High-reliability emergency broadcast terminal

Abstract

The utility model belongs to the technical field of emergency broadcast, and particularly relates to a high-reliability emergency broadcast terminal, which comprises a shell and a circuit board, the circuit board is fixed inside the shell, and the circuit board is provided with a power supply module, a DTMB (Digital Terrestrial Multimedia Broadcasting) receiving module, an FM (Frequency Modulation) receiving module, a main control module, a 4G network module, a wired network module, a power amplifier module, a loudspeaker and a temperature control module; a heating film is arranged at the bottom of the circuit board; the temperature control module is used for controlling the heating temperature of the heating film according to the environment temperature in the shell. According to the utility model, networking can be carried out through 4G or a wired network, and unified management of the emergency broadcast platform on high-reliability terminals is realized. And the functions of emergency broadcasting such as frequency modulation broadcasting, DTMB broadcasting and the like are set, so that the coverage of broadcasting audio broadcasting is improved. The temperature control module is additionally arranged in the device, a temperature control mechanism can be triggered when the temperature is low, the internal temperature of the device is controlled within the temperature range suitable for operation, the device can be normally started when the temperature is minus 40 DEG C, and the reliability of the device is improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of emergency broadcasting, and particularly relates to a highly reliable emergency broadcasting terminal. Background Art

[0002] Currently, the public has an increasingly high demand for obtaining emergency information comprehensively, accurately and in a timely manner. The public service demand of governments at all levels for releasing emergency and rescue information to the public is becoming more and more urgent. How to quickly and effectively deliver various types of emergency information to thousands of households has become an urgent problem to be solved at present. In order to minimize disaster losses, it is necessary to establish an emergency broadcasting system, and it is extremely important and urgent to release disaster warning and forecast information in a timely and effective manner. Emergency broadcasting can facilitate the government to issue administrative orders in a timely manner, dispel doubts, reduce losses caused by accidents and crises, and better maintain social stability.

[0003] However, the existing emergency broadcasting terminals have the problem of low reliability. For example, in some frigid regions, when the outdoor temperature is below -20°C, conventional consumer-grade design products cannot perform cold start, and the equipment cannot operate normally. Summary of the Utility Model

[0004] In order to solve the technical problems existing in the prior art, the purpose of the utility model is to provide a highly reliable emergency broadcasting terminal. The specific technical solutions are as follows:

[0005] A highly reliable emergency broadcasting terminal, including a housing and a circuit board. The circuit board is fixed inside the housing. The circuit board is provided with a power supply module, a DTMB receiving module, an FM frequency modulation receiving module, a main control module, a 4G network module, a wired network module, a power amplifier module, and a speaker.

[0006] The power supply module, the DTMB receiving module, the FM frequency modulation receiving module, the 4G network module, the wired network module, and the power amplifier module are respectively connected to the main control module; the speaker is connected to the power amplifier module; the main control module is used to amplify the audio signal received through the DTMB receiving module or the FM frequency modulation receiving module or the 4G network module or the wired network module through the power amplifier module and input it into the speaker for output.

[0007] The circuit board is also provided with a temperature control module, and a heating film is arranged at the bottom of the circuit board; the temperature control module is used to control the heating temperature of the heating film according to the ambient temperature inside the housing.

[0008] Preferably, the temperature control module includes a temperature sensor, a temperature control unit, and a PWM heating control unit; the temperature sensor and the PWM heating control unit are respectively connected to the temperature control unit, and the PWM heating control unit is connected to the heating film; the temperature sensor is used to collect the ambient temperature inside the housing and transmit the collected temperature to the temperature control unit, and the temperature control unit is used to control the working state of the PWM heating control unit according to the ambient temperature inside the housing to adjust the power supply voltage applied by the PWM heating control unit to the heating film.

[0009] Preferably, the power supply module includes a switching power supply, a solar power supply, a lithium battery, and a power selection unit;

[0010] The switching power supply is connected to the mains power supply through a power filter;

[0011] The lithium battery, the switching power supply, the solar power supply, and the main control module are respectively connected to the power selection unit; the power selection unit is used to select one of the lithium battery, the switching power supply, and the solar power supply to supply power to the main control module.

[0012] Preferably, the power supply module further includes a voltage conversion unit, and the voltage conversion unit is respectively connected to the power selection unit and the main control module;

[0013] The voltage conversion unit is used to convert the power supply voltage output by the lithium battery / switching power supply / solar power supply into a suitable working voltage for the main control module.

[0014] Preferably, the power supply module further includes a lithium battery charging control circuit and a lithium battery control circuit;

[0015] The lithium battery charging control circuit is respectively connected to the switching power supply, the solar power supply, and the lithium battery, and the lithium battery control circuit is connected to the lithium battery;

[0016] The lithium battery charging control circuit is used to supply power to the lithium battery from the power supply output by the switching power supply or the solar power supply, and the lithium battery control circuit is used to control whether the lithium battery is enabled to supply power.

[0017] Preferably, the DTMB receiving module includes two Tuner tuners and can simultaneously receive DTMB signal sources on two different channels.

[0018] Preferably, the FM frequency modulation receiving module includes two FM frequency modulation receiving units and can simultaneously receive signal sources in two FM frequency bands.

[0019] Preferably, the emergency broadcast terminal further includes an AM amplitude modulation receiving module, which is connected to the main control module. The main control module is also used to amplify the audio signal received through the AM amplitude modulation receiving module by the power amplifier module and then input it into the speaker for output.

[0020] Compared with the existing technologies, the utility model has the following beneficial effects:

[0021] 1. The previous emergency broadcast terminals could only broadcast locally, could not be connected to the network, and could not be uniformly managed through a platform, with weak security. In particular, the systems mainly based on FM radio technology had serious security hazards and management loopholes. The utility model is provided with a 4G network module and a wired network module, which can be connected to the network through 4G or wired network to realize the unified management of high-reliability terminals by the emergency broadcast platform. And it is provided with functions such as FM radio and DTMB broadcast for emergency broadcasts. When the 4G and wired networks are not available, it can still receive the emergency broadcast messages sent by the FM radio transmitting station and the DTMB transmitting station, improving the coverage of the broadcast audio and the reliability of the equipment.

[0022] 2. The utility model internally adds a temperature control module, which will trigger the temperature control mechanism at low temperatures to control the internal temperature of the equipment within the suitable operating temperature range. The equipment can also be normally started at -40°C, improving the reliability of the equipment.

[0023] 3. The utility model adopts a multi-channel power supply scheme, including mains power supply, solar power supply system power supply, and built-in lithium battery power supply. The three-way power supply can achieve power supply complementarity, greatly improving the reliability of the emergency broadcast terminal for outdoor work. When there are sudden unstable factors in the external power supply, there is a backup power supply of the built-in lithium battery for supplement; when both the mains power supply and the solar power supply exist, the mains power supply is preferentially selected for power supply, and the solar power supply maintains the battery charging or standby state. When the mains power supply does not exist, it automatically switches to the solar power supply for power supply.

[0024] 4. The DTMB receiving module and the FM radio receiving module use a dual-tuner design, which can receive two-way broadcast messages simultaneously, improving the reliability of the equipment.

[0025] 5. The utility model is also provided with an AM amplitude modulation receiving module, which can realize the function of broadcasting emergency broadcasts through the AM broadcast channel, improving the coverage of the broadcast audio and the reliability of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for description in the embodiments. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to actual scale.

[0027] Figure 1 This is the schematic diagram of the hardware design principle of the present utility model;

[0028] Figure 2 This is the circuit schematic diagram of the power supply selection unit;

[0029] Figure 3 This is the circuit schematic diagram of the voltage conversion unit;

[0030] Figure 4 This is the schematic diagram of the lithium battery charging control circuit;

[0031] Figure 5 This is the schematic diagram of the lithium battery control circuit;

[0032] Figure 6 This is the schematic diagram of the two tuners of the DTMB receiving module;

[0033] Figure 7 This is the schematic diagram of the demodulator unit of the DTMB receiving module;

[0034] Figure 8 This is the schematic diagram of the FM receiving module;

[0035] Figure 9 This is the schematic diagram of the AM receiving module;

[0036] Figure 10 This is the schematic diagram of the 4G network module;

[0037] Figure 11 This is the schematic diagram of the wired network module;

[0038] Figure 12 This is the schematic diagram of the power amplifier module;

[0039] Figure 13 This is the working schematic diagram of the temperature control module;

[0040] Figure 14 This is the circuit schematic diagram of the temperature control module;

[0041] Figure 15 This is the application schematic diagram of the present utility model. Specific embodiments

[0042] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present utility model.

[0043] In the description of the present utility model, it should be noted that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "top part", "bottom part", "top surface", "bottom surface", "inner", "outer", "inner side", "outer side", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present utility model.

[0044] In the description of the present utility model, the meaning of "several" is one or more, the meaning of "multiple" is two or more. Understandings such as "greater than", "less than", "exceeding", etc. do not include the present number, and understandings such as "above", "below", "within", etc. include the present number. If there are descriptions of the terms "first", "second", "third", etc., they are only for the purpose of description and distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features or the sequence relationship of the indicated technical features.

[0045] In the description of the present utility model, it should be noted that unless otherwise clearly specified and defined, the terms "installed", "connected", "connected to", "set" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific situations. The following will describe the embodiments according to the overall structure of the present utility model.

[0046] As Figure 1 shown, this embodiment provides a highly reliable emergency broadcast terminal, including a housing and a circuit board. The circuit board is fixed inside the housing. A power module, a DTMB receiving module, an FM frequency modulation receiving module, a main control module, a 4G network module, a wired network module, a power amplifier module, and a speaker are arranged on the circuit board;

[0047] The power module, the DTMB receiving module, the FM frequency modulation receiving module, the 4G network module, the wired network module, and the power amplifier module are respectively connected to the main control module; the speaker is connected to the power amplifier module; the main control module is used to amplify the audio signal received through the DTMB receiving module or the FM frequency modulation receiving module or the 4G network module or the wired network module through the power amplifier module and input it to the speaker for output;

[0048] A temperature control module is also provided on the circuit board, and a heating film is provided at the bottom of the circuit board; the temperature control module is used to control the heating temperature of the heating film according to the ambient temperature inside the housing.

[0049] Among them, the main control module includes the main control chip Allwinner H3. As the main control chip of the design, the main USB, Ethernet, GPIO, IIC, TS, analog audio and other interfaces all use H3 as the control main body.

[0050] The utility model adds a temperature control module inside the housing. When the ambient temperature inside the housing is lower than the set threshold, the temperature control mechanism will be triggered to control the temperature inside the housing within a suitable operating temperature range. The device can also start normally at -40°C, improving the reliability of the device.

[0051] The power supply of the terminal in the current emergency broadcast system is single, generally only powered by the mains power. When the mains power has problems, it affects the normal use of the terminal and cannot meet the requirements of the emergency broadcast. When the power supply voltage is unstable, it cannot ensure the long-term normal operation of the terminal; therefore, as a preferred embodiment, the power supply module includes a switching power supply, a solar power supply, a lithium battery, and a power selection unit; the switching power supply is connected to the mains power supply through a power filter; the lithium battery, the switching power supply, the solar power supply, and the main control module are respectively connected to the power selection unit; the power selection unit is used to select one of the lithium battery, the switching power supply, and the solar power supply to supply power to the main control module.

[0052] Specifically, the mains power supply AC 220V voltage is connected to the power filter through a power socket. The power filter has a function of anti-common mode interference and integrates a fuse inside. The fuse blows when the device is overcurrent. The switching power supply is a 24V 2.2A switching power supply (50W), and the switching power supply converts the AC 220V AC power into DC 24V output. The solar power supply is connected using an M16 aviation plug. The solar power supply uses a 50W solar charging panel, and the lithium battery is a 12V / 20Ah lithium battery, providing DC12V power for the utility model.

[0053] Specifically, as Figure 2 shown, the power selection unit includes a terminal block J2, a terminal block J3, and Schottky diodes D9, D13, and D54.

[0054] The terminal block J2 is connected to the output end of the solar power supply, the terminal block J3 is connected to the output end of the switching power supply. The terminal block J2 is respectively connected to one end of the GDT discharge tube D57, one end of the TVS diode D10, and the anode of the Schottky diode D9. The other end of the GDT discharge tube D57 and the other end of the TVS diode D10 are respectively grounded;

[0055] The wiring terminal J3 is respectively connected to one end of the GDT discharge tube D58, one end of the TVS diode D14, and the anode of the Schottky diode D13. The other ends of the GDT discharge tube D58 and the TVS diode D14 are respectively grounded;

[0056] The cathodes of the Schottky diode D9, the Schottky diode D13, and the Schottky diode D54 serve as the output terminals of the 24V power supply voltage, and are respectively connected to the positive electrode of the polarized capacitor C113 and one end of the capacitor C114. The negative electrode of the polarized capacitor C113 and the other end of the capacitor C114 are grounded.

[0057] The solar power supply system DC 12V, the switching power supply DC 24V, and the internal lithium battery DC 12V are isolated from each other by the Schottky diode D9, the Schottky diode D13, and the Schottky diode D54. The three power supplies cannot supply power to each other, and there will be no impact between different power supply voltages. Among them, the GDT discharge tubes D57 and D58 are used for the lightning protection of the first stage of the power supply, and the TVS diodes D10 and D14 are used for the lightning protection of the second stage to release the residual voltage on the GDT discharge tube.

[0058] As a preferred embodiment, the power supply module further includes a voltage conversion unit, and the voltage conversion unit is respectively connected to the power supply selection unit and the main control module;

[0059] The voltage conversion unit is used to convert the power supply voltage output by the lithium battery / switching power supply / solar power supply into a working voltage suitable for the main control module.

[0060] As Figure 3 shown, the voltage conversion unit converts the DC24V or DC 12V power supply output by the switching power supply, the solar power supply, or the internal lithium battery into a DC 5V power supply, and then converts it into DC1.35V, DC1.2V, and DC1.2V power supplies through the first conversion circuit, the second conversion circuit, and the third conversion circuit respectively, and outputs them to the main control chip and other peripherals.

[0061] The first conversion circuit converts the input 5V voltage into DC1.35V, where DC1.35V is the DDR power supply for the main control module. The first conversion circuit includes the first power conversion chip U3, and the first power conversion chip U3 is the RY9121 chip. The first power conversion chip U3 filters the input 5V voltage through capacitors C75 and C76 and enters the power input pin of the first power conversion chip U3. The output voltage of the first power conversion chip U3 is adjusted to 1.35V by the resistance values of the feedback resistors R34 and R36. The output voltage calculation formula is Vout = 0.6 * (1 + R34 / R36), and the feedback voltage is connected to the FB pin of the first power conversion chip U3. The sensitivity and stability of the circuit can be improved by paralleling the capacitor C74. Capacitors C59, C71, and C72 are output filter capacitors, and L1 is the output inductor to stabilize the output voltage. Whether the first power conversion chip U3 works can be controlled through the control pin PWR-DRAM.

[0062] One of the DC1.2V is the system power supply for the main control chip. The second conversion circuit converts the input 5V voltage into DC1.2V, which specifically includes the second power conversion chip U4. The second power conversion chip U4 is the RY9121 chip. The second power conversion chip U4 filters the input 5V voltage through capacitors C86 and C152 and enters the power input pin of the second power conversion chip U4. The output voltage of the second power conversion chip U4 is adjusted to 1.2V by the resistance values of the feedback resistors R37 and R38. The output voltage calculation formula is Vout = 0.6 * (1 + R37 / R38), and the feedback voltage is connected to the FB pin of the second power conversion chip U4. The sensitivity and stability of the circuit can be improved by paralleling the capacitor C83. Capacitors C77, C78, and C81 are output filter capacitors, and L2 is the output inductor to stabilize the output voltage. Whether the second power conversion chip U4 works can be controlled through the control pin PWR-STB.

[0063] Another DC 1.2V is the CPU power supply for the main control chip. The third conversion circuit converts the input 5V voltage into DC 1.2V. Specifically, it includes the third power conversion chip U6, and the third power conversion chip U6 is a SY8113BAD chip. The third power conversion chip U6 filters the input 5V voltage through capacitors C96, C97, C98, and C99 and enters the power input pin of the third power conversion chip U6. The output voltage of the third power conversion chip U6 is adjusted to 1.2V by the resistance values of the feedback resistors R39 and R40. The output voltage calculation formula is Vout = 0.6 * (1 + R39 / R40), and the feedback voltage is connected to the FB pin of the third power conversion chip U6. The sensitivity and stability of the circuit can be improved by connecting a capacitor C92 in parallel. Capacitors C93, C94, and C95 are output filter capacitors, and L7 is the output inductor to stabilize the output voltage. Whether the third power conversion chip U6 works can be controlled through the control pin PWR-STB.

[0064] As a preferred embodiment, the power supply module further includes a lithium battery charging control circuit and a lithium battery control circuit; the lithium battery charging control circuit is respectively connected to the switching power supply, the solar power supply, and the lithium battery, and the lithium battery control circuit is connected to the lithium battery; the lithium battery charging control circuit is used to supply power to the lithium battery from the power output by the switching power supply or the solar power supply, and the lithium battery control circuit is used to control whether the lithium battery is enabled to supply power.

[0065] Specifically, the lithium battery charging control circuit is as Figure 4 shown. The lithium battery charging control circuit includes a charging chip U28, and the charging chip U28 is a CN3795. The charging chip U28 filters the input 24V through capacitors C315, C316, and C317. The resistor R182 and the light-emitting diode D63 form a charging status display circuit, and the light-emitting diode D63 lights up when charging; the resistors R185 and R187 divide the input 24V voltage to configure the MPPT working voltage point of the charging chip U28; the resistor R183 and the capacitor C319 are used as the loop compensation input terminal of the charging chip U28; the resistors R181, R186, and R188 form the feedback resistors of the charging chip U28 to control the charging voltage of the charging chip U28 as:

[0066] Vbat = 1.205 * (1 + R181 / (R186 + R188)) + Ib * R181;

[0067] where Ib is the bias current of the FB pin, and its typical value is 60nA.

[0068] The resistor R170 is a charging current detection resistor, and the charging current of the lithium battery is controlled by Ich = 120mV / R170. The designed charging current is 300mA. The DRV pin of the charging chip U28 controls the on / off of the charging PMOS transistor Q6. The diodes D59 and D60 use Schottky diodes to ensure that their rated current should be greater than the set charging current. The diode D59 is used as a choke diode to prevent the battery energy from being consumed when the input power supply loses power. D60 provides a freewheeling circuit for the charging circuit. The inductor L4 is the inductor in the charging circuit, which is used for energy storage and release, suppresses current mutation, and improves the stability of the output voltage. The capacitors C154, C304, and C310 are output filter capacitors, which are used to stabilize the charging output voltage.

[0069] The lithium battery control circuit is as Figure 5 shown. The lithium battery control circuit includes an NMOS transistor Q13, a PMOS transistor Q5, and a button SW1. After the system starts up successfully, the EN_BAT network outputs a high level, the NMOS transistor Q13 conducts, and through the voltage division of the resistors R178 and R179, the turn-on of the PMOS transistor Q5 is controlled. After the external power supply is cut off, it switches to the internal lithium battery power supply. When it is necessary to cut off the internal lithium battery power supply, the button SW1 can be long-pressed. After the BUT_DET network detects that the high level changes to a low level for a period of time, it controls the EN_BAT network to output a low level, the NMOS transistor Q13 turns off, the gate-source voltage VGS of the PMOS transistor Q5 approaches 0, the PMOS transistor Q5 turns off, and thus the internal lithium battery power supply VCCBAT is cut off, and the entire terminal powers off.

[0070] As a preferred embodiment, the DTMB receiving module includes two Tuner tuners, which can simultaneously receive the signal sources of DTMB on two different channels. Specifically, the two Tuner tuners communicate with the main control chip H3 through I2C, and the Tuner tuner chip can be basically configured, switched to the DTMB channel to be received, and the received system can be set. The two tuners are distinguished by different I2C buses.

[0071] As Figure 6As shown, the chips U20 and U21 are the first Tuner tuning chip and the second Tuner tuning chip respectively, with the model number of ATBM253. They are used to amplify and process DTMB signals, extract signals at specific frequency points in the DTMB channel, lock on the specified operating frequency, eliminate interference signals, and improve the signal-to-noise ratio. RF1 is an antenna socket with a shielding cover, which is used to receive DTMB signals, reduce the outward radiation of high-frequency interference, increase the heat dissipation area, and lower the temperature when the Tuner operates. D28 and D30 are ESD tubes with the model number of UDD32C05L01, and D29 and D31 are GDT discharge tubes with the model number of 4532-091-LF, which are used to protect the antenna interface and improve the resistance to electrostatic and surge. The capacitor C234, capacitor C235, inductor L19, inductor L20, and inductor L21 form the Tuner1 antenna input filter circuit, and the capacitor C248, capacitor C249, inductor L23, inductor L24, and inductor L25 form the Tuner2 antenna input filter circuit. The antenna trace needs to maintain a single-ended impedance of 75Ω. The analog power supply and the digital power supply are isolated by the magnetic beads L18 and L22 to reduce the interference between the analog and digital. The crystal oscillator load capacitance should not be too large to prevent the crystal oscillator from failing to start normally.

[0072] The DTMB receiving module further includes a demodulator unit, such as Figure 7 As shown, the demodulator unit includes a demodulator chip U19, and U19 is an ATBM8880 chip. The main control chip H3 configures with the demodulator chip U19 through the I2C bus to set the clock, working mode, etc. of the TS output. The demodulator chip U19 receives the IF differential signal locked on a specific frequency by the tuner U20 through pins 43 and 44, and the demodulator chip U19 receives the IF differential signal locked on a specific frequency by the tuner U21 through pins 39 and 40; in the dual-tuner U20 and U21, a one-out-of-two selection can be made through configuration to convert the analog IF signal into a digital signal and output it to the TS interface of the main control chip H3 through the pins TS[0:7], TSCLK, TSVLD, and TSSYNC, specifically corresponding to the pins TS_D[0:7], TS_CLK, TS_DVLD, and TS_SYNC of the main control chip H3, using the parallel data transmission method to accelerate the transmission rate of the TS stream. The analog power supply and the digital power supply of the demodulator chip U19 are isolated by the magnetic bead L17 to reduce the interference between the power supplies. At least one capacitor is placed near each power pin of the chip to reduce crosstalk and improve reliability.

[0073] As a preferred embodiment, the FM receiving module includes two FM receiving units, which can simultaneously receive signal sources in two FM frequency bands and can receive RDS FM subcarrier messages through the interrupt method to receive emergency broadcast instructions. Such as Figure 8As shown in the figure, the two FM receiving units of the FM receiving module respectively include FM receiving chips U24 and U25, and the models of U24 and U25 are QN8035. The main control chip H3 communicates with the FM receiving chips through the I2C bus, and then configures the basic information of the FM receiving chips, and can configure or obtain information such as the frequency channel of FM reception, the audio volume size, the signal strength, and whether there is a radio station on the current channel.

[0074] Figure 8 In the figure, J11 is an antenna socket for receiving FM broadcast signals. D50 is an ESD device for eliminating static electricity contact. Inductors L28, capacitor C276, inductor L29, and capacitor C282 form an antenna high-pass filter circuit. Capacitor C277 is a filter capacitor for crystal oscillator input, reducing the interference received by the clock input. Resistors R152 and R156 are pull-up resistors for interrupt output. When the FM chips U24 and U25 receive RDS data, a low-triggered terminal signal will be generated on pin 6 of the QN8035 chip, and after passing through resistors R153 and R156, it will be transmitted to the IO port of the main control chip H3. The two interrupts of the main control chip Allwinner H3 are used to process the RDS interrupt signals of the two FM chips respectively; ALO and ARO of the FM chip U24 are analog audio output ports. After connecting resistors R149 and R150 in series, the FM analog audio is input to the LINEINL and LINEINR pins of the sound card. The sound card has been integrated inside the Allwinner H3 chip.

[0075] As a preferred embodiment, the emergency broadcast terminal further includes an AM receiving module. The AM receiving module is connected to the main control module, and the main control module is also used to amplify the audio signal received through the AM receiving module through the power amplifier module and then input it to the speaker for output. As Figure 9 shown in the figure, the AM receiving module includes an AM chip U27, and the specific model is SI4730. The AM signal enters the AM receiving module through the antenna socket J10 and is isolated by the intermediate frequency transformer J9. The isolated signal is connected to pin 12 AMI of the AM chip U27 through capacitor C293; Pins 17 and 18 of the AM chip U27 are I2C bus pins and are connected to the main control chip H3. The main control chip H3 can configure the AM chip U27 through the I2C bus and set the basic parameters for the operation of the AM chip U27, such as the AM reception frequency, reception parameters, working mode, output volume, etc.; Pins 23 and 24 of the AM chip U27 are analog audio left and right channel output pins, which can parse the audio signal sent by the AM transmitting station and convert it into analog audio output; Since the amplitude of the analog audio output of the AM chip U27 is small, it needs to be amplified by a post-stage operational amplifier chip U29A, and the amplification factor is R189 / R190; The second-stage chip U29B is used as a voltage follower to facilitate input and output impedance matching and isolate signal interference.

[0076] As Figure 10 shown, the 4G network module is connected to the main control chip H3 through the USB bus. The 4G network can stably pull the audio stream from the external cloud server, and the audio stream is transmitted to the main control chip H3 through the USB, so as to realize the function of remotely playing specific audio. The 4G network module includes a 4G communication module EC800E-CN, which uses an LGA package, can reduce the module volume, and reduce the material cost; the 4G module U23 is connected to the SIM card slot SIM1, and can directly obtain various operator SIM cards inserted externally, supporting SIM cards of China Radio and Television, China Mobile, China Unicom, and China Telecom; D44, D45, D46, D47, D48 are ESD tubes on the signal line of the SIM card slot to prevent the static electricity generated during card insertion and removal from interfering with the 4G module; the resistor R143, the light-emitting diode D49, the NMOS transistor Q9, and the resistor R144 form the operation indicator circuit of the 4G module, which is used to display the operation status of the 4G module; the 4G module U23 is connected to the B8 and B9 pins of the main control chip H3 through the USB bus of pins 59 and 60. After the main control chip H3 loads the USB driver of the 4G module, 4G dial-up Internet access can be realized.

[0077] The wired network module includes a 100M Ethernet data interface, a transformer, and an RJ45 network port; the main control chip, the 100M Ethernet data interface, the transformer, and the RJ45 network port are connected in sequence. The main control chip H3 integrates a network PHY chip and a MAC chip, and can directly lead out the 100M Ethernet data interface from the main control chip H3 and connect it to the RJ45 network port through a transformer, so as to realize the wired communication function of the present invention. As Figure 11 shown, RJ1 is a 100M Ethernet RJ45 socket, which forms an Ethernet interface circuit with the external transformer U22 to transmit two pairs of Ethernet high-speed differential signals; D33 and D35 are GDT discharge tubes, which are used to reduce the surge impact on the network port; D32 and D34 are ESD devices, which reduce the static electricity interference that the network port may receive; the resistors R131, R133, R134, R135 and the capacitors C254, C255, C256, C257 form a resistor-capacitor filter network to improve the stability of network communication.

[0078] As Figure 12As shown in the figure, the power amplifier module of the present utility model includes operational amplifier U17 NE5532DR and power amplifier chip U18 TPA3116D2DADR. U17 is a pre-power amplifier operational amplifier, which is used for amplifying and isolating the pre-power amplifier audio signal. The first stage is an inverting amplifier circuit, and the amplification factor is -R80 / R81; the 3-pin of U17 introduces a 2.5V bias voltage, adding a voltage bias to the AC signal isolated by capacitor C166 to ensure the normal passage of the audio signal. Capacitor C165 can provide the stability of the feedback loop; the second stage of operational amplifier U17 is a voltage follower, which is used for isolating the audio signal and reducing the interference of the audio signal.

[0079] The power amplifier gain of power amplifier chip U18 can be adjusted by the resistance values of resistor R89 and resistor R90. The larger the value of R89 / R90, the smaller the gain. Resistor R86 and light-emitting diode D22 are used to indicate abnormal power amplification. When the output of power amplifier chip U18 is short-circuited, the light-emitting diode D22 will light up. Ferrite bead L16 is used to isolate the analog power supply and the digital power supply, reducing the interference between the power supplies; inductors L14 and L15 are output large inductors; capacitors C182, C186, resistor R88, and resistor R89 form an output filter circuit; D21, D24, and D26 are lightning protection tubes to resist external input surges, and D23 and D25 are TVS tubes, serving as a secondary absorption circuit for anti-surge.

[0080] Existing emergency broadcast terminals have the problem of low reliability. For example, in some cold regions, when the outdoor temperature is below -20°C, conventional consumer-grade design products cannot perform cold start, and the equipment cannot operate normally. Therefore, the present utility model is provided with a temperature control module.

[0081] As a preferred embodiment, as Figure 13 - 14 shown, the temperature control module includes a temperature sensor, a temperature control unit, and a PWM heating control unit; the temperature sensor and the PWM heating control unit are respectively connected to the temperature control unit, and the PWM heating control unit is connected to the heating film; the temperature sensor is used to collect the ambient temperature inside the housing and transmit the collected temperature to the temperature control unit, and the temperature control unit is used to control the working state of the PWM heating control unit according to the ambient temperature inside the housing to adjust the power supply voltage applied by the PWM heating control unit to the heating film.

[0082] As a preferred embodiment, the temperature control module includes a heater power supply unit, a heater control power supply unit, a temperature control unit, a temperature sensor power control unit, a temperature sensor, and a PWM heating control unit;

[0083] The heater power supply unit is respectively connected to the power supply module and the heater control power supply unit. The heater control power supply unit is respectively connected to the temperature control unit and the temperature sensor power control unit. The temperature sensor power control unit is respectively connected to the temperature control unit and the temperature sensor. The PWM heating control unit is respectively connected to the temperature control unit, the heater power supply unit and the heating film. The temperature sensor is connected to the temperature control unit.

[0084] Specifically, the heater power supply unit includes a DC-DC power chip U31, which serves as the power supply for the heating film. The heater control power supply unit includes a power chip U30, which serves as the power supply for the temperature sensor and the temperature control unit. The temperature control unit selects a single-chip microcomputer control chip U32, with the specific model STM32G030C8T6. U1 is a temperature sensor chip SHT31. The above power chips, control chips and sensor chips are all industrial-grade chips, and the operating temperature range reaches -40 to 85°C.

[0085] The temperature sensor power control unit includes an NMOS transistor Q17 and a PMOS transistor Q15. Among them, the single-chip microcomputer control chip U32 is respectively connected to one end of a resistor R211 and the G pole of the NMOS transistor Q17 through a pin SHT-PWR. The other end of the resistor R211 and the S pole of the NMOS transistor Q17 are grounded. The D pole of the NMOS transistor Q17 is respectively connected to one end of a resistor R209, one end of a capacitor C346 and the G pole of the PMOS transistor Q15 through the resistor R209. The other end of the resistor R206, the other end of the capacitor C346 and the D pole of the PMOS transistor Q15 are respectively connected to the output end of the heater control power supply unit. The S pole of the PMOS transistor Q15 is respectively connected to the temperature sensor and one end of a capacitor C347. The other end of the capacitor C347 is grounded. The single-chip microcomputer control chip U32 can control the power supply of the temperature sensor U1 through the combination of the NMOS transistor Q17 and the PMOS transistor Q15, and communicate with the temperature sensor U1 through the I2C bus, collect the ambient temperature data inside the highly reliable emergency broadcast terminal through the temperature sensor U1, and read the ambient temperature data through the I2C bus.

[0086] The PWM heating control unit includes an NMOS transistor Q16 and a PMOS transistor Q14. The PWM interface network port TIM3_CH1 of the single-chip microcomputer control chip U32 is connected to the G pole of the NMOS transistor Q16, which can control the conduction of the NMOS transistor Q16. By opening and closing the NMOS transistor Q16, the on-off of the PMOS transistor Q14 can be controlled. The PMOS transistor Q14 is the main switch for controlling the startup of the heating film; CN2 is the heating film interface, which is used to connect the PWM heating control unit to the heating film. The power supply voltage of the heating film power supply can be controlled by PWM regulation. Since the heating film is a constant-resistance device, according to W = U*U / R, the higher the voltage applied to the heating film, the higher the heating power, thus realizing the closed-loop of temperature control. Precise and highly reliable internal temperature control of the terminal can be achieved through single-chip microcomputer control, ensuring the normal operation of the highly reliable emergency broadcast terminal in a severe cold environment; when the temperature sensor U1 detects that the internal environment temperature of the shell is within the appropriate range, the heating function of the heating film is turned off through the PWM heating control unit, and the highly reliable emergency broadcast terminal operates normally.

[0087] Next, the working principle of this embodiment will be described in detail to enable those skilled in the art to better understand the present invention:

[0088] As Figure 15 shown, the power supply of the terminal in the current emergency broadcast system is single, generally only powered by the commercial power supply. When there is a problem with the commercial power supply, it affects the normal use of the terminal and cannot meet the requirements of the emergency broadcast. When the power supply voltage is unstable, the long-term normal operation of the terminal cannot be guaranteed. The present invention is provided with commercial power supply, solar power supply and lithium battery power supply. In actual deployment, the present invention can choose to use commercial power supply or solar power supply system for power supply according to actual needs. When the commercial power supply exists, the highly reliable terminal preferentially uses the commercial power supply to work. When the commercial power supply is cut off, the present invention seamlessly switches to solar power supply. At the same time, the present invention is designed with an internal lithium battery power supply. When the external commercial power supply and solar power supply are both disconnected, the present invention can still maintain operation for a period of time relying on the internal lithium battery. After the switching power supply of the present invention is connected to the commercial power supply AC220V, the commercial power supply is converted into a DC24V power supply, and the solar power supply system converts solar energy into a DC 12V power supply.

[0089] In the current construction plan, there is usually only one mode for the platform to transmit to towns (townships), villages, and the terminal network, and there is no disaster recovery transmission channel. The present utility model can be connected to the cloud platform through a wired network and a 4G network, and it can ensure that the wired network and the 4G network are both connected. When one of the network communications is abnormal, it can still maintain normal communication with the platform. The cloud platform can obtain the basic operation information of the present utility model and manage the present utility model connected to the cloud platform. Through area management, it is possible to specify a single or multiple present utility models to broadcast broadcast audio. In some extreme network-disconnected situations, the highly reliable terminal can also receive the audio broadcasts sent by the DTMB transmitter, AM amplitude modulation transmitter, or FM frequency modulation transmitter, ensuring that the broadcast work can be carried out even in a network-disconnected environment.

[0090] In summary, the previous emergency broadcast terminals could only broadcast locally, could not be connected to the network, could not be uniformly managed through the platform, had weak security, and in particular, the systems mainly based on frequency modulation broadcast technology had serious security hazards and management loopholes. Through the present utility model, it is possible to implement the function of broadcasting emergency broadcasts through five channels, namely IP network, frequency modulation broadcast, amplitude modulation broadcast, DTMB broadcast, and local broadcast. It can be connected to the network through a 4G or wired network to achieve the unified management of highly reliable terminals by the emergency broadcast platform. When the 4G and wired networks are not connected, it can still receive the emergency broadcast messages sent by the FM frequency modulation transmitter, AM amplitude modulation transmitter, and DTMB transmitter, improving the coverage of the broadcast audio.

[0091] In addition, the housing of the present utility model adopts a rainproof and sealed design, increasing the reliability of outdoor deployment.

[0092] The foregoing description of the specific exemplary embodiments of the present utility model is for the purposes of illustration and exemplification. These descriptions are not intended to limit the present utility model to the precise forms disclosed, and obviously, many changes and variations can be made in accordance with the above teachings. Although the embodiments of the present utility model have been shown and described, the specific embodiments are merely interpretations of the present utility model and not limitations thereof. The specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. The purpose of selecting and describing the exemplary embodiments is to explain the specific principles and practical applications of the present utility model, so that those skilled in the art can, after reading this specification, make modifications, substitutions, variations, and various different selections and changes that do not make creative contributions to the embodiments as needed, but as long as they are within the scope of the claims of the present utility model, they are protected by the patent law.

Claims

1. A highly reliable emergency broadcast terminal, comprising a housing and a circuit board, wherein the circuit board is fixed inside the housing, and the circuit board is provided with a power module, a DTMB receiving module, an FM frequency modulation receiving module, a main control module, a 4G network module, a wired network module, a power amplifier module, and a speaker; The power module, DTMB receiving module, FM receiving module, 4G network module, wired network module, and power amplifier module are respectively connected to the main control module; the speaker is connected to the power amplifier module; the main control module is used to amplify the audio signal received by the DTMB receiving module or the FM receiving module or the 4G network module or the wired network module through the power amplifier module and input it into the speaker for output; It is characterized in that A temperature control module is also provided on the circuit board, and a heating film is provided at the bottom of the circuit board; the temperature control module is used to control the heating temperature of the heating film according to the ambient temperature inside the shell.

2. A high-reliability emergency broadcast terminal according to claim 1, characterized in that: The temperature control module includes a temperature sensor, a temperature control unit, and a PWM heating control unit; the temperature sensor and the PWM heating control unit are respectively connected to the temperature control unit, and the PWM heating control unit is connected to the heating film; the temperature sensor is used to collect the ambient temperature inside the shell and transmit the collected temperature to the temperature control unit, and the temperature control unit is used to control the working state of the PWM heating control unit according to the ambient temperature inside the shell, so as to adjust the power supply voltage applied to the heating film by the PWM heating control unit.

3. A high-reliability emergency broadcast terminal according to claim 1, characterized in that: The power module includes a switching power supply, a solar power supply, a lithium battery, and a power selection unit; The switching power supply is connected to the mains power supply through a power filter; The lithium battery, switching power supply, solar power supply and main control module are respectively connected to the power selection unit; the power selection unit is used to select one of the lithium battery, switching power supply and solar power supply to power the main control module.

4. A high-reliability emergency broadcast terminal according to claim 1, characterized in that: The power module also includes a voltage conversion unit, which is connected to the power selection unit and the main control module respectively; The voltage conversion unit is used to convert the power supply voltage output by the lithium battery / switching power supply / solar power supply into a suitable working voltage for the main control module.

5. A high-reliability emergency broadcast terminal according to claim 1, characterized in that: The power module also includes a lithium battery charging control circuit and a lithium battery control circuit; The lithium battery charging control circuit is connected to the switching power supply, the solar power supply and the lithium battery respectively, and the lithium battery control circuit is connected to the lithium battery; The lithium battery charging control circuit is used to supply power to the lithium battery from the power output of the switching power supply or the solar power supply, and the lithium battery control circuit is used to control whether the lithium battery is enabled to supply power.

6. A high-reliability emergency broadcast terminal according to claim 1, characterized in that: The DTMB receiving module includes two tuners, which can simultaneously receive DTMB signal sources on two different channels.

7. A high-reliability emergency broadcast terminal according to claim 1, characterized in that: The FM receiving module includes two FM receiving units, which can simultaneously receive signal sources of two FM frequency bands.

8. A high-reliability emergency broadcast terminal according to claim 1, characterized in that: The emergency broadcast terminal also includes an AM amplitude modulation receiving module, which is connected to the main control module. The main control module is also used to amplify the audio signal received by the AM amplitude modulation receiving module through the power amplifier module and input it into the speaker for output.

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