Circuit for reducing audio noise of baby monitor

Abstract

The utility model relates to the technical field of noise processing, in particular to a circuit for reducing audio noise of a baby monitor. Comprising a monitor camera used for obtaining audio and video data of a baby, a main control circuit board, a WIFI module, a microphone used for obtaining audio signals, an LCD display screen assembly used for outputting images and the audio signals, a loudspeaker, an audio amplification circuit and a power supply, and the main control circuit board is in communication connection with the WIFI module through an SDIO 2.0 interface. Through reasonable hardware connection and specific audio amplification circuit design, the infant monitoring system with complete functions is constructed, audio noise is reduced through design of the audio amplification circuit, noise generated by interference of communication on audio signals is reduced on the premise that the maximum communication transmitting power and the optimal audio performance are guaranteed, and the communication performance of the infant monitoring system is improved. According to the application, the structure is simple, the practicability is high, the cost is low, and the maximum transmitting power and the audio performance of communication are not influenced.

Description

Technical Field

[0001] The utility model relates to the technical field of noise processing, in particular to a circuit for reducing audio noise of a baby monitor. Background Art

[0002] In addition to the commonly used 2.4GHz Wi-Fi, baby monitors often utilize IEEE 802.11ah Wi-Fi to communicate between the surveillance camera and the display terminal, meeting the long-distance communication needs of overseas users. This Wi-Fi protocol operates in the 730MHz to 950MHz frequency band, with a transmit power of up to 25dBm and a communication range of up to 1200 meters. However, this increased communication range also increases the transmit power, which can interfere with the audio signal, causing a clicking noise from the speaker, which negatively impacts the user experience. Currently, many baby monitors reduce audio noise by reducing transmit power or sacrificing some audio performance, but these measures often result in suboptimal performance. Utility Model Content

[0003] The utility model aims to solve the defects and shortcomings of the prior art and provides a circuit for reducing audio noise of a baby monitor which has a simple structure and can reduce noise.

[0004] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is a circuit for reducing the audio noise of a baby monitor, comprising a monitor camera for obtaining audio and video data of a baby, a main control circuit board, a WIFI module, a microphone for obtaining audio signals, an LCD display assembly for outputting images and audio signals, a speaker, an audio amplifier circuit and a power supply. The main control circuit board is communicatively connected to the WIFI module via an SDIO 2.0 interface, the monitor camera is communicatively connected to the WIFI module via a wireless signal, the microphone is electrically connected to the main control circuit board, the output end of the main control circuit board is electrically connected to the input end of the audio amplifier circuit, the speaker is electrically connected to the audio amplifier circuit, the LCD display assembly is communicatively connected to the main control circuit board via a MIPI interface, and the main control circuit board is electrically connected to the power supply.

[0005] Furthermore, a control circuit is provided on the main control circuit board, and the control circuit includes a main control chip and a first resistor; one end of the first resistor is electrically connected to the LCD display assembly, and the other end is electrically connected to the eleventh pin of the main control chip, and the thirty-fourth pin and the thirty-fifth pin of the main control chip are both electrically connected to the LCD display assembly.

[0006] Further; the audio amplification circuit includes an audio power amplifier, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a fifth capacitor, a sixth capacitor, a first inductor, a second inductor, a third inductor and a speaker interface, one end of the second resistor is electrically connected to the first pin of the audio power amplifier, and the other end is electrically connected to the seventy-sixth pin of the main control chip; one end of the first capacitor is electrically connected to the second pin of the audio power amplifier, and the other end is grounded, the third resistor, the fourth resistor and the second capacitor are connected in series, one end is electrically connected to the third pin of the audio power amplifier, and the other end is electrically connected to the one hundred and sixth pin of the main control chip; one end of the third capacitor is grounded, and the other end is electrically connected to the second capacitor, the fifth resistor, the sixth inductor and the first inductor are electrically connected to the speaker interface, The resistor and the fourth capacitor are connected in series, one end of which is grounded, and the other end is electrically connected to the fourth pin of the audio power amplifier; one end of the first inductor is electrically connected to the sixth pin of the audio power amplifier, and the other end is electrically connected to the power supply; one end of the fifth capacitor is grounded, and the other end is electrically connected to the sixth pin of the audio power amplifier; one end of the sixth capacitor is electrically connected to the fifth capacitor, and the other end is electrically connected to the first inductor; one end of the second inductor is electrically connected to the second pin of the speaker interface, and the other end is electrically connected to the eighth pin of the audio power amplifier; one end of the third inductor is electrically connected to the first pin of the speaker interface, and the other end is electrically connected to the fifth pin of the audio power amplifier; the third pin and the fourth pin of the speaker interface are both grounded, and the seventh pin of the audio power amplifier is grounded.

[0007] Further; A WIFI antenna is installed on the WIFI module, and the WIFI module includes a WIFI transmitting chip, a seventh resistor, an eighth resistor, a ninth resistor, a seventh capacitor, an eighth capacitor, a ninth capacitor, a tenth capacitor, a fourth inductor, a fifth inductor and a FLASH circuit; one end of the seventh resistor is electrically connected to the thirty-eighth pin of the main control chip, and the other end is electrically connected to the twenty-second pin of the WIFI transmitting chip; one end of the eighth resistor is grounded, and the other end is electrically connected to the seventh resistor; one end of the fourth inductor is connected to the seventh pin of the WIFI transmitting chip, and the other end is electrically connected to the FLASH circuit; one end of the fifth inductor is connected to the The sixth pin of the WIFI transmitting chip, and the other end are electrically connected to the FLASH circuit, the fifth pin and the fourth pin of the WIFI transmitting chip are both electrically connected to the FLASH circuit, one end of the seventh capacitor is grounded, and the other end is electrically connected to the fourth inductor; one end of the eighth capacitor is grounded, and the other end is electrically connected to the fifth inductor; one end of the ninth resistor is electrically connected to the WIFI antenna, and the other end is electrically connected to the second pin of the WIFI transmitting chip; one end of the ninth capacitor is grounded, and the other end is electrically connected to the second pin of the WIFI transmitting chip; one end of the tenth capacitor is grounded, and the other end is electrically connected to the second pin of the WIFI transmitting chip.

[0008] Furthermore, the model of the main control chip is AK3760E.

[0009] Furthermore, the circuit for reducing audio noise of the baby monitor further includes a NOR Flash memory, and the NOR Flash memory is electrically connected to the main control chip via an SPI interface.

[0010] Furthermore, the circuit for reducing audio noise of the baby monitor also includes an SD card device, and the SD card device is electrically connected to the main control chip via an SDIO 2.0 interface.

[0011] Furthermore, the circuit for reducing audio noise of the baby monitor also includes an RGB status indicator light, and the RGB status indicator light is electrically connected to the main control chip through an IO interface.

[0012] Beneficial effects of the utility model:

[0013] The utility model provides a circuit for reducing audio noise of a baby monitor through reasonable hardware connection and specific audio amplifier circuit design, aiming to build a fully functional baby monitoring system, and reducing audio noise by designing an audio amplifier circuit. Under the premise of ensuring maximum communication transmission power and optimal audio performance, the noise generated by communication interference with the audio signal is reduced, thereby improving user experience. The application is not only simple in structure, highly practical, and low in cost, but also does not affect the maximum communication transmission power and audio performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a module diagram of a circuit for reducing audio noise in a baby monitor according to the present invention;

[0015] Figure 2 This is a circuit schematic diagram of a control circuit U1A in a circuit for reducing audio noise of a baby monitor according to the present invention;

[0016] Figure 3 This is a circuit schematic diagram of a main control circuit U1B in a circuit for reducing audio noise of a baby monitor according to the present invention;

[0017] Figure 4 This is a circuit schematic diagram of a main control circuit U1C in a circuit for reducing audio noise of a baby monitor according to the present invention;

[0018] Figure 5 This is a circuit schematic diagram of an audio amplifier circuit in a circuit for reducing audio noise in a baby monitor according to the present invention;

[0019] Figure 6 This is a circuit schematic diagram of a WIFI module in a circuit for reducing audio noise in a baby monitor according to the present invention;

[0020] Figure 7 This is a circuit schematic diagram of a FLASH circuit in a circuit for reducing audio noise in a baby monitor according to the present invention;

[0021] Figure 8 This is a circuit schematic diagram of an RGB status indicator light in a circuit for reducing audio noise in a baby monitor according to the present invention;

[0022] Figure 9 The utility model is a circuit schematic diagram of a microphone in a circuit for reducing audio noise of a baby monitor. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0024] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0025] In addition, the descriptions of "first," "second," etc. in this utility model are for descriptive purposes only and should not be understood as indicating or implying their relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between the various embodiments can be combined with each other, but this must be based on the fact that they can be implemented by ordinary technicians in this field. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this utility model.

[0026] The utility model provides a circuit for reducing audio noise of a baby monitor.

[0027] In the embodiment of the present utility model, Figure 1-9 As shown, a circuit for reducing audio noise of a baby monitor includes a monitor camera for obtaining audio and video data of a baby, a main control circuit board, a WIFI module, a microphone for obtaining audio signals, an LCD display assembly for outputting images and audio signals, a speaker, an audio amplification circuit and a power supply. The main control circuit board is communicatively connected to the WIFI module via an SDIO 2.0 interface, the monitor camera is communicatively connected to the WIFI module via a wireless signal, the microphone is electrically connected to the main control circuit board, the output end of the main control circuit board is electrically connected to the input end of the audio amplification circuit, the speaker is electrically connected to the audio amplification circuit, the LCD display assembly is communicatively connected to the main control circuit board via a MIPI interface, and the main control circuit board is electrically connected to the power supply.

[0028] This baby monitor utilizes rational hardware connections and an efficient communication protocol to capture, process, transmit, and display audio and video data. The design incorporates coordinated interoperability between components, ensuring system stability and reliability. This allows users to obtain clear audio and video information, enabling better monitoring of their infants.

[0029] In this embodiment, a control circuit is provided on the main control circuit board, and the control circuit includes a main control chip and a first resistor; one end of the first resistor is electrically connected to the LCD display screen assembly, and the other end is electrically connected to the eleventh pin of the main control chip, and the thirty-fourth pin and the thirty-fifth pin of the main control chip are both electrically connected to the LCD display screen assembly.

[0030] In this embodiment, the audio amplifier circuit includes an audio power amplifier, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a fifth capacitor, a sixth capacitor, a first inductor, a second inductor, a third inductor and a speaker interface, one end of the second resistor is electrically connected to the first pin of the audio power amplifier, and the other end is electrically connected to the seventy-sixth pin of the main control chip; one end of the first capacitor is electrically connected to the second pin of the audio power amplifier, and the other end is grounded; the third resistor, the fourth resistor and the second capacitor are connected in series, one end is electrically connected to the third pin of the audio power amplifier, and the other end is electrically connected to the one hundred and sixth pin of the main control chip; one end of the third capacitor is grounded, and the other end is electrically connected to the second capacitor; Six resistors and the fourth capacitor are connected in series, one end of which is grounded, and the other end is electrically connected to the fourth pin of the audio power amplifier; one end of the first inductor is electrically connected to the sixth pin of the audio power amplifier, and the other end is electrically connected to the power supply; one end of the fifth capacitor is grounded, and the other end is electrically connected to the sixth pin of the audio power amplifier; one end of the sixth capacitor is electrically connected to the fifth capacitor, and the other end is electrically connected to the first inductor; one end of the second inductor is electrically connected to the second pin of the speaker interface, and the other end is electrically connected to the eighth pin of the audio power amplifier; one end of the third inductor is electrically connected to the first pin of the speaker interface, and the other end is electrically connected to the fifth pin of the audio power amplifier; the third pin and the fourth pin of the speaker interface are both grounded, and the seventh pin of the audio power amplifier is grounded.

[0031] In this embodiment, a WIFI antenna is installed on the WIFI module, and the WIFI module includes a WIFI transmitting chip, a seventh resistor, an eighth resistor, a ninth resistor, a seventh capacitor, an eighth capacitor, a ninth capacitor, a tenth capacitor, a fourth inductor, a fifth inductor and a FLASH circuit; one end of the seventh resistor is electrically connected to the thirty-eighth pin of the main control chip, and the other end is electrically connected to the twenty-second pin of the WIFI transmitting chip; one end of the eighth resistor is grounded, and the other end is electrically connected to the seventh resistor; one end of the fourth inductor is connected to the seventh pin of the WIFI transmitting chip, and the other end is electrically connected to the FLASH circuit; one end of the fifth inductor is connected to the The sixth pin of the WIFI transmitting chip, the other end is electrically connected to the FLASH circuit, the fifth pin and the fourth pin of the WIFI transmitting chip are both electrically connected to the FLASH circuit, one end of the seventh capacitor is grounded, and the other end is electrically connected to the fourth inductor; one end of the eighth capacitor is grounded, and the other end is electrically connected to the fifth inductor, one end of the ninth resistor is electrically connected to the WIFI antenna, and the other end is electrically connected to the second pin of the WIFI transmitting chip, one end of the ninth capacitor is grounded, and the other end is electrically connected to the second pin of the WIFI transmitting chip; one end of the tenth capacitor is grounded, and the other end is electrically connected to the second pin of the WIFI transmitting chip.

[0032] In this embodiment, the model of the main control chip is AK3760E.

[0033] In this embodiment, the circuit for reducing audio noise of a baby monitor further includes a NOR Flash memory, and the NOR Flash memory is electrically connected to the main control chip via an SPI interface.

[0034] In this embodiment, the circuit for reducing audio noise of a baby monitor further includes an SD card device, and the SD card device is electrically connected to the main control chip via an SDIO 2.0 interface.

[0035] In this embodiment, the circuit for reducing audio noise of the baby monitor further includes an RGB status indicator light, and the RGB status indicator light is electrically connected to the main control chip via an IO interface.

[0036] Specifically, the main control chip adopts the AK3760E model, and its crystal oscillator is 24MHz. The main control chip communicates with the NOR Flash memory through the SPI interface and runs the program. The main control chip controls the LCD display component with a resolution of 720x1080 to output image and audio signals through the MIPI interface. The main control chip controls the status of the RGB status indicator light through the IO interface output. It also includes a key circuit. The main control chip detects the key status of the external key circuit through the IO interface input. The main control chip reads the external SD card device through the SDIO 2.0 interface.

[0037] Among them, the microphone is used to obtain audio signals and convert the audio signals into analog signals and then input them into the main control chip for processing. The main control chip outputs the processed audio signals to the audio power amplifier. The audio signals are amplified by the audio power amplifier and then output through the speaker.

[0038] Specifically, the Wi-Fi transmitter chip uses the IEEE 802.11ah standard. The Wi-Fi module communicates with the monitor camera via wireless signals, capturing the baby's audio and video data and transmitting it to the main control chip via the SDIO 2.0 interface. The monitor contains a 2800mAh lithium battery, which is charged via USB power input to the charging IC. The back-end DCDC then converts the battery voltage into various system voltages to power the system.

[0039] U2 is a Class D audio power amplifier, which is NS4150, where SPK is the speaker interface, the first inductor L116 is a power filter bead, the second inductor L5 and the third inductor L6 are amplifier output filter beads, the sixth capacitor C598 and the fifth capacitor C597 are amplifier power filter capacitors, the first capacitor C599 is the common-mode voltage bypass capacitor inside the amplifier, the second capacitor C600 and the fourth capacitor C601 are audio signal DC blocking capacitors, the fourth resistor R8 and the sixth resistor R10 are audio signal input resistors, the third resistor R7 and the third capacitor C13 form a low-pass filter circuit for the audio signal, and the fifth resistor R9 is the impedance matching resistor for the reverse audio input pin of the amplifier.

[0040] Among them, the purpose of the first inductor L116, the sixth capacitor C598 and the fifth capacitor C597 is to improve the stability of the power supply and reduce the power supply voltage drop caused by the communication signal transmission. The second inductor L5 and the third inductor L6 improve the anti-interference ability of the speaker wiring. The second capacitor C599 reduces the noise introduced by the common mode voltage inside the power amplifier, which is beneficial to improve the stability of the power amplifier. The third resistor R7 and the third capacitor C13 form an RC low-pass filter circuit for the audio signal input to the power amplifier. The cutoff frequency calculation formula of the RC low-pass filter is Where R = 1kΩ, C = 15nF, π is 3.14, and f is calculatedc =10616Hz, where R=1kΩ, C=15nF, take 3.14, and calculate Hz. Since the audio response range of commonly used baby monitors is 100~4000Hz, the RC low-pass filter will attenuate the high-frequency noise generated by the communication signal transmission without having a significant impact on the actual audio signal. The resistance value of the fifth resistor R9 is the same as that of the third resistor R7, and the purpose is to ensure that the impedance of the forward and reverse inputs of the power amplifier is consistent. Among them, the second capacitor C600, the fourth capacitor C601, the fourth resistor R8, and the sixth resistor R10 form a high-pass filter, and the cut-off frequency calculation formula is Where R = 30kΩ, C = 100nF, and 3.14 is taken, which is calculated to be 53Hz. Therefore, the RC high-pass filter can attenuate the low-frequency noise generated by the communication switch without having a significant impact on the actual audio signal.

[0041] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made by using the contents of the present invention specification and drawings under the utility model concept, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A circuit for reducing audio noise in a baby monitor, characterized in that The invention comprises a monitoring camera for acquiring audio and video data of an infant, a main control circuit board, a WIFI module, a microphone for acquiring audio signals, an LCD display assembly for outputting images and audio signals, a speaker, an audio amplifying circuit and a power supply. The main control circuit board is communicatively connected to the WIFI module via an SDIO 2.0 interface, the monitoring camera is communicatively connected to the WIFI module via a wireless signal, the microphone is electrically connected to the main control circuit board, the output end of the main control circuit board is electrically connected to the input end of the audio amplifying circuit, the speaker is electrically connected to the audio amplifying circuit, the LCD display assembly is communicatively connected to the main control circuit board via a MIPI interface, and the main control circuit board is electrically connected to the power supply.

2. The circuit for reducing audio noise of a baby monitor according to claim 1, wherein A control circuit is provided on the main control circuit board, and the control circuit includes a main control chip and a first resistor; one end of the first resistor is electrically connected to the LCD display screen assembly, and the other end is electrically connected to the eleventh pin of the main control chip, and the thirty-fourth pin and the thirty-fifth pin of the main control chip are both electrically connected to the LCD display screen assembly.

3. The circuit for reducing audio noise of a baby monitor according to claim 2, wherein: The audio amplification circuit includes an audio power amplifier, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a fifth capacitor, a sixth capacitor, a first inductor, a second inductor, a third inductor and a speaker interface, one end of the second resistor is electrically connected to the first pin of the audio power amplifier, and the other end is electrically connected to the seventy-sixth pin of the main control chip; one end of the first capacitor is electrically connected to the second pin of the audio power amplifier, and the other end is grounded; the third resistor, the fourth resistor and the second capacitor are connected in series, one end is electrically connected to the third pin of the audio power amplifier, and the other end is electrically connected to the one hundred and sixth pin of the main control chip; one end of the third capacitor is grounded, and the other end is electrically connected to the second capacitor; the fifth resistor, the sixth resistor The three are connected in series with the fourth capacitor, one end of which is grounded, and the other end is electrically connected to the fourth pin of the audio power amplifier; one end of the first inductor is electrically connected to the sixth pin of the audio power amplifier, and the other end is electrically connected to the power supply; one end of the fifth capacitor is grounded, and the other end is electrically connected to the sixth pin of the audio power amplifier; one end of the sixth capacitor is electrically connected to the fifth capacitor, and the other end is electrically connected to the first inductor; one end of the second inductor is electrically connected to the second pin of the speaker interface, and the other end is electrically connected to the eighth pin of the audio power amplifier; one end of the third inductor is electrically connected to the first pin of the speaker interface, and the other end is electrically connected to the fifth pin of the audio power amplifier; the third pin and the fourth pin of the speaker interface are both grounded, and the seventh pin of the audio power amplifier is grounded.

4. The circuit for reducing audio noise of a baby monitor according to claim 3, wherein: The WIFI module is equipped with a WIFI antenna, and includes a WIFI transmitting chip, a seventh resistor, an eighth resistor, a ninth resistor, a seventh capacitor, an eighth capacitor, a ninth capacitor, a tenth capacitor, a fourth inductor, a fifth inductor and a FLASH circuit; one end of the seventh resistor is electrically connected to the thirty-eighth pin of the main control chip, and the other end is electrically connected to the twenty-second pin of the WIFI transmitting chip; one end of the eighth resistor is grounded, and the other end is electrically connected to the seventh resistor; one end of the fourth inductor is connected to the seventh pin of the WIFI transmitting chip, and the other end is electrically connected to the FLASH circuit; one end of the fifth inductor is connected to the WIFI The sixth pin of the I transmitting chip, and the other end is electrically connected to the FLASH circuit, the fifth pin and the fourth pin of the WIFI transmitting chip are both electrically connected to the FLASH circuit, one end of the seventh capacitor is grounded, and the other end is electrically connected to the fourth inductor; one end of the eighth capacitor is grounded, and the other end is electrically connected to the fifth inductor; one end of the ninth resistor is electrically connected to the WIFI antenna, and the other end is electrically connected to the second pin of the WIFI transmitting chip; one end of the ninth capacitor is grounded, and the other end is electrically connected to the second pin of the WIFI transmitting chip; one end of the tenth capacitor is grounded, and the other end is electrically connected to the second pin of the WIFI transmitting chip.

5. The circuit for reducing audio noise of a baby monitor according to claim 4, wherein: The model of the main control chip is AK3760E.

6. The circuit for reducing audio noise of a baby monitor according to claim 5, wherein: The circuit for reducing audio noise of a baby monitor further includes a NOR Flash memory, and the NOR Flash memory is electrically connected to the main control chip via an SPI interface.

7. The circuit for reducing audio noise of a baby monitor according to claim 6, wherein: The circuit for reducing audio noise of a baby monitor further includes an SD card device, and the SD card device is electrically connected to the main control chip via an SDIO 2.0 interface.

8. The circuit for reducing audio noise of a baby monitor according to claim 7, wherein: The circuit for reducing audio noise of a baby monitor further includes an RGB status indicator light, which is electrically connected to the main control chip via an IO interface.

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