A Bluetooth device based on Sub-GHz frequency band and implementation method

Abstract

The present application discloses a Bluetooth device based on the Sub-GHz frequency band and an implementation method thereof, wherein the Bluetooth device includes a controller, a communication bus, a baseband processing unit, a modem, and a radio frequency transceiver unit, wherein the controller is connected to the baseband processing unit via the communication bus, and the radio frequency transceiver unit is connected to the baseband processing unit via the modem. The radio frequency transceiver unit includes a local oscillator circuit, a mixer circuit, a transceiver port, and an analog-to-digital conversion circuit, wherein the mixer circuit can convert the input signal to an intermediate frequency, and the analog-to-digital conversion circuit performs analog-to-digital conversion on the intermediate frequency signal so that the baseband processing unit can process it; the local oscillator circuit converts the signal output by the modulator into an analog signal of a preset frequency band through a phase-locked loop and a Sigma-Delta modulator and outputs it through the transceiver port. Through the above structure, the Bluetooth device converts the Bluetooth transceiver signal into a preset frequency band signal that is not easily attenuated, so as to solve the problem of side effects in the process of optimizing the Bluetooth connection.

Description

Technical Field

[0001] The present application relates to the field of Internet of Things, and in particular to a Sub-GHz frequency band-based Bluetooth device and an implementation method thereof. Background Art

[0002] With the rise of the Internet of Things and smart home concepts, Bluetooth technology is widely used to achieve communication between different devices in the Internet of Things due to its low cost and low power consumption. A typical Internet of Things sets up a Bluetooth gateway to wirelessly connect to surrounding electronic devices with built-in Bluetooth chips, such as smart lamps, cameras, and even smart home appliances. After receiving the Bluetooth signal sent by the electronic device, the Bluetooth gateway converts the data information contained in the signal into a WIFI or Ethernet signal and sends it to the device connected to the Ethernet, such as a router.

[0003] The Bluetooth signal transmitted by Bluetooth technology is an electromagnetic wave signal in the 2.4GHz frequency band. The propagation modes of electromagnetic wave signals are diffraction and penetration. When the wavelength of the electromagnetic wave is comparable to the size of the obstacle, it is propagated by diffraction; when the wavelength of the electromagnetic wave is much smaller than the size of the obstacle, it is propagated by penetration. According to the electromagnetic wave velocity, the wavelength of the electromagnetic wave signal in the 2.4GHz frequency band is about 12cm. When the Bluetooth gateway and the electronic equipment connected to the Bluetooth gateway are set up indoors, there will be obstacles in the propagation of the Bluetooth signal and it is difficult to diffract because there are many indoor walls and the thickness of the wall is usually greater than 12cm. If the penetration mode is used for signal propagation, each wall penetrated will greatly attenuate the strength of the Bluetooth signal, which is not conducive to the transmission of data information. Usually, the reception of Bluetooth signals can be optimized by increasing the transmission power, improving the receiving sensitivity of the Bluetooth gateway, or using mesh technology.

[0004] However, in actual applications, increasing the transmission power will increase the power consumption of the device and increase the cost; increasing the receiving sensitivity of the Bluetooth gateway will reduce the transmission rate, which is not suitable for high throughput or scenarios that require fast feedback; mesh technology is to achieve communication between adjacent devices, so that all devices can connect to the Bluetooth gateway, which is difficult to design, and because different devices need to communicate, there is also a problem of low transmission rate. Therefore, it is necessary to provide a technical solution to avoid the problem of poor optimization effect and side effects in the process of optimizing Bluetooth connection. Summary of the invention

[0005] The present application provides a Sub-GHz frequency band-based Bluetooth device and implementation method to solve the problem of poor optimization effect and side effects in the process of optimizing Bluetooth connection.

[0006] According to a first aspect of an embodiment of the present invention, there is provided a Sub-GHz frequency band based Bluetooth device, comprising a controller, a communication bus, a baseband processing unit, a modem and a radio frequency transceiver unit, wherein: the controller is connected to the baseband processing unit via the communication bus; the modem comprises a modulator and a demodulator, the input end of the modulator is connected to the baseband processing unit, and the output end of the demodulator is connected to the baseband processing unit; the radio frequency transceiver unit comprises a local oscillator circuit, a mixer circuit, a transceiver port and an analog-to-digital conversion circuit, the mixer circuit comprises two parallel mixers, and the mixer circuit The local oscillator circuit and the analog-to-digital conversion circuit are connected in series with the transceiver port; the local oscillator circuit and the analog-to-digital conversion circuit are connected to the two mixers respectively; the output end of the analog-to-digital conversion circuit is connected to the input end of the demodulator; the local oscillator circuit includes a phase-locked loop and a Sigma-Delta modulator, and the phase-locked loop is connected to the output end of the modulator through the input end of the Sigma-Delta modulator; the Sigma-Delta modulator is used to perform digital-to-analog conversion on the output signal of the output end of the modulator; the phase-locked loop is used to convert the output signal of the Sigma-Delta modulator to a preset frequency band.

[0007] The RF transceiver unit can receive and transmit RF signals of a specific frequency band, so that the Bluetooth device can avoid the situation where the 2.4GHz RF signal transmitted by the Bluetooth device is greatly attenuated after passing through the wall and cannot be received by other Bluetooth devices. The local oscillator circuit in the RF transceiver unit can modulate the baseband signal, convert the baseband signal after preliminary modulation into an analog signal format and frequency-convert it to a preset frequency band for output.

[0008] Optionally, the preset frequency band is a Sub-GHz frequency band. The preset frequency band is a Sub-GHz frequency band. The electromagnetic wave signal wavelength in this frequency band is relatively long, and can be diffracted and propagated in an indoor environment, and the attenuation of the signal during propagation is small.

[0009] Optionally, the RF transceiver unit also includes a power amplifier circuit, in which an output power amplifier and an input power amplifier are provided; the input end of the output power amplifier is connected to the output end of the phase-locked loop, and the output end of the output power amplifier is connected in series with the transceiver port; the output power amplifier is used to amplify the power of the output signal of the phase-locked loop; the output end of the input power amplifier is connected in series with the mixer circuit, and the input end of the input power amplifier is connected in series with the transceiver port; the input power amplifier is used to amplify the power of the RF signal received by the transceiver port. The power amplifier circuit can perform power amplification for the input RF signal and the output RF signal respectively. Power amplification of the output RF signal can prevent insufficient signal power, so that the signal can still be detected and received after attenuation during the propagation process; power amplification of the input RF signal can extract as much information as possible from the signal to avoid information loss.

[0010] Optionally, the RF transceiver unit further includes a transceiver switch, one end of which is connected in series with the transceiver port, and the other end is connected to the power amplifier circuit, and the transceiver switch is used to connect the transceiver port with the output power amplifier or connect the transceiver port with the input power amplifier. The transceiver switch can control whether the Bluetooth device receives or transmits signals, so that the Bluetooth device can separate reception and transmission through only one port to avoid signal interference.

[0011] Optionally, the phase-locked loop includes a voltage-controlled oscillator, a loop filter, a frequency detector and a multi-mode divider, wherein: the multi-mode divider is connected to the output end of the Sigma-Delta modulator; the frequency detector is connected in series with the multi-mode divider, and the frequency detector is connected in series with the input end of the voltage-controlled oscillator through the loop filter; the output end of the voltage-controlled oscillator is connected to the output power amplifier and the multi-mode divider respectively. The voltage-controlled oscillator can convert the received signal into a high-frequency signal output, and a part of the output high-frequency signal is output to the multi-mode divider, and the other part is output to the output power amplifier for amplification and output.

[0012] Optionally, the phase frequency detector is provided with two input terminals, and the phase locked loop further includes a reference signal terminal; one input terminal of the phase frequency detector is connected to the multi-mode frequency divider, and the other input terminal of the phase frequency detector is connected to the reference signal terminal; the reference signal terminal is configured to output a reference signal with a frequency of the preset frequency band. By comparing the reference signal with the signal output by the multi-mode frequency divider by the phase frequency detector, the output signal frequency of the phase locked loop can be limited to the preset frequency band.

[0013] Optionally, the phase-locked loop further includes a charge pump, which is connected in series between the phase frequency detector and the loop filter; the charge pump is used to gain the signal output by the phase frequency detector to eliminate spurious and quantization noise.

[0014] Optionally, the radio frequency transceiver unit further includes a filter circuit, and the filter circuit is arranged between the mixer circuit and the analog-to-digital conversion circuit to limit the bandwidth of the output signal of the mixer circuit.

[0015] According to the second aspect of an embodiment of the present invention, a Bluetooth implementation method based on the Sub-GHz frequency band is provided, which is applied to any of the above-mentioned Bluetooth devices, including a transmitting implementation method and a receiving implementation method: wherein the steps of the transmitting implementation method include: controlling the baseband processing unit to generate a baseband signal and performing GFSK modulation to obtain a modulated signal; performing Sigma-Delta modulation on the modulated signal to generate a radio frequency signal in an analog signal format; converting the radio frequency signal to a preset frequency band; and sending the radio frequency signal in the preset frequency band through broadcasting; the steps of the receiving implementation method include: receiving a signal in the preset frequency band to obtain a received signal; converting the received signal to an intermediate frequency; performing analog-to-digital conversion on the received signal after frequency conversion to generate a processed signal in a digital signal format; performing GFSK demodulation on the processed signal, and sending it to the baseband processing unit for processing.

[0016] Optionally, the preset frequency band is a Sub-GHz frequency band.

[0017] It can be seen from the above technical solutions that the present application provides a Bluetooth device based on the Sub-GHz frequency band and an implementation method, wherein the Bluetooth device includes a controller, a communication bus, a baseband processing unit, a modem and a radio frequency transceiver unit, wherein the controller is connected to the baseband processing unit via the communication bus, and the radio frequency transceiver unit is connected to the baseband processing unit via the modem. The radio frequency transceiver unit includes a local oscillator circuit, a mixer circuit, a transceiver port and an analog-to-digital conversion circuit, wherein the mixer circuit can convert the input signal to an intermediate frequency, and the analog-to-digital conversion circuit can convert the intermediate frequency signal into an analog-to-digital signal for processing by the baseband processing unit; the local oscillator circuit includes a phase-locked loop and a Sigma-Delta modulator, which can convert the signal output by the modem into an analog signal of a preset frequency band and output it through the transceiver port. By setting the above structure, the Bluetooth device makes the signal generated and processed by Bluetooth become a preset frequency band signal that is not easy to attenuate, thereby avoiding problems such as rate reduction and cost increase when optimizing Bluetooth connection. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solution of the present application, the drawings required for use in the embodiments are briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0019] Figure 1 This is a schematic diagram of the structure of a Sub-GHz frequency band Bluetooth device in an embodiment of the present application;

[0020] Figure 2 This is a structural diagram of a radio frequency transceiver unit in an embodiment of the present application;

[0021] Figure 3 This is a flow chart of a method for implementing Bluetooth transmission based on the Sub-GHz frequency band in an embodiment of the present application;

[0022] Figure 4 This is a flow chart of a method for implementing Bluetooth reception based on the Sub-GHz frequency band in an embodiment of the present application.

[0023] Illustration: 100-RF transceiver unit; 110-transceiver port; 120-mixer circuit; 130-analog-to-digital conversion circuit; 140-local oscillator circuit; 150-power amplifier circuit; 160-transceiver switch; 170-filter circuit; 200-modem; 300-baseband processing unit; 400-communication bus; 500-controller; 121-mixer; 141-phase-locked loop; 142-Sigma-Delta modulator; 151-output power amplifier; 152-input power amplifier; 210-modulator; 220-demodulator; 1410-voltage-controlled oscillator; 1411-loop filter; 1412-frequency detector and phase detector; 1413-reference signal terminal; 1414-multi-mode divider; 1415-charge pump. DETAILED DESCRIPTION

[0024] The following embodiments are described in detail, and examples thereof are shown in the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementations described in the following embodiments do not represent all implementations consistent with the present application. They are only examples of devices and methods consistent with some aspects of the present application as detailed in the claims.

[0025] Bluetooth technology is a short-range wireless communication technology that can achieve convenient, fast, flexible, secure, low-cost, and low-power data and voice communications between different devices. With the popularity of the Internet of Things and smart home concepts, Bluetooth technology has been widely used in various devices due to its advantages to enable wireless connections with other devices.

[0026] Since the distance of wireless communication achieved by Bluetooth is short, the solution of using Bluetooth for device interconnection is usually applied in indoor environments, for example, by building Bluetooth modules in different home appliances or electronic devices such as lamps, remote control of indoor electronic devices is realized. On this basis, star networking is often used for connection, that is, a Bluetooth gateway is set as a node, and other devices with built-in Bluetooth modules are wirelessly connected to the Bluetooth gateway. However, there are many obstacles that cannot be avoided during signal propagation in indoor environments, such as walls, large furniture, etc. In some embodiments, Bluetooth technology uses electromagnetic wave signals in the 2.4GHz frequency band for transmission. According to the wave speed and frequency, it can be known that the wavelength of the electromagnetic wave signal in this frequency band is about 12cm, which is less than the thickness of the wall in the indoor environment. According to the characteristics of electromagnetic waves, when electromagnetic waves encounter obstacles when propagating in space, there are two propagation modes: penetration and diffraction. Among them, when the wavelength of the electromagnetic wave is comparable to the size of the obstacle, it is generally propagated by diffraction; when the wavelength of the electromagnetic wave is much smaller than the size of the obstacle, it is generally propagated by penetration. However, since the wavelength of Bluetooth signals in the 2.4GHz frequency band is much smaller than the thickness of indoor walls, in indoor environments, if Bluetooth signals encounter obstacles such as walls during propagation, they need to propagate by penetrating them.

[0027] However, since obstacles such as walls are solid and contain metal supports, electromagnetic wave signals will be greatly attenuated in the walls, thereby affecting the quality of wireless connection. In some embodiments, the quality of wireless connection can be improved by increasing the power of the Bluetooth transmitter, increasing the sensitivity of the Bluetooth receiver, and using mesh technology for networking. In order to achieve interaction between different devices, the built-in Bluetooth in the device has the functions of transmitting and receiving. At this time, if the Bluetooth connection is optimized by increasing the power of the Bluetooth transmitter, the power consumption of Bluetooth will increase, and the cost of using Bluetooth will increase. If the optimization method of increasing the sensitivity of the receiving end is adopted, the device can receive a smaller signal through Bluetooth to avoid the electromagnetic wave signal from being unable to be received through Bluetooth after attenuation, but increasing the sensitivity of the receiving end requires reducing the data rate. The reduction in the data rate may cause a longer device response delay and is not suitable for high-throughput application scenarios. Mesh technology optimizes Bluetooth connection by networking between different devices in pairs, but the design difficulty is high in scenarios with more Bluetooth devices, and because different devices are required to transfer signals, the data rate will also be reduced, which is also not suitable for high-throughput application scenarios.

[0028] To avoid problems such as increased power consumption and reduced speed during Bluetooth connection optimization, see Figure 1 , is a schematic diagram of the structure of a Bluetooth device based on the Sub-GHz frequency band in an embodiment of the present application. Figure 1As shown, the present application provides a Bluetooth device based on the Sub-GHz frequency band, including a controller 500, a communication bus 400, a baseband processing unit 300, a modem 200 and a radio frequency transceiver unit 100. In the embodiment of the present application, the Bluetooth device may be a Bluetooth chip including the above components. It should be noted that the Bluetooth device in the embodiment of the present application is built into different electronic devices, and different electronic devices will only affect the data information contained in the Bluetooth signal emitted by the Bluetooth device, but will not affect its physical properties.

[0029] The controller 500 is connected to the baseband processing unit 300 via the communication bus 400. The controller 500 is used to control the Bluetooth device to send and receive Bluetooth signals via the baseband processing unit 300. In some embodiments, the controller 500 can be implemented by a single-chip microcomputer, and the single-chip microcomputer stores Bluetooth protocol stack information to facilitate connection between different devices.

[0030] The modem 200 includes a modulator 210 and a demodulator 220. The input end of the modulator 210 is connected to the baseband processing unit 300, and the output end of the demodulator 220 is connected to the baseband processing unit 300. Specifically, the modem 200 is used to decode the received Bluetooth signal into a signal that can be processed by the baseband processing unit 300, and to preliminarily modulate the baseband signal sent by the baseband processing unit 300 into an output signal. It should be noted that the modulation method used by the Bluetooth device in the embodiment of the present application is GFSK modulation, that is, Gaussian frequency shift keying modulation, which can limit the spectrum width of the baseband signal, thereby achieving the purpose of reducing power consumption.

[0031] The radio frequency transceiver unit 100 includes a local oscillator circuit 140, a mixer circuit 120, a transceiver port 110 and an analog-to-digital conversion circuit 130, wherein the mixer circuit 120 includes two parallel mixers, and the mixer circuit 120 is connected in series with the transceiver port 110. The local oscillator circuit 140 and the analog-to-digital conversion circuit 130 are respectively connected to the two mixers, and the output end of the analog-to-digital conversion circuit 130 is connected to the input end of the demodulator. It should be noted that the transceiver port 110 needs an external antenna in actual use to receive and / or transmit Bluetooth signals. In some embodiments, an antenna with both transceiver functions is used as the external antenna of the Bluetooth device.

[0032] In this embodiment, when the Bluetooth device receives a signal transmitted by another Bluetooth device, it first collects the Bluetooth signal as an input signal through the antenna, and then reduces the input signal to an intermediate frequency through the mixer and the local oscillator circuit 140. The intermediate frequency is 1 MHz in this embodiment. Finally, the analog-to-digital conversion circuit 130 converts the input signal in analog signal format into a digital format, so that the demodulator 220 can demodulate it and the baseband processing unit 300 can process and analyze it.

[0033] The local oscillator circuit 140 includes a phase-locked loop 141 and a Sigma-Delta modulator 142. The phase-locked loop 141 is connected to the output end of the modulator 210 through the input end of the Sigma-Delta modulator 142; the Sigma-Delta modulator 142 is used to perform digital-to-analog conversion on the output signal of the output end of the modulator 210, and the phase-locked loop is used to convert the output signal of the Sigma-Delta modulator to a preset frequency band. On this basis, the RF transceiver unit 100 can receive and transmit RF signals of a specific frequency band, so that the Bluetooth device can avoid the situation where the 2.4GHz RF signal transmitted is greatly attenuated after passing through the wall and cannot be received by other Bluetooth devices.

[0034] In some embodiments of the present application, the preset frequency band is the Sub-GHz frequency band. The Sub-GHz frequency band is the sub-GHz frequency band, specifically referring to the frequency range of 27MHz to 960MHz. The electromagnetic wave signal wavelength in this frequency band is relatively long, and it can be diffracted and propagated in an indoor environment. The attenuation during signal propagation is small. Even if it needs to be propagated by penetration during the propagation process, the signal attenuation degree will be small compared to the 2.4GHz frequency band, which is convenient for other devices to collect.

[0035] Specifically, the frequency of the radio frequency signal transmitted and received by the Bluetooth device can be expressed as:

[0036] f rf_subghz =27MHz+N*ChannelSpacing

[0037] Wherein, N is the number of channels of the RF signal in Sub-GHz; ChannelSpacing is the channel spacing. Specifically, the channel spacing is the same as the intermediate frequency. In the embodiment of the present application, when the intermediate frequency is 1MHz, the channel spacing is also 1MHz. In theory, the channel spacing and the intermediate frequency can be freely defined, for example, set to 0.5MHz, etc., but because the channel spacing used in the general Bluetooth protocol is 1MHz, changing the channel spacing requires changing the Bluetooth protocol stack in the controller 500 and the baseband processing unit 300. Therefore, in some embodiments of the present application, the channel spacing and the intermediate frequency are still set to 1MHz.

[0038] In order to enable the Bluetooth device to better process the received and transmitted signals, the RF transceiver unit 100 further includes a power amplifier circuit 150, in which an output power amplifier 151 and an input power amplifier 152 are provided. The input end of the output power amplifier 151 is connected to the output end of the phase-locked loop 141, and the output end of the output power amplifier 151 is connected in series with the transceiver port 110. Specifically, the output power amplifier 151 can be a power amplifier PA, which can perform power gain on the RF signal output by the phase-locked loop 141, so that the transmitted signal power is higher and is easily received by other Bluetooth devices.

[0039] The input power amplifier 152 is arranged between the transceiver port 110 and the mixer circuit 120, the output end of the input power amplifier 152 is connected in series with the mixer circuit 120, and the input end of the input power amplifier 152 is connected in series with the transceiver port 110. In some embodiments of the present application, the input power amplifier 152 may be a low noise power amplifier LNA. Compared with PA, LNA can eliminate the noise generated by the amplified signal while amplifying the power of the RF signal received by the transceiver port 110, thereby improving the signal-to-noise ratio of the signal received by the transceiver port 110 and avoiding signal distortion caused by the noise generated during the amplification process when the received signal power is low.

[0040] Since a transceiver port 110 is used to transmit and receive signals in the present application, in order to avoid interference between the received signal and the transmitted signal, in some embodiments, the RF transceiver unit 110 also includes a transceiver switch 160, one end of the transceiver switch 160 is connected in series with the transceiver port 110, and the other end is connected to the power amplifier circuit 150. The transceiver switch 160 is used to connect the transceiver port 110 with the output power amplifier 151 or to connect the transceiver port 110 with the input power amplifier 152.

[0041] It should be noted that the method of transmitting and receiving signals through a transceiver port 110 is called time division duplex, that is, by dividing different time slots within a period of time, the transceiver port 110 only performs one task of receiving or sending in the same time slot. Specifically, the time slot width can be set by itself, and the number of receiving and sending time slots may not be 1:1, that is, the number of receiving time slots and the number of sending time slots within a period of time may be different, and the specific ratio can be manually set through the setting position of the Bluetooth device.

[0042] In some embodiments of the present application, in order to ensure that reception and transmission do not interfere with each other, a protection time slot exists when the reception time slot and the transmission time slot are switched. During the protection time slot, the Bluetooth device neither receives nor sends signals, thereby ensuring that reception and transmission are not interfered with.

[0043] In some embodiments of the present application, the transceiver switch 160 may be a single-pole double-throw switch or a PIN-type diode. The specific type of switch is not limited in the present application, as long as it can realize the switching function of receiving and sending the Bluetooth device.

[0044] like Figure 2 As shown, in some embodiments, the phase-locked loop 141 includes a voltage-controlled oscillator 1410, a loop filter 1411, a frequency detector 1412, and a multi-mode divider 1414. The multi-mode divider 1414 is connected to the output end of the Sigma-Delta modulator 142, and the multi-mode divider 1414 receives the modulation signal in the analog signal format output by the Sigma-Delta modulator 142, so that the multi-mode divider 1414 can separate the signals in different frequency bands from the modulation signal to avoid interference.

[0045] The phase detector 1412 is connected in series with the multi-mode frequency divider 1414, and the phase detector 1412 is connected in series with the input end of the voltage-controlled oscillator 1410 through the loop filter 1411, and the output end of the voltage-controlled oscillator 1410 is connected to the output power amplifier 151 and the multi-mode frequency divider 1414 respectively. The phase detector 1412 can control the voltage-controlled oscillator 1410 to convert the signal and output it by comparing the phase difference between the signals. The loop filter 1411 can filter out the high-frequency error component in the signal output by the phase detector 1412, thereby improving the anti-interference performance of the phase-locked loop 141.

[0046] It should be noted that the multi-mode divider 1414 can also receive a part of the output signal of the voltage-controlled oscillator 1410. This part of the output signal can be used as a feedback signal of the phase-locked loop 141, and is then sent to the frequency detector 1412 through the multi-mode divider 1414, so that the phase-locked loop 141 can lock the output signal frequency of the voltage-controlled oscillator 1410.

[0047] In order to enable the phase-locked loop 141 to limit the output of the voltage-controlled oscillator 1410 to a preset frequency band, in some embodiments, the phase frequency detector 1412 is provided with two input terminals, and the phase frequency detector 1412 further includes a reference signal terminal 1413, and the reference signal terminal 1413 can provide a reference signal with a frequency in the preset frequency band. One input terminal of the phase frequency detector 1412 is connected to the multi-mode frequency divider 1414, and the other input terminal of the phase frequency detector 1412 is connected to the reference signal terminal 1413. The phase frequency detector 1412 can use the signal output by the multi-mode frequency divider 1414 as an input signal, and generate a frequency conversion control signal for the signal output by the multi-mode frequency divider 1414 by comparing the phase difference between the signal output by the multi-mode frequency divider 1414 and the phase difference of the output signal of the voltage-controlled oscillator 1410, so that the frequency of the output signal of the voltage-controlled oscillator 1410 is the preset frequency.

[0048] In some embodiments of the present application, the reference signal output by the reference signal terminal 1413 can also provide a reference clock to prevent the input and output of the transceiver port 110 from being interfered with due to time error.

[0049] In some embodiments, the phase-locked loop 141 also includes a charge pump 1415, which is connected in series between the frequency detector 1412 and the loop filter 1411. The charge pump 1415 can gain the signal output by the frequency detector 1412 to eliminate spurious and quantization noise, so as to generate a control signal for the voltage-controlled oscillator 1410. The control signal controls the voltage-controlled oscillator 1410 to convert the signal to a preset frequency and output it.

[0050] In the process of signal reception by the Bluetooth device, in order to enable the baseband processing unit 300 to process the received signal more quickly and without interference, the RF transceiver unit 100 also includes a filter circuit 170, which is arranged between the mixer circuit 120 and the analog-to-digital conversion circuit 130 to limit the bandwidth of the output signal of the mixer circuit 120. It should be noted that the bandwidth is the frequency bandwidth, and the filter circuit 170 can limit the frequency bandwidth of its own output signal, so that the non-frequency interference of the mixed signal of the mixer circuit 120 can be filtered out. In some embodiments, the filter in the filter circuit 170 can be a bandpass filter, which can suppress signals below or above the limit range by limiting the frequency band of the signal, thereby eliminating the interference of clutter.

[0051] Based on the above Bluetooth device, such as Figure 3 to Figure 4 As shown, the present application also provides a Bluetooth implementation method based on the Sub-GHz frequency band, which is applied to any of the above-mentioned Bluetooth devices. Since the RF transceiver and transmitter of the Bluetooth device are integrated together, the Bluetooth implementation method also includes a transmission implementation method and a reception implementation method.

[0052] Among them, the steps of the transmission implementation method include: controlling the baseband processing unit 300 to generate a baseband signal and performing GFSK modulation to obtain a modulated signal; performing Sigma-Delta modulation on the modulated signal to generate a radio frequency signal in an analog signal format; converting the radio frequency signal to a preset frequency band; and sending the radio frequency signal in the preset frequency band through broadcasting.

[0053] The steps of the receiving implementation method include: receiving a signal in a preset frequency band to obtain a received signal; converting the received signal to an intermediate frequency; performing analog-to-digital conversion on the received signal after the frequency conversion to generate a processed signal in a digital signal format; performing GFSK demodulation on the processed signal and sending it to the baseband processing unit 300 for processing. It should be noted that in this embodiment, the intermediate frequency is 1 MHz.

[0054] It should be noted that, in some embodiments, in order to ensure that the Bluetooth output signal can be diffracted in an indoor environment, the preset frequency band is the Sub-GHz frequency band, and the specific frequency range is between 27MHz and 960MHz.

[0055] As can be seen from the above technical solutions, the present application provides a Bluetooth device based on the Sub-GHz frequency band, the Bluetooth device includes a controller 500, a communication bus 400, a baseband processing unit 300, a modem 200 and a radio frequency transceiver unit 100, the controller 500 is connected to the baseband processing unit 300 through the communication bus 400, and the radio frequency transceiver unit 100 is connected to the baseband processing unit 300 through the modem 200. The radio frequency transceiver unit 100 includes a local oscillator circuit 140, a mixer circuit 120, a transceiver port 110 and an analog-to-digital conversion circuit 130, wherein the mixer circuit 120 can convert the input signal to an intermediate frequency, and the analog-to-digital conversion circuit 130 can perform analog-to-digital conversion on the intermediate frequency signal for processing by the baseband processing unit 300; the local oscillator circuit 140 includes a phase-locked loop 141 and a Sigma-Delta modulator 142, which can convert the signal output by the modem 200 into an analog signal of a preset frequency band and output it through the transceiver port 110. By setting the above structure, the Bluetooth device can convert the signal generated and processed by Bluetooth into a preset frequency band signal that is not easily attenuated, thereby avoiding problems such as rate reduction and cost increase when optimizing Bluetooth connection.

[0056] Similar parts between the embodiments provided in this application can be referenced to each other. The specific implementation methods provided above are only a few examples under the general concept of this application and do not constitute a limitation on the protection scope of this application. For those skilled in the art, any other implementation methods expanded based on the scheme of this application without creative work belong to the protection scope of this application.

Claims

1. A Bluetooth device based on the Sub-GHz frequency band, characterized in that: It includes a controller, a communication bus, a baseband processing unit, a modem and a radio frequency transceiver unit, wherein: The controller is connected to the baseband processing unit via a communication bus; The modem comprises a modulator and a demodulator, the input end of the modulator is connected to the baseband processing unit, and the output end of the demodulator is connected to the baseband processing unit; The radio frequency transceiver unit includes a local oscillator circuit, a mixer circuit, a transceiver port and an analog-to-digital conversion circuit, wherein the mixer circuit includes two parallel mixers, and the mixer circuit is connected in series with the transceiver port; the local oscillator circuit and the analog-to-digital conversion circuit are connected to the two mixers respectively; the output end of the analog-to-digital conversion circuit is connected to the input end of the demodulator; The local oscillator circuit includes a phase-locked loop and a Sigma-Delta modulator, wherein the phase-locked loop is connected to the output end of the modulator through the input end of the Sigma-Delta modulator; the Sigma-Delta modulator is used to perform digital-to-analog conversion on the output signal of the modulator output end; the phase-locked loop is used to convert the output signal of the Sigma-Delta modulator to a preset frequency band, wherein the preset frequency band is a Sub-GHz frequency band; the phase-locked loop includes a voltage-controlled oscillator, a loop filter, a frequency detector, a multi-mode divider and a reference signal end. ; The multi-mode frequency divider is connected to the output end of the Sigma-Delta modulator; the frequency detector is connected in series with the multi-mode frequency divider, and the frequency detector is connected in series with the input end of the voltage-controlled oscillator through the loop filter; the frequency detector is provided with two input ends, one input end of the frequency detector is connected to the multi-mode frequency divider, and the other input end of the frequency detector is connected to the reference signal end; the reference signal end is configured to output a reference signal with a frequency of the preset frequency band; the output end of the voltage-controlled oscillator is respectively connected to the output power amplifier and the multi-mode frequency divider.

2. The Sub-GHz band Bluetooth device according to claim 1, characterized in that: The radio frequency transceiver unit further comprises a power amplifier circuit, wherein the power amplifier circuit is provided with an output power amplifier and an input power amplifier; The input end of the output power amplifier is connected to the output end of the phase-locked loop, and the output end of the output power amplifier is connected in series with the transceiver port; the output power amplifier is used to amplify the power of the output signal of the phase-locked loop; The output end of the input power amplifier is connected in series with the mixer circuit, and the input end of the input power amplifier is connected in series with the transceiver port; the input power amplifier is used to amplify the power of the radio frequency signal received by the transceiver port.

3. The Sub-GHz band Bluetooth device according to claim 2, characterized in that: The RF transceiver unit also includes a transceiver switch, one end of which is connected in series with the transceiver port, and the other end is connected to the power amplifier circuit, and the transceiver switch is used to connect the transceiver port with the output power amplifier or connect the transceiver port with the input power amplifier.

4. The Sub-GHz band Bluetooth device according to claim 1, characterized in that: The phase-locked loop further includes a charge pump, which is connected in series between the phase frequency detector and the loop filter; the charge pump is used to gain the signal output by the phase frequency detector to eliminate spurious and quantization noise.

5. The Sub-GHz band Bluetooth device according to claim 1, characterized in that: The radio frequency transceiver unit further includes a filter circuit, which is arranged between the mixer circuit and the analog-to-digital conversion circuit to limit the bandwidth of the output signal of the mixer circuit.

6. A method for implementing Bluetooth based on the Sub-GHz frequency band, applied to the Bluetooth device according to any one of claims 1 to 5, characterized in that: Including the transmission implementation method and the reception implementation method: The steps of the transmission implementation method include: controlling the baseband processing unit to generate a baseband signal and performing GFSK modulation to obtain a modulation signal; performing Sigma-Delta modulation on the modulation signal to generate a radio frequency signal in an analog signal format; converting the radio frequency signal to a preset frequency band, the preset frequency band being a Sub-GHz frequency band; and sending the radio frequency signal in the preset frequency band through broadcasting; The steps of the receiving implementation method include: receiving a signal in the preset frequency band to obtain a received signal; converting the received signal to an intermediate frequency; performing analog-to-digital conversion on the received signal after the frequency conversion to generate a processed signal in a digital signal format; performing GFSK demodulation on the processed signal and sending it to a baseband processing unit for processing.

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