CN114884782A - Decision correction method and device applied to GFSK receiver - Google Patents
Decision correction method and device applied to GFSK receiver Download PDFInfo
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Abstract
The invention discloses a decision correction method and a device applied to a GFSK receiver, wherein the method comprises the steps of calculating the gradient between the optimal sampling point of a first symbol and the optimal sampling point of a second symbol by judging that the polarities of the first symbol and the second symbol are the same, judging whether the first symbol and the second symbol are reversed or not according to the gradient, if so, correcting the first symbol to be the opposite value of the second symbol, and if not, carrying out processing; or when the polarities of the first symbol and the second symbol are consistent and the amplitude absolute value of the optimal sampling point is smaller than a first threshold value, detecting the zero crossing point of two adjacent sampling points in a certain range, and correcting the current symbol of the zero crossing point to be the opposite value of the previous symbol; the zero-crossing point means that the signs of two adjacent sampling points are opposite. The technical scheme of the invention improves the decoding accuracy of the judgment correction method applied to the GFSK receiver.
Description
Technical Field
The invention relates to the technical field of signal judgment and detection, in particular to a judgment correction method and a judgment correction device applied to a GFSK receiver.
Background
In the bluetooth technology, a GFSK modulation scheme is used. In the GFSK receiver, the calculated frequency word has deviation and even polarity transmission change due to the influence of multiple factors such as intersymbol interference, white Gaussian noise, frequency offset, time drift and the like; for example, the bits of "101" (or "010"), the middle "0" (or "1"), and "energy" are small, and are affected by intersymbol interference and white gaussian noise of the symbols on both sides, so that the symbols of the middle bits cannot be "inverted", and decoding is erroneous. In order to further improve the robustness of the receiving decision, different detection modes need to be designed to correct the receiving decision result.
In the prior art, CN201811258214 proposes an adaptive equalizer in a GFSK receiver; in the patent, a first filter and a second filter are designed for carrying out forward filtering and backward filtering to eliminate intersymbol interference; the first equalization module is used for filtering an input signal to obtain a first filtered signal, and the first equalization module works at 4 times of symbol rate; the second equalization module is used for filtering the output signal to obtain a second filtered signal, and the second equalization module works at 1 time of symbol rate; an adder for performing addition operation on the first filtered signal and the second filtered signal and outputting a sum signal; the decision module is used for carrying out decision processing on the summation signal to obtain an output signal; the error generating module outputs a first error signal and a second error signal; the device comprises a first tap coefficient configuration module and a second tap coefficient configuration module, wherein the first tap coefficient configuration module and the second tap coefficient configuration module are used for generating tap coefficients. In the technology, because two filter structures are designed, 4 times of symbol rate and 1 time of symbol rate are needed to be calculated, and the power consumption is relatively large; meanwhile, the patent does not directly correct the judgment result, and the robustness of receiving judgment is not directly improved.
Disclosure of Invention
The invention provides a decision correction method and a decision correction device applied to a GFSK receiver, which improve the decoding accuracy of the decision correction method applied to the GFSK receiver.
An embodiment of the present invention provides a decision correction method applied to a GFSK receiver, including the following steps:
when the polarities of a first symbol and a second symbol are the same, calculating the gradient between the optimal sampling point of the first symbol and the optimal sampling point of the second symbol, judging whether the first symbol and the second symbol are reversed or not according to the gradient, if so, correcting the first symbol to be the opposite value of the second symbol, and if not, not processing;
or when the polarities of the first symbol and the second symbol are consistent and the amplitude absolute value of the optimal sampling point is smaller than a first threshold value, detecting zero crossing points of two adjacent sampling points in a certain range, and correcting the current symbol of the zero crossing point to be the opposite value of the previous symbol; the zero crossing points mean that the signs of two adjacent sampling points are opposite;
the first symbol is a current symbol and the second symbol is a symbol previous to the current symbol.
Another embodiment of the present invention provides a decision correction method applied to a GFSK receiver, including the following steps:
when the polarities of the first symbol and the second symbol are consistent, judging whether the amplitude absolute value of the optimal sampling point is smaller than a first threshold value; the first symbol is a current symbol, and the second symbol is a symbol previous to the current symbol;
if yes, detecting the zero crossing point of two adjacent sampling points in a certain range, and correcting the current symbol of the zero crossing point to be the opposite value of the previous symbol; the zero crossing points mean that the signs of two adjacent sampling points are opposite;
if not, calculating the gradient between the optimal sampling point of the first symbol and the optimal sampling point of the second symbol, and judging whether the first symbol and the second symbol are reversed or not according to the gradient, if so, correcting the first symbol to be the opposite value of the second symbol, and if not, not processing.
Further, calculating a gradient between the optimal sampling point of the first symbol and the optimal sampling point of the second symbol, and determining whether the first symbol and the second symbol are reversed according to the gradient, if so, modifying the first symbol to be an opposite value of the second symbol, specifically:
calculating a first gradient between an optimal sampling point of the first symbol and an optimal sampling point of the second symbol when both the first symbol and the second symbol are decided as 0, and correcting the first symbol to 1 when the first gradient is greater than a first preset threshold;
when both the first symbol and the second symbol are decided as 1, calculating a second gradient between the optimal sampling point of the first symbol and the optimal sampling point of the second symbol, and correcting the first symbol to 0 when the second gradient is greater than a second preset threshold.
Further, the detecting zero crossing points of two adjacent sampling points within a certain range specifically includes:
determining a plurality of starting positions and a plurality of ending positions of the range according to the first symbol and the second symbol; the certain range is a set of a plurality of combinations of the starting position and the ending position;
and traversing all adjacent sampling points in the certain range, and detecting the zero crossing point of two adjacent sampling points.
Further, the start position includes a position of an optimal sampling point of a previous symbol, a position of a last sampling point of a previous symbol decoding range, a position of a first sampling point of a current symbol decoding range, and a position of a last sampling point within a previous symbol period range.
Further, the end position includes a position of a best sampling point of the current symbol, a position of a last sampling point of a decoding range of the current symbol, and a position of a last sampling point within a period range of the current symbol.
Another embodiment of the present invention provides a decision detection apparatus applied to a GFSK receiver, including a first detection module or a second detection module;
the first detection module is used for calculating the gradient between the optimal sampling point of the first symbol and the optimal sampling point of the second symbol when the polarities of the first symbol and the second symbol are the same, judging whether the first symbol and the second symbol are reversed or not according to the gradient, if so, correcting the first symbol to be the opposite value of the second symbol, and if not, processing; the first symbol is a current symbol, and the second symbol is a symbol previous to the current symbol;
the second detection module is used for detecting the zero crossing point of two adjacent sampling points in a certain range and correcting the current symbol of the zero crossing point to be the opposite value of the previous symbol when the polarities of the first symbol and the second symbol are consistent and the amplitude absolute value of the optimal sampling point is lower than a first threshold value.
Another embodiment of the present invention provides a decision detection apparatus applied to a GFSK receiver, including a first detection module and a second detection module;
the first detection module is used for detecting the zero crossing point of two adjacent sampling points in a certain range and correcting the current symbol of the zero crossing point to be the opposite value of the previous symbol when the polarities of the first symbol and the second symbol are consistent and the amplitude absolute value of the optimal sampling point is smaller than a first threshold value; the first symbol is a current symbol, and the second symbol is a symbol previous to the current symbol;
the second detection module is used for calculating the gradient between the optimal sampling point of the first symbol and the optimal sampling point of the second symbol when the polarities of the first symbol and the second symbol are consistent and the absolute value of the amplitude of the optimal sampling point is larger than or equal to a first threshold value, and judging whether the first symbol and the second symbol are reversed or not according to the gradient, if yes, correcting the first symbol to be the opposite value of the second symbol, and if not, not processing.
The embodiment of the invention has the following beneficial effects:
the invention provides a decision correction method and a device applied to a GFSK receiver, wherein the method detects whether a current symbol is correct or not by calculating the gradient between an optimal sampling point of a first symbol and an optimal sampling point of a second symbol and combining the polarities of the first symbol and a second amplitude, and corrects the current symbol according to an error symbol. Meanwhile, when the polarities of the first symbol and the second symbol are consistent and the amplitude absolute value of the optimal sampling point is smaller than a first threshold value, zero crossing points of two adjacent sampling points in a certain range are detected, the current symbol of the zero crossing point is corrected to be the opposite value of the previous symbol, whether the current symbol is correct is detected, and correction is carried out on the wrong symbol. Therefore, the invention improves the decoding accuracy of the decision correction method applied to the GFSK receiver.
Drawings
Fig. 1 is a schematic flowchart of a decision correction method applied to a GFSK receiver according to an embodiment of the present invention;
fig. 2 is a schematic flowchart of a decision correction method applied to a GFSK receiver according to an embodiment of the present invention;
FIG. 3 is a schematic illustration of the homopolar gradient statistical probability density distribution function without AWGN;
FIG. 4 is a graphical illustration of a heteropolar gradient statistical probability density distribution function without AWGN;
FIG. 5 is a diagram illustrating gradient statistical probability density distribution functions of different polarity adjacent codewords during error decoding;
FIG. 6 is a diagram illustrating a gradient statistical probability density distribution function of adjacent codewords with the same polarity during error decoding;
FIG. 7 is a diagram of demodulation decoding errors of a GFSK receiver;
fig. 8 is a schematic diagram illustrating a relationship between a GFSK received symbol period, an optimal sampling point, and an access code decoding range of a decision correction method applied to a GFSK receiver according to an embodiment of the present invention;
fig. 9 is a schematic diagram of a zero-crossing detection range of a decision correction method applied to a GFSK receiver according to an embodiment of the present invention;
fig. 10 is a schematic structural diagram of a decision detection apparatus applied to a GFSK receiver according to an embodiment of the present invention.
Detailed Description
The technical solutions in the present invention will be described clearly and completely with reference to the accompanying drawings, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
An embodiment of the present invention provides a decision correction method applied to a GFSK receiver, including the following steps:
as shown in fig. 1, in the decision of the current time, when the polarities of the first symbol and the second symbol are the same, calculating a gradient between the optimal sampling point of the first symbol and the optimal sampling point of the second symbol, and determining whether the first symbol and the second symbol are reversed according to the gradient, if so, correcting the first symbol to be an opposite value of the second symbol, and if not, not performing processing; the first symbol is a current symbol and the second symbol is a symbol previous to the current symbol. The detection process adopts a gradient detection method (namely a gradient correction method) to carry out detection and correction.
Or in the judgment of the current moment, when the polarities (namely demodulation bits) of the first symbol and the second symbol are consistent and the amplitude absolute value of the optimal sampling point is smaller than a first threshold value gamma (namely a predefined frequency word threshold value), detecting zero-crossing points of two adjacent sampling points in a certain range T, and correcting the current symbol of the zero-crossing point to be the opposite value of the previous symbol; the zero-crossing point means that the signs of two adjacent sampling points are opposite. The detection process adopts a zero-crossing detection method for detection.
When the GFSK receiver receives a signal, a symbol polarity decision method is generally adopted for the decision of a frequency word, that is, a "positive number" decision is 1; the "negative number" is decided as "0". To describe the decision word distribution of a GFSK receiver, a gradient d (i) ═ S (i) -S (i-1) is defined; wherein S (i) is a frequency word at the ith moment; the gradient d (i) characterizes the variation of the amplitude difference between adjacent symbols. Under the condition of no Gaussian white noise, the amplitude difference of the demodulated symbols with the same polarity is small, namely the absolute value of the gradient is small, and FIG. 3 is a gradient statistical probability density function; in the case of white gaussian noise, the difference between the amplitudes of the demodulated heteropolar symbols is large, i.e. the absolute value of the gradient is large, as shown in fig. 4. The probability density function of the gradient statistics changes in the presence of AWGN (white gaussian noise). When the decoding is wrong, the adjacent code word which should be in different polarity is decoded into the code word in "same polarity" because the gradient becomes smaller, as shown in fig. 5. On the other hand, when decoding is wrong, the adjacent codewords that should have the same polarity are decoded into "different polarity" codewords as the gradient becomes larger, as shown in fig. 6.
As an embodiment, a gradient between the optimal sampling point of the first symbol and the optimal sampling point of the second symbol is calculated, and whether the first symbol and the second symbol are reversed is determined according to the gradient, if yes, the first symbol is modified to be an opposite value of the second symbol, specifically:
when both the first symbol and the second symbol are decided as 0, a first gradient d (i) between the optimal sampling point S (i) of the first symbol and the optimal sampling point S (i-1) of the second symbol is calculated, and when the first gradient d (i) is greater than a first preset threshold α, the first symbol is corrected to 1. The first gradient may be an amplitude difference value between a maximum value of the sampling points within the sampling period of the first symbol and a minimum value of the sampling points within the sampling period of the second symbol. Missing detection of 0 to 1 changes can be achieved by this process.
When both the first symbol and the second symbol are decided as 1, calculating a second gradient d (i) between the optimal sampling point S (i) of the first symbol and the optimal sampling point S (i-1) of the second symbol, and correcting the first symbol to 0 when the second gradient d (i) is greater than a second preset threshold β. Missing detection of 1 to 0 changes can be achieved by this process. The second gradient may be an amplitude difference between a minimum value of the sampling points within the sampling period of the first symbol and a maximum value of the sampling points within the sampling period of the second symbol. The gradient of the embodiment of the invention refers to the difference between the amplitudes of the optimal sampling points corresponding to the previous symbol and the current symbol in the sampling period.
The embodiment of the invention mainly aims at detecting the gradient when homopolar demodulation is judged, and realizes secondary correction of the judgment result. In this way, for 010/101 type symbols, due to inter-symbol crosstalk and the presence of white gaussian noise, the middle symbol may be of the same polarity as the preceding and following symbols, but with a change in gradient. In this case, the symbol can be corrected by the present invention.
When the GFSK receiver is affected by multiple factors such as inter-symbol crosstalk, white gaussian noise, frequency offset, time drift, etc., under the condition of the optimal sampling point, the symbol energy of the current decision may not be the optimal value, thus causing symbol polarity errors at the optimal sampling point, as shown in fig. 7. The embodiment of the invention captures the polarity change brought by the energy peak by adopting a zero-crossing detection method.
At GFSK reception, the optimum sampling point is typically determined by the access code. When the optimal sampling point is determined, a plurality of sampling points often meet the decoding requirement, the range of the plurality of sampling points can be used as one of the parameters of the zero-crossing detection, and the range of the plurality of sampling points is the range of sampling points decodable by the access code. As shown in fig. 8, the relationship between the GFSK received symbol period, the optimal sampling point, and the access code decoding range can be known.
As an embodiment, the detecting zero-crossing points of two adjacent sampling points within a certain range specifically includes:
determining a plurality of starting positions and a plurality of ending positions of the range according to the first symbol and the second symbol; as shown in fig. 9, the certain range is a set of various combinations (t1, t2, t3, t4) of the start position and the end position;
and traversing all adjacent sampling points in the certain range, and detecting the zero crossing point of two adjacent sampling points. If the signs of adjacent 2 samples are "opposite," then a "zero crossing" can be considered to exist; otherwise there is no "zero crossing".
As an example, the start position includes a position of an optimal sampling point of a previous symbol, a position of a last sampling point of a decoding range of the previous symbol (i.e., a range of sampling points decodable by an access code), a position of a first sampling point of a current symbol, a position of a first sampling point of the decoding range of the current symbol (i.e., a range of sampling points decodable by an access code), and a position of a last sampling point of a period range of the previous symbol.
The end position includes, as one of the embodiments, the position of the best sample point of the current symbol, the position of the last sample point of the decoding range of the current symbol (i.e., the range of sample points decodable by the access code), and the position of the last sample point within the period range of the current symbol.
The GFSK receiver may be affected by multiple factors such as intersymbol interference, white gaussian noise, frequency offset, and time drift, which may cause decoding errors. The invention has two schemes: and zero-crossing detection and gradient detection, namely correcting the judgment result of the receiver to capture a weak signal with a changed symbol so as to correct the judgment result. This approach works best for the middle bit and the next two bits with opposite polarity. For example, when a "101" codeword is transmitted, the symbols of the three best sampling points may all be "positive", "positive"; but zero-crossing points exist in the sampling point range between the middle symbol and the first symbol, and the judgment result can be corrected through zero-crossing detection; if the zero point is not crossed, but the gradient meets the descending trend, the judgment result can be corrected by a gradient detection method. The embodiment of the invention can enhance the robustness of the decision demodulation of the receiver, improve the decoding performance and accuracy and improve the sensitivity of the receiver.
As shown in fig. 3, another embodiment of the present invention provides a decision correction method applied to a GFSK receiver, including the following steps:
in a GFSK receiver, zero crossing detection parameters are defined: a threshold gamma, a detection range starting position a and an end position b; defining gradient detection parameters: a first preset threshold α (i.e., a first gradient threshold), a second preset threshold β (i.e., a second gradient threshold);
when the polarities of the first symbol and the second symbol are consistent, judging whether the amplitude absolute value of the optimal sampling point is smaller than a first threshold value; the first symbol is a current symbol, and the second symbol is a symbol previous to the current symbol;
if yes, detecting the zero crossing point of two adjacent sampling points in a certain range, and correcting the current symbol of the zero crossing point to be the opposite value of the previous symbol; the zero crossing points mean that the signs of two adjacent sampling points are opposite;
if not, calculating the gradient between the optimal sampling point of the first symbol and the optimal sampling point of the second symbol, and judging whether the first symbol and the second symbol are reversed or not according to the gradient, if so, correcting the first symbol to be the opposite value of the second symbol, and if not, not processing.
As one embodiment, as an embodiment, a gradient between the optimal sampling point of the first symbol and the optimal sampling point of the second symbol is calculated, and whether the first symbol and the second symbol are reversed is determined according to the gradient, if yes, the first symbol is corrected to be an opposite value of the second symbol, specifically:
when both the first symbol and the second symbol are decided as 0, a first gradient d (i) between the optimal sampling point S (i) of the first symbol and the optimal sampling point S (i-1) of the second symbol is calculated, and when the first gradient d (i) is greater than a first preset threshold α, the first symbol is corrected to 1. The first gradient may be an amplitude difference value between a maximum value of the sampling points within the sampling period of the first symbol and a minimum value of the sampling points within the sampling period of the second symbol. Missing detection of 0 to 1 changes can be achieved by this process.
When both the first symbol and the second symbol are decided as 1, calculating a second gradient d (i) between the optimal sampling point S (i) of the first symbol and the optimal sampling point S (i-1) of the second symbol, and correcting the first symbol to 0 when the second gradient d (i) is greater than a second preset threshold β. The second gradient may be an amplitude difference between a minimum value of the sampling points within the sampling period of the first symbol and a maximum value of the sampling points within the sampling period of the second symbol. Missing detection of 1 to 0 changes can be achieved by this process.
As an embodiment, the detecting zero-crossing points of two adjacent sampling points within a certain range specifically includes:
determining a plurality of starting positions and a plurality of ending positions of the range according to the first symbol and the second symbol; as shown in fig. 9, the certain range is a set of various combinations (t1, t2, t3, t4) of the start position and the end position;
and traversing all adjacent sampling points in the certain range, and detecting the zero crossing point of two adjacent sampling points. If the signs of adjacent 2 samples are "opposite," then a "zero crossing" can be considered to exist; otherwise there is no "zero crossing".
As an example, the start position includes a position of an optimal sampling point of a previous symbol, a position of a last sampling point of a decoding range of the previous symbol (i.e., a range of sampling points decodable by an access code), a position of a first sampling point of a current symbol, a position of a first sampling point of the decoding range of the current symbol (i.e., a range of sampling points decodable by an access code), and a position of a last sampling point of a period range of the previous symbol.
The end position includes, as one of the embodiments, the position of the best sample point of the current symbol, the position of the last sample point of the decoding range of the current symbol (i.e., the range of sample points decodable by the access code), and the position of the last sample point within the period range of the current symbol.
As shown in fig. 10, another embodiment of the present invention provides a decision detection apparatus applied to a GFSK receiver, including a first detection module and a second detection module;
the first detection module is used for detecting the zero crossing point of two adjacent sampling points in a certain range and correcting the current symbol of the zero crossing point to be the opposite value of the previous symbol when the polarities of the first symbol and the second symbol are consistent and the amplitude absolute value of the optimal sampling point is smaller than a first threshold value; the first symbol is a current symbol, and the second symbol is a symbol previous to the current symbol;
the second detection module is used for calculating the gradient between the optimal sampling point of the first symbol and the optimal sampling point of the second symbol when the polarities of the first symbol and the second symbol are consistent and the absolute value of the amplitude of the optimal sampling point is larger than or equal to a first threshold value, and judging whether the first symbol and the second symbol are reversed or not according to the gradient, if yes, correcting the first symbol to be the opposite value of the second symbol, and if not, not processing.
For convenience and simplicity of description, the decision detection apparatus applied to the GFSK receiver in this embodiment of the apparatus includes all the embodiments in the above decision correction method applied to the GFSK receiver, and details are not described here again.
It should be noted that the above-described device embodiments are merely illustrative, where the units described as separate parts may or may not be physically separate, and the parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment. In addition, in the drawings of the embodiment of the apparatus provided by the present invention, the connection relationship between the modules indicates that there is a communication connection therebetween, and may be specifically implemented as one or more communication buses or signal lines. One of ordinary skill in the art can understand and implement it without inventive effort.
While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention.
It will be understood by those skilled in the art that all or part of the processes of the above embodiments may be implemented by hardware related to instructions of a computer program, and the computer program may be stored in a computer readable storage medium, and when executed, may include the processes of the above embodiments. The storage medium may be a magnetic disk, an optical disk, a Read-only Memory (ROM), a Random Access Memory (RAM), or the like.
Claims (8)
1. A decision correction method for use in a GFSK receiver, comprising the steps of:
when the polarities of a first symbol and a second symbol are the same, calculating the gradient between the optimal sampling point of the first symbol and the optimal sampling point of the second symbol, judging whether the first symbol and the second symbol are reversed or not according to the gradient, if so, correcting the first symbol to be the opposite value of the second symbol, and if not, not processing;
or when the polarities of the first symbol and the second symbol are consistent and the amplitude absolute value of the optimal sampling point is smaller than a first threshold value, detecting zero crossing points of two adjacent sampling points in a certain range, and correcting the current symbol of the zero crossing point to be the opposite value of the previous symbol; the zero crossing points mean that the signs of two adjacent sampling points are opposite;
the first symbol is a current symbol and the second symbol is a symbol previous to the current symbol.
2. A decision correction method for use in a GFSK receiver, comprising the steps of:
when the polarities of the first symbol and the second symbol are consistent, judging whether the amplitude absolute value of the optimal sampling point is smaller than a first threshold value; the first symbol is a current symbol, and the second symbol is a symbol previous to the current symbol;
if yes, detecting the zero crossing point of two adjacent sampling points in a certain range, and correcting the current symbol of the zero crossing point to be the opposite value of the previous symbol; the zero crossing points mean that the signs of two adjacent sampling points are opposite;
if not, calculating the gradient between the optimal sampling point of the first symbol and the optimal sampling point of the second symbol, and judging whether the first symbol and the second symbol are reversed or not according to the gradient, if so, correcting the first symbol to be the opposite value of the second symbol, and if not, not processing.
3. The decision correction method applied to a GFSK receiver according to claim 1 or 2, wherein a gradient between the optimal sampling point of the first symbol and the optimal sampling point of the second symbol is calculated, and whether the first symbol and the second symbol are reversed is determined according to the gradient, if yes, the first symbol is corrected to be an opposite value of the second symbol, specifically:
when both a first symbol and a second symbol are judged to be 0, calculating a first gradient between an optimal sampling point of the first symbol and an optimal sampling point of the second symbol, and when the first gradient is greater than a first preset threshold value, correcting the first symbol to be 1;
when both the first symbol and the second symbol are decided as 1, calculating a second gradient between the optimal sampling point of the first symbol and the optimal sampling point of the second symbol, and correcting the first symbol to 0 when the second gradient is greater than a second preset threshold.
4. The decision correction method applied to a GFSK receiver according to claim 3, wherein the detecting zero-crossing points of two adjacent sampling points within a certain range is specifically:
determining a plurality of starting positions and a plurality of ending positions of the range according to the first symbol and the second symbol; the range is a collection of a plurality of combinations of the starting position and the ending position;
and traversing all adjacent sampling points in the certain range, and detecting the zero crossing point of two adjacent sampling points.
5. The decision correction method for a GFSK receiver of claim 4, wherein the starting position comprises a position of an optimal sample of a previous symbol, a position of a last sample of a decoding range of a previous symbol, a position of a first sample of a current symbol, a position of a first sample of a decoding range of a current symbol, and a position of a last sample in a period range of a previous symbol.
6. The decision correction method for a GFSK receiver of claim 5, wherein the end position comprises a position of a best sample of a current symbol, a position of a last sample of a decoding range of the current symbol, and a position of a last sample of a period range of the current symbol.
7. A decision detection device applied to a GFSK receiver is characterized by comprising a first detection module or a second detection module;
the first detection module is used for calculating the gradient between the optimal sampling point of the first symbol and the optimal sampling point of the second symbol when the polarities of the first symbol and the second symbol are the same, judging whether the first symbol and the second symbol are reversed or not according to the gradient, if so, correcting the first symbol to be the opposite value of the second symbol, and if not, processing; the first symbol is a current symbol, and the second symbol is a symbol previous to the current symbol;
the second detection module is used for detecting the zero crossing point of two adjacent sampling points in a certain range and correcting the current symbol of the zero crossing point to be the opposite value of the previous symbol when the polarities of the first symbol and the second symbol are consistent and the amplitude absolute value of the optimal sampling point is lower than a first threshold value.
8. A decision detection device applied to a GFSK receiver is characterized by comprising a first detection module and a second detection module;
the first detection module is used for detecting the zero crossing point of two adjacent sampling points in a certain range and correcting the current symbol of the zero crossing point to be the opposite value of the previous symbol when the polarities of the first symbol and the second symbol are consistent and the amplitude absolute value of the optimal sampling point is smaller than a first threshold value; the first symbol is a current symbol, and the second symbol is a symbol previous to the current symbol;
the second detection module is used for calculating the gradient between the optimal sampling point of the first symbol and the optimal sampling point of the second symbol when the polarities of the first symbol and the second symbol are consistent and the absolute value of the amplitude of the optimal sampling point is larger than or equal to a first threshold value, and judging whether the first symbol and the second symbol are reversed or not according to the gradient, if yes, correcting the first symbol to be the opposite value of the second symbol, and if not, not processing.
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