CN113556154A - Low-delay transmission method between Bluetooth chips - Google Patents
Low-delay transmission method between Bluetooth chips Download PDFInfo
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- CN113556154A CN113556154A CN202110672719.XA CN202110672719A CN113556154A CN 113556154 A CN113556154 A CN 113556154A CN 202110672719 A CN202110672719 A CN 202110672719A CN 113556154 A CN113556154 A CN 113556154A
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- 230000005236 sound signal Effects 0.000 claims abstract description 25
- OIGNJSKKLXVSLS-VWUMJDOOSA-N prednisolone Chemical compound O=C1C=C[C@]2(C)[C@H]3[C@@H](O)C[C@](C)([C@@](CC4)(O)C(=O)CO)[C@@H]4[C@@H]3CCC2=C1 OIGNJSKKLXVSLS-VWUMJDOOSA-N 0.000 claims description 9
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W4/00—Services specially adapted for wireless communication networks; Facilities therefor
- H04W4/80—Services using short range communication, e.g. near-field communication [NFC], radio-frequency identification [RFID] or low energy communication
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B5/00—Near-field transmission systems, e.g. inductive or capacitive transmission systems
- H04B5/40—Near-field transmission systems, e.g. inductive or capacitive transmission systems characterised by components specially adapted for near-field transmission
- H04B5/48—Transceivers
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L7/00—Arrangements for synchronising receiver with transmitter
- H04L7/02—Speed or phase control by the received code signals, the signals containing no special synchronisation information
- H04L7/033—Speed or phase control by the received code signals, the signals containing no special synchronisation information using the transitions of the received signal to control the phase of the synchronising-signal-generating means, e.g. using a phase-locked loop
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W56/00—Synchronisation arrangements
- H04W56/001—Synchronization between nodes
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W56/00—Synchronisation arrangements
- H04W56/004—Synchronisation arrangements compensating for timing error of reception due to propagation delay
- H04W56/005—Synchronisation arrangements compensating for timing error of reception due to propagation delay compensating for timing error by adjustment in the receiver
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Abstract
A low-delay transmission method between Bluetooth chips relates to a wireless signal transmission technology, which connects an intelligent terminal with Bluetooth function or a common Bluetooth chip with a Bluetooth chip, then obtains the sampling frequency of a sending end and a receiving end by using the built-in software of the Bluetooth chip, then calculates the deviation value between the sending end signal and the receiving end sampling frequency, and then makes the audio signals of the sending end and the receiving end the same by a sampling frequency adjusting method.
Description
Technical Field
The invention relates to the technical field of wireless transmission, in particular to a low-delay transmission method between Bluetooth chips.
Background
The Bluetooth equipment is taken as the current mainstream wireless transmission technology, the application field is very wide, the problem of receiving and sending short-distance information is mainly solved through the technology, the influence of the internet network quality is not limited, the requirement of the communication technology of the Bluetooth is higher and higher due to the requirement of practical application, and meanwhile, the conditions of interruption, jumping, poor quality and the like of signals occur in the transmission process due to the problems of more protocol layers, transmission frequency difference, processing capacity of a chip and the like.
Sampling frequencies generated by any equipment and chips cannot be completely consistent, in the process of transmitting and transmitting the Bluetooth signals, the same frequency of the signals is very important in order to ensure that the signal playing effect is optimal, most of the current Bluetooth playing terminals do not optimize or process the signals, and the output signal effect is poor; or the processing is excessive, and the output signal is distorted; or other signal loss and interruption conditions occur.
Chinese patent publication No. CN112256087A discloses a dynamic digital signal synchronization algorithm, and the present invention refers to the relevant contents in the patent.
Disclosure of Invention
The invention aims to provide a low-delay transmission method between Bluetooth chips aiming at the defects and shortcomings of the prior art, which utilizes a sampling frequency adjusting method and can realize that the data infinitely close to the original signal can be output without any signal adjustment on the signal by a hardware or software adjusting method, so that the listening effect of the audio frequency is optimal.
In order to achieve the purpose, the invention adopts the following technical scheme: a low-delay transmission method between Bluetooth chips comprises the following steps:
connecting an intelligent terminal with a Bluetooth function or a common Bluetooth chip with a Bluetooth chip to form a sending end and a receiving end;
step two, acquiring the first sampling frequency F of the sending end in the step one by using the built-in software of the Bluetooth chip0And a second sampling frequency F of the receiving end1And the output audio signal M of the Bluetooth chip of the sending end0And the output audio signal M of the Bluetooth chip of the receiving end1Calculating a first sampling frequency F by said software0And a second sampling frequency F1The deviation value delta F therebetween;
step three, according to the delta F in the step two, the output audio signal M of the Bluetooth chip at the receiving end is enabled to be obtained by adjusting a digital signal dynamic synchronization algorithm or adjusting a phase-locked loop PLL1Output audio signal M of Bluetooth chip of sending terminal0；
And step four, outputting the audio.
Further, Δ F in the second step is a deviation value between the clock of the second sampling frequency at the receiving end and the first sampling frequency at the transmitting end, and the deviation value is calculated by measuring a time interval PT of receiving the data packet of the second sampling frequency at the receiving end.
Further, the calculation formula of the deviation value between the clock of the second sampling frequency at the receiving end and the first sampling frequency at the transmitting end is RXppm 1000000 × (PTrx-PT)/PT,
in the formula (I), the compound is shown in the specification,
RXppm represents the deviation of the time,
RTrx denotes the time interval of packet reception at the second sampling frequency at the receiving end,
RT denotes a time interval of packet reception at the first sampling frequency of the transmitting end.
Further, the dynamic synchronization algorithm for adjusting digital signals or the PLL method in step three is a hardware adjustment method or a digital signal processing method, the hardware adjustment method is a PLL method supporting fractional frequency division, the fractional bits are at least 24 bits, the minimum adjustable precision is obtained by a formula 1000000/(16 × 1024 × 1024-1) ═ 0.0596ppm, the digital signal processing method utilizes a dynamic digital audio synchronization method in software, the fractional bits of the method are adjusted to 32 bits, the minimum adjustable precision is obtained by a formula 1000000/(4 × 1024 × 1024 × 1024-1) ═ 0.00023283ppm, the minimum adjustable precision is utilized to adjust the signals sent by the second sampling frequency of the receiving end, so that the phase of the signals received by the second sampling frequency of the receiving end is the same as the phase of the signals sent by the first sampling frequency of the sending end, make the output audio signal M of the bluetooth chip of the receiving end1Output audio signal M of Bluetooth chip of sending terminal0。
The working principle of the invention is as follows: according to the invention, after the Bluetooth chip is connected with the Bluetooth chip, sampling frequencies are respectively generated at the transmitting end and the receiving end, then the sampling frequencies of the Bluetooth signal transmitting end and the receiving end are obtained through the built-in software of the Bluetooth chip, the sampling frequency deviation value between the Bluetooth signal transmitting end and the receiving end is calculated, and the deviation is calculated according to wireless transmission, wherein the deviation is caused by the asynchronous clock of the wireless transmission transmitting end and the wireless transmission receiving end, so that the problem of the deviation can be solved by solving the problem of asynchronous clock.
Firstly, measuring the time deviation between the clock of the wireless transmission receiving end and the clock of the wireless transmission transmitting end, wherein the deviation is calculated by measuring the time interval PT of receiving the data packet of the wireless transmission receiving end, according to the following formula, RXppm is 1000000 x (PTrx-PT)/PT, wherein RXppm represents the time deviation, RTrx represents the time interval of receiving the data packet of the receiving end, and RT represents the time interval of receiving the data packet of the transmitting end.
After calculating RXppm, two methods can be used for solving the time deviation problem at the receiving end of wireless transmission, the first method is a hardware adjusting method, the minimum adjustable precision is obtained by a phase-locked loop PLL with high precision and supporting fractional frequency division, and the formula is 1000000/(16 multiplied by 1024-1) ═ 0.0596ppm, and the second method is a digital signal processing method, the decimal adjusting bit of the method is 32 bits, the minimum adjustable precision is obtained by using a formula of 1000000/(4 multiplied by 1024-1) ═ 0.00023283ppm, and finally the obtained minimum adjustable precision is used for adjusting the sampling frequency of a receiving end to send out a signal, so that the phase of the signal received by the sampling frequency of the receiving end is the same as that of the signal sent by a sending end, and the output audio signal of the Bluetooth chip at the receiving end is the same as the output audio signal of the Bluetooth chip at the sending end.
After the technical scheme is adopted, the invention has the beneficial effects that:
1. the invention realizes that the data infinitely close to the original signal can be output without any signal adjustment on the signal, thereby leading the listening effect of the audio frequency to be optimal.
2. The sampling frequency adjusting method is utilized, and the method can be adjusted through hardware or software, and has the characteristics of good applicability, high reliability and the like.
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In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
FIG. 1 is a schematic flow diagram of the present invention.
Fig. 2 is a schematic diagram of signal transceiving of a transmitting end bluetooth chip and a receiving end bluetooth chip in the present invention.
Fig. 3 is a schematic diagram illustrating the principle of the cause of the deviation of the digital audio signal in the wireless transmission according to the embodiment of the present invention.
Fig. 4 is a schematic diagram of an application of an embodiment of the present invention.
Detailed Description
Referring to fig. 1 to 4, the technical solution adopted by the present embodiment is: a low-delay transmission method between Bluetooth chips comprises the following steps:
step one, connecting an intelligent terminal with a Bluetooth function or a common Bluetooth chip with a Bluetooth chip PTK5280 to form a sending end and a receiving end;
step two, acquiring the first sampling frequency F of the sending end in the step one by using the built-in software of the Bluetooth chip0And a second sampling frequency F of the receiving end1And the output audio signal M of the Bluetooth chip of the sending end0The output audio signal M of the Bluetooth chip PTK5280 of the receiving end1Calculating a first sampling frequency F by said software0And a second sampling frequency F1The deviation value delta F therebetween;
step three, according to the delta F in the step two, the output audio signal M of the Bluetooth chip PTK5280 at the receiving end is enabled to be obtained by adjusting a digital signal dynamic synchronization algorithm or adjusting a phase-locked loop PLL1Of bluetooth chip as transmitting endOutput audio signal M0；
And step four, outputting the audio.
And the delta F in the second step is a deviation value of the clock of the second sampling frequency of the receiving end and the first sampling frequency of the sending end, and the deviation value is obtained by measuring the time interval PT of receiving the data packet of the second sampling frequency of the receiving end.
The calculation formula of the deviation value between the clock of the second sampling frequency at the receiving end and the first sampling frequency at the sending end is RXppm 1000000 × (PTrx-PT)/PT,
in the formula (I), the compound is shown in the specification,
RXppm represents the deviation of the time,
RTrx denotes the time interval of packet reception at the second sampling frequency at the receiving end,
RT denotes a time interval of packet reception at the first sampling frequency of the transmitting end.
The method for adjusting digital signal dynamic synchronization or phase-locked loop PLL in the third step is a hardware adjusting method or a digital signal processing method, the hardware adjusting method is to use a phase-locked loop PLL supporting fractional frequency division to adjust, the fractional bit is 24 bits, the minimum adjustable precision is obtained by a formula of 1000000/(16 × 1024 × 1024-1) ═ 0.0596ppm, the digital signal processing method uses a dynamic digital audio frequency synchronization method on software, the adjusted fractional bit of the method is 32 bits, the minimum adjustable precision is obtained by a formula of 1000000/(4 × 1024 × 1024 × 0.00023283 ppm), the minimum adjustable precision is used for adjusting a signal sent by a second sampling frequency of a receiving end, so that the phase of the signal received by the second sampling frequency of the receiving end is the same as the phase of the signal sent by a first sampling frequency of a sending end, make the output audio signal M of the bluetooth chip of the receiving end1Output audio signal M of Bluetooth chip of sending terminal0。
The invention utilizes the Bluetooth chip to generate sampling frequency at a sending end and a receiving end respectively after being connected with the Bluetooth chip, then obtains the sampling frequency of the Bluetooth signal sending end and the receiving end through the built-in software of the Bluetooth chip, calculates the sampling frequency deviation value between the Bluetooth signal sending end and the receiving end, and calculates according to wireless transmission, the deviation is caused by the asynchronous clock of the wireless transmission sending end and the wireless transmission receiving end, the problem of the deviation can be solved by solving the problem of asynchronous clock, the attached figure 3 is a schematic diagram of the principle of the deviation generation of digital audio signals in the wireless transmission, and t3, t6 and t7 in the attached figure 3 are the sending time of each data packet. For low latency transmission, the transmission time interval of the data packet must be fixed, labeled pt (packettime), and the transmission of the data packet must be ready to complete before the transmission times t3, t6, t 7. The preparation time t6-t5 is mainly the time of packet compression, and t5-t4 is the delay of the compression algorithm, so the packet sent at t6 is the data from t1(t1 ═ t4-PT) to t 4. The wireless transmission sender sends data packets from t6 to t7(t6+ PT) from t1(t 1-t 4-PT) to t4, and the wireless transmission receiver starts data packet decompression after stopping receiving the data packets from t1(t 1-t 4-PT) to t4 at t7, which requires time from t8 to t 7. Since the clocks of the wireless transmission sender and the wireless transmission receiver cannot be completely consistent, a certain space (t9-t8) is needed for the wireless transmission receiver to deal with the problem that the clocks of the wireless transmission sender and the wireless transmission receiver are not synchronous. In summary, the data of the wireless transmission sender t1 starts to be output at the wireless transmission receiver t 9. The wireless transmission delay t9-t1 PT 2+ t6-t5 (time of packet compression) + t5-t4 (delay of compression algorithm) + t8-t7 (time of packet decompression) + t9-t8 (time of processing unsynchronized clocks of wireless transmission sender and wireless transmission receiver), t9-t8 is represented by Tsyn, and except for Tsyn, the wireless transmission delay is basically fixed after selecting compression algorithm and hardware in other items, so the important point is to solve Tsyn, and the Tsyn is as small and stable as possible, so if the clock of the wireless transmission receiver is slower than that of the wireless transmission sender, t9 will shift to the right, and the wireless transmission delay will increase and accumulate. If the clock of the wireless transmission receiver is faster than that of the wireless transmission transmitter, t9 will shift to the left, the wireless transmission delay will be reduced and accumulated, and once the clock shifts to the left at t8, the wireless transmission receiver will cause the reading of invalid data.
Firstly, by measuring the time deviation between the clock of the wireless transmission receiving end and the clock of the wireless transmission transmitting end, the deviation is calculated by measuring the time interval PT of receiving the data packet of the wireless transmission receiving end, according to the following formula, RXppm is 1000000 x (PTrx-PT) PT, wherein RXppm represents the time deviation, RTrx represents the time interval of receiving the data packet of the receiving end, and RT represents the time interval of receiving the data packet of the transmitting end.
After calculating RXppm, two methods can be used to solve the time deviation problem at the receiving end of wireless transmission, the first method is a hardware adjusting method, which uses a phase-locked loop PLL with high precision and supporting decimal frequency division to adjust, the decimal digit is 24 bits, the minimum adjustable precision is obtained by the formula 1000000/(16 × 1024 × 1024 — 11) ═ 0.0596ppm, the second method is a digital signal processing method, the decimal digit is adjusted to 32 bits by using a dynamic digital audio synchronization method on software, the minimum adjustable precision is obtained by the formula 1000000/(4 × 1024 × 1024-1) — 0.00023283ppm, finally the minimum adjustable precision is obtained to adjust the sampling frequency of the receiving end to send out signals, so that the phase of the signals received by the sampling frequency of the receiving end is the same as the phase of the signals sent by the sending end, and the output audio signal of the Bluetooth chip at the receiving end is the same as the output audio signal of the Bluetooth chip at the sending end.
The above description is only for the purpose of illustrating the technical solutions of the present invention and not for the purpose of limiting the same, and other modifications or equivalent substitutions made by those skilled in the art to the technical solutions of the present invention should be covered within the scope of the claims of the present invention without departing from the spirit and scope of the technical solutions of the present invention.
Claims (4)
1. A low-delay transmission method between Bluetooth chips is characterized in that: it comprises the following steps:
connecting an intelligent terminal with a Bluetooth function or a common Bluetooth chip with a Bluetooth chip to form a sending end and a receiving end;
step two, acquiring the sending end in the step one by using the built-in software of the Bluetooth chipFirst sampling frequency F0And a second sampling frequency F of the receiving end1And the output audio signal M of the Bluetooth chip of the sending end0And the output audio signal M of the Bluetooth chip of the receiving end1Calculating a first sampling frequency F by said software0And a second sampling frequency F1The deviation value delta F therebetween;
step three, according to the delta F in the step two, the output audio signal M of the Bluetooth chip at the receiving end is enabled to be obtained by adjusting a digital signal dynamic synchronization algorithm or adjusting a phase-locked loop PLL1Output audio signal M of Bluetooth chip of sending terminal0；
And step four, outputting the audio.
2. The method of claim 1, wherein the method comprises: and the delta F in the second step is a deviation value of the clock of the second sampling frequency of the receiving end and the first sampling frequency of the sending end, and the deviation value is obtained by measuring the time interval PT of receiving the data packet of the second sampling frequency of the receiving end.
3. The method of claim 2, wherein the transmission between bluetooth chips is performed with low latency, and wherein: the calculation formula of the deviation value between the clock of the second sampling frequency at the receiving end and the first sampling frequency at the sending end is RXppm 1000000 × (PTrx-PT)/PT,
in the formula (I), the compound is shown in the specification,
RXppm represents the deviation of the time,
RTrx denotes the time interval of packet reception at the second sampling frequency at the receiving end,
RT denotes a time interval of packet reception at the first sampling frequency of the transmitting end.
4. The method of claim 1, wherein the method comprises: the method for adjusting the phase-locked loop PLL in the third step is a hardware adjusting method or a digital signal processing method, wherein the hardware adjusting method is a method for using digital signals supporting fractional frequency division to dynamically synchronizeThe digital signal processing method is characterized in that a dynamic digital audio synchronization method is used on software, the adjusted decimal place of the method is 32 bits, the minimum adjustable precision is obtained by the formula 1000000/(16 multiplied by 1024-1) ═ 0.00023283ppm, the minimum adjustable precision is used for adjusting a second sampling frequency of a receiving end to send a signal, the phase of the signal received by the second sampling frequency of the receiving end is the same as the phase of the signal sent by the first sampling frequency of a sending end, and the output audio signal M of a Bluetooth chip of the receiving end is enabled to be the same as the phase of the signal sent by the first sampling frequency of the sending end, so that the decimal place is at least 24 bits, and the minimum adjustable precision is obtained by the formula 1000000/(16 multiplied by 1024-1) ═ 0.0596ppm1Output audio signal M of Bluetooth chip of sending terminal0。
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| Application Number | Priority Date | Filing Date | Title |
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| CN202110672719.XA CN113556154A (en) | 2021-06-17 | 2021-06-17 | Low-delay transmission method between Bluetooth chips |
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| CN202110672719.XA CN113556154A (en) | 2021-06-17 | 2021-06-17 | Low-delay transmission method between Bluetooth chips |
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Application publication date: 20211026 |