阅读说明：本技术 Usb遥测信号降采样率实现方法、装置与电子设备 (Method and device for realizing USB telemetering signal down-sampling rate and electronic equipment ) 是由 王晓峰 孔飞 范炬 于 2019-10-21 设计创作，主要内容包括：本发明实施例提供一种USB遥测信号降采样率实现方法、装置与电子设备,其中所述方法包括：对USB遥测信号和遥测子载波进行PM/BPSK复合信号调制,得到调制信号,并通过将所述调制信号由所述遥测子载波搬移到零频,对所述调制信号进行下变频运算；根据整数倍抽取倍数,对下变频后的遥测信号进行整数倍下采样,并根据设置的符号定时环路和分数抽取倍数,对下采样的遥测信号进行采样率的分数倍转换,实现USB遥测信号降采样；其中,所述符号定时环路包括farrow分数倍采样率回路、环路滤波回路和符号定时鉴相回路。本发明实施例能够有效降低运算复杂程度并降低维护成本,同时有效增强方案适用性。(The embodiment of the invention provides a method and a device for realizing the sampling rate reduction of a USB telemetering signal and electronic equipment, wherein the method comprises the following steps: carrying out PM/BPSK composite signal modulation on the USB telemetering signal and the telemetering subcarrier to obtain a modulation signal, and carrying out down-conversion operation on the modulation signal by moving the modulation signal from the telemetering subcarrier to zero frequency; according to the integral multiple extraction multiple, integral multiple down sampling is carried out on the telemetering signals after down conversion, fractional multiple conversion of the sampling rate is carried out on the down-sampled telemetering signals according to the set symbol timing loop and the fractional extraction multiple, and USB telemetering signal down sampling is achieved; the symbol timing loop comprises a farrow fractional sampling rate loop, a loop filtering loop and a symbol timing phase discrimination loop. The embodiment of the invention can effectively reduce the operation complexity and the maintenance cost, and simultaneously effectively enhance the applicability of the scheme.)

1. A method for realizing the sampling rate reduction of a USB telemetering signal is characterized by comprising the following steps:

carrying out PM/BPSK composite signal modulation on the USB telemetering signal and the telemetering subcarrier to obtain a modulation signal, and carrying out down-conversion operation on the modulation signal by moving the modulation signal from the telemetering subcarrier to zero frequency;

according to the integral multiple extraction multiple, integral multiple down sampling is carried out on the telemetering signals after down conversion, fractional multiple conversion of the sampling rate is carried out on the down-sampled telemetering signals according to the set symbol timing loop and the fractional extraction multiple, and USB telemetering signal down sampling is achieved;

the symbol timing loop comprises a farrow fractional sampling rate loop, a loop filtering loop and a symbol timing phase discrimination loop.

2. The method of claim 1, wherein the step of performing fractional conversion of the sampling rate of the down-sampled telemetry signal comprises:

based on the down-sampled telemetry signal, the adjustment factor output by the symbol timing phase discrimination loop and the fractional decimation multiple, performing fractional conversion of a sampling rate by using the farrow fractional sampling rate loop, and outputting a baseband sampling rate;

wherein, the obtaining process of the adjustment factor comprises: and filtering the baseband sampling rate by using the loop filtering loop to filter self-noise which does not carry timing error information in the symbol timing loop, calculating a fractional-time converted timing sampling error by using the symbol timing phase discrimination loop based on the filtered sampling rate, and taking the timing sampling error as the adjustment factor.

3. The method for implementing the USB telemetry signal down-sampling rate according to claim 1 or 2, wherein the step of down-converting the modulated signal specifically includes:

and shifting the modulation signal to zero frequency from the telemetering subcarrier, mixing the shifted signal with the digital NCO, and adjusting the frequency of the digital NCO through a frequency control word to realize down-conversion operation under different subcarriers.

4. The method for implementing the USB telemetry signal down-sampling rate of claim 1, wherein the step of performing PM/BPSK composite signal modulation on the USB telemetry signal and the telemetry sub-carrier specifically comprises:

and performing PM demodulation on the received USB telemetering signals, and performing BPSK demodulation on the telemetering subcarriers to realize PM/BPSK composite signal modulation.

5. The method of claim 1 or 2, wherein the farrow fractional sample rate loop is expressed as follows:

wherein n is the current sampling time, X (n-i) is the input of the farrow fractional sampling rate loop at the time i before the current time point, y (n) is the output of the farrow fractional sampling rate loop, a is an adjustment factor, μ is the fractional sampling time point, and h (0, μ), h (1, μ), h (2, μ), and h (3, μ) are the iteration factors at different time points.

6. The method of claim 2, wherein the step of calculating the fractional-fold converted timing sampling error using the symbol timing phase detection loop specifically comprises:

and calculating the timing sampling error by using the symbol timing phase detection loop and a Gardner algorithm, wherein a timing error detection formula in the Gardner algorithm is as follows:

in the formula, e_nTo calculate the error, R (-) is the maximum likelihood estimation function, y ((n-1/2) T) is the sample of half chip, denotes the conjugate, y (nT) is the current sample, y ((n-1) T) is the previous sample, and the subscripts I and Q denote the real and imaginary parts of the data, respectively.

7. The USB telemetry signal down-sampling rate implementation method of claim 1 or 2, wherein after the step of down-sampling the down-converted telemetry signal by an integer multiple, and before the step of down-sampling the down-sampled telemetry signal by a fraction multiple of the sampling rate, further comprising:

sequentially carrying out low-pass filtering processing and digital gain adjustment processing on the downsampled telemetry signal to obtain an amplitude-adjusted signal;

correspondingly, according to the symbol timing loop and the fraction extraction multiple, the fraction multiple conversion of the sampling rate is carried out on the signal after the amplitude adjustment, and the USB telemetering signal down-sampling is realized.

8. A USB telemetry signal down-sampling rate implementation apparatus, comprising:

the signal modulation and down-conversion operation module is used for carrying out PM/BPSK composite signal modulation on the USB telemetering signals and the telemetering subcarriers to obtain modulation signals, and carrying out down-conversion operation on the modulation signals by shifting the modulation signals from the telemetering subcarriers to zero frequency;

the down-sampling and fractional-multiple conversion module is used for performing integral-multiple down-sampling on the telemetering signal after down-conversion according to an integral-multiple extraction multiple, and performing fractional-multiple conversion of the sampling rate on the down-sampled telemetering signal according to a set symbol timing loop and the fractional extraction multiple to realize USB telemetering signal down-sampling;

the symbol timing loop comprises a farrow fractional sampling rate loop, a loop filtering loop and a symbol timing phase discrimination loop.

9. An electronic device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, wherein the processor, when executing the computer program, performs the steps of the USB telemetry signal down-sampling rate implementation method of any one of claims 1 to 7.

10. A non-transitory computer readable storage medium having stored thereon computer instructions, wherein the computer instructions, when executed by a computer, implement the steps of the USB telemetry signal down-sampling rate implementation method of any one of claims 1 to 7.

Technical Field

The invention relates to the technical field of USB measurement and control equipment, in particular to a method and a device for realizing the sampling rate reduction of a USB telemetering signal and electronic equipment.

Background

The USB measurement and control equipment is a device for directly performing tracking measurement and control on a spacecraft (including a carrier rocket), is a basic component of a space measurement and control network, and has the tasks of measuring motion parameters of the spacecraft, communicating with the spacecraft, receiving telemetering information of the spacecraft, sending remote control instructions to the spacecraft and the like under the organization of a space control center.

To meet the processing requirements of the demodulation system, it is usually necessary to perform sampling rate conversion on the USB telemetry signal transmitted by the spacecraft, i.e. to convert the oversampled signal into a baseband signal, which is called telemetry signal downsampling. At present, sampling rates of different USB measurement and control devices are different according to different models, but the telemetry signal down-sampling adopts integral multiple sampling rate conversion, on one hand, symbol synchronization needs to be processed independently, complexity is increased, system upgrading is complex, cost is high, and on the other hand, the measurement and control devices cannot be adapted to measurement and control networks with different subcarrier configurations and different sampling rate configurations.

Disclosure of Invention

In order to overcome the above problems or at least partially solve the above problems, embodiments of the present invention provide a method, an apparatus, and an electronic device for implementing a USB telemetry signal down-sampling rate, so as to effectively reduce the complexity of operation and the maintenance cost, and simultaneously effectively enhance the applicability of the scheme.

In a first aspect, an embodiment of the present invention provides a method for implementing a USB telemetry signal down-sampling rate, including:

carrying out PM/BPSK composite signal modulation on the USB telemetering signal and the telemetering subcarrier to obtain a modulation signal, and carrying out down-conversion operation on the modulation signal by moving the modulation signal from the telemetering subcarrier to zero frequency;

according to the integral multiple extraction multiple, integral multiple down sampling is carried out on the telemetering signals after down conversion, fractional multiple conversion of the sampling rate is carried out on the down-sampled telemetering signals according to the set symbol timing loop and the fractional extraction multiple, and USB telemetering signal down sampling is achieved;

the symbol timing loop comprises a farrow fractional sampling rate loop, a loop filtering loop and a symbol timing phase discrimination loop.

Optionally, the step of performing fractional conversion of the sampling rate on the down-sampled telemetry signal specifically includes: based on the down-sampled telemetry signal, the adjustment factor output by the symbol timing phase discrimination loop and the fractional decimation multiple, performing fractional conversion of a sampling rate by using the farrow fractional sampling rate loop, and outputting a baseband sampling rate;

wherein, the obtaining process of the adjustment factor comprises: and filtering the baseband sampling rate by using the loop filtering loop to filter self-noise which does not carry timing error information in the symbol timing loop, calculating a fractional-time converted timing sampling error by using the symbol timing phase discrimination loop based on the filtered sampling rate, and taking the timing sampling error as the adjustment factor.

Optionally, the step of performing down-conversion operation on the modulation signal specifically includes: and shifting the modulation signal to zero frequency from the telemetering subcarrier, mixing the shifted signal with the digital NCO, and adjusting the frequency of the digital NCO through a frequency control word to realize down-conversion operation under different subcarriers.

Optionally, the step of performing PM/BPSK composite signal modulation on the USB telemetry signal and the telemetry subcarrier specifically includes: and performing PM demodulation on the received USB telemetering signals, and performing BPSK demodulation on the telemetering subcarriers to realize PM/BPSK composite signal modulation.

Optionally, an expression of the farrow fractional sampling rate loop is as follows:

wherein n is the current sampling time, X (n-i) is the input of the farrow fractional sampling rate loop at the time i before the current time point, y (n) is the output of the farrow fractional sampling rate loop, a is an adjustment factor, μ is the fractional sampling time point, and h (0, μ), h (1, μ), h (2, μ), and h (3, μ) are the iteration factors at different time points.

Optionally, the step of calculating the fractional-time converted timing sampling error by using the symbol timing phase detection loop specifically includes: and calculating the timing sampling error by using the symbol timing phase detection loop and a Gardner algorithm, wherein a timing error detection formula in the Gardner algorithm is as follows:

in the formula, e_nTo calculate the error, R (-) is the maximum likelihood estimation function, y ((n-1/2) T) is the sample of half chip, denotes the conjugate, y (nT) is the current sample, y ((n-1) T) is the previous sample, and the subscripts I and Q denote the real and imaginary parts of the data, respectively.

Further, after the step of performing integer-multiple down-sampling on the down-converted telemetry signal and before the step of performing fractional-multiple conversion on the down-sampled telemetry signal, the method of the embodiment of the present invention further includes: sequentially carrying out low-pass filtering processing and digital gain adjustment processing on the downsampled telemetry signal to obtain an amplitude-adjusted signal;

correspondingly, according to the symbol timing loop and the fraction extraction multiple, the fraction multiple conversion of the sampling rate is carried out on the signal after the amplitude adjustment, and the USB telemetering signal down-sampling is realized.

In a second aspect, an embodiment of the present invention provides an apparatus for implementing a USB telemetry signal down-sampling rate, including:

the signal modulation and down-conversion operation module is used for carrying out PM/BPSK composite signal modulation on the USB telemetering signals and the telemetering subcarriers to obtain modulation signals, and carrying out down-conversion operation on the modulation signals by shifting the modulation signals from the telemetering subcarriers to zero frequency;

the down-sampling and fractional-multiple conversion module is used for performing integral-multiple down-sampling on the telemetering signal after down-conversion according to an integral-multiple extraction multiple, and performing fractional-multiple conversion of the sampling rate on the down-sampled telemetering signal according to a set symbol timing loop and the fractional extraction multiple to realize USB telemetering signal down-sampling;

the symbol timing loop comprises a farrow fractional sampling rate loop, a loop filtering loop and a symbol timing phase discrimination loop.

In a third aspect, an embodiment of the present invention provides an electronic device, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor, where the processor executes the computer program to implement the steps of the USB telemetry signal down-sampling rate implementation method according to the first aspect.

In a fourth aspect, embodiments of the present invention provide a non-transitory computer readable storage medium having stored thereon computer instructions, which when executed by a computer, implement the steps of the USB telemetry signal down-sampling rate implementation method as described in the first aspect above.

The method, the device and the electronic equipment for realizing the sampling rate reduction of the USB telemetering signal provided by the embodiment of the invention adopt the symbol timing loop consisting of the farrow fractional sampling rate loop, the loop filtering loop and the symbol timing phase discrimination loop to perform fractional conversion of the sampling rate on the telemetering signal. Meanwhile, due to the fact that a farrow fractional sampling rate loop is adopted, conversion of any baseband sampling rate can be achieved under the condition that the ADC sampling rate is fixed, the device can be adapted to different USB measurement and control networks, and the applicability is strong.

Drawings

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 some embodiments of the present invention, and those skilled in the art can also obtain other drawings according to the drawings without creative efforts.

FIG. 1 is a schematic flow chart illustrating a method for implementing a USB telemetry signal down-sampling rate according to an embodiment of the present invention;

FIG. 2 is a schematic diagram illustrating the principle of the Gardner algorithm in the method for implementing the sampling rate reduction of the USB telemetry signal according to the embodiment of the present invention;

FIG. 3 is a schematic flow chart illustrating a method for implementing a USB telemetry signal down-sampling rate according to another embodiment of the present invention;

FIG. 4 is a schematic structural diagram of a USB telemetry signal down-sampling rate implementation apparatus according to an embodiment of the present invention;

fig. 5 is a schematic physical structure diagram of an electronic device according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments of the present invention without any creative efforts belong to the protection scope of the embodiments of the present invention.

Aiming at the problems of higher operation complexity, higher operation cost and poorer applicability in the prior art, the embodiment of the invention adopts the symbol timing loop consisting of a farrow fractional sampling rate loop, a loop filtering loop and a symbol timing phase demodulation loop to perform fractional conversion of the sampling rate on the telemetering signal. Meanwhile, due to the fact that a farrow fractional sampling rate loop is adopted, conversion of any baseband sampling rate can be achieved under the condition that the ADC sampling rate is fixed, the device can be adapted to different USB measurement and control networks, and the applicability is strong. Embodiments of the present invention will be described and illustrated with reference to various embodiments.

Fig. 1 is a schematic flow chart of a method for implementing a USB telemetry signal down-sampling rate according to an embodiment of the present invention, as shown in fig. 1, the method includes:

and S101, carrying out PM/BPSK composite signal modulation on the USB telemetering signal and the telemetering subcarrier to obtain a modulation signal, and carrying out down-conversion operation on the modulation signal by shifting the modulation signal from the telemetering subcarrier to zero frequency.

It can be understood that the USB measurement and control device according to the embodiment of the present invention is modulated by a PM/BPSK composite signal. That is, the PM demodulation is performed for reception of the telemetry signal, and then the BPSK demodulation is performed for the telemetry subcarrier, and the modulated signal is output. And then carrying out down-conversion on the modulation signal, moving the signal to zero frequency by a subcarrier, and carrying out down-conversion operation on the modulation signal on the basis to obtain a telemetering signal after down-conversion.

S102, performing integral multiple down-sampling on the telemetering signal after down-conversion according to the integral multiple extraction multiple, and performing fractional multiple conversion of the sampling rate on the down-sampled telemetering signal according to the set symbol timing loop and the fractional extraction multiple to realize USB telemetering signal down-sampling; the symbol timing loop comprises a farrow fractional sampling rate loop, a loop filtering loop and a symbol timing phase discrimination loop.

It can be understood that, on the basis of the down-conversion of the telemetry signal under the sub-carrier, the frequency-converted telemetry signal needs to be subjected to integral multiple down-sampling. Specifically, 2 is realized by using N stages of half-band filter cascade connection according to set integral multiple decimation multiple^NAnd carrying out integral multiple down-sampling to obtain the down-sampled telemetry signal. Wherein, the cascade number N can be calculated by the following formula:

in the formula, symbolDenotes lower rounding, f_{s_tm}Representing the sampling rate of the input subcarrier block, f_{s_base}Representing the baseband sampling rate obtained after the conversion.

After integral multiple down-sampling, the sampling rate becomes between 4 and 8 times of the baseband sampling rate.

And then, inputting the downsampled telemetering signal and the set fractional extraction multiple into a symbol timing loop, converting the fractional extraction multiple with the sampling rate through feedback control of the symbol timing loop, and outputting the converted baseband sampling rate to realize downsampling of the USB telemetering signal.

The symbol timing loop consists of three loop modules, namely a farrow fractional sampling rate loop, a loop filtering loop and a symbol timing phase discrimination loop, and a feedback adjustment factor is introduced into the symbol timing phase discrimination loop, and the loop filtering loop filters noise in the loop.

The method for realizing the sampling rate reduction of the USB telemetering signal provided by the embodiment of the invention adopts the symbol timing loop consisting of the farrow fractional sampling rate loop, the loop filtering loop and the symbol timing phase discrimination loop to perform fractional conversion of the sampling rate on the telemetering signal. Meanwhile, due to the fact that a farrow fractional sampling rate loop is adopted, conversion of any baseband sampling rate can be achieved under the condition that the ADC sampling rate is fixed, the device can be adapted to different USB measurement and control networks, and the applicability is strong.

Optionally, according to the above embodiment, the step of performing PM/BPSK composite signal modulation on the USB telemetry signal and the telemetry subcarrier specifically includes: and PM demodulation is carried out on the reception of the USB telemetering signal, and BPSK demodulation is carried out on the telemetering subcarrier, so that PM/BPSK composite signal modulation is realized.

Optionally, according to the foregoing embodiments, the step of performing down-conversion operation on the modulation signal specifically includes: and moving the modulation signal to zero frequency from the telemetering subcarrier, mixing the moved signal with the digital NCO, and adjusting the frequency of the digital NCO through a frequency control word to realize down-conversion operation under different subcarriers.

It will be appreciated that embodiments of the present invention perform downconversion of telemetry signals. The signal is shifted by the subcarrier to zero frequency and then mixed using the digital NCO and telemetry signals. The frequency of the digital NCO can be adjusted through the frequency control word, so that the down-conversion of different subcarriers can be realized.

Optionally, according to the above embodiments, the step of performing fractional conversion of the sampling rate on the downsampled telemetry signal specifically includes: based on the down-sampled telemetering signal, the adjustment factor and the fractional extraction multiple output by the symbol timing phase discrimination loop, fractional conversion of the sampling rate is carried out by using a farrow fractional sampling rate loop, and the baseband sampling rate is output; the acquisition process of the adjustment factor comprises the following steps: and filtering the baseband sampling rate by using a loop filtering loop to filter the self-noise which does not carry timing error information in the symbol timing loop, calculating the timing sampling error after fractional time conversion by using a symbol timing phase discrimination loop based on the filtered sampling rate, and taking the timing sampling error as an adjusting factor.

It can be understood that the embodiment of the invention utilizes the symbol timing loop to realize fractional conversion of the sampling rate of the telemetry signal and output the baseband sampling rate. Specifically, fractional conversion of the sampling rate of the telemetry signal is mainly realized through a farrow fractional sampling rate loop in a symbol timing loop, so that the output sampling rate is 2 times of the baseband sampling rate. Namely, the downsampled telemetry signal, the adjustment factor of the loop and the set fractional decimation multiple are used as the input of a farrow fractional sampling rate loop, and the baseband sampling rate is finally output through fractional conversion of the farrow fractional sampling rate loop.

Optionally, the form of the farrow fractional sampling rate loop is as follows:

in the formula, n is the current sampling time, X (n-i) is the input of the farrow fractional sampling rate loop at the time i before the current time point, y (n) is the output of the farrow fractional sampling rate loop, a is an adjustment factor, μ is the fractional sampling time point, and h (0, μ), h (1, μ), h (2, μ), and h (3, μ) are iteration factors at different time points.

Where it is understood that for the symbol timing loop, by forming a complete closed loop, it is able to generate itself and provide the adjustment factor in the form of a feedback loop for the farrow fractional sample rate loop. That is, after the fractional-multiple sampling rate conversion is performed on the downsampled telemetry signal in the farrow fractional-multiple sampling rate loop to generate a baseband sampling rate, the baseband sampling rate is input into the loop filtering loop, and the loop filtering loop filters noise in the loop to obtain a filtered sampling rate. And then, the filtered sampling rate is further input into a symbol timing phase discrimination loop, the symbol timing phase discrimination loop completes the calculation of a sampling error, and a final adjusting factor is determined based on the error obtained by calculation. The adjustment factor is input into a farrow fractional sampling rate loop in a feedback mode, and finally feedback adjustment of the output baseband sampling rate is achieved.

Optionally, according to the foregoing embodiments, the step of calculating the fractional-time converted timing sampling error by using the symbol timing phase detection loop specifically includes: and calculating a timing sampling error by using a symbol timing phase discrimination loop and a Gardner algorithm, wherein a timing error detection formula in the Gardner algorithm is as follows:

in the formula, e_nTo calculate the error, R (-) is the maximum likelihood estimation function, y ((n-1/2) T) is the sample of half chip, denotes the conjugate, y (nT) is the current sample, y ((n-1) T) is the previous sample, and the subscripts I and Q denote the real and imaginary parts of the data, respectively.

That is to say, the symbol timing phase detection loop in the embodiment of the present invention mainly completes the calculation of the sampling error, and is specifically implemented by using a Gardner algorithm. The Gardner algorithm requires two samples per symbol, one being the best sample for the symbol and the other being the point between two consecutive best samples for the symbol. Wherein, the schematic diagram of the Gardner algorithm is shown in fig. 2, which is a schematic diagram of the principle of the Gardner algorithm in the method for implementing the sampling rate reduction of the USB telemetry signal according to the embodiment of the present invention, in the figure, the Gardner algorithm requires two sampling points, one, per symbolOne is the optimum sampling point (y (nT), y ((n-1) T)) of the symbol, and the other is the point (y ((n-1/2) T)) between two successive optimum sampling points of the symbol, and the Gardner algorithm makes the error e by adjusting the positions of the sampling points_nAnd at the minimum, adjusting the sampling point is realized by a farrow fractional sampling rate loop.

In addition, in each of the above embodiments, after the step of performing integer-multiple down-sampling on the down-converted telemetry signal and before the step of performing fractional-multiple conversion of the sampling rate on the down-sampled telemetry signal, the method further includes: sequentially carrying out low-pass filtering processing and digital gain adjustment processing on the down-sampled telemetry signal to obtain an amplitude-adjusted signal; correspondingly, according to the symbol timing loop and the fraction extraction multiple, the fraction multiple conversion of the sampling rate is carried out on the signal after the amplitude is adjusted, and the USB telemetering signal down-sampling is realized.

Specifically, in the actual down-sampling rate processing process, some spurious signals may be introduced to cause signal pollution, and after integer-multiple down-sampling, the amplitude of the output signal may exceed a certain range, resulting in signal distortion. In view of this, in the embodiment of the present invention, after performing integer-times down-sampling on the telemetry signal, a low-pass filter is used to perform low-pass filtering processing on the down-sampled telemetry signal to obtain a filtered signal. Then, the filtered signal is input to a digital gain adjustment loop to perform digital gain adjustment processing, and the output signal is an amplitude-adjusted signal. Accordingly, the signal input to the farrow fractional sample rate loop for processing is replaced with the amplitude adjusted signal.

To further illustrate the technical solutions of the embodiments of the present invention, the embodiments of the present invention provide the following specific processing flows according to the above embodiments, but do not limit the scope of the embodiments of the present invention.

As shown in fig. 3, a schematic flow chart of a method for implementing a USB telemetry signal down-sampling rate according to another embodiment of the present invention includes the following processing steps:

firstly, the USB measurement and control system modulates PM/BPSK composite signals. The reception of the telemetry signal requires PM demodulation followed by subcarrier demodulationBPSK demodulation. The sample rate input to the telemetry sub-carrier module in fig. 1 is denoted as f_{s_tm}。

Second, a down conversion of the telemetry signal is performed. The signal is shifted by subcarrier to zero frequency and mixed with the telemetry signal using a digital NCO. The frequency of the digital NCO can be adjusted through the frequency control word, so that the down-conversion of different subcarriers can be realized.

Again, implementation 2 using N-stage half-band filter cascade^NAnd sampling by integral multiple of multiple. Wherein the cascade number N can be calculated by the following formula:

in the formula, symbol

Denotes lower rounding, f_{s_tm}Representing the sampling rate of the input subcarrier block, f_{s_base}Representing the baseband sampling rate obtained after the conversion.

After integral multiple down-sampling, the sampling rate becomes between 4 and 8 times of the baseband sampling rate.

Then, low-pass filtering is performed. And filtering out the stray signals outside the band by using a low-pass filter, and avoiding stray and signal aliasing after farrow fractional filtering.

Then, digital gain adjustment is performed. The process adjusts the amplitude of the input signal to the symbol timing loop to be within a target value range.

And finally, inputting the amplitude-adjusted signal into a symbol timing loop, and performing fractional-multiple conversion of the sampling rate to obtain the baseband sampling rate. The symbol timing loop comprises a farrow fractional sampling rate loop, a loop filtering loop and a symbol timing phase discrimination loop.

The farrow fractional sampling rate loop mainly completes fractional conversion of the sampling rate, and the output sampling rate is 2 times of the baseband sampling rate. Controlled by the decimation multiple and the output of the phase detector, the farrow fractional sampling rate loop in the embodiment of the invention has the following form:

in the formula, n is the current sampling time, X (n-i) is the input of the farrow fractional sampling rate loop at the time i before the current time point, y (n) is the output of the farrow fractional sampling rate loop, a is an adjustment factor, μ is the fractional sampling time point, and h (0, μ), h (1, μ), h (2, μ), and h (3, μ) are iteration factors at different time points.

The loop filter loop is mainly used for filtering noise in the timing loop. Simulation results show that the loop filter is added in the timing error detection, so that most of self-noise which does not carry timing error information is filtered, and the timing jitter of the loop is effectively reduced.

The symbol timing phase detection loop mainly completes the calculation of sampling errors and is specifically realized by a Gardner algorithm. The Gardner algorithm requires two samples per symbol, one being the best sample for the symbol and the other being the point between two consecutive best samples for the symbol. The timing error detection formula in the Gardner algorithm is as follows:

in the formula, e_nTo calculate the error, R (-) is the maximum likelihood estimation function, y ((n-1/2) T) is the sample of half chip, denotes the conjugate, y (nT) is the current sample, y ((n-1) T) is the previous sample, and the subscripts I and Q denote the real and imaginary parts of the data, respectively.

The embodiment of the invention can support the adjustment of the telemetering subcarrier frequency, the adjustment unit is 1Hz, and the conversion of any baseband sampling rate can be realized under the condition of fixing the ADC sampling rate, so that the embodiment of the invention can be adapted to different USB measurement and control networks, and simultaneously, the symbol timing synchronization and the sampling rate conversion module are combined together, thereby being convenient to realize.

Based on the same inventive concept, the embodiments of the present invention provide a USB telemetry signal down-sampling rate implementation apparatus according to the above embodiments, where the apparatus is used to implement the USB telemetry signal down-sampling rate implementation in the above embodiments. Therefore, the description and definition in the USB telemetry signal down-sampling rate implementation method in each embodiment may be used for understanding each execution module in the embodiment of the present invention, and reference may be made to the embodiment specifically, and details are not described here.

According to an embodiment of the present invention, a structure of a USB telemetry signal down-sampling rate implementation apparatus is shown in fig. 4, which is a schematic structural diagram of the USB telemetry signal down-sampling rate implementation apparatus provided in the embodiment of the present invention, and the apparatus may be used to implement the USB telemetry signal down-sampling rate implementation in the foregoing method embodiments, and the apparatus includes: a signal modulation and down-conversion operation module 401 and a down-sampling and fractional multiple conversion module 402. Wherein:

the signal modulation and down-conversion operation module 401 is configured to perform PM/BPSK composite signal modulation on the USB telemetry signal and the telemetry subcarrier to obtain a modulation signal, and perform down-conversion operation on the modulation signal by shifting the modulation signal from the telemetry subcarrier to zero frequency; the down-sampling and fractional-multiple conversion module 402 is used for performing integer-multiple down-sampling on the down-converted telemetering signals according to integer-multiple extraction multiples, and performing fractional-multiple conversion of the sampling rate on the down-sampled telemetering signals according to the set symbol timing loop and the fractional extraction multiples, so as to realize the down-sampling of the USB telemetering signals; the symbol timing loop comprises a farrow fractional sampling rate loop, a loop filtering loop and a symbol timing phase discrimination loop.

Specifically, the signal modulation and down-conversion operation module 401 performs PM demodulation on the reception of the telemetry signal, performs BPSK demodulation on the telemetry subcarrier, and outputs a modulated signal. Then, the signal modulation and down-conversion operation module 401 down-converts the modulated signal, the signal is shifted to zero frequency by the subcarrier, and on this basis, down-conversion operation is performed on the modulated signal to obtain a down-converted telemetry signal.

Then, the down-sampling and fractional-multiple conversion module 402 is configured to perform the integer-based down-sampling and fractional-multiple conversionMultiple extraction, using N-stage half-band filter cascade to realize 2^NAnd carrying out integral multiple down-sampling to obtain the down-sampled telemetry signal. Wherein, the cascade number N can be calculated by the following formula:

in the formula, symbol

Denotes lower rounding, f_{s_tm}Representing the sampling rate of the input subcarrier block, f_{s_base}Representing the baseband sampling rate obtained after the conversion.

After integral multiple down-sampling, the sampling rate becomes between 4 and 8 times of the baseband sampling rate.

Then, the down-sampling and fractional-multiple conversion module 402 inputs the down-sampled telemetry signal and the set fractional-multiple together into the symbol timing loop, and outputs the converted baseband sampling rate through the feedback control of the symbol timing loop and the fractional-multiple conversion of the sampling rate, thereby realizing the down-sampling of the USB telemetry signal.

The symbol timing loop consists of three loop modules, namely a farrow fractional sampling rate loop, a loop filtering loop and a symbol timing phase discrimination loop, and a feedback adjustment factor is introduced into the symbol timing phase discrimination loop, and the loop filtering loop filters noise in the loop.

According to the device for realizing the sampling rate reduction of the USB telemetering signal, provided by the embodiment of the invention, the corresponding execution module is arranged, the symbol timing loop consisting of the farrow fractional sampling rate loop, the loop filtering loop and the symbol timing phase discrimination loop is adopted, the fractional conversion of the sampling rate is carried out on the telemetering signal, and the symbol timing synchronization and the sampling rate conversion module are combined together, so that the operation complexity can be effectively reduced, and the maintenance cost can be reduced. Meanwhile, due to the fact that a farrow fractional sampling rate loop is adopted, conversion of any baseband sampling rate can be achieved under the condition that the ADC sampling rate is fixed, the device can be adapted to different USB measurement and control networks, and the applicability is strong.

It is understood that, in the embodiment of the present invention, each relevant program module in the apparatus of each of the above embodiments may be implemented by a hardware processor (hardware processor). Moreover, the USB telemetry signal down-sampling rate implementation apparatus according to the embodiment of the present invention can implement the implementation process of the USB telemetry signal down-sampling rate of each method embodiment by using the program modules, and when the apparatus is used to implement the implementation of the USB telemetry signal down-sampling rate in each method embodiment, the beneficial effects produced by the apparatus according to the embodiment of the present invention are the same as those of the corresponding method embodiments, and the apparatus may refer to the method embodiments, and will not be described herein again.

As a further aspect of the embodiments of the present invention, in accordance with the above embodiments, the present embodiment provides an electronic device, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor, and when the processor executes the computer program, the steps of the USB telemetry signal down-sampling rate implementation method according to the above embodiments are implemented.

Further, the electronic device of the embodiment of the present invention may further include a communication interface and a bus. Referring to fig. 5, an entity structure diagram of an electronic device provided in an embodiment of the present invention includes: at least one memory 501, at least one processor 502, a communication interface 503, and a bus 504.

The memory 501, the processor 502 and the communication interface 503 complete mutual communication through the bus 504, and the communication interface 503 is used for information transmission between the electronic device and the USB measurement and control device; the memory 501 stores a computer program that can be executed on the processor 502, and when the processor 502 executes the computer program, the steps of the USB telemetry signal down-sampling rate implementation method according to the embodiments are implemented.

It is understood that the electronic device at least includes a memory 501, a processor 502, a communication interface 503 and a bus 504, and the memory 501, the processor 502 and the communication interface 503 are connected in communication with each other through the bus 504, and can complete communication with each other, for example, the processor 502 reads program instructions of the USB telemetry signal down-sampling rate implementation method from the memory 501. In addition, the communication interface 503 may also implement communication connection between the electronic device and the USB measurement and control device, and may complete mutual information transmission, for example, read USB telemetry signals through the communication interface 503.

When the electronic device is running, the processor 502 calls the program instructions in the memory 501 to perform the methods provided by the above-described method embodiments, including for example: carrying out PM/BPSK composite signal modulation on the USB telemetering signal and the telemetering subcarrier to obtain a modulation signal, and carrying out down-conversion operation on the modulation signal by moving the modulation signal from the telemetering subcarrier to zero frequency; and performing integral multiple down sampling on the telemetering signals after down conversion according to the integral multiple extraction multiple, and performing fractional multiple conversion of the sampling rate on the down-sampled telemetering signals according to the set symbol timing loop and the fractional extraction multiple to realize USB telemetering signal down sampling and the like.

The program instructions in the memory 501 may be implemented in the form of software functional units and may be stored in a computer readable storage medium when sold or used as a stand-alone product. Alternatively, all or part of the steps for implementing the method embodiments may be implemented by hardware related to program instructions, where the program may be stored in a computer-readable storage medium, and when executed, the program performs the steps including the method embodiments; and the aforementioned storage medium includes: various media capable of storing program codes, such as a usb disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk, or an optical disk.

Embodiments of the present invention further provide a non-transitory computer-readable storage medium according to the above embodiments, on which computer instructions are stored, and when the computer instructions are executed by a computer, the steps of the USB telemetry signal down-sampling rate implementation method according to the above embodiments are implemented, for example, the steps include: carrying out PM/BPSK composite signal modulation on the USB telemetering signal and the telemetering subcarrier to obtain a modulation signal, and carrying out down-conversion on the modulation signal by moving the modulation signal from the telemetering subcarrier to zero frequency; and performing integral multiple down sampling on the telemetering signals after down conversion according to the integral multiple extraction multiple, and performing fractional multiple conversion of the sampling rate on the down-sampled telemetering signals according to the set symbol timing loop and the fractional extraction multiple to realize USB telemetering signal down sampling and the like.

The electronic device and the non-transitory computer readable storage medium provided by the embodiments of the present invention perform the steps of the USB telemetry signal down-sampling rate implementation method described in each of the above embodiments, and perform fractional conversion of the sampling rate on the telemetry signal by using the symbol timing loop composed of the farrow fractional sampling rate loop, the loop filtering loop, and the symbol timing phase demodulation loop. Meanwhile, due to the fact that a farrow fractional sampling rate loop is adopted, conversion of any baseband sampling rate can be achieved under the condition that the ADC sampling rate is fixed, the device can be adapted to different USB measurement and control networks, and the applicability is strong.

It is to be understood that the above-described embodiments of the apparatus, the electronic device and the storage medium are merely illustrative, and that elements described as separate components may or may not be physically separate, may be located in one place, or may be distributed on different network elements. Some or all of the modules can be selected according to actual needs to achieve the purpose of the scheme of the embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.

Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware. Based on such understanding, the technical solutions mentioned above may be embodied in the form of a software product, which may be stored in a computer-readable storage medium, such as a usb disk, a removable hard disk, a ROM, a RAM, a magnetic or optical disk, etc., and includes several instructions for causing a computer device (such as a personal computer, a server, or a network device, etc.) to execute the methods described in the method embodiments or some parts of the method embodiments.

In addition, it should be understood by those skilled in the art that in the specification of the embodiments of the present invention, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

In the description of the embodiments of the invention, numerous specific details are set forth. It is understood, however, that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description. Similarly, it should be appreciated that in the foregoing description of exemplary embodiments of the invention, various features of the embodiments of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects.

However, the disclosed method should not be interpreted as reflecting an intention that: that is, the claimed embodiments of the invention require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of an embodiment of this invention.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the embodiments of the present invention, and not to limit the same; although embodiments of the present invention have been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the spirit and scope of the technical solutions of the embodiments of the present invention.