly changes to 0, resulting in a large voltage amplitude difference between adjacent target analog signals output by the audio conversion circuit, thus generating a popping sound and affecting the user experience. It can be seen that the existing audio conversion circuit has a small scope of application. Summary of the invention

[0004] The purpose of the present application is to provide an audio digital-to-analog conversion circuit and an electronic device, aiming to solve the problem of a small application range of traditional audio digital-to-analog conversion circuits.

[0005] A first aspect of an embodiment of the present application provides an audio digital-to-analog conversion circuit, comprising:

[0006] A filtering unit is configured to, when receiving target audio data of a digital audio signal, perform a filtering operation based on the target audio data according to a preset filtering frequency until a voltage amplitude of the filtered target audio data is less than a preset threshold, and then output a filtering completion signal; wherein the target audio data is obtained by upsampling the end audio data of the digital audio signal; and the filtering completion signal is used to indicate that the filtering operation on the digital audio signal is completed;

[0007] a modulation unit, configured to modulate the filtered target audio data to obtain a digital signal to be converted;

[0008] The digital-to-analog conversion unit is configured to perform digital-to-analog conversion on the digital signal to be converted and output a target analog signal.

[0009] A second aspect of an embodiment of the present application provides an electronic device, comprising the audio digital-to-analog conversion circuit provided by the first aspect.

[0010] Compared with the prior art, the embodiments of the present invention have the following beneficial effects: the above-mentioned audio digital-to-analog conversion circuit includes: a filtering unit, a modulation unit, and an analog-to-digital conversion unit. The filtering unit is configured with a preset filtering frequency. When receiving the target audio data of the digital audio signal, the filtering unit can perform a filtering operation based on the target audio data according to the preset filtering frequency until the voltage amplitude of the filtered target audio data is less than the preset threshold value, and then output a filtering completion signal. The filtered target audio data is modulated by the modulation unit to obtain a digital signal to be converted. The digital-to-analog conversion unit then performs digital-to-analog conversion on the digital signal to be converted, and then outputs the target analog signal. In the above scheme, the tail audio data of the digital audio signal is upsampled to obtain the target audio data, and the filtering unit is used to perform a filtering operation based on the target audio data according to the preset filtering frequency, and when the voltage amplitude of the filtered target audio data is less than the preset threshold, a filtering completion signal is output to indicate that the filtering operation on the target audio data is completed. Then, when the new digital audio signal is converted into digital-to-analog according to the filtering completion signal, the voltage amplitude difference between two adjacent groups of target analog signals can be reduced, thereby avoiding the generation of explosive sounds, improving the user experience, and broadening the scope of application of the audio conversion circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 A schematic diagram of the structure of an audio digital-to-analog conversion circuit provided in an embodiment of the present application;

[0012] Figure 2 A specific structural diagram of an audio digital-to-analog conversion circuit provided in an embodiment of the present application Figure 1 ;

[0013] Figure 3 A specific structural diagram of an audio digital-to-analog conversion circuit provided in an embodiment of the present application Figure 2 ;

[0014] Figure 4 A schematic diagram of the structure of an audio digital-to-analog conversion circuit provided by another embodiment of the present application;

[0015] Figure 5 A schematic diagram of the structure of an audio digital-to-analog conversion circuit provided in yet another embodiment of the present application;

[0016] Figure 6 A schematic diagram of the structure of an audio digital-to-analog conversion circuit provided by another embodiment of the present application;

[0017] Figure 7 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0018] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0019] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0020] It should be understood that the orientation or position relationship indicated by terms such as "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0021] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0022] As electronic devices become more intelligent, most electronic devices have audio transceiver functions. When playing or listening to audio using an electronic device, the electronic device needs to convert the audio into digital-to-analog format through an audio conversion circuit, and then output a sound signal that can be heard by the human ear, that is, output a target analog signal.

[0023] However, in a scenario, such as a call using a headset (e.g., a Bluetooth headset) connected to a mobile phone terminal, if the (Bluetooth) connection between the headset and the mobile phone terminal is suddenly disconnected, or the call is hung up, there is a large voltage amplitude difference between adjacent target analog signals output by the audio conversion circuit. That is, the voltage value of the target analog signal at the previous moment is an effective value greater than 0V, and the voltage value of the target analog signal at the current moment is close to or equal to 0V, so a DC step occurs between the voltage value of the target analog signal at the previous moment and the voltage value of the target analog signal at the current moment, thereby generating a popping sound, affecting the user experience.

[0024] In another scenario, such as using a Bluetooth headset to listen to an audio file, when the first audio file is played, the last audio data of the first audio file is retained. For audio files, the voltage value of the target analog signal corresponding to the first audio data is close to or equal to 0V. Therefore, after the last audio data of the first audio file is retained, if the first audio data of the second audio file is played, there is a large voltage amplitude difference between the adjacent target analog signals output by the audio conversion circuit. That is, the voltage value of the target analog signal at the previous moment is an effective value greater than 0V, and the voltage value of the target analog signal at the current moment is close to or equal to 0V. Therefore, a DC step occurs between the voltage value of the target analog signal at the previous moment and the voltage value of the target analog signal at the current moment, thereby generating a popping sound, affecting the user experience.

[0025] As a result, the audio conversion circuit is not suitable for being configured in all electronic devices with audio conversion requirements, and has the problem of a small scope of application.

[0026] In order to solve the above technical problems, an embodiment of the present application provides an audio digital-to-analog conversion circuit, including: a filtering unit, a modulation unit, and an analog-to-digital conversion unit. The filtering unit is configured with a preset filtering frequency. When receiving the target audio data of the digital audio signal, the filtering unit can perform a filtering operation based on the target audio data according to the preset filtering frequency until the voltage amplitude of the filtered target audio data is less than a preset threshold, and then output a filtering completion signal. The filtered target audio data is modulated by the modulation unit to obtain a digital signal to be converted. The digital-to-analog conversion unit then performs digital-to-analog conversion on the digital signal to be converted, and then outputs a target analog signal. In the above scheme, the target audio data is obtained by up-sampling the end audio data of the digital audio signal, and a filtering operation is performed based on the target audio data according to the preset filtering frequency by using a filtering unit, and when the voltage amplitude of the filtered target audio data is less than a preset threshold, a filtering completion signal is output to indicate that the filtering operation on the target audio data is completed. Then, when the new digital audio signal is converted into digital-to-analog according to the filtering completion signal, the voltage amplitude difference between two adjacent groups of target analog signals can be reduced, thereby avoiding the generation of explosive sounds, improving the user experience, and broadening the scope of application of the audio conversion circuit.

[0027] See also Figure 1 , Figure 1 The following is a schematic diagram of the structure of an audio digital-to-analog conversion circuit provided in an embodiment of the present application. For ease of explanation, only the parts related to the present embodiment are shown, which are described in detail as follows:

[0028] exist Figure 2In the embodiment, the audio digital-to-analog conversion circuit 100 includes: a filtering unit 10, a modulation unit 20 and a digital-to-analog conversion unit 30. Specifically:

[0029] The filtering unit 10 is configured to perform a filtering operation based on the target audio data according to a preset filtering frequency when receiving the target audio data of the digital audio signal, until the voltage amplitude of the filtered target audio data is less than a preset threshold, and then output a filtering completion signal; wherein the target audio data is obtained by upsampling the end audio data of the digital audio signal; and the filtering completion signal is used to indicate that the filtering operation on the target audio data is completed.

[0030] The modulation unit 20 is configured to modulate the filtered target audio data to obtain a digital signal to be converted.

[0031] The digital-to-analog conversion unit 30 is configured to perform digital-to-analog conversion on the digital signal to be converted and output a target analog signal.

[0032] In this embodiment, the end audio data of the digital audio signal refers to the data of the last sampling point of the digital audio signal, which can also be understood as the last data of the digital audio signal. By upsampling the end audio data of the digital audio signal, the target audio data can be obtained.

[0033] It should be noted that when the digital audio signal is generally sampled, it can be sampled according to a set sampling frequency, which is the number of samples per second. For example, the sampling frequency is 48 kHz, that is, the number of samples of the digital audio signal per second is 48,000 audio data.

[0034] In this embodiment, in order to reduce the quantization noise, unlike general sampling of the digital audio signal, up-sampling is performed on the end audio data of the digital audio signal, and the sampling operation is performed at a higher sampling frequency. For example, the sampling frequency is 3 MHz, that is, the number of samples of the digital audio signal per second is 300,000 audio data.

[0035] Here, when the filter unit 10 receives the target audio data, it indicates that the digital audio signal has been received, and the audio digital-to-analog conversion circuit 100 can be turned off after outputting the target analog signal, or a new digital audio signal can be received for digital-to-analog conversion.

[0036] It is understandable that when filtering the audio signal, the filtering unit 10 may configure a preset filtering frequency to thereby determine to filter out the content of a certain frequency band in the audio signal.

[0037] In all embodiments of the present application, the preset filter frequency is used to indicate the audio frequency band filtered by the filter unit 10. Here, the filter frequency determines the filter duration, and the higher the frequency setting, the shorter the filter duration. Since most noises and blasts are low-frequency sounds, as an example, the preset filter frequency can be 10 Hz. In this way, audio signals in the audio range of 20 Hz to 20 kHz that can be heard by the human ear will not be filtered out by the filter unit 10.

[0038] In a specific implementation, since the filtering unit 10 performs a filtering operation based on the target audio data, which is a continuous periodic filtering operation, it is necessary to continuously provide the target audio data to the filtering unit 10. Here, when the target audio data is received, the filtering unit 10 can continuously use the target audio data as input and perform a filtering operation according to a preset filtering frequency. Alternatively, a pre-stage circuit is configured for the filtering unit 10 to save or continuously provide the target audio data to the filtering unit 10 when the target audio data is received.

[0039] In this embodiment, the voltage amplitude of the filtered target audio data refers to the voltage amplitude corresponding to the target analog signal obtained after the filtered target audio data is converted from digital to analog. Only when the voltage amplitude of the filtered target audio data is less than the preset threshold value, the filtering unit 10 outputs a filtering completion signal. Since the filtering completion signal is used to indicate that the filtering operation of the digital audio signal is completed, only after the filtering completion signal is output, the transmission and filtering operation of the new digital audio signal is allowed. That is, when the voltage amplitude of the filtered target audio data is less than the preset threshold value, if the audio data of the new digital audio signal is converted from digital to analog to output a new target analog signal, the voltage difference between the new target analog signal and the target analog signal is small, and thus no DC step phenomenon will occur, that is, no blasting sound will be generated.

[0040] The filtering unit 10 performs filtering operations based on the target audio data at a preset filtering frequency until the voltage amplitude of the filtered target audio data is less than a preset threshold value, and then outputs a filtering completion signal, thereby achieving the avoidance of a DC step phenomenon and a blasting sound by reducing the voltage difference between two adjacent groups of target analog signals corresponding to adjacent audio data before the next audio data is input.

[0041] In a specific implementation, the modulation unit 20 may include a modulator (Sigma Delta Modulator, SDM), through which the filtered target audio data is modulated to obtain a digital signal to be converted.

[0042] Exemplarily, the modulator included in the modulation unit 20 has a quantizer for performing noise shaping on the quantization noise so that the quantization noise is distributed at high frequencies while maintaining a high signal-to-noise ratio within the bandwidth of the input signal.

[0043] The digital-to-analog conversion unit 30 may specifically select an existing digital-to-analog conversion unit to perform digital-to-analog conversion on the digital signal to be converted, and then output a target analog signal.

[0044] As an embodiment, the filtering unit 10 is specifically configured to, when receiving a preset flag signal, use the received audio data as target audio data, perform filtering operations based on the target audio data according to a preset filtering frequency, and output a filtering completion signal until the voltage amplitude of the filtered target audio data is less than a preset threshold.

[0045] In this embodiment, the preset flag signal is used to indicate that the audio data content of the digital audio signal is about to be empty, that is, the digital audio signal has been transmitted. When the filter unit 10 receives the preset flag signal, it indicates that the target audio data can be filtered at this time, and the voltage amplitude of the filtered target audio data is controlled within a range less than the preset threshold, and then the filtering completion signal is output.

[0046] In specific implementation, the preset flag signal can be triggered by a hardware circuit or by software.

[0047] For example, a pre-stage cache unit may be configured for the filter unit 10 , and when the audio data content of the digital audio signal in the cache unit is about to be empty, the cache unit may send a preset flag signal to the filter unit 10 .

[0048] For another example, when the program software in the electronic device where the filter unit 10 is located detects that the audio data content of the digital audio signal is about to be empty, a preset flag signal is sent to the filter unit 10 .

[0049] Figure 2 The specific structure of an audio digital-to-analog conversion circuit provided in an embodiment of the present application is shown in FIG. Figure 1 .like Figure 2 As shown, as an embodiment, the filtering unit 10 includes: a high-pass filter 11 and a comparator 12 .

[0050] The high-pass filter 11 is configured to, when receiving a preset flag signal, use the received audio data as target audio data, perform a filtering operation based on the target audio data according to a preset filtering frequency, and output the filtered target audio data.

[0051] The comparator 12 is configured to compare the voltage amplitude of the filtered target audio data with a preset threshold value, and output a filtering completion signal when the voltage amplitude of the filtered target audio data is less than the preset threshold value.

[0052] In the present embodiment, the high-pass filter 11 is configured with a status bit receiving terminal, through which a preset flag bit signal can be received. The preset threshold value can be used to describe the expected attenuation degree of filtering the target audio data, and can also be understood as the reference voltage of the comparator 12, which can be a constant voltage greater than 0V. Here, when the preset threshold value is set smaller, the longer time is required to make the voltage amplitude of the filtered target audio data less than the preset threshold value, but the filtering effect is also better. When the preset threshold value is set larger, the shorter time is required to make the voltage amplitude of the filtered target audio data less than the preset threshold value. Based on this, in actual applications, the size of the preset threshold value can be configured according to the actual delay requirements and filtering accuracy requirements, and there is no restriction here.

[0053] In specific implementation, the high-pass filter 11 can be a finite impulse response filter, that is, a FIR filter, or an infinite impulse response filter, that is, an IIR filter. Here, the above different types of filters can be selected according to different actual audio signal digital-to-analog conversion requirements.

[0054] It should be noted that the IIR filter is a filter with a feedback path, so it is also called a recursive filter. In addition, the IIR filter has higher filtering efficiency and lower delay time, can achieve more complex filtering characteristics, and can meet the needs of higher real-time requirements. Therefore, in electronic devices with higher delay requirements, IIR filters can be used. FIR filters have higher stability and reliability, will not have stability problems and nonlinear distortion, can achieve accurate filtering characteristics and flexible filter design, and can meet signal processing requirements with higher signal phase requirements. Therefore, FIR filters can be used in electronic devices with lower delay requirements and higher precision.

[0055] Taking the high-pass filter 11 as an IIR filter as an example, when the IIR filter receives a preset flag signal, the received audio data is used as the target audio data, and the target audio data is filtered according to the preset filtering frequency. Assuming that the preset threshold is a value greater than 0V, after the first filtering cycle, the voltage amplitude of the target audio data after the first filtering output by the IIR filter is not less than the preset threshold. At this time, the target audio data after the first filtering is fed back to the IIR filter, so that the IIR filter performs a filtering operation again based on the target audio data and the target audio data after the first filtering in the second filtering cycle. By analogy, the target audio data is continuously filtered by the IIR filter so that it can gradually decay. When the comparator 12 compares the voltage amplitude of the filtered target audio data with the preset threshold, and when the voltage amplitude of the filtered target audio data is less than the preset threshold, that is, the voltage value of the target analog signal corresponding to the filtered target audio data is less than the preset threshold, and when it approaches 0V, the filtering completion signal is output. In this way, according to the filtering completion signal, a new round of analog-to-digital conversion operation can be performed, that is, filtering the new digital audio signal. Here, when the new analog signal is output after the digital-to-analog conversion of the new digital audio signal, since the voltage value of the new analog signal is 0V, compared with the voltage value of the target analog signal that is constantly approaching 0V, the voltage difference between the two is small, so no popping sound will be generated.

[0056] In some embodiments, the high-pass filter 11 may also be configured with an enable terminal for receiving an enable signal. When the high-pass filter 11 receives the enable signal, it may start to perform a high-pass filtering operation on the received audio data. In a specific implementation, the enable signal here may be provided by a constant current source or a constant voltage source, or may be provided by other functional units having a control signal output capability.

[0057] As an embodiment, the comparator 12 is specifically configured to, when receiving a preset flag signal, compare the voltage amplitude of the filtered target audio data with a preset threshold, and output a filtering completion signal when the voltage amplitude of the filtered target audio data is less than the preset threshold.

[0058] In this embodiment, the trigger condition of the comparator 12 may also be whether a preset flag signal is received.

[0059] It is understandable that, in order to save energy, the voltage amplitude of the filtered target audio data is compared with the preset threshold only when the comparator 12 receives the preset flag signal. That is, the comparator 12 starts working only when it also receives the preset flag signal.

[0060] As another embodiment, the comparator 12 is further configured to output a filtering incomplete signal when the voltage amplitude of the filtered target audio data is greater than or equal to a preset threshold.

[0061] In this embodiment, when the comparator 12 compares the voltage amplitude of the filtered target audio data with the preset threshold value, and when the voltage amplitude of the filtered target audio data is greater than or equal to the preset threshold value, it indicates that the filtering of the target audio data by the high-pass filter 11 has not reached the expected level, that is, the voltage amplitude attenuation of the filtered target audio data has not reached the expected level. Therefore, the comparator 12 outputs a filtering incomplete signal at this time, which can avoid the generation of a DC step due to a large voltage difference between two adjacent groups of target analog signals corresponding to two adjacent groups of audio data after the digital-to-analog conversion according to the new digital signal, thereby generating a plosive sound.

[0062] Figure 3 The specific structure of an audio digital-to-analog conversion circuit provided in an embodiment of the present application is shown in FIG. Figure 2 .like Figure 3 As shown, as another embodiment, the filtering unit 10 further includes: a first register 13 and a second register 14 .

[0063] The first register 13 is used to store filtering information, where the filtering information is used to indicate a preset filtering frequency. The second register 14 is used to store a filtering completion signal.

[0064] In this embodiment, the preset filter frequency is configured in the first register 13. In practical applications, multiple sets of preset filter frequencies can be configured in the first register 13, so that the high-pass filter 11 can filter the target audio data at multiple sets of preset filter frequencies.

[0065] The second register 14 is used to store a filtering completion signal. When the comparator 12 outputs the filtering completion signal, the filtering completion signal can be stored in the second register 14. By accessing the second register 14, it can be known whether the filtering operation on the digital audio signal is completed.

[0066] Figure 4 FIG. 2 shows a schematic diagram of the structure of an audio digital-to-analog conversion circuit provided by another embodiment of the present application. Figure 4 As shown, the audio digital-to-analog conversion circuit 100 further includes: an up-sampling unit 40. Specifically:

[0067] The up-sampling unit 40 is configured to up-sample the digital audio signal according to a preset sampling rate, and when receiving the end audio data of the digital audio signal, up-sample the end audio data to obtain the target audio data.

[0068] In this embodiment, in order to reduce its quantization noise, unlike the general sampling of the digital audio signal, the upsampling unit 40 upsamples the digital audio signal according to a preset sampling rate, and performs the sampling operation at a higher sampling frequency, so that the obtained target audio data is a high-precision digital signal, and the target audio data is passed to the filtering unit 10 for filtering operation.

[0069] For example, the sampling frequency is 3 MHz, which means that the number of samples of the digital audio signal per second is 300,000 audio data.

[0070] Figure 5 FIG. 2 shows a schematic diagram of the structure of an audio digital-to-analog conversion circuit provided by another embodiment of the present application. Figure 5 As shown, the audio digital-to-analog conversion circuit 100 further includes:

[0071] The buffer unit 50 is configured to buffer the received digital audio signal, and output a preset flag signal to the filter unit 10 when receiving the end audio data of the digital audio signal.

[0072] In this embodiment, when the digital audio signal is converted into digital-to-analog by the audio digital-to-analog conversion circuit 100, the digital audio signal is first read into the cache unit 50. When the cache unit 50 receives the end audio data of the digital audio signal, it can output a preset flag signal to the filter unit 10, thereby instructing the filter unit 10 to maintain the target audio data corresponding to the end audio data of the digital audio signal and perform a filtering operation.

[0073] Combination Figure 2 In some examples, the cache unit 50 may be configured with a state transmission terminal for transmitting the preset flag signal to the high-pass filter 11 and the comparator 12 in the filtering unit 10.

[0074] As an embodiment, the audio digital-to-analog conversion circuit 100 may further include a control unit (not shown in the figure). Here, the control unit may be configured to output a preset flag signal to the filter unit when the end audio data of the digital audio signal is monitored.

[0075] As an embodiment, the control unit is further configured to, upon acquiring a filtering completion signal, instruct the filtering unit 10 to perform a filtering operation upon receiving a new digital audio signal.

[0076] Figure 6 FIG. 2 shows a schematic diagram of the structure of an audio digital-to-analog conversion circuit provided by another embodiment of the present application. Figure 6 As shown, the audio digital-to-analog conversion circuit 100 further includes: an audio playing unit 60, which is used to play the target analog signal.

[0077] Exemplarily, after the digital-to-analog conversion unit 30 performs digital-to-analog conversion on the digital signal to be converted, it outputs the target analog signal, which can be output through the audio playback unit 60, and then outputs the sound information that can be heard by the human ear. Among them, the audio playback unit 60 can be a device that outputs the target analog signal, such as a speaker or earphone. That is, in a specific implementation, a suitable audio output device can be selected as the audio playback unit 60 according to the actual configuration requirements or usage scenarios, so it will not be repeated here.

[0078] Figure 7 FIG. 1 is a schematic diagram showing the structure of an electronic device provided by an embodiment of the present application. Figure 7 As shown, the electronic device 200 includes the audio digital-to-analog conversion circuit provided by any one of the embodiments of the present application.

[0079] exist Figure 7 In the electronic device 200 shown, the digital audio signal may be a digital audio signal corresponding to an audio file stored in the electronic device, or may be a digital audio signal received by the electronic device 200. Similarly, the target analog signal may also be a sound signal output by the electronic device.

[0080] It is easy to understand that in Figure 7 In the embodiment shown, due to the improvements and specific implementations related to the present application, Figures 1 to 6 The corresponding embodiments are described in detail, so they will not be described again here.

[0081] Those skilled in the art can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example. In actual applications, the above-mentioned functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units.

[0082] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. An audio digital-to-analog conversion circuit, characterized in that: include: The filtering unit is configured to, when receiving the target audio data of the digital audio signal, perform a filtering operation based on the target audio data according to a preset filtering frequency until the voltage amplitude of the filtered target audio data is less than a preset threshold, and then output a filtering completion signal; wherein the target audio data is obtained by upsampling the end audio data of the digital audio signal; and the filtering completion signal is used to indicate that the filtering operation on the target audio data is completed; a modulation unit, configured to modulate the filtered target audio data to obtain a digital signal to be converted; The digital-to-analog conversion unit is configured to perform digital-to-analog conversion on the digital signal to be converted and output a target analog signal.

2. The audio digital-to-analog conversion circuit according to claim 1, characterized in that: The filtering unit is specifically configured to, when receiving a preset flag signal, use the received audio data as the target audio data, perform a filtering operation based on the target audio data according to a preset filtering frequency, and output a filtering completion signal until the voltage amplitude of the filtered target audio data is less than a preset threshold.

3. The audio digital-to-analog conversion circuit according to claim 2, characterized in that: The filtering unit comprises: a high-pass filter and a comparator; The high-pass filter is configured to, when receiving the preset flag signal, use the received audio data as the target audio data, perform a filtering operation based on the target audio data according to a preset filtering frequency, and output the filtered target audio data; The comparator is configured to compare the voltage amplitude of the filtered target audio data with a preset threshold, and output a filtering completion signal when the voltage amplitude of the filtered target audio data is less than the preset threshold.

4. The audio digital-to-analog conversion circuit according to claim 3, characterized in that: The comparator is specifically configured to, when receiving the preset flag signal, compare the voltage amplitude of the filtered target audio data with a preset threshold, and output a filtering completion signal when the voltage amplitude of the filtered target audio data is less than the preset threshold.

5. The audio digital-to-analog conversion circuit according to claim 4, characterized in that: The comparator is further configured to output a filtering incomplete signal when the voltage amplitude of the filtered target audio data is greater than or equal to the preset threshold.

6. The audio digital-to-analog conversion circuit according to claim 4, characterized in that: The filtering unit further includes: a first register and a second register; The first register is used to store filtering information, and the filtering information is used to indicate the preset filtering frequency; The second register is used to store the filtering completion signal.

7. The audio digital-to-analog conversion circuit according to claim 2, characterized in that: Also includes: The cache unit is configured to cache the received digital audio signal and output the preset flag signal to the filter unit when receiving the end audio data of the digital audio signal.

8. The audio digital-to-analog conversion circuit according to claim 1, characterized in that: Also includes: The up-sampling unit is configured to up-sample the digital audio signal according to a preset sampling rate, and when receiving the end audio data of the digital audio signal, up-sample the end audio data to obtain the target audio data.

9. The audio digital-to-analog conversion circuit according to claim 2, characterized in that: Also includes: The control unit is configured to output the preset flag signal to the filtering unit when the end audio data of the digital audio signal is monitored.

10. The audio digital-to-analog conversion circuit according to claim 9, characterized in that: The control unit is further configured to, upon acquiring the filtering completion signal, instruct the filtering unit to perform a filtering operation when receiving a new digital audio signal.

11. The audio digital-to-analog conversion circuit according to any one of claims 1 to 10, characterized in that: Also includes: The audio playing unit is used to play the target analog signal.

12. An electronic device, characterized in that: The electronic device comprises the audio digital-to-analog conversion circuit according to any one of claims 1 to 11.

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