A broadcast sound box device and a broadcast system

Abstract

The application discloses a broadcast sound box device and a broadcast system. The broadcast sound box device comprises a main control chip, a signal limiting circuit, a front-stage operational amplifier circuit, a rear-stage power amplifier circuit and a loudspeaker. After the main control chip receives an audio signal from a server host, the audio signal is output to the signal limiting circuit. After the signal limiting circuit processes the signal, the signal is delivered to the front-stage operational amplifier circuit for preliminary amplification. Then, the signal enters the rear-stage power amplifier circuit for power amplification, and finally drives the loudspeaker to produce sound. The application can normalize and amplify input audio signals of different levels, thereby improving the stability and consistency of volume output, and helping the power amplifier work closer to its rated power to improve broadcast volume and user experience. The application can be widely applied in the technical field of broadcast sound boxes.

Description

Technical Field

[0001] This utility model relates to the field of broadcast speaker technology, and in particular to a broadcast speaker device and broadcast system. Background Technology

[0002] The public address system is the core terminal for public address systems, background music systems, and emergency voice broadcasts. It is widely used in various public places such as schools, shopping malls, and train stations. Its core function is to amplify audio signals and convert them into sound to ensure that information can clearly and fully cover the target area.

[0003] In related technologies, the performance of broadcast speakers highly depends on the matching degree between the power output capability of their built-in amplifier module and the audio input signal. However, existing broadcast speaker devices suffer from significant technical bottlenecks in practical applications: generally, they use 0dB audio signals as the maximum volume for broadcasting, often resulting in low volume that fails to meet consumer requirements. Secondly, due to the significant sensitivity differences in the audio source files themselves, such as the signal levels of different audio files potentially fluctuating drastically between -10dB and 0dB, the playback volume fluctuates wildly, affecting the user experience.

[0004] In summary, the problems existing in the relevant technologies urgently need to be solved. Utility Model Content

[0005] The purpose of this utility model is to at least partially solve one of the technical problems existing in the related technologies.

[0006] Therefore, one objective of this utility model is to provide a broadcast speaker device.

[0007] To achieve the above-mentioned technical objectives, the technical solution adopted by this utility model includes: On one hand, this utility model embodiment provides a broadcast speaker device, including: Main control chip, signal limiting circuit, pre-stage operational amplifier circuit, power amplifier circuit, and speaker; The main control chip is used to communicate with the server host and receive audio signals from the server host; the output of the main control signal is connected to the signal limiting circuit, the output of the signal limiting circuit is connected to the pre-amplifier circuit, the output of the pre-amplifier circuit is connected to the power amplifier circuit, and the output of the power amplifier circuit is played through the speaker.

[0008] In addition, a broadcast speaker device according to the above embodiments of the present invention may also have the following additional technical features: Furthermore, in one embodiment of this utility model, the main control chip is an ARM Cortex-A7.

[0009] Furthermore, in one embodiment of this utility model, the audio signal level received by the main control chip is between -12dB and 10dB.

[0010] Furthermore, in one embodiment of this utility model, the voltage of the input signal of the preamplifier circuit is less than or equal to 0.33V.

[0011] Furthermore, in one embodiment of this utility model, the signal limiting circuit includes an NJM2762 chip.

[0012] Furthermore, in one embodiment of this utility model, the preamplifier circuit includes an SGM8904 chip.

[0013] Furthermore, in one embodiment of this utility model, the power amplifier circuit includes a TPA3116 chip.

[0014] On the other hand, this utility model embodiment also provides a broadcasting system, including: a server host and a broadcast speaker device as described above; The broadcast speaker device and the server host are connected in communication.

[0015] The advantages and beneficial effects of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this invention: This application discloses a broadcast speaker device and broadcasting system, aiming to improve the problems of unstable volume and inability to fully utilize power amplifier power caused by fluctuations in audio signal levels in the prior art. The broadcast speaker device mainly includes a main control chip, a signal limiting circuit, a pre-amplifier circuit, a power amplifier circuit, and a speaker. The main control chip receives audio signals from a server host and outputs them to the signal limiting circuit. The signal limiting circuit processes the signal and then sends it to the pre-amplifier circuit for initial amplification. Subsequently, the signal enters the power amplifier circuit for power amplification, ultimately driving the speaker to produce sound. This application can regulate and amplify input audio signals of different levels, thereby improving the stability and consistency of the volume output and helping the power amplifier operate closer to its rated power, thus improving broadcast volume and user experience. Attached Figure Description

[0016] Figure 1 A schematic diagram of the structure of a broadcast speaker device provided in an embodiment of this application is shown; Figure 2A schematic diagram of the circuit principle of a signal limiting circuit and a pre-amplifier circuit provided in an embodiment of this application is shown. Figure 3 A schematic diagram of the circuit principle of a power amplifier circuit provided in an embodiment of this application is shown. Detailed Implementation

[0017] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0018] In the description of this utility model, it should be understood that the terms "length," "upper," "lower," "front," "rear," "left," "right," "top," "inner," "outer," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, features defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0019] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0020] The public address system is the core terminal for public address systems, background music systems, and emergency voice broadcasts. It is widely used in various public places such as schools, shopping malls, and train stations. Its core function is to amplify audio signals and convert them into sound to ensure that information can clearly and fully cover the target area.

[0021] In related technologies, the performance of broadcast speakers highly depends on the matching degree between the power output capability of their built-in amplifier module and the audio input signal. However, existing broadcast speaker devices suffer from significant technical bottlenecks in practical applications: generally, they use 0dB audio signals as the maximum volume for broadcasting, often resulting in low volume that fails to meet consumer requirements. Secondly, due to the significant sensitivity differences in the audio source files themselves, such as the signal levels of different audio files potentially fluctuating drastically between -10dB and 0dB, the playback volume fluctuates wildly, affecting the user experience.

[0022] In view of this, this application provides a broadcast speaker device to improve the problems of unstable volume and inability to fully utilize power amplifier power caused by fluctuations in audio signal levels in the prior art. The broadcast speaker device mainly includes a main control chip, a signal limiting circuit, a pre-amplifier circuit, a power amplifier circuit, and a speaker. The main control chip receives audio signals from the server host and outputs them to the signal limiting circuit. The signal limiting circuit processes the signal and then sends it to the pre-amplifier circuit for initial amplification. Subsequently, the signal enters the power amplifier circuit for power amplification, ultimately driving the speaker to produce sound. This application can regulate and amplify input audio signals of different levels, thereby improving the stability and consistency of the volume output and helping the power amplifier operate closer to its rated power, thus improving broadcast volume and user experience.

[0023] The following is a detailed description of a broadcast speaker device provided in the embodiments of this application, with reference to the specific accompanying drawings.

[0024] This application provides a broadcast speaker device, specifically referring to... Figure 1 The broadcast speaker device provided in this application embodiment mainly includes: Main control chip, signal limiting circuit, pre-stage operational amplifier circuit, power amplifier circuit, and speaker; The main control chip is used to communicate with the server host and receive audio signals from the server host; the output of the main control signal is connected to the signal limiting circuit, the output of the signal limiting circuit is connected to the pre-amplifier circuit, the output of the pre-amplifier circuit is connected to the power amplifier circuit, and the output of the power amplifier circuit is played through the speaker.

[0025] This application provides a broadcast speaker device, including a main control chip, a signal limiting circuit, a pre-amplifier circuit, a power amplifier circuit, and a speaker. The main control chip is responsible for communicating with the server host and receiving audio signals. Its output is sequentially connected to the signal limiting circuit, the pre-amplifier circuit, and the power amplifier circuit, ultimately driving the speaker to produce sound. In this application, the signal limiting circuit normalizes the level of the input audio signal, and after processing by the pre- and post-amplifier circuits, it can effectively suppress level fluctuations from different sound sources, avoid sudden changes in volume, and ensure that the power amplifier circuit operates close to its rated power within a safe range, thereby achieving a broadcast effect with sufficient loudness and stable consistency.

[0026] The broadcast speaker device provided in this application embodiment has a signal processing flow sequentially completed by a main control chip, a signal limiting circuit, a pre-amplifier circuit, a power amplifier circuit, and a speaker. The main control chip, as the core of the device's control and communication, is responsible for establishing a connection with a remote server host, receiving the raw digital audio signal from the host, performing necessary decoding or format conversion, and outputting an analog audio signal. This chip is the foundation of the device's intelligence, enabling remote acquisition and initial processing of audio signals. Exemplarily, in some embodiments, the main control chip may be an ARM Cortex-A7 chip.

[0027] The audio signal output by the main control chip is sent to the signal limiting circuit. This circuit is a key component for achieving volume stability in the technical solution of this application. Its core function is to dynamically regulate and limit the input signal with drastic amplitude fluctuations. In particular, it smooths and compresses or clips high-level signals that exceed the set threshold, thereby effectively preventing the subsequent amplification circuit from distorting or triggering protection due to input overload. At the same time, it ensures that low-level signals can be effectively boosted, providing a relatively stable and pure audio signal for subsequent amplification.

[0028] The clipped signal then enters the preamplifier circuit, which primarily amplifies the voltage, aiming to increase the signal's voltage amplitude rather than its output power. It amplifies the standard-level signal from the clipping circuit to a sufficient intensity to drive the subsequent power amplifier with a high enough signal-to-noise ratio and appropriate level. Its performance directly affects the clarity and noise floor of the final sound.

[0029] Exemplarily, in some embodiments, the signal limiting circuit includes an NJM2762 chip, and the preamplifier circuit includes an SGM8904 chip. Please refer to... Figure 2 , Figure 2 This paper shows a schematic diagram of a signal limiting circuit and a pre-amplifier circuit provided in an embodiment of this application. Figure 2In this circuit, the signal processing link begins with the audio signal output from the main control chip. This audio signal first enters the limiting device U3 chip NJM2762 via resistor R12 and coupling capacitor C12. The NJM2762 is a dedicated automatic gain control (AGC) and limiting amplifier, characterized by its ability to precisely set the upper limit of the output signal amplitude through an external resistor. In practical applications, the output voltage amplitude of the chip can be precisely limited to below 330 millivolts (330mV) by configuring the resistor value at pin 6 (SENCE pin) according to the chip's datasheet. This ensures that regardless of the fluctuation of the input signal (e.g., from a strong 0dB signal to a weak -10dB signal), the signal output from the NJM2762 can be normalized to a stable amplitude range that does not exceed the input tolerance of the preamplifier circuit. This improves the power amplifier overload distortion problem caused by excessively strong input signals and provides a stable basis for processing weak signals.

[0030] After being clipped, the signal, with its amplitude stabilized below 330mV, is fed into the preamplifier circuit composed of the SGM8904 operational amplifier chip (U1) via coupling capacitor C3 and resistor R4. The SGM8904 is a high-performance operational amplifier that performs voltage amplification here. The clipped signal undergoes precise linear amplification, with the gain determined by the gain value set by the external resistor network surrounding the op-amp. The amplified signal has a higher level and driving capability to meet the input signal strength requirements of the subsequent power amplifier. Finally, this regulated, amplified, and stable signal with moderate amplitude is sent to the power amplifier circuit for final power amplification to drive the speaker. The coordinated operation of the entire signal chain ensures that the broadcast speaker can provide consistent, stable, and distortion-free amplification output to audio sources of varying sensitivities, effectively increasing volume and eliminating fluctuations in sound volume.

[0031] In this embodiment, the audio signal level received by the main control chip can be between -12dB and 10dB. For example, a signal with a design sensitivity of -10dB can be output at full power. In this case, traditional devices would output more than three times the rated power when playing a 0dB signal, causing the power amplifier to overload and trigger protection. To solve this problem, this application adds a signal limiting circuit, which limits the output amplitude after the power amplifier reaches its rated power, thereby improving the overload problem and increasing the playback sensitivity.

[0032] In some embodiments, the power amplifier circuit includes a TPA3116 chip. Please refer to... Figure 3 , Figure 3 This paper shows a schematic diagram of a power amplifier circuit provided in an embodiment of this application. Figure 3In this circuit, the audio signal, amplified by the preamplifier SGM8904, enters the subsequent power amplifier circuit through coupling capacitor C36 and resistor R38. The core of this circuit is the U5 chip, a high-efficiency Class D audio power amplifier TPA3116. The signal is differentially input from pins 7 (IN+) and 6 (IN-) of the TPA3116, providing the energy basis for high-power output. Power supply filter capacitors, such as C31 and C32, are placed near the chip's power supply pins to filter out power supply noise and ensure a stable and clean operating voltage. Key components around the chip include bootstrap capacitors to increase the output swing and a resistor network to set the amplifier gain and operating mode.

[0033] The TPA3116 efficiently amplifies the input signal and outputs a high-current signal from its output pins (OUT+ and OUT-). This signal then passes through an LC low-pass filter network composed of inductors L3 and L4 and capacitors C43, C46, ​​and C47. This filter removes high-frequency switching noise generated by the Class D amplifier, restoring a clean audio signal. Finally, the filtered high-power audio signal is output through interface J1, directly driving a speaker to produce sound, thus completing the final conversion from a weak electrical signal to a loud sound. The entire design ensures efficient and stable power amplification and effectively suppresses electromagnetic interference.

[0034] In this embodiment of the application, a broadcasting system is also provided, including a server host and the aforementioned broadcasting speaker device; The broadcast speaker device and the server host are connected in communication.

[0035] This application embodiment also provides an integrated broadcasting system, which consists of a server host and the aforementioned broadcast speaker device, connected by a communication link. The server host, as the system's control and audio source center, is responsible for storing or generating audio content to be played and sending control commands and audio data streams to the broadcast speaker device. The broadcast speaker device, as the system's terminal execution unit, has its main control chip responsible for receiving commands and signals from the server host and driving its internal high-efficiency audio processing links—namely, the signal limiting circuit, preamplifier circuit, and power amplifier circuit—to operate. Through centralized management by the server host and intelligent signal regulation and amplification by the speaker terminal, this system effectively solves the problems of unstable volume, insufficient loudness, and amplifier underload caused by differences in audio source levels in traditional broadcasting, ultimately providing stable, loud, and clear sound broadcasting in various public places.

[0036] In the description of this specification, references to terms such as "one embodiment," "another embodiment," or "some embodiments," etc., indicate that a specific feature, structure, material, or characteristic described in connection with an embodiment or example is included in at least one embodiment or example of this utility model. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0037] Although embodiments of the present invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A broadcast speaker device, characterized in that, include: Main control chip, signal limiting circuit, pre-stage operational amplifier circuit, power amplifier circuit, and speaker; The main control chip is used to communicate with the server host and receive audio signals from the server host; the output of the main control chip is connected to the signal limiting circuit, the output of the signal limiting circuit is connected to the pre-amplifier circuit, the output of the pre-amplifier circuit is connected to the power amplifier circuit, and the output of the power amplifier circuit is played through the speaker.

2. The broadcast speaker device according to claim 1, characterized in that, The main control chip is an ARM Cortex-A7.

3. The broadcast speaker device according to claim 1, characterized in that, The audio signal level received by the main control chip is between -12dB and 10dB.

4. A broadcast speaker device according to claim 3, characterized in that, The input signal voltage of the preamplifier circuit is less than or equal to 0.33V.

5. A broadcast speaker device according to claim 1, characterized in that, The signal limiting circuit includes an NJM2762 chip.

6. A broadcast speaker device according to claim 1, characterized in that, The preamplifier circuit includes an SGM8904 chip.

7. A broadcast speaker device according to claim 1, characterized in that, The power amplifier circuit includes a TPA3116 chip.

8. A broadcasting system, characterized in that, include: The server host and the broadcast speaker device as described in any one of claims 1-7; The broadcast speaker device and the server host are connected in communication.

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