Sound source device, audio playback device system clock calibration method and system

Abstract

The application discloses a kind of sound source equipment system clock calibration methods, for audio playing system, audio playing system includes first wireless device and at least one second wireless device, first wireless device receives audio signal from second wireless device for playing, comprising: in the process that first wireless device and second wireless device carry out audio transmission, first wireless device sends clock calibration signal according to preset time interval, second wireless device does not include crystal oscillator;Second wireless device receives clock calibration signal, and calibrates the system clock of itself not by crystal oscillator according to clock calibration signal, so that the system clock of second wireless device is consistent with the system clock of first wireless device.Second wireless device does not need crystal oscillator, according to the interval time of pre-set, clock calibration signal is acquired in time, and accurate calibration is carried out to the clock signal of itself, to be used for the demand of work, both save hardware cost, also make second device itself have the same effect of crystal oscillator.

Description

Technical Field

[0001] This invention relates to the field of clock circuit technology, and in particular to a clock calibration method and system for audio source devices and audio playback devices. Background Technology

[0002] Crystal oscillators operate on the principle of the piezoelectric effect of quartz crystals, working in a resonant state to provide stable and precise single-frequency oscillation. Under normal operating conditions, the absolute frequency accuracy of ordinary crystal oscillators can reach 50 parts per million, while high-end crystal oscillators offer even higher accuracy. Some crystal oscillators can also have their frequency adjusted within a certain range by an applied voltage; these are called voltage-controlled oscillators (VCOs). Crystal oscillators have a wide range of applications, including but not limited to digital circuits, communication systems, microcontrollers, electronic devices, computers, watches, and other applications requiring highly stable signals. The main functions of crystal oscillators include: providing a frequency reference, generating stable pulse signals, phase-locked loops, filtering, and providing startup time for electronic devices.

[0003] To ensure the proper functioning of electronic devices, current technologies require the inclusion of active or passive crystal oscillators in the circuitry. This undoubtedly increases the hardware cost of electronic devices, especially small and micro electronic devices. Summary of the Invention

[0004] Based on the above situation, the main objective of this invention is to provide a clock calibration method for an audio source device or an audio playback device system. The first or second wireless device does not require a crystal oscillator. Instead, it periodically acquires the clock calibration signal sent by the second or first wireless device according to a preset interval and performs precise calibration of its own clock signal, which is not generated by a crystal oscillator. This saves hardware costs and also makes the first or second wireless device itself have the same effect as a crystal oscillator.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A method for calibrating the clock of an audio source device system, applied to an audio playback system, the audio playback system including a first wireless device and at least one second wireless device, wherein the first wireless device receives and plays audio signals from the second wireless device, the method comprising the steps of:

[0007] S100, during the audio transmission between the first wireless device and the second wireless device, the first wireless device sends a clock calibration signal according to a preset time interval, and the second wireless device does not contain a crystal oscillator.

[0008] S200, the second wireless device receives the clock calibration signal and calibrates its own system clock (not generated by the crystal oscillator) according to the clock calibration signal, so that the system clock of the second wireless device is consistent with the system clock of the first wireless device.

[0009] Preferably, the preset time interval is 50ms.

[0010] Preferably, the first wireless device transmits the clock calibration signal via broadcast or via point-to-point transmission.

[0011] Preferably, the step S200 of calibrating the system clock that is not generated by the crystal oscillator according to the clock calibration signal includes calibrating the oscillation frequency of the RC, LC and / or PLL modules in the second wireless device.

[0012] Preferably, calibrating the oscillation frequency of the RC and / or LC modules based on the oscillation frequency received by the second wireless module includes:

[0013] The adjustable resistor R and adjustable capacitor C in the RC module are adjusted according to the oscillation frequency received by the second wireless module, and / or the adjustable inductor L and adjustable capacitor C in the LC module are adjusted, thereby calibrating the oscillation frequency of the RC module and / or LC module in the second wireless device.

[0014] Preferably, calibrating the oscillation frequency of the PLL module in the second wireless device includes:

[0015] The second wireless device calculates an adjustment coefficient based on the received oscillation frequency. This adjustment coefficient, together with the original adjustment coefficient of the frequency divider in the PLL module, forms the input parameters of the phase detector in the PLL module, thereby achieving calibration of the oscillation frequency of the PLL module.

[0016] Preferably, when the control voltage obtained by the voltage-controlled oscillator in the PLL module fluctuates, the second wireless device can also output a compensation signal to the voltage-controlled oscillator to further compensate for the calibration performed according to the adjustment coefficient.

[0017] This invention also discloses a system clock calibration method for an audio playback device, applied to an audio playback system. The audio playback system includes a first wireless device and at least one second wireless device. The first wireless device receives audio signals from the second wireless device for playback. The method includes the following steps:

[0018] T100, during audio transmission between any second wireless device and the first wireless device, the second wireless device sends a clock calibration signal according to a preset time interval, and the first wireless device does not contain a crystal oscillator.

[0019] T200, the first wireless device receives the clock calibration signal and calibrates its own system clock (not generated by the crystal oscillator) according to the clock calibration signal, so that the system clock of the first wireless device is consistent with the system clock of the second wireless device.

[0020] Preferably, the preset time interval is 50ms.

[0021] Preferably, the second wireless device transmits the clock calibration signal via broadcast or via point-to-point transmission.

[0022] Preferably, the step T200 of calibrating the system clock that is not generated by the crystal oscillator according to the clock calibration signal includes calibrating the oscillation frequency of the RC, LC and / or PLL modules in the first wireless device.

[0023] Preferably, calibrating the oscillation frequency of the RC and / or LC modules based on the oscillation frequency received by the first wireless module includes:

[0024] The oscillation frequency of the RC module and / or the LC module in the first wireless device is calibrated by adjusting the value of the adjustable resistor R and the adjustable capacitor C in the RC module according to the oscillation frequency received by the first wireless module.

[0025] Preferably, calibrating the oscillation frequency of the PLL module in the first wireless device includes:

[0026] The first wireless device calculates an adjustment coefficient based on the received oscillation frequency. The adjustment coefficient, together with the original adjustment coefficient of the frequency divider in the PLL module, forms the input parameters of the phase detector in the PLL module, thereby achieving calibration of the oscillation frequency of the PLL module.

[0027] Preferably, when the control voltage obtained by the voltage-controlled oscillator in the PLL module fluctuates, the first wireless device can also output a compensation signal to the voltage-controlled oscillator to further compensate for the calibration performed according to the adjustment coefficient.

[0028] The present invention also discloses a computer-readable storage medium storing a program, wherein the program is configured to be executed to implement the audio source device system clock calibration method or the audio playback device system clock calibration method according to any one of the present invention.

[0029] The present invention also discloses a wireless audio playback system, comprising a wireless audio playback device and at least one wireless audio source device, wherein the wireless audio playback device receives and plays a first audio signal from the wireless audio source device.

[0030] The wireless audio playback device includes a crystal oscillator, while the wireless audio source device does not include a crystal oscillator. The wireless audio playback device is used to send a clock calibration signal according to a preset time interval during the audio transmission process between the wireless audio playback device and the wireless audio device.

[0031] The wireless audio source device is used to receive the clock calibration signal and calibrate its own system clock (not generated by a crystal oscillator) according to the clock calibration signal, so that the system clock of the wireless audio source device is consistent with the system clock of the wireless audio playback device.

[0032] Preferably, the preset time interval is 50ms.

[0033] Preferably, the wireless audio playback device includes a main control module and an antenna module, wherein the main control module is used to send a clock calibration signal through the antenna module according to a preset time interval.

[0034] Preferably, the main control module broadcasts the clock calibration signal through the antenna module according to a preset time interval, or sends the clock calibration signal in a point-to-point manner.

[0035] Preferably, the wireless audio source device includes an antenna module, a main control module, a calibration module, and a module to be calibrated.

[0036] The antenna module is used to receive the clock calibration signal sent by the wireless audio playback device;

[0037] The main control module is used to calculate the frequency modulation data of the wireless audio source device based on the clock calibration signal;

[0038] The calibration module is used to adjust the oscillation frequency of the module to be calibrated based on the frequency modulation data.

[0039] Preferably, the module to be calibrated includes an RC oscillator, an LC oscillator, and / or a PLL oscillator.

[0040] Preferably, adjusting the oscillation frequency of the RC oscillator and / or LC oscillator according to the frequency modulation data includes:

[0041] The calibration module adjusts the adjustable resistor R and adjustable capacitor C in the RC module according to the frequency modulation data, and / or adjusts the adjustable inductor L and adjustable capacitor C in the LC module, thereby calibrating the oscillation frequency of the RC and / or LC modules in the wireless audio source device.

[0042] Preferably, adjusting the oscillation frequency of the PLL oscillator according to the frequency modulation data includes:

[0043] The calibration module calculates the adjustment coefficient based on the frequency modulation data. The adjustment coefficient, together with the original adjustment coefficient of the frequency divider in the PLL oscillator, forms the input parameter of the phase detector in the PLL oscillator, thereby realizing the calibration of the oscillation frequency of the PLL oscillator.

[0044] Preferably, when the control voltage obtained by the voltage-controlled oscillator in the PLL oscillator fluctuates, the calibration module can also output a compensation signal to the voltage-controlled oscillator to further compensate for the calibration performed according to the adjustment coefficient.

[0045] Preferably, it also includes another wireless audio source device, and the wireless audio playback device further receives a second audio signal from the other wireless audio source device and combines it with the first audio signal for playback.

[0046] The present invention also discloses another wireless audio playback system, including a wireless audio playback device and at least one wireless audio source device, wherein the wireless audio playback device receives and plays a first audio signal from the wireless audio source device.

[0047] The wireless audio playback device does not include a crystal oscillator, the wireless audio source device does not include a crystal oscillator, and any of the wireless audio source devices is used to send a clock calibration signal according to a preset time interval during audio transmission with the wireless audio playback device.

[0048] The wireless audio playback device is used to receive the clock calibration signal and calibrate its own system clock (not generated by a crystal oscillator) according to the clock calibration signal, so that the system clock of the wireless audio playback device is consistent with the system clock of the wireless audio playback device.

[0049] Preferably, the preset time interval is 50ms.

[0050] Preferably, the wireless audio source device includes a main control module and an antenna module, wherein the main control module is used to send a clock calibration signal through the antenna module according to a preset time interval.

[0051] Preferably, the main control module broadcasts the clock calibration signal through the antenna module according to a preset time interval, or sends the clock calibration signal in a point-to-point manner.

[0052] Preferably, the wireless audio playback device includes an antenna module, a main control module, a calibration module, and a module to be calibrated.

[0053] The antenna module is used to receive the clock calibration signal sent by the wireless audio source device;

[0054] The main control module is used to calculate the frequency modulation data of the wireless audio playback device based on the clock calibration signal;

[0055] The calibration module is used to adjust the oscillation frequency of the module to be calibrated based on the frequency modulation data.

[0056] Preferably, the module to be calibrated includes an RC oscillator, an LC oscillator, and / or a PLL oscillator.

[0057] Preferably, adjusting the oscillation frequency of the RC oscillator and / or LC oscillator according to the frequency modulation data includes:

[0058] The calibration module adjusts the adjustable resistor R and adjustable capacitor C in the RC module according to the frequency modulation data, and / or adjusts the adjustable inductor L and adjustable capacitor C in the LC module, thereby calibrating the oscillation frequency of the RC and / or LC modules in the wireless audio playback device.

[0059] Preferably, adjusting the oscillation frequency of the PLL oscillator according to the frequency modulation data includes:

[0060] The calibration module calculates the adjustment coefficient based on the frequency modulation data. The adjustment coefficient, together with the original adjustment coefficient of the frequency divider in the PLL oscillator, forms the input parameter of the phase detector in the PLL oscillator, thereby realizing the calibration of the oscillation frequency of the PLL oscillator.

[0061] Preferably, when the control voltage obtained by the voltage-controlled oscillator in the PLL oscillator fluctuates, the calibration module can also output a compensation signal to the voltage-controlled oscillator to further compensate for the calibration performed according to the adjustment coefficient.

[0062] In the system clock calibration method of the present invention, the first wireless device or the second wireless device does not require a crystal oscillator. Instead, it periodically acquires the clock calibration signal sent by the second wireless device or the first wireless device according to a preset interval, and performs precise calibration of its own clock signal, which is not generated by a crystal oscillator, to meet the needs of operation. This saves hardware costs and also makes the first wireless device or the second device itself have the same effect as a crystal oscillator.

[0063] Other beneficial effects of the present invention will be explained in detail through the introduction of specific technical features and technical solutions in specific embodiments. Those skilled in the art should be able to understand the beneficial technical effects brought about by these technical features and technical solutions through the introduction of these technical features and technical solutions. Attached Figure Description

[0064] A preferred embodiment of the system clock calibration method according to the present invention will now be described with reference to the accompanying drawings. In the drawings:

[0065] Figure 1 This is a flowchart of a preferred embodiment of a sound source device system clock calibration method according to the present invention;

[0066] Figure 2 This is a schematic diagram of the internal structure of an RC module according to a preferred embodiment of the present invention;

[0067] Figure 3 This is a schematic diagram of the internal structure of a PLL module according to a preferred embodiment of the present invention;

[0068] Figure 4 This is a timing diagram of a clock calibration method for an audio source device system according to a preferred embodiment of the present invention;

[0069] Figure 5 This is a timing diagram of a clock calibration method for an audio source device system according to another preferred embodiment of the present invention;

[0070] Figure 6 This is a flowchart of a clock calibration method for an audio playback device system according to a preferred embodiment of the present invention;

[0071] Figure 7 This is a timing diagram of an audio playback device system clock calibration method according to a preferred embodiment of the present invention;

[0072] Figure 8 This is a timing diagram of an audio playback device system clock calibration method according to another preferred embodiment of the present invention;

[0073] Figure 9 This is a schematic diagram of a system clock calibration system according to a preferred embodiment of the present invention;

[0074] Figure 10 This is a block diagram of a wireless audio playback device and a wireless audio source device in a clock calibration system for an audio source device system according to a preferred embodiment of the present invention;

[0075] Figure 11 This is a schematic diagram illustrating an application scenario of a wireless audio system implemented according to the technical solution of the present invention;

[0076] Figure 12 This is a block diagram of a wireless audio playback device and a wireless audio source device in an audio playback device system clock calibration system according to a preferred embodiment of the present invention. Detailed Implementation

[0077] Figure 1 This is a flowchart of a clock calibration method for an audio source device system according to a preferred embodiment of the present invention. The method is applied to an audio playback system, which includes a first wireless device and at least one second wireless device. The first wireless device receives and plays audio signals from the second wireless device. The method includes the following steps:

[0078] S100, during audio transmission between the first wireless device and the second wireless device, the first wireless device sends a clock calibration signal according to a preset time interval, and the second wireless device does not contain a crystal oscillator. In a specific embodiment, the clock calibration signal may be the oscillation frequency data of the first wireless device.

[0079] S200, the second wireless device receives the clock calibration signal and calibrates its own system clock (not generated by the crystal oscillator) according to the clock calibration signal, so that the system clock of the second wireless device is consistent with the system clock of the first wireless device.

[0080] In the audio source device system clock calibration method of the present invention, the second wireless device does not require a crystal oscillator. Instead, it periodically acquires the clock calibration signal sent by the first wireless device according to a preset interval and performs precise calibration of its own clock signal, which is not generated by a crystal oscillator, to meet the needs of operation. This saves hardware costs and also makes the second device itself have the same effect as a crystal oscillator.

[0081] In a preferred embodiment, the preset time interval is 50ms. That is, during normal audio data (data) transmission and acknowledgment (ack) transmission, every 50ms, the first wireless device sends a clock calibration signal (data-f), and the second wireless device obtains this data to perform frequency modulation operation without an external crystal oscillator.

[0082] In a preferred embodiment, the first wireless device can transmit the clock calibration signal either via broadcast or via point-to-point communication. If the clock calibration signal is transmitted via broadcast, all second wireless devices can receive it through the broadcast communication channel without requiring an ACK response. If the clock calibration signal is transmitted via point-to-point communication, the second wireless devices need to establish a separate communication channel with the first wireless device and return an ACK response signal upon receiving the clock calibration signal.

[0083] When a point-to-point clock calibration signal is transmitted and frequency modulation is required for multiple second wireless devices, the first wireless device and the multiple second wireless devices can perform wireless frequency modulation operations through Time Division Multiple Access (TDMA).

[0084] In a preferred embodiment, the step S200 of calibrating the system clock, which is not generated by a crystal oscillator, according to the clock calibration signal may include calibrating the oscillation frequency of the RC / LC module and / or PLL module in the second wireless device.

[0085] In a preferred embodiment, calibrating the oscillation frequency of the RC and / or LC modules according to the oscillation frequency received by the second wireless module includes: adjusting the adjustable resistor R and adjustable capacitor C in the RC module according to the oscillation frequency received by the second wireless module, and / or adjusting the adjustable resistor L and adjustable capacitor C in the LC module, thereby calibrating the oscillation frequency of the RC and / or LC modules in the second wireless device.

[0086] The RC module is the oscillation source of the second wireless device itself. Since the second wireless device does not have an external crystal oscillator, the oscillation signal generated by its own RC module cannot meet the needs of other functional modules. Figure 2 The internal structure of an RC oscillator is shown, which mainly includes an adjustable resistor R and an adjustable capacitor C. The main control module of the second wireless device obtains the clock calibration signal of the first wireless device and generates its own internal oscillation signal by adjusting the adjustable resistor R and the adjustable capacitor C, which is then used for the operation requirements of other functional modules.

[0087] Similar to the RC module, the main control module of the second wireless device generates its own internal oscillation signal by adjusting the adjustable inductor L and the adjustable capacitor C based on the clock calibration signal obtained from the first wireless device, and uses it for the working requirements of other functional modules.

[0088] In a preferred embodiment, calibrating the oscillation frequency of the PLL module in the second wireless device includes: the second wireless device calculating an adjustment coefficient based on the received oscillation frequency, and the adjustment coefficient, together with the original adjustment coefficient of the frequency divider in the PLL module, forming the input parameters of the phase detector in the PLL module, thereby achieving the calibration of the oscillation frequency of the PLL module.

[0089] In specific implementation methods, such as Figure 3 As shown, the PLL module is the phase-locked loop of the second wireless device itself, including a phase detector (PD), a loop low-pass filter (LPF), a voltage-controlled oscillator (VCO), and a frequency divider. Because a PLL can automatically track the frequency of the input signal to the frequency of the output signal, it is typically used in closed-loop tracking circuits. During operation, when the frequency of the output signal equals the frequency of the input signal, the output voltage maintains a fixed phase difference with the input voltage; that is, the phase of the output voltage is locked to the input voltage.

[0090] A phase detector (PD), also known as a phase comparator, is usually composed of an analog multiplier. Its function is to detect the phase difference between the input signal and the output signal and convert the detected phase difference signal into a phase difference voltage signal for output. This phase difference voltage signal is filtered by a low-pass filter to form the control voltage signal of the voltage-controlled oscillator (VCO). This control voltage signal controls the frequency of the VCO output signal.

[0091] The working principle of a phase detector: Let the external input signal voltage and the output signal voltage of the voltage-controlled oscillator be respectively:

[0092] U i (t)=u m sin[ω i t+θ i (t)];

[0093] U o (t)=u om cos[ω o t+θ o (t)].

[0094] ω in the formula o The angular frequency of a voltage-controlled oscillator when the input control voltage is zero or a DC voltage is called the natural angular frequency of the circuit. The output voltage u of the analog multiplier... D for:

[0095] u D =Ku i (t)u o (t)=KU m U om sin[ω i t+θi (t)]cos[ω o t+θ o (t)]

[0096] =KU m U om sin[ω i t+θ i (t)+ω o t+θ o (t)]+KU m U om sin{[ω i t+θ i (t)]-[ω o t+θ o (t)]}

[0097] The sum-frequency component in the above equation is filtered out using a low-pass filter LF, and the remaining difference-frequency component is used as the input control voltage u of the voltage-controlled oscillator. C (t). That is, u C (t) is:

[0098] u C (t)=KU m U om sin{[ω i t+θ i (t)]-[ω o t+θ o (t)]}=U dm sin{(ω i -ω o )+[θ i (t)-θ o (t)]t}

[0099] ω in the formula i Let θ be the instantaneous angular frequency of the input signal. i (t) and θ o Let ω(t) and θ(t) be the instantaneous phases of the input and output signals, respectively. According to the phasor relationship, the relationship between the instantaneous frequency and the instantaneous phase is: ω(t) = dθ(t) / dt, that is, θ(t) = ∫ω(t)dt + θ do , then θ d =(ω i -ω o )t+θ i (t)-θ o Taking the differential of both sides of (t), we can obtain the relationship for the frequency difference as follows:

[0100] dθ d / dt=d(ω i -ω o )t / dt+d[θi (t)-θ o (t)] / dt

[0101] The above equation equals zero, indicating that the phase-locked loop has entered a phase-locked state. At this time, the frequency and phase of the output and input signals remain constant. c (t) is a constant value. When the above equation is not equal to zero, it indicates that the phase of the phase-locked loop is not yet locked, and the frequencies of the input and output signals are not equal. c (t) varies over time.

[0102] This characteristic indicates that the oscillation frequency ω of the voltage-controlled oscillator u With ω o Centered on the input signal voltage u c The property changes with the change of (t). The expression for this property is: ω u (t)=ω o +K o u c (t). The above formula shows that when u c (t) As time changes, the oscillation frequency ω of the voltage-controlled oscillator u As time progresses, the phase-locked loop (PLL) enters a "frequency traction" state, automatically tracking and capturing the frequency of the input signal, causing the PLL to enter a locked state and maintain ω. o =ω i The state remains unchanged.

[0103] The main function of the LPF filter is to convert the square wave voltage output by the phase detector, which may be high or low, into a stable DC voltage.

[0104] A voltage-controlled oscillator (VCO) is mainly used to control the oscillation frequency with voltage; the higher the input voltage, the higher the output frequency.

[0105] Based on the working principle of the PLL module described above, such as Figure 3 As shown, the second wireless device acquires the clock calibration signal sent by the first wireless device. The calibration module generates a coefficient k for the frequency divider in the PLL of the second wireless device. Combined with the frequency divider's own coefficient n(fo / fi), the coefficient parameter of the phase detector PD is (n+k)fo / fi. Here, coefficient k has a precise adjustment effect on the final output frequency fo.

[0106] In a preferred embodiment, when the control voltage acquired by the voltage-controlled oscillator in the PLL module fluctuates, the second wireless device can also output a compensation signal to the voltage-controlled oscillator to further compensate for the calibration performed according to the adjustment coefficient. For example... Figure 3As shown, when the control voltage uc acquired by the voltage-controlled oscillator (VCO) fluctuates or is itself unstable, the calibration module of the second wireless device can also directly output a compensation signal ub to the VCO as compensation for insufficient adjustment of the coefficient k.

[0107] The wireless communications, wireless devices, and wireless broadcasting mentioned above can include WiFi, Bluetooth, Zigbee, and other types.

[0108] Figure 4 The diagram illustrates a timing sequence for a preferred embodiment of a clock calibration method for an audio source device system according to the present invention. A first wireless device periodically initiates FM broadcasts to a second wireless device within a preset fixed time period (T). As shown in the diagram, the communication between the first and second wireless devices includes data transmission and acknowledgment transmission (ack). Assuming that the first wireless device initiates an FM broadcast (data-f) at 50ms, and the second wireless device or other wireless devices acquire this broadcast data, they can perform the aforementioned FM operation without an external crystal oscillator. Thus, the second wireless device can operate and communicate normally without a crystal oscillator.

[0109] Similarly, such as Figure 5 As shown, the first wireless device initiates frequency modulation operations to the second wireless device at preset fixed time periods (T). The first wireless device and the second wireless device establish a point-to-point connection. The second wireless device obtains the frequency modulation data (data-f) of the first wireless device and returns an acknowledgment signal (ack), thus enabling the aforementioned frequency modulation operation without an external crystal oscillator.

[0110] Figure 6 This is a flowchart of a clock calibration method for an audio playback device system according to a preferred embodiment of the present invention. The method is applied to an audio playback system, which includes a first wireless device and at least one second wireless device. The first wireless device receives audio signals from the second wireless device for playback. The method includes the following steps:

[0111] T100, during audio transmission between any of the second wireless devices and the first wireless device, the second wireless device sends a clock calibration signal according to a preset time interval, wherein the first wireless device does not contain a crystal oscillator. In a specific embodiment, the clock calibration signal may be the oscillation frequency data of the second wireless device.

[0112] T200, the first wireless device receives the clock calibration signal and calibrates its own system clock (not generated by the crystal oscillator) according to the clock calibration signal, so that the system clock of the first wireless device is consistent with the system clock of the first wireless device.

[0113] In the system clock calibration method of the present invention, the first wireless device does not require a crystal oscillator. Instead, it periodically acquires the clock calibration signal sent by the second wireless device according to a preset interval and performs precise calibration of its own clock signal, which is not generated by a crystal oscillator, to meet the needs of operation. This saves hardware costs and also makes the first device itself have the same effect as a crystal oscillator.

[0114] In a preferred embodiment, the preset time interval is 50ms. That is, during normal audio data (data) transmission and acknowledgment (ack) transmission between the first wireless device and any second wireless device, every 50ms, the second wireless device sends a clock calibration signal (data-f), and the first wireless device obtains this data to perform frequency modulation operation without an external crystal oscillator.

[0115] In a preferred embodiment, the second wireless device can transmit the clock calibration signal either via broadcast or via point-to-point communication. If the clock calibration signal is transmitted via broadcast, the first wireless device can receive the clock calibration signal through the broadcast communication channel without requiring an ACK response. If the clock calibration signal is transmitted via point-to-point communication, the first wireless device needs to establish a separate communication channel with the second wireless device and return an ACK response signal after receiving the clock calibration signal.

[0116] When a point-to-point method is used to send clock calibration signals, the first wireless device and multiple second wireless devices can perform wireless frequency modulation operations through Time Division Multiple Access (TDMA).

[0117] In a preferred embodiment, the step T200 of calibrating the system clock, which is not generated by a crystal oscillator, according to the clock calibration signal may include calibrating the oscillation frequency of the RC / LC module and / or PLL module in the first wireless device.

[0118] In a preferred embodiment, calibrating the oscillation frequency of the RC and / or LC modules based on the oscillation frequency received by the first wireless module includes: adjusting the adjustable resistor R and adjustable capacitor C in the RC module based on the oscillation frequency received by the first wireless module, and / or adjusting the adjustable resistor L and adjustable capacitor C in the LC module, thereby calibrating the oscillation frequency of the RC and / or LC modules in the first wireless device.

[0119] In a preferred embodiment, calibrating the oscillation frequency of the PLL module in the first wireless device includes: the first wireless device calculating an adjustment coefficient based on the received oscillation frequency, and the adjustment coefficient, together with the original adjustment coefficient of the frequency divider in the PLL module, forming the input parameters of the phase detector in the PLL module, thereby achieving calibration of the oscillation frequency of the PLL module.

[0120] In a preferred embodiment, when the control voltage acquired by the voltage-controlled oscillator in the PLL module fluctuates, the first wireless device can also output a compensation signal to the voltage-controlled oscillator to further compensate for the calibration performed according to the adjustment coefficient.

[0121] Figure 7 The diagram illustrates a timing sequence for a clock calibration method in an audio playback device system according to a preferred embodiment of the present invention. The second wireless device periodically initiates FM broadcasts to the first wireless device within a preset fixed time period (T). As shown in the diagram, the communication between the first and second wireless devices includes data transmission and acknowledgment transmission (ack). Assuming that the calculation begins from time t1, at 50ms, the second wireless device initiates an FM broadcast (data-f). The first wireless device receives this broadcast data and can then perform the aforementioned FM operation without an external crystal oscillator. Thus, the first wireless device can operate and communicate normally without a crystal oscillator.

[0122] Similarly, such as Figure 8 As shown, the second wireless device initiates frequency modulation operations to the first wireless device at preset fixed time periods (T). The first wireless device and the second wireless device establish a point-to-point connection. The first wireless device obtains the frequency modulation data (data-f) of the second wireless device and returns an acknowledgment signal (ack), thus enabling the aforementioned frequency modulation operation without an external crystal oscillator.

[0123] The present invention also discloses a computer-readable storage medium storing a program, wherein the program is configured to be executed to implement the audio source device system clock calibration method or the audio playback device system clock calibration method described in the present invention.

[0124] This invention also discloses a wireless audio playback system, such as... Figure 9As shown, the device includes a wireless audio playback device and at least one wireless audio source device. Wireless audio source devices 1, 2, 3…N are shown in the figure. The wireless audio playback device receives and plays a first audio signal from the wireless audio source devices. The wireless audio playback device includes a crystal oscillator, while the wireless audio source devices do not. During audio transmission between the wireless audio playback device and the wireless audio source devices, the wireless audio playback device sends a clock calibration signal at a preset time interval. The wireless audio source device receives the clock calibration signal and calibrates its own system clock (not generated by the crystal oscillator) according to the clock calibration signal, so that the system clock of the wireless audio source device is consistent with the system clock of the wireless audio playback device.

[0125] In a preferred embodiment, the preset time interval is 50ms.

[0126] In a preferred embodiment, the wireless audio playback device includes a main control module and an antenna module, wherein the main control module is used to send a clock calibration signal through the antenna module according to a preset time interval.

[0127] In a preferred embodiment, the main control module broadcasts the clock calibration signal through the antenna module according to a preset time interval, or sends the clock calibration signal in a point-to-point manner.

[0128] In a preferred embodiment, such as Figure 10 As shown, the wireless audio source device includes an antenna module, a main control module, a calibration module, and a module to be calibrated. The antenna module is used to receive a clock calibration signal sent by the wireless audio playback device. The main control module is used to calculate the frequency modulation data of the wireless audio source device based on the clock calibration signal. The calibration module is used to adjust the oscillation frequency of the module to be calibrated based on the frequency modulation data.

[0129] In a preferred embodiment, the module to be calibrated includes an RC oscillator, an LC oscillator, and / or a PLL oscillator.

[0130] In a preferred embodiment, adjusting the oscillation frequency of the RC oscillator and / or LC oscillator according to the frequency modulation data includes: the calibration module adjusting the adjustable resistor R and adjustable capacitor C in the RC module according to the frequency modulation data, and / or adjusting the adjustable inductor L and adjustable capacitor C in the LC module, thereby calibrating the oscillation frequency of the RC and / or LC modules in the wireless audio source device.

[0131] In a preferred embodiment, adjusting the oscillation frequency of the PLL oscillator according to the frequency modulation data includes: the calibration module calculating an adjustment coefficient based on the frequency modulation data; the adjustment coefficient and the original adjustment coefficient of the frequency divider in the PLL oscillator together form the input parameters of the phase detector in the PLL oscillator, thereby achieving calibration of the oscillation frequency of the PLL oscillator.

[0132] In a preferred embodiment, when the control voltage obtained by the voltage-controlled oscillator in the PLL oscillator fluctuates, the calibration module can also output a compensation signal to the voltage-controlled oscillator to further compensate for the calibration performed according to the adjustment coefficient.

[0133] In a preferred embodiment, the wireless audio playback system may further include another wireless audio source device, which also receives a second audio signal from the other wireless audio source device and combines it with the first audio signal for playback.

[0134] Figure 11 This is a schematic diagram illustrating an application scenario of the wireless audio system implemented according to the technical solution of the present invention. The first wireless device (Bluetooth speaker) is a wireless audio playback device in the audio playback system, and the second wireless device (microphone) is a wireless audio source device in the audio playback system, including three microphones, each of which does not use a crystal oscillator. A mobile phone is another wireless audio source device in the audio playback system. During the Bluetooth audio data transmission interval between the microphones and the Bluetooth speaker, at preset intervals (50ms), the Bluetooth speaker will send a clock calibration signal to each microphone for calibration via wireless communication. This wireless communication calibration includes point-to-point and / or broadcast methods. This saves on the crystal oscillators inside each microphone, reducing the hardware cost of the electronic product.

[0135] In a specific implementation, the Bluetooth speaker may not use a crystal oscillator, while the wireless microphones include crystal oscillators. During the Bluetooth audio data transmission intervals between the microphone and the Bluetooth speaker, at preset intervals (50ms), each microphone, while communicating with the Bluetooth speaker, will send a clock calibration signal to the Bluetooth speaker for calibration. This wireless communication calibration includes point-to-point and / or broadcast methods. This saves on the internal crystal oscillator of the Bluetooth device, reducing the hardware cost of the electronic product.

[0136] This invention also discloses another wireless audio playback system, such as Figure 9As shown, the system includes a wireless audio playback device and at least one wireless audio source device. Wireless audio source devices 1, 2, 3…N are shown in the figure. The wireless audio playback device receives and plays a first audio signal from the wireless audio source device. The wireless audio playback device does not include a crystal oscillator, while the wireless audio source device does. Each of the wireless audio source devices is used to send a clock calibration signal according to a preset time interval during audio transmission with the wireless audio playback device. The wireless audio playback device is used to receive the clock calibration signal and calibrate its own system clock (not generated by the crystal oscillator) according to the clock calibration signal, so that the system clock of the wireless audio playback device is consistent with the system clock of the wireless audio source device.

[0137] In a preferred embodiment, the preset time interval is 50ms.

[0138] In a preferred embodiment, the wireless audio source device includes a main control module and an antenna module, wherein the main control module is used to send a clock calibration signal through the antenna module according to a preset time interval.

[0139] In a preferred embodiment, the main control module broadcasts the clock calibration signal through the antenna module according to a preset time interval, or sends the clock calibration signal in a point-to-point manner.

[0140] In a preferred embodiment, such as Figure 12 As shown, the wireless audio playback device includes an antenna module, a main control module, a calibration module, and a module to be calibrated. The antenna module is used to receive a clock calibration signal sent by the wireless audio source device. The main control module is used to calculate the frequency modulation data of the wireless audio playback device based on the clock calibration signal. The calibration module is used to adjust the oscillation frequency of the module to be calibrated based on the frequency modulation data.

[0141] In a preferred embodiment, the module to be calibrated includes an RC oscillator, an LC oscillator, and / or a PLL oscillator.

[0142] In a preferred embodiment, adjusting the oscillation frequency of the RC oscillator and / or LC oscillator according to the frequency modulation data includes: the calibration module adjusting the adjustable resistor R and adjustable capacitor C in the RC module according to the frequency modulation data, and / or adjusting the adjustable inductor L and adjustable capacitor C in the LC module, thereby calibrating the oscillation frequency of the RC and / or LC modules in the wireless audio playback device.

[0143] In a preferred embodiment, adjusting the oscillation frequency of the PLL oscillator according to the frequency modulation data includes: the calibration module calculating an adjustment coefficient based on the frequency modulation data; the adjustment coefficient and the original adjustment coefficient of the frequency divider in the PLL oscillator together form the input parameters of the phase detector in the PLL oscillator, thereby achieving calibration of the oscillation frequency of the PLL oscillator.

[0144] In a preferred embodiment, when the control voltage obtained by the voltage-controlled oscillator in the PLL oscillator fluctuates, the calibration module can also output a compensation signal to the voltage-controlled oscillator to further compensate for the calibration performed according to the adjustment coefficient.

[0145] It should be noted that the use of step numbers (letters or numbers) to refer to certain specific method steps in this invention is merely for the purpose of convenience and brevity in description, and is by no means intended to restrict the order of these method steps. Those skilled in the art will understand that the order of the relevant method steps should be determined by the technology itself and should not be unduly restricted by the existence of step numbers.

[0146] Those skilled in the art will understand that, without conflict, the above-mentioned preferred solutions can be freely combined and superimposed.

[0147] It should be understood that the above embodiments are merely exemplary and not restrictive. Various obvious or equivalent modifications or substitutions that can be made by those skilled in the art regarding the above details without departing from the basic principles of the present invention will be included within the scope of the claims of the present invention.

Claims

1. A method for calibrating a system clock of a sound source device, applied to an audio playing system, the audio playing system comprising a first wireless device and at least one second wireless device, the first wireless device receiving an audio signal from the second wireless device for playing, and the method characterized in that, The method includes the following steps: S100, during the audio transmission between the first wireless device and the second wireless device, the first wireless device sends a clock calibration signal according to a preset time interval, and the second wireless device does not contain a crystal oscillator. S200, the second wireless device receives the clock calibration signal and calibrates its own system clock (not generated by the crystal oscillator) according to the clock calibration signal, so that the system clock of the second wireless device is consistent with the system clock of the first wireless device. The clock calibration signal is the oscillation frequency data of the first wireless device; Calibrating its own non-crystal-generated system clock according to the clock calibration signal includes calibrating the oscillation frequency of the RC, LC and / or PLL modules in the second wireless device.

2. The audio source device system clock calibration method of claim 1, wherein, The preset time interval is 50ms.

3. The audio source device system clock calibration method of claim 1, wherein, The first wireless device transmits the clock calibration signal via broadcast or via point-to-point transmission.

4. The audio source device system clock calibration method of claim 1, wherein, Calibrling the oscillation frequency of the RC and / or LC modules based on the oscillation frequency received by the second wireless device includes: The adjustable resistor R and adjustable capacitor C in the RC module are adjusted according to the oscillation frequency received by the second wireless device, and / or the adjustable inductor L and adjustable capacitor C in the LC module are adjusted, thereby calibrating the oscillation frequency of the RC module and / or LC module in the second wireless device.

5. The audio source device system clock calibration method of claim 1, wherein, Calibrling the oscillation frequency of the PLL module in the second wireless device includes: The second wireless device calculates an adjustment coefficient based on the received oscillation frequency. This adjustment coefficient, together with the original adjustment coefficient of the frequency divider in the PLL module, forms the input parameters of the phase detector in the PLL module, thereby achieving calibration of the oscillation frequency of the PLL module.

6. The audio source device system clock calibration method of claim 5, wherein, When the control voltage obtained by the voltage-controlled oscillator in the PLL module fluctuates, the second wireless device can also output a compensation signal to the voltage-controlled oscillator to further compensate for the calibration performed according to the adjustment coefficient.

7. A method for calibrating a system clock of an audio playing device, applied to an audio playing system, the audio playing system comprising a first wireless device and at least one second wireless device, the first wireless device receiving an audio signal from the second wireless device for playing, characterized in that, The method includes the following steps: T100, during audio transmission between any second wireless device and the first wireless device, the second wireless device sends a clock calibration signal according to a preset time interval, and the first wireless device does not contain a crystal oscillator. T200, the first wireless device receives the clock calibration signal and calibrates its own system clock (not generated by the crystal oscillator) according to the clock calibration signal, so that the system clock of the first wireless device is consistent with the system clock of the second wireless device; The clock calibration signal is the oscillation frequency data of the second wireless device; Calibrating its own non-crystal-generated system clock according to the clock calibration signal includes calibrating the oscillation frequency of the RC, LC and / or PLL modules in the first wireless device.

8. The audio playback device system clock calibration method of claim 7, wherein, The preset time interval is 50ms.

9. The audio playback device system clock calibration method according to claim 7, characterized in that, The second wireless device transmits the clock calibration signal via broadcast or via point-to-point transmission.

10. The audio playback device system clock calibration method according to claim 7, characterized in that, Calibrling the oscillation frequency of the RC and / or LC modules based on the oscillation frequency received by the first wireless device includes: The oscillation frequency of the RC module and / or the LC module in the first wireless device is calibrated by adjusting the value of the adjustable resistor R and the adjustable capacitor C in the RC module according to the oscillation frequency received by the first wireless device.

11. The audio playback device system clock calibration method according to claim 7, characterized in that, Calibrling the oscillation frequency of the PLL module in the first wireless device includes: The first wireless device calculates an adjustment coefficient based on the received oscillation frequency. The adjustment coefficient, together with the original adjustment coefficient of the frequency divider in the PLL module, forms the input parameters of the phase detector in the PLL module, thereby achieving calibration of the oscillation frequency of the PLL module.

12. The audio playback device system clock calibration method according to claim 11, characterized in that, When the control voltage obtained by the voltage-controlled oscillator in the PLL module fluctuates, the first wireless device can also output a compensation signal to the voltage-controlled oscillator to further compensate for the calibration performed according to the adjustment coefficient.

13. A computer-readable storage medium, characterized in that, The storage medium stores a program, wherein the program is executed to implement the audio source device system clock calibration method as described in any one of claims 1-6, or the audio playback device system clock calibration method as described in any one of claims 7-12.

14. A wireless audio playback system, characterized in that, It includes a wireless audio playback device and at least one wireless audio source device, wherein the wireless audio playback device receives and plays a first audio signal from the wireless audio source device. The wireless audio playback device includes a crystal oscillator, while the wireless audio source device does not include a crystal oscillator. The wireless audio playback device is used to send a clock calibration signal according to a preset time interval during the audio transmission process between the wireless audio playback device and the wireless audio source device. The wireless audio source device is used to receive the clock calibration signal and calibrate its own system clock (not generated by a crystal oscillator) according to the clock calibration signal, so that the system clock of the wireless audio source device is consistent with the system clock of the wireless audio playback device. The wireless audio source device includes an antenna module, a main control module, a calibration module, and a module to be calibrated. The antenna module is used to receive the clock calibration signal sent by the wireless audio playback device; The main control module is used to calculate the frequency modulation data of the wireless audio source device based on the clock calibration signal; The calibration module is used to adjust the oscillation frequency of the module to be calibrated based on the frequency modulation data.

15. The wireless audio playback system according to claim 14, characterized in that, The preset time interval is 50ms.

16. The wireless audio playback system according to claim 14, characterized in that, The wireless audio playback device includes a main control module and an antenna module. The main control module is used to send a clock calibration signal through the antenna module according to a preset time interval.

17. The wireless audio playback system according to claim 16, characterized in that, The main control module broadcasts the clock calibration signal through the antenna module at preset time intervals, or sends the clock calibration signal in a point-to-point manner.

18. The wireless audio playback system according to claim 14, characterized in that, The module to be calibrated includes an RC oscillator, an LC oscillator, and / or a PLL oscillator.

19. The wireless audio playback system according to claim 18, characterized in that, Adjusting the oscillation frequency of the RC oscillator and / or LC oscillator based on the frequency modulation data includes: The calibration module adjusts the adjustable resistor R and adjustable capacitor C in the RC oscillator according to the frequency modulation data, and / or adjusts the adjustable inductor L and adjustable capacitor C in the LC oscillator, thereby calibrating the oscillation frequency of the RC and / or LC oscillators in the wireless audio source device.

20. The wireless audio playback system according to claim 18, characterized in that, Adjusting the oscillation frequency of the PLL oscillator based on the frequency modulation data includes: The calibration module calculates the adjustment coefficient based on the frequency modulation data. The adjustment coefficient, together with the original adjustment coefficient of the frequency divider in the PLL oscillator, forms the input parameter of the phase detector in the PLL oscillator, thereby realizing the calibration of the oscillation frequency of the PLL oscillator.

21. The wireless audio playback system according to claim 20, characterized in that, When the control voltage obtained by the voltage-controlled oscillator in the PLL oscillator fluctuates, the calibration module can also output a compensation signal to the voltage-controlled oscillator to further compensate for the calibration performed according to the adjustment coefficient.

22. The wireless audio playback system according to any one of claims 14-21, characterized in that, It also includes another wireless audio source device, and the wireless audio playback device also receives a second audio signal from the other wireless audio source device and combines it with the first audio signal for playback.

23. A wireless audio playback system, characterized in that, It includes a wireless audio playback device and at least one wireless audio source device, wherein the wireless audio playback device receives and plays a first audio signal from the wireless audio source device. The wireless audio playback device does not include a crystal oscillator, the wireless audio source device includes a crystal oscillator, and any of the wireless audio source devices is used to send a clock calibration signal according to a preset time interval during audio transmission with the wireless audio playback device. The wireless audio playback device is used to receive the clock calibration signal and calibrate its own system clock (not generated by a crystal oscillator) according to the clock calibration signal, so that the system clock of the wireless audio playback device is consistent with the system clock of the wireless audio source device. The wireless audio playback device includes an antenna module, a main control module, a calibration module, and a module to be calibrated. The antenna module is used to receive the clock calibration signal sent by the wireless audio source device; The main control module is used to calculate the frequency modulation data of the wireless audio playback device based on the clock calibration signal; The calibration module is used to adjust the oscillation frequency of the module to be calibrated based on the frequency modulation data.

24. The wireless audio playback system according to claim 23, characterized in that, The preset time interval is 50ms.

25. The wireless audio playback system according to claim 23, characterized in that, The wireless audio source device includes a main control module and an antenna module. The main control module is used to send a clock calibration signal through the antenna module according to a preset time interval.

26. The wireless audio playback system according to claim 25, characterized in that, The main control module broadcasts the clock calibration signal through the antenna module at preset time intervals, or sends the clock calibration signal in a point-to-point manner.

27. The wireless audio playback system according to claim 23, characterized in that, The module to be calibrated includes an RC oscillator, an LC oscillator, and / or a PLL oscillator.

28. The wireless audio playback system according to claim 27, characterized in that, Adjusting the oscillation frequency of the RC oscillator and / or LC oscillator based on the frequency modulation data includes: The calibration module adjusts the adjustable resistor R and adjustable capacitor C in the RC oscillator according to the frequency modulation data, and / or adjusts the adjustable inductor L and adjustable capacitor C in the LC oscillator, thereby calibrating the oscillation frequency of the RC and / or LC oscillators in the wireless audio playback device.

29. The wireless audio playback system according to claim 27, characterized in that, Adjusting the oscillation frequency of the PLL oscillator based on the frequency modulation data includes: The calibration module calculates the adjustment coefficient based on the frequency modulation data. The adjustment coefficient, together with the original adjustment coefficient of the frequency divider in the PLL oscillator, forms the input parameter of the phase detector in the PLL oscillator, thereby realizing the calibration of the oscillation frequency of the PLL oscillator.

30. The wireless audio playback system according to claim 29, characterized in that, When the control voltage obtained by the voltage-controlled oscillator in the PLL oscillator fluctuates, the calibration module can also output a compensation signal to the voltage-controlled oscillator to further compensate for the calibration performed according to the adjustment coefficient.

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