CN109922017B - Decoding method and device for FM0 coded data and reader-writer - Google Patents
Decoding method and device for FM0 coded data and reader-writer Download PDFInfo
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Abstract
The invention discloses a method and a device for decoding FM0 coded data. The method comprises the following steps: acquiring FM0 coded data; the FM0 encoded data is a baseband waveform; if the baseband waveform has no edge ambiguity, determining the maximum value and the minimum value of the amplitude value of the baseband waveform in one period, and determining the time length according to the time corresponding to the maximum value and the minimum value of the amplitude value respectively; determining decoded data of the FM0 encoded data according to the time length and an FM0 decoding rule. In this way, the time length used for decoding the baseband waveform without edge ambiguity is determined by the maximum value and the minimum value of the amplitude value of the baseband waveform, which is helpful for improving the accuracy of decoding.
Description
Technical Field
The present invention relates to the field of wireless communication technologies, and in particular, to a method and an apparatus for decoding FM0 encoded data, and a reader.
Background
With the development of wireless communication technology, electronic tags are more and more commonly used, the electronic tags carry important information, communication equipment scans the electronic tags through a reader-writer to further acquire the information in the electronic tags, and the communication equipment can perform information interaction with the electronic tags.
Conventionally, after a reader scans an electronic tag, FM0 encoding is obtained, so the reader needs to decode FM0 encoding, and a common decoding method is to use a rising edge of FM0 encoding data (baseband waveform) as a trigger, calculate a time length between two adjacent rising edges, obtain the time length, and then decode according to the time length and an FM0 decoding rule to obtain FM0 decoding data.
In the actual operation process, since the baseband waveform is prone to have a malformed jump, the rising edge as a trigger may cause a false trigger, and further cause a decoding error.
Disclosure of Invention
The invention provides a decoding method and device of FM0 coded data and a reader-writer, which are used for solving the technical problem that decoding errors are easy to occur in the decoding process of FM0 coded data in the prior art.
The invention provides a method for decoding FM0 coded data, which comprises the following steps:
acquiring FM0 coded data; the FM0 encoded data is a baseband waveform;
if the baseband waveform has no edge ambiguity, determining the maximum value and the minimum value of the amplitude value of the baseband waveform in one period, and determining the time length according to the time corresponding to the maximum value and the minimum value of the amplitude value respectively;
determining decoded data of the FM0 encoded data according to the time length and an FM0 decoding rule.
Optionally, determining the time length according to the respective corresponding times of the maximum value and the minimum value of the amplitude value, includes:
determining a time point which is later than a first time by a preset time as a starting point, wherein the amplitude value corresponding to the first time is equal to one half of the maximum value of the amplitude value;
determining a time point earlier than a second time by the preset time as an end point, wherein the amplitude value corresponding to the second time is equal to one half of the minimum value of the amplitude value;
determining a time period between the start point and the end point as the time length.
Optionally, the method further includes:
judging whether the bit number occupied by each data in the decoded data is equal to a preset bit number or not;
and if the bit number occupied by each data is equal to the preset bit number, outputting the decoded data.
Optionally, before determining the maximum value of the amplitude value and the minimum value of the amplitude value in one period of the baseband waveform, the method further includes:
comparing the baseband waveform with a preset waveform, wherein the preset waveform is a waveform conforming to the FM0 encoding rule;
and if the baseband waveform is the same as the preset waveform, determining that the baseband waveform has no edge ambiguity.
Optionally, if the baseband waveform includes a co-directional I branch and a quadrature Q branch, before determining the maximum value and the minimum value of the amplitude value of the baseband waveform in one period, the method further includes:
processing the I branch and the Q branch to obtain at least two branches of different types;
if the baseband waveform has no edge ambiguity, determining the maximum value and the minimum value of the amplitude value of the baseband waveform in one period, including:
determining waveforms without edge ambiguity in waveforms corresponding to the I branch, the Q branch and the at least two branches of different types respectively;
and determining the maximum value and the minimum value of the amplitude value in one period of the determined waveform without edge blurring.
Optionally, the I branch and the Q branch are processed to obtain at least two different types of branches, including:
adding or subtracting amplitude values at a first time in the respective waveforms of the I branch and the Q branch to obtain a first amplitude value, and taking the first amplitude value as the amplitude value at the first time to obtain the waveform of the first type branch;
and adding or subtracting squares of the amplitude values at the second time in the respective waveforms of the I branch and the Q branch to obtain a second amplitude value, and taking the second amplitude value as the amplitude value at the second time to obtain the waveform of the second type branch.
A second aspect of the present invention provides an apparatus for decoding FM0 encoded data, comprising:
the acquisition module is used for acquiring FM0 coded data; the FM0 encoded data is a baseband waveform;
the decoding module is used for determining the maximum value and the minimum value of the amplitude value of the baseband waveform in one period when the baseband waveform has no edge ambiguity, and determining the time length according to the time corresponding to the maximum value and the minimum value of the amplitude value respectively; and determining the decoding data of the FM0 coded data according to the time length and the FM0 decoding rule.
Optionally, the decoding module is specifically configured to:
determining a time point which is later than a first time by a preset time as a starting point, wherein the amplitude value corresponding to the first time is equal to one half of the maximum value of the amplitude value;
determining a time point earlier than a second time by the preset time as an end point, wherein the amplitude value corresponding to the second time is equal to one half of the minimum value of the amplitude value;
determining a time period between the start point and the end point as the time length.
Optionally, the apparatus further includes a logic determining module connected to the decoding module, where the logic determining module is configured to:
acquiring the decoded data, and judging whether the bit number occupied by each data in the coded data is equal to a preset bit number or not;
and if the bit number occupied by each data is equal to the preset bit number, outputting the decoded data.
Optionally, the decoding module is further configured to:
comparing the baseband waveform with a preset waveform, wherein the preset waveform is a waveform conforming to the FM0 encoding rule;
and if the baseband waveform is the same as the preset waveform, determining that the baseband waveform has no edge ambiguity.
Optionally, if the baseband waveform includes an equidirectional I branch and an orthogonal Q branch, the apparatus further includes a shunt processing module, one end of the shunt processing module is connected to the obtaining module, and the other end of the shunt processing module is connected to the decoding module, and the shunt processing module is configured to:
processing the I branch and the Q branch to obtain at least two branches of different types;
when determining the maximum value and the minimum value of the amplitude value of the baseband waveform in one period, the decoding module is specifically configured to:
determining waveforms without edge ambiguity in waveforms corresponding to the I branch, the Q branch and the at least two branches of different types respectively;
and determining the maximum value and the minimum value of the amplitude value in one period of the determined waveform without edge blurring.
Optionally, the preprocessing module is specifically configured to:
adding or subtracting amplitude values at a first time in the respective waveforms of the I branch and the Q branch to obtain a first amplitude value, and taking the first amplitude value as the amplitude value at the first time to obtain the waveform of the first type branch;
and adding or subtracting squares of the amplitude values at the second time in the respective waveforms of the I branch and the Q branch to obtain a second amplitude value, and taking the second amplitude value as the amplitude value at the second time to obtain the waveform of the second type branch.
A third aspect of the present invention provides an apparatus for decoding FM0 encoded data, comprising: a processor and a memory;
the memory is for storing computer executable instructions which, when executed by the processor, cause the decoding apparatus for FM0 encoded data to perform a method of decoding FM0 encoded data as provided in the first aspect of the invention.
A fourth aspect of the present invention provides a computer readable storage medium comprising instructions which, when run on a computer, cause the computer to perform a method of decoding FM0 encoded data as provided by the first aspect of the present invention.
The technical scheme in the embodiment of the invention has the following beneficial effects:
in the technical scheme provided by the embodiment of the invention, FM0 coded data is obtained; the FM0 encoded data is a baseband waveform; if the baseband waveform has no edge ambiguity, determining the maximum value and the minimum value of the amplitude value of the baseband waveform in one period, and determining the time length according to the time corresponding to the maximum value and the minimum value of the amplitude value respectively; determining decoded data of the FM0 encoded data according to the time length and an FM0 decoding rule. In this way, the time length adopted when decoding the baseband waveform without edge ambiguity is determined by the maximum value and the minimum value of the amplitude value of the baseband waveform, and the decoding is not triggered according to the rising edge of the baseband waveform, which is beneficial to improving the accuracy of the decoding.
Drawings
Fig. 1 is a flowchart of a method for decoding FM0 encoded data according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of a time duration determination process according to an embodiment of the present invention;
fig. 3 is a block diagram of an apparatus for decoding FM0 encoded data according to an embodiment of the present invention;
fig. 4 is a block diagram of an apparatus for decoding FM0 encoded data according to an embodiment of the present invention.
Detailed Description
The invention provides a decoding method and device of FM0 coded data and a reader-writer, which are used for solving the technical problem that decoding errors are easy to occur in the decoding process of FM0 coded data in the prior art.
Conventionally, after a reader scans an electronic tag, FM0 encoding is obtained, so the reader needs to decode FM0 encoding, and a common decoding method is to use a rising edge of FM0 encoding data (baseband waveform) as a trigger, calculate a time length between two adjacent rising edges, obtain the time length, and then decode according to the time length and an FM0 decoding rule to obtain FM0 decoding data. However, in the actual operation process, since the baseband waveform is prone to have a malformed jump, the rising edge as a trigger may cause a false trigger, and further cause a decoding error.
In order to solve the technical problem, the technical scheme in the embodiment of the invention has the following general idea:
in the technical scheme provided by the embodiment of the invention, FM0 coded data is obtained; the FM0 encoded data is a baseband waveform; if the baseband waveform has no edge ambiguity, determining the maximum value and the minimum value of the amplitude value of the baseband waveform in one period, and determining the time length according to the time corresponding to the maximum value and the minimum value of the amplitude value respectively; determining decoded data of the FM0 encoded data according to the time length and an FM0 decoding rule. In this way, the time length adopted when decoding the baseband waveform without edge ambiguity is determined by the maximum value and the minimum value of the amplitude value of the baseband waveform, and the decoding is not triggered according to the rising edge of the baseband waveform, which is helpful for improving the accuracy of the decoding.
In order to better understand the technical solutions of the present invention, the following detailed descriptions of the technical solutions of the present invention are provided with the accompanying drawings and the specific embodiments, and it should be understood that the specific features of the embodiments and the examples of the present invention are the detailed descriptions of the technical solutions of the present invention, and are not limitations of the technical solutions of the present invention, and the technical features of the embodiments and the examples of the present invention can be combined with each other without conflict.
Referring to fig. 1, a flowchart of a method for decoding FM0 encoded data according to an embodiment of the present invention is shown. The method can be applied to any device capable of decoding FM0 encoded data, such as a reader-writer, which can be arranged on a communication device needing to read information in an Electronic tag, for example, a drive test device arranged in an Electronic Toll Collection (ETC) system to scan the Electronic tag of a vehicle on the road for charging. In the following description, the method is described as being applied to a reader/writer as an example. As can be seen in fig. 1, the method comprises:
step 101: acquiring FM0 coded data; the FM0 encoded data is a baseband waveform;
step 102: if the baseband waveform has no edge ambiguity, determining the maximum value and the minimum value of the amplitude value of the baseband waveform in one period, and determining the time length according to the time corresponding to the maximum value and the minimum value of the amplitude value respectively;
step 103: determining decoded data of the FM0 encoded data according to the time length and an FM0 decoding rule.
Optionally, in step 101, the mode of acquiring the FM0 encoded data by the reader may be obtained by scanning an electronic tag, or may be sent to the reader by other devices, which is not specifically limited by comparing the embodiment of the present invention.
Optionally, before step 101, what is obtained after the reader scans the electronic tag may not be FM0 encoded data but ADC data, and the reader may further process the ADC data to obtain FM0 encoded data. In the embodiment of the invention, the process of processing the ADC data by the reader-writer can be divided into three steps, wherein in the first step, the reader-writer samples the ADC data. In the second step, the reader detects the valid signal in the ADC data, i.e., FM0 encoded data. And thirdly, detecting the lead code signal in the effective signal by the reader-writer.
Optionally, in the first step, the reader may sample ADC data to obtain a sampling waveform. For example, the analog signal corresponding to the ADC data is used to obtain a partial signal, i.e. a partial waveform, in the analog signal, and then the sampled waveform is decoded.
In the actual operation process, the ADC data may be doped with other noise, so in the second step, the reader may filter the obtained sampling waveform to obtain a valid signal, which is the FM0 encoded data.
Optionally, in the third step, after the valid signal is detected, the detection of the preamble signal is started. The preamble signal is understood to be a signal that is added before the valid signal, and the detection of the preamble signal may be performed according to the standard of the preamble signal specified in the null interface protocol, and after the detection of the preamble signal is successful, the processing of the ADC data is terminated.
Optionally, after obtaining the FM0 encoded data, the reader starts to execute step 102, that is, if the baseband waveform has no edge ambiguity, the maximum value and the minimum value of the amplitude value of the baseband waveform in one period are determined, and the time length is determined according to the time corresponding to the maximum value and the minimum value of the amplitude value.
Optionally, in step 102, the reader may determine whether the baseband waveform has edge ambiguity, for example, the reader compares the baseband waveform with a preset waveform, where the preset waveform is a waveform conforming to the FM0 encoding rule, and if the baseband waveform is the same as the preset waveform, it is determined that the baseband waveform has no edge ambiguity.
Optionally, the reader/writer may store in advance or obtain a waveform meeting the FM0 encoding rule from another device, where the waveform is an ideal waveform, and if the baseband waveform matches the ideal waveform, that is, a waveform without abrupt shape change on the baseband waveform, especially each rising edge of the baseband waveform, is smooth and has no protrusion or recess, and the like, it indicates that the baseband waveform has no edge ambiguity. Of course, in the actual operation process, there may be other ways to determine whether the baseband waveform has edge ambiguity, such as determining whether the baseband waveform is smooth.
If the baseband waveform is edge-free, the reader may determine a length of time and then decode FM0 encoded data based on the length of time. The process of decoding FM0 encoded data based on the time length will be described later in the description of step 103, where a specific process of determining the time length by the reader/writer will be described first.
As an example, reading and writing determines a time point which is later than a first time by a preset time as a starting point, wherein the amplitude value corresponding to the first time is equal to one half of the maximum value of the amplitude value; determining a time point earlier than a second time by the preset time as an end point, wherein the amplitude value corresponding to the second time is equal to one half of the minimum value of the amplitude value; determining a time period between the start point and the end point as the time length.
Fig. 2 shows a schematic diagram of determining the time length provided by the embodiment of the present invention. In fig. 2, the preset time is 0, and the baseband waveform is a sine wave, as shown in the figure, the starting point on the first curve is point a, the ending point is point B, and the time between point a and point B constitutes the time length. The amplitude value of the point A is one half of the maximum value of the amplitude value in the first period, and the amplitude value of the point B is one half of the minimum value of the amplitude value in the period. It should be noted that the preset time is required to be less than one eighth of the first period of the baseband waveform, i.e., the amplitude value at the point a is ensured to be greater than 0.
Referring to fig. 2, in the prior art, the reader/writer determines the time length by using the rising trend of the baseband waveform as a trigger, and the time between two adjacent rising trends as the time length, i.e., the time length between the point C and the point D on the second curve in fig. 2.
Optionally, after obtaining the time length, step 103 is executed, that is, decoding is performed according to the time length and the decoding rule. It should be noted that the decoding rule specifically includes: the baseband waveform represents different logic with level changes within a bit window (length of time). For example, if the level is flipped only at the beginning of the bit window and not at other positions, a logic "1" is indicated, and if the level is flipped both at the beginning of the bit window and in the middle of the bit window, a logic "0" is indicated. Therefore, the reader-writer compares the obtained time length with the time period of the ideal waveform according to the decoding rule, determines data to be decoded according to the comparison result, and then determines final FM0 decoded data according to the data to be decoded. The specific process is described in three cases, i.e. the time length is equal to T, 1.5T, 2T, and will be described separately below:
in the first case, the duration length is equal to T. The data to be decoded corresponding to the time length is 01.
In the second case, the duration length is equal to 1.5T, if the falling edge in the duration length is located at a position on the left side of the middle in the duration length, the data to be decoded corresponding to the duration length is 011, and if the falling edge in the duration length is located at a position on the right side of the middle in the duration length, the data to be decoded corresponding to the duration length is 001.
In the third case, if the time length is equal to 2T, the data to be decoded corresponding to the time length is 0011.
After the data to be decoded is obtained according to the FM0 decoding rule, the data "01" and "10" to be decoded should be decoded to be "0", and the data "00" and "11" to be decoded should be decoded to be "1". Therefore, the reader-writer can decode the obtained data to be decoded according to the FM0 encoding rule to obtain the final FM0 decoded data.
Optionally, after the reader obtains the FM0 decoded data, it may further determine whether the FM0 decoded data is correct, and specific determination manners may be various, which will be described below.
In a first possible implementation manner, as mentioned above, information interaction may be performed between the electronic tag and the reader/writer, so that the reader/writer may send a test signal to the electronic tag while, before, or after scanning the electronic tag to obtain FM0 encoded data, receive a response signal fed back by the electronic tag, determine a data length of each data in the response signal, that is, a bit number occupied by each data, store the data length by parsing the response signal, compare the data length of each data in the FM0 decoded data with the stored data length after obtaining the FM0 decoded data, and if the data length is the same, indicate that the decoding is correct.
In a second possible implementation manner, the reader/writer may store the data length of each piece of FM0 decoded data of each electronic tag in advance, for example, after the reader/writer decodes the FM0 decoded data of each electronic tag, the reader/writer stores the data length of the electronic tag and the data length of the FM0 decoded data in a corresponding relationship, and when the FM0 decoded data of the electronic tag is decoded again, the corresponding relationship may be called directly. Namely, when the data length of the FM0 interface data is equal to the data length stored in the corresponding relation, the decoding is correct.
Optionally, after the reader/writer determines that the decoding is correct, the decoded data may be output.
Optionally, in an actual operation process, the baseband waveform may include an I branch in the same direction and a Q branch in the orthogonal direction, and for this situation, if the baseband waveform needs to be decoded, the reader/writer may process the I branch and the Q branch to obtain at least two different types of branches; then, step 102 and step 103 are performed respectively for determining the waveforms corresponding to the I branch, the Q branch and the at least two different types of branches.
For example, the reader/writer couples to the I branch in the baseband waveformAnd Q branch, to obtain several branches, e.g. I + Q branch, I-Q branch, I2+Q2Branch, I2-Q2And (4) branching. The specific process is as follows:
adding or subtracting amplitude values at a first time in the respective waveforms of the I branch and the Q branch to obtain a first amplitude value, and taking the first amplitude value as the amplitude value at the first time to obtain the waveform of the first type branch; i.e., I + Q, I-Q.
And adding or subtracting squares of the amplitude values at the second time in the respective waveforms of the I branch and the Q branch to obtain a second amplitude value, and taking the second amplitude value as the amplitude value at the second time to obtain the waveform of the second type branch. I.e. I2+Q2、I2-Q2。
With I + Q branch, I-Q branch, I2+Q2For example, the reader/writer may determine a branch without edge ambiguity from the five branches (five waveforms), and then decode the branch. The specific decoding process has been described above and will not be repeated here.
Optionally, in an actual operation process, the reader may perform priority classification on the five branches, for example, the priority classes of the five branches are respectively: i is2+Q2Branch, I + Q branch, I-Q branch, I branch and Q branch. When the reader-writer is paired with I2+Q2If the decoding is correct after the branch is executed in the steps 102 and 103, the other four branches do not need to be decoded. If the reader-writer is paired with I2+Q2Incorrect decoding after branch execution of steps 102-103, e.g. for I2+Q2If the data length after decoding the branch is not equal to the predetermined data length, the I + Q branch needs to perform step 102-103. If the five branches have no branch which is successfully decoded, the data decoded at this time is abandoned, and prompt information that the decoding is unsuccessful is output.
As can be seen from the above description, in the technical solution provided by the embodiment of the present invention, FM0 encoded data is obtained; the FM0 encoded data is a baseband waveform; if the baseband waveform has no edge ambiguity, determining the maximum value and the minimum value of the amplitude value of the baseband waveform in one period, and determining the time length according to the time corresponding to the maximum value and the minimum value of the amplitude value respectively; determining decoded data of the FM0 encoded data according to the time length and an FM0 decoding rule. In this way, the time length adopted when decoding the baseband waveform without edge ambiguity is determined by the maximum value and the minimum value of the amplitude value of the baseband waveform, and the decoding is not triggered according to the rising edge of the baseband waveform, which is beneficial to improving the accuracy of the decoding.
A second aspect of the embodiment of the present invention provides a decoding apparatus for FM0 encoded data, and please refer to fig. 3, which is a structural diagram of the decoding apparatus for FM0 encoded data according to the embodiment of the present invention. The decoding apparatus 300 for FM0 encoded data includes:
an obtaining module 301, configured to obtain FM0 encoded data; the FM0 encoded data is a baseband waveform;
a decoding module 302, configured to determine a maximum value and a minimum value of an amplitude value of the baseband waveform in one period when the baseband waveform has no edge ambiguity, and determine a time length according to respective corresponding times of the maximum value and the minimum value of the amplitude value; and determining the decoding data of the FM0 coded data according to the time length and the FM0 decoding rule.
Optionally, the decoding module 302 is specifically configured to:
determining a time point which is later than a first time by a preset time as a starting point, wherein the amplitude value corresponding to the first time is equal to one half of the maximum value of the amplitude value;
determining a time point earlier than a second time by the preset time as an end point, wherein the amplitude value corresponding to the second time is equal to one half of the minimum value of the amplitude value;
determining a time period between the start point and the end point as the time length.
Optionally, the decoding apparatus 300 for FM0 encoded data further includes a logic determining module (not shown in the figure) connected to the decoding module 302, and the logic determining module is configured to:
acquiring the decoded data, and judging whether the bit number occupied by each data in the coded data is equal to a preset bit number or not;
and if the bit number occupied by each data is equal to the preset bit number, outputting the decoded data.
Optionally, the decoding module is further configured to:
comparing the baseband waveform with a preset waveform, wherein the preset waveform is a waveform conforming to the FM0 encoding rule;
and if the baseband waveform is the same as the preset waveform, determining that the baseband waveform has no edge ambiguity.
Optionally, if the baseband waveform includes a co-directional I branch and a quadrature Q branch, the decoding apparatus 300 for FM0 encoded data further includes a splitting processing module (not shown in the figure), one end of the splitting processing module is connected to the 301 obtaining module, and the other end of the splitting processing module is connected to the decoding module 302, and the splitting processing module is configured to:
processing the I branch and the Q branch to obtain at least two branches of different types;
when determining the maximum value and the minimum value of the amplitude value in one period of the baseband waveform, the decoding module 302 is specifically configured to:
determining waveforms without edge ambiguity in waveforms corresponding to the I branch, the Q branch and the at least two branches of different types respectively;
and determining the maximum value and the minimum value of the amplitude value in one period of the determined waveform without edge blurring.
Optionally, the shunting processing module is specifically configured to:
adding or subtracting amplitude values at a first time in the respective waveforms of the I branch and the Q branch to obtain a first amplitude value, and taking the first amplitude value as the amplitude value at the first time to obtain the waveform of the first type branch;
and adding or subtracting squares of the amplitude values at the second time in the respective waveforms of the I branch and the Q branch to obtain a second amplitude value, and taking the second amplitude value as the amplitude value at the second time to obtain the waveform of the second type branch.
Since the decoding apparatus for FM0 encoded data provided in this embodiment and the decoding method for FM0 encoded data shown in fig. 1-2 are based on the same idea, and through the foregoing detailed description of the decoding method for FM0 encoded data and its variations, those skilled in the art can clearly understand the implementation process of the decoding apparatus for FM0 encoded data in this embodiment, and therefore, for the sake of brevity of the description, no further description is provided here.
Referring to fig. 4, a third aspect of the present invention provides a decoding apparatus for FM0 encoded data, which is a structural diagram of the decoding apparatus for FM0 encoded data according to an embodiment of the present invention. The decoding apparatus 400 for FM0 encoded data includes: a memory 401 and a processor 402.
The memory 401 is used for storing computer executable instructions which, when executed by the processor 402, cause the decoding apparatus for FM0 encoded data to perform the method for decoding FM0 encoded data as provided by the first aspect of the invention.
Alternatively, the processor 402 may be a general-purpose Central Processing Unit (CPU) or an Application Specific Integrated Circuit (ASIC), may be one or more Integrated circuits for controlling program execution, may be a hardware Circuit developed by using a Field Programmable Gate Array (FPGA), and may be a baseband processor.
Optionally, the Memory 401 may include one or more of a Read Only Memory (ROM), a Random Access Memory (RAM), and a disk Memory. The memory 401 is used for storing data and/or instructions required by the processor 402 when running. The number of the memories 401 may be one or more.
Since the decoding apparatus for FM0 encoded data provided in this embodiment and the decoding method for FM0 encoded data shown in fig. 1-2 are based on the same idea, and through the foregoing detailed description of the decoding method for FM0 encoded data and its variations, those skilled in the art can clearly understand the implementation process of the decoding apparatus for FM0 encoded data in this embodiment, and therefore, for the sake of brevity of the description, no further description is provided here.
As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, optical storage, and the like) having computer-usable program code embodied therein.
The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.
Claims (12)
1. A method of decoding FM0 encoded data, comprising:
acquiring FM0 coded data; the FM0 encoded data is a baseband waveform;
if the baseband waveform has no edge ambiguity, determining the maximum value and the minimum value of the amplitude value of the baseband waveform in one period, and determining the time length according to the time corresponding to the maximum value and the minimum value of the amplitude value respectively;
determining a starting point as a time point later than a first time by a preset time, wherein the amplitude value corresponding to the first time is equal to one half of the maximum value of the amplitude value, and determining an ending point as a time point earlier than a second time by the preset time, wherein the amplitude value corresponding to the second time is equal to one half of the minimum value of the amplitude value, and the preset time needs to be less than one eighth of a first period of the baseband waveform; determining a time period between the starting point and the ending point as the time length;
determining decoded data of the FM0 encoded data according to the time length and an FM0 decoding rule.
2. The method of claim 1, wherein the method further comprises:
judging whether the bit number occupied by each data in the decoded data is equal to a preset bit number or not;
and if the bit number occupied by each data is equal to the preset bit number, outputting the decoded data.
3. The method of claim 1, wherein prior to determining the maximum value of the amplitude value and the minimum value of the amplitude value within one period of the baseband waveform, the method further comprises:
comparing the baseband waveform with a preset waveform, wherein the preset waveform is a waveform conforming to the FM0 encoding rule;
and if the baseband waveform is the same as the preset waveform, determining that the baseband waveform has no edge ambiguity.
4. The method of claim 1, wherein if the baseband waveform includes a uni-branch and a quadrature Q-branch, before determining the maximum and minimum amplitude values of the baseband waveform in a cycle, the method further comprises:
processing the I branch and the Q branch to obtain at least two branches of different types;
if the baseband waveform has no edge ambiguity, determining the maximum value and the minimum value of the amplitude value of the baseband waveform in one period, including:
determining waveforms without edge ambiguity in waveforms corresponding to the I branch, the Q branch and the at least two branches of different types respectively;
and determining the maximum value and the minimum value of the amplitude value in one period of the determined waveform without edge blurring.
5. The method of claim 4, wherein processing the I branch and the Q branch to obtain at least two different types of branches comprises:
adding or subtracting amplitude values at a first time in the respective waveforms of the I branch and the Q branch to obtain a first amplitude value, and taking the first amplitude value as the amplitude value at the first time to obtain the waveform of the first type branch;
and adding or subtracting squares of the amplitude values at the second time in the respective waveforms of the I branch and the Q branch to obtain a second amplitude value, and taking the second amplitude value as the amplitude value at the second time to obtain the waveform of the second type branch.
6. An apparatus for decoding FM0 encoded data, comprising:
the acquisition module is used for acquiring FM0 coded data; the FM0 encoded data is a baseband waveform;
the decoding module is used for determining the maximum value and the minimum value of the amplitude value of the baseband waveform in one period when the baseband waveform has no edge ambiguity, and determining the time length according to the time corresponding to the maximum value and the minimum value of the amplitude value respectively; determining a starting point as a time point later than a first time by a preset time, wherein the amplitude value corresponding to the first time is equal to one half of the maximum value of the amplitude value, and determining an ending point as a time point earlier than a second time by the preset time, wherein the amplitude value corresponding to the second time is equal to one half of the minimum value of the amplitude value, and the preset time needs to be less than one eighth of a first period of the baseband waveform; determining a time period between the starting point and the ending point as the time length;
and determining the decoding data of the FM0 coded data according to the time length and the FM0 decoding rule.
7. The apparatus of claim 6, further comprising a logic determination module coupled to the decode module, the logic determination module to:
acquiring the decoded data, and judging whether the bit number occupied by each data in the decoded coded data is equal to a preset bit number or not;
and if the bit number occupied by each data is equal to the preset bit number, outputting the decoded data.
8. The apparatus of claim 6, wherein the decoding module is further to:
comparing the baseband waveform with a preset waveform, wherein the preset waveform is a waveform conforming to the FM0 encoding rule;
and if the baseband waveform is the same as the preset waveform, determining that the baseband waveform has no edge ambiguity.
9. The apparatus of claim 6, wherein if the baseband waveform includes a co-directional I branch and a quadrature Q branch, the apparatus further comprises a demultiplexing module coupled to the acquisition module at one end and to the decoding module at another end, the demultiplexing module configured to:
processing the I branch and the Q branch to obtain at least two branches of different types;
when determining the maximum value and the minimum value of the amplitude value of the baseband waveform in one period, the decoding module is specifically configured to:
determining waveforms without edge ambiguity in waveforms corresponding to the I branch, the Q branch and the at least two branches of different types respectively;
and determining the maximum value and the minimum value of the amplitude value in one period of the determined waveform without edge blurring.
10. The apparatus of claim 9, wherein the bifurcating processing module is specifically configured to:
adding or subtracting amplitude values at a first time in the respective waveforms of the I branch and the Q branch to obtain a first amplitude value, and taking the first amplitude value as the amplitude value at the first time to obtain the waveform of the first type branch;
and adding or subtracting squares of the amplitude values at the second time in the respective waveforms of the I branch and the Q branch to obtain a second amplitude value, and taking the second amplitude value as the amplitude value at the second time to obtain the waveform of the second type branch.
11. An apparatus for decoding FM0 encoded data, comprising: a processor and a memory;
the memory is for storing computer-executable instructions that, when executed by the processor, cause the decoding apparatus of FM0 encoded data to perform the method of any of claims 1-5.
12. A computer-readable storage medium comprising instructions that, when executed on a computer, cause the computer to perform the method of any one of claims 1-5.
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