CN109412757B - Modified Miller self-adaptive decoding method and device - Google Patents
Modified Miller self-adaptive decoding method and device Download PDFInfo
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- CN109412757B CN109412757B CN201811500010.6A CN201811500010A CN109412757B CN 109412757 B CN109412757 B CN 109412757B CN 201811500010 A CN201811500010 A CN 201811500010A CN 109412757 B CN109412757 B CN 109412757B
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L1/00—Arrangements for detecting or preventing errors in the information received
- H04L1/0001—Systems modifying transmission characteristics according to link quality, e.g. power backoff
- H04L1/0036—Systems modifying transmission characteristics according to link quality, e.g. power backoff arrangements specific to the receiver
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
- G06K7/00—Methods or arrangements for sensing record carriers, e.g. for reading patterns
- G06K7/10—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation
- G06K7/10009—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/26—Systems using multi-frequency codes
- H04L27/2601—Multicarrier modulation systems
- H04L27/2647—Arrangements specific to the receiver only
- H04L27/2655—Synchronisation arrangements
- H04L27/2689—Link with other circuits, i.e. special connections between synchronisation arrangements and other circuits for achieving synchronisation
- H04L27/2692—Link with other circuits, i.e. special connections between synchronisation arrangements and other circuits for achieving synchronisation with preamble design, i.e. with negotiation of the synchronisation sequence with transmitter or sequence linked to the algorithm used at the receiver
- H04L27/2694—Link with other circuits, i.e. special connections between synchronisation arrangements and other circuits for achieving synchronisation with preamble design, i.e. with negotiation of the synchronisation sequence with transmitter or sequence linked to the algorithm used at the receiver adaptive design
Abstract
The invention discloses a modified Miller self-adaptive decoding method and a modified Miller self-adaptive decoding device, wherein the self-adaptive decoding method is to decode by taking a code element combination consisting of basic code elements as a unit when a modified Miller data frame is decoded, compare the high level time length of the current code element combination with a decoding threshold value to determine a specific code element, and determine the decoding threshold value of the next decoding according to the low level time length of the current code element combination.
Description
Technical Field
The invention relates to the field of ISO/IEC 14443A non-contact communication radio frequency communication, in particular to a modified Miller self-adaptive decoding method and a modified Miller self-adaptive decoding device.
Background
The industry of the smart card in China is rapidly developed, the industrial scale is large, the smart card plays an increasingly important role in the fields of mobile communication, public transportation, medical security, identity recognition, safety control, payment and the like, the use of the smart card is more and more convenient, various products emerge endlessly, and the wide application of the smart card also promotes the rapid development of the smart card technology and industry.
The intelligent card is formed by packaging an IC chip and an induction antenna in a standard PVC card, and the chip and the antenna have no exposed part. When the intelligent card is used, the intelligent card is close to the surface of a reader-writer within a certain distance range (generally 5-10 cm), and data reading and writing operations are realized by transmitting radio waves between the intelligent card and the reader-writer. When the smart card meeting ISO/IEC 14443A on the market is used in different card readers and wireless environments, the analog decoding of the smart card is influenced due to the influences of signal distortion, analog decoding circuit errors and the like in the wireless transmission process, the low-level time of a decoded digital baseband signal cannot meet the requirement of a fixedly set decoding threshold value, and finally the decoding fails.
Disclosure of Invention
The invention aims to provide a self-adaptive decoding method and a self-adaptive decoding device, which can dynamically adjust a decoding threshold value according to the low level time length so as to reduce the influence of card reader difference and wireless environment factors on the decoding performance of an intelligent card.
Specifically, the present invention provides a modified Miller adaptive decoding method for decoding in units of symbol combinations composed of basic symbols when decoding a modified Miller data frame, the decoding method comprising the steps of:
s1: demodulating the modified Miller data frame signal;
s2: calculating the high level duration of two adjacent low level signal periods of the data frame;
s3: comparing the high level duration with a preset decoding threshold or a decoding threshold determined after the last decoding, determining each symbol of the current symbol combination to realize the current decoding, and determining a decoding threshold for the next decoding through the following steps S4 and S5;
s4: calculating the low level time length of the current code element combination according to the current code element combination and the high level time length;
s5: and determining a decoding threshold value of the next decoding according to the low level duration, and repeating the steps S2-S5.
Preferably, the symbol combination includes a first type of symbol combination, a second type of symbol combination, a third type of symbol combination, and a fourth type of symbol combination, the decoding threshold includes a first decoding threshold, a second decoding threshold, and a third decoding threshold, and the type of the current symbol combination is determined before each symbol of the current symbol combination is determined in step S3, specifically:
if the high level duration of the current code element combination is smaller than the first decoding threshold, the current code element combination is a first type code element combination;
if the high level duration of the current code element combination is greater than the first decoding threshold and less than the second decoding threshold, the current code element combination is a second type code element combination;
if the high level duration of the current code element combination is greater than the second decoding threshold and less than a third decoding threshold, the current code element combination is a third type code element combination;
and if the high level duration of the current code element combination is greater than the third decoding threshold, combining the current code element combination into a fourth type code element combination.
Preferably, the basic symbol includes X, Y and Z, the first type of symbol combination includes ZZ and XX, the second type of symbol combination includes XYZ and ZX, the third type of symbol combination includes XYX and ZY, and the fourth type of symbol combination includes XYY.
Preferably, the first symbol of the current symbol combination is the starting symbol Z of the modified Miller data frame or the last symbol of the previous symbol combination, and the specific step of determining each symbol of the current symbol combination is:
if the current code element is combined into the first type code element combination, if the first code element is X, the current code element is XX, and if the first code element is Z, the current code element is ZZ;
if the current code element is combined into the second type code element combination, if the first code element is X, the current code element is XYZ, and if the first code element is Z, the current code element is ZX;
if the current code element is combined into the third type code element combination, if the first code element is X, the current code element is XYX, and if the first code element is Z, the current code element combination is an end signal ZY;
if the current code element is combined into the fourth type code element combination, if the first code element is X, the current code element combination is an ending signal XYY.
Preferably, if the current symbol is combined to the ending signal ZY or XYY, the decoding of the data frame is ended.
Preferably, the sum of the high level duration and the low level duration of the first type of symbol combination is equal to one basic time unit; the sum of the high level duration and the low level duration of the second type of symbol combination is equal to 3/2 basic time units; the sum of the high level duration and the low level duration of the third type of code element combination is equal to 2 × basic time unit; the sum of the high level duration and the low level duration of the fourth type of code element combination is greater than 2 × basic time unit; the specific steps of calculating the low level duration of the code element combination are as follows:
if the current code element is combined into the first code element combination, the corresponding low level time length is the basic time unit-high level time length;
if the current code element is combined into the second type of code element combination, the corresponding low level duration is 3/2 × basic time unit-high level duration;
if the current code element is combined into the third type of code element combination, the corresponding low level time length is 2 × basic time unit-high level time length;
if the current code element combination is the fourth type code element combination, the low level time length does not need to be calculated.
Preferably, after the current symbol combination is decoded successfully, the first decoding threshold, the second decoding threshold and the third decoding threshold for the next decoding are determined according to the low level duration of the current symbol combination, and the specific steps are as follows:
if the low level time length of the current code element is equal to the low level time length of the last code element combination, the first decoding threshold value, the second decoding threshold value and the third decoding threshold value are unchanged;
if the low level duration of the current code element is greater than or less than the low level duration of the previous code element combination, calculating dynamic adjustment ranges of a first decoding threshold, a second decoding threshold and a third decoding threshold according to the low level duration, and selecting and replacing the optimal decoding threshold with the corresponding first decoding threshold, second decoding threshold and third decoding threshold in the dynamic adjustment range, wherein the adjustment range of the first decoding threshold is [ basic time unit-low level duration, 3/2 [ basic time unit-low level duration ], the adjustment range of the second decoding threshold is [3/2 [ basic time unit-low level duration, 2 [ basic time unit-low level duration ], and the adjustment range of the third decoding threshold is greater than (2 [ basic time unit-low level duration ");
if the low level duration of the current code element exceeds the decodable range, an error signal is generated and the decoding of the data frame is ended.
Preferably, the optimal value of the first decoding threshold is (5/4 × basic time unit — low level duration).
Preferably, the second decoding threshold is preferably (7/4 × basic time unit — low level duration).
The present invention also provides a modified Miller adaptive decoding apparatus for decoding a modified Miller data frame in units of symbol combinations composed of basic symbols, including
A radio frequency receiving unit for demodulating and correcting Miller data frame signals;
the high level duration calculating unit is used for calculating the high level duration of two adjacent low level signal periods of the data frame;
the decoding unit compares the high level time length with a preset decoding threshold or a decoding threshold determined after the last decoding, and determines each code element of the current code element combination to realize the current decoding;
a low level time length calculating unit, which calculates the low level time length of the code element combination according to the code element combination and the high level time length;
and the decoding threshold value calculating unit is used for determining the decoding threshold value of the next decoding according to the low level duration.
Compared with the prior art, the invention has the following technical effects:
1. the invention dynamically adjusts the decoding threshold value according to the low level time length, can effectively reduce the influence of the difference of signal sending equipment and wireless environment factors on the decoding performance of the intelligent card, and improves the decoding success rate.
2. The invention combines the high and low level time length characteristics of the code element combination, sets the stepped first decoding threshold, the second decoding threshold and the third decoding threshold, realizes the quick confirmation of the code element combination type, and improves the decoding success rate.
Of course, it is not necessary for any product in which the invention is practiced to achieve all of the above-described advantages at the same time.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts. In the drawings:
FIG. 1 is a flow chart of a decoding method of an embodiment of the modified Miller adaptive decoding method of the present invention;
FIG. 2 is a diagram of basic symbols of an embodiment of the modified Miller adaptive decoding method of the present invention, wherein FIG. 2(a) is basic symbol X, FIG. 2(b) is basic symbol Y, and FIG. 2(c) is basic symbol Z;
FIG. 3 is a diagram of the combined high level duration + low level duration of the first type of symbol in an embodiment of the modified Miller adaptive decoding method of the present invention;
FIG. 4 is a diagram illustrating the second type symbol combination high level duration + low level duration according to an embodiment of the modified Miller adaptive decoding method of the present invention;
FIG. 5 is a diagram of the combined high-level duration + low-level duration of the third type of symbol according to the modified Miller adaptive decoding method of the present invention;
FIG. 6 is a diagram of the combined high-level duration + low-level duration of a fourth type of symbol according to the modified Miller adaptive decoding method of the present invention;
fig. 7 is a schematic structural diagram of an embodiment of a modified Miller adaptive decoding apparatus according to the present invention.
Detailed Description
The modified Miller adaptive decoding method and apparatus provided by the present invention will be described in detail with reference to the accompanying drawings, which are provided for implementation on the premise of the technical solution of the present invention, and the detailed implementation manner and the specific operation process are given, but the protection scope of the present invention is not limited to the following embodiments, and those skilled in the art can modify and revise the method and apparatus without changing the spirit and content of the present invention.
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.
Example one
Referring to fig. 1, a modified Miller adaptive decoding method for decoding a modified Miller data frame in units of symbol combinations composed of basic symbols, the decoding method comprising the steps of:
s1: demodulating the modified Miller data frame signal;
s2: calculating the high level duration of two adjacent low level signal periods of the data frame;
s3: comparing the high level duration with a preset decoding threshold or a decoding threshold determined after the last decoding, determining each symbol of the current symbol combination to realize the current decoding, and determining a decoding threshold for the next decoding through the following steps S4 and S5;
s4: calculating the low level time length of the current code element combination according to the current code element combination and the high level time length;
s5: and determining a decoding threshold value of the next decoding according to the low level duration, and repeating the steps S2-S5.
In the demodulated modified Miller data frame signal, there is no clock in the low level signal period, and due to the influence of the difference of signal transmission equipment, signal distortion in the wireless transmission process, error of an analog decoding circuit and the like, the low level time length finally decoded may have a large error, which does not reach the requirement of a fixed decoding threshold, and finally decoding fails. Therefore, the decoding threshold value is dynamically set according to the low level duration, the influence of the difference of the signal sending equipment and the wireless environment factors on the decoding performance of the intelligent card can be effectively reduced, and the decoding success rate is improved.
When decoding, firstly, identifying the high level time length of the adjacent low level period of the first code element combination of the data frame, combining the initial code element Z of the data frame, namely the first code element of the first code element combination of the data frame is the code element Z, comparing the high level time length with the preset decoding threshold value, determining other code elements of the first code element combination of the data frame, and realizing the complete determination of the first code element combination of the data frame.
Then, after each code element combination is determined, the low level time length of the code element combination is calculated according to the code element information of the code element combination and the high level time length thereof, and the decoding threshold value of the next code element combination is determined according to the low level time length.
And finally, taking the last symbol of the last symbol combination as the first symbol of the current symbol combination, and entering the decoding of the next symbol combination.
And repeating the steps until the decoding of the whole data frame is completed.
As an embodiment, the symbol combination includes a first type of symbol combination, a second type of symbol combination, a third type of symbol combination, and a fourth type of symbol combination, where the decoding threshold includes a first decoding threshold, a second decoding threshold, and a third decoding threshold, before determining each symbol of the current symbol combination in step S3, it is first determined whether the current symbol combination belongs to the first type of symbol combination, the second type of symbol combination, the third type of symbol combination, or the fourth type of symbol combination, that is, the high level duration of the current symbol combination is compared with the decoding threshold, so as to obtain the specific type to which the current symbol combination belongs, which specifically includes the following steps:
if the high level duration of the current code element combination is smaller than the first decoding threshold, the current code element combination is a first type code element combination;
if the high level duration of the current code element combination is greater than the first decoding threshold and less than the second decoding threshold, the current code element combination is a second type code element combination;
if the high level duration of the current code element combination is greater than the second decoding threshold and less than a third decoding threshold, the current code element combination is a third type code element combination;
and if the high level duration of the current code element combination is greater than the third decoding threshold, combining the current code element combination into a fourth type code element combination.
Preferably, the basic symbol includes X, Y and Z, the first type of symbol combination includes ZZ and XX, the second type of symbol combination includes XYZ and ZX, the third type of symbol combination includes XYX and ZY, and the fourth type of symbol combination includes XYY.
As an embodiment, the first symbol of the current symbol combination is the starting symbol Z of the modified Miller data frame or the last symbol of the previous symbol combination, and determining each symbol of the current symbol combination specifically includes the following steps:
if the current code element is combined into the first type code element combination, if the first code element is X, the current code element is XX, and if the first code element is Z, the current code element is ZZ;
if the current code element is combined into the second type code element combination, if the first code element is X, the current code element is XYZ, and if the first code element is Z, the current code element is ZX;
if the current code element is combined into the third type code element combination, if the first code element is X, the current code element is XYX, and if the first code element is Z, the current code element combination is an end signal ZY;
if the current code element is combined into the fourth type code element combination, if the first code element is X, the current code element combination is an ending signal XYY.
As an embodiment, if the current symbol is combined to the end signal ZY or XYY, the decoding of the present data frame is ended.
According to the ISO/IEC 14443A protocol, the symbol combination XYY or ZY is the end signal of the data frame.
Referring to fig. 3 to fig. 6, the sum of the high level duration and the low level duration of the first type symbol combination is equal to a basic time unit; the sum of the high level duration and the low level duration of the second type of symbol combination is equal to 3/2 basic time units; the sum of the high level duration and the low level duration of the third type of code element combination is equal to 2 × basic time unit; the sum of the high level duration and the low level duration of the fourth type of code element combination is greater than 2 × basic time unit; the specific steps of calculating the low level duration of the code element combination are as follows:
if the current code element is combined into the first code element combination, the corresponding low level time length is the basic time unit-high level time length;
if the current code element is combined into the second type of code element combination, the corresponding low level duration is 3/2 × basic time unit-high level duration;
if the current code element is combined into the third type of code element combination, the corresponding low level time length is 2 × basic time unit-high level time length;
if the current code element combination is the fourth type code element combination, the low level time length does not need to be calculated.
In this embodiment, when the current symbol is the end signal ZY or XYY, the decoding of the data frame is ended without calculating the low level duration and determining the decoding threshold for the next decoding.
According to the ISO/IEC 14443A protocol, the modified Miller code includes symbols X, Y and Z, one symbol period being one basic time unit (ETU), see fig. 2, where fig. 2(a) is basic symbol X, fig. 2(b) is basic symbol Y, fig. 2(c) is basic symbol Z, basic symbols X, Y and Z are both one basic time unit in length, low levels of symbols X and Z occur at different positions, and symbol Y has no low level throughout the basic time unit. And under the same speed, the frequency division factor is constant, and the length of the basic time unit is also fixed.
Referring to fig. 3 to 6, the low level duration refers to a low level period adjacent to and preceding a high level period corresponding to the high level duration.
As an embodiment, after the current symbol combination is successfully decoded, the first decoding threshold, the second decoding threshold, and the third decoding threshold for the next decoding are determined according to the low level duration of the current symbol combination, and the specific steps are as follows:
if the low level time length of the current code element is equal to the low level time length of the last code element combination, the first decoding threshold value, the second decoding threshold value and the third decoding threshold value are unchanged;
if the low level duration of the current code element is greater than or less than the low level duration of the previous code element combination, calculating dynamic adjustment ranges of a first decoding threshold, a second decoding threshold and a third decoding threshold according to the low level duration, and selecting and replacing the optimal decoding threshold with the corresponding first decoding threshold, second decoding threshold and third decoding threshold in the dynamic adjustment range, wherein the adjustment range of the first decoding threshold is [ basic time unit-low level duration, 3/2 [ basic time unit-low level duration ], the adjustment range of the second decoding threshold is [3/2 [ basic time unit-low level duration, 2 [ basic time unit-low level duration ], and the adjustment range of the third decoding threshold is greater than (2 [ basic time unit-low level duration ");
if the low level duration of the current code element exceeds the decodable range, an error signal is generated and the decoding of the data frame is ended.
As an embodiment, the optimal value of the first decoding threshold is (5/4 × basic time unit — low level duration).
The second decoding threshold is preferably (7/4 × basic time unit — duration of low level).
Example two
The present embodiment explains the decoding method of the present invention by taking a specific data frame decoding process as an example. Assuming that a basic time unit is 128 clock cycles, the preset first decoding threshold is 115 clock cycles, the second decoding threshold is 181 clock cycles, and the third decoding threshold is 246 clock cycles, wherein one time cycle is 1/13.56 MHZ.
When decoding the first symbol combination of the data frame, first, the first symbol of the first symbol combination is set as the starting symbol Z of the data frame. Assuming that the calculated high level duration is 100 clock cycles, because the high level duration is less than the first decoding threshold 115 clock cycles, the current symbol combination is a first type of symbol combination, and the current symbol combination is ZZ determined according to the first symbol being Z;
then, calculating the low level duration, wherein the current symbol combination is the first type of symbol combination, so that the corresponding low level duration is the basic time unit-the high level duration, and the low level duration is calculated to be 28 clock cycles;
finally, determining a first decoding threshold, a second decoding threshold and a third decoding threshold of next decoding according to the low level time length, taking the first decoding threshold as (5/4 × basic time unit-low level time length), the second decoding threshold as (7/4 × basic time unit-low level time length), the third decoding threshold as (2 × basic time unit-low level time length +2 clock cycles), and calculating to obtain that the first decoding threshold is 132 clock cycles, the second decoding threshold is 196 clock cycles, and the third decoding threshold is 230 clock cycles;
in decoding the second symbol combination of the data frame, the first symbol is set to the last symbol Z of the last symbol combination. Assuming that the calculated high level duration is 180 clock cycles, since the high level duration is greater than the first decoding threshold 132 clock cycles and less than the second decoding threshold 196 clock cycles, the current symbol combination is the second type of symbol combination, and the current symbol combination is determined to be ZX according to the first symbol being Z;
then, calculating the low level duration, wherein the current symbol combination is the second type of symbol combination, so that the corresponding low level duration is 3/2 × basic time unit-high level duration, and the low level duration is calculated to be 12 clock cycles;
finally, determining a first decoding threshold, a second decoding threshold and a third decoding threshold of next decoding according to the low level time length, taking the first decoding threshold as (5/4 × basic time unit-low level time length), the second decoding threshold as (7/4 × basic time unit-low level time length), the third decoding threshold as (2 × basic time unit-low level time length +2 clock cycles), and calculating to obtain that the first decoding threshold is 148 clock cycles, the second decoding threshold is 212 clock cycles, and the third decoding threshold is 246 clock cycles;
decoding until the N-2 code element combination according to the method, and assuming that the last code element of the N-2 code element combination is X, updating the determined first decoding threshold value to be 140 clock cycles, the second decoding threshold value to be 214 clock cycles, and the third decoding threshold value to be 248 clock cycles;
when decoding the (N-1) th symbol combination of the data frame, the first symbol is set as the last symbol X of the last symbol combination. Assuming that the calculated high level duration is 230 clock cycles, since the high level duration is greater than the second decoding threshold 214 clock cycles and less than the third decoding threshold 248 clock cycles, the current symbol combination is the third type of symbol combination, and the current symbol combination is determined to be XYX according to the first symbol thereof being X;
then, calculating the low level duration, wherein the current symbol combination is a third type symbol combination, so that the corresponding low level duration is 2 × basic time unit-high level duration, and the low level duration is calculated to be 26 clock cycles;
finally, determining a first decoding threshold, a second decoding threshold and a third decoding threshold of next decoding according to the low level time length, taking the first decoding threshold as (5/4 × basic time unit-low level time length), the second decoding threshold as (7/4 × basic time unit-low level time length), the third decoding threshold as (2 × basic time unit-low level time length +2 clock cycles), and calculating to obtain that the first decoding threshold is 134 clock cycles, the second decoding threshold is 198 clock cycles and the third decoding threshold is 230 clock cycles;
when decoding the nth symbol combination of the decoded data frame, the first symbol is set as the last symbol X of the last symbol combination. Assuming that the calculated high level duration is 240 clock cycles, since the high level duration is greater than the third decoding threshold 230 clock cycles, the current symbol combination is the fourth type of symbol combination, and the current symbol combination is determined to be XYY according to the first symbol thereof being X.
Since XYY is an end signal, the present data frame is recorded and finally decoded to zzx.
EXAMPLE III
Referring to fig. 7, the present invention also discloses a modified Miller adaptive decoding apparatus, wherein in decoding a modified Miller data frame, decoding is performed in units of symbol combinations composed of basic symbols, including
A radio frequency receiving unit 1 for demodulating and correcting Miller data frame signals;
a high level duration calculation unit 3 for calculating the high level duration of two adjacent low level signal periods of the data frame;
the decoding unit 2 compares the high level time length with a preset decoding threshold or a decoding threshold determined after the last decoding, and determines each code element of the current code element combination to realize the current decoding; for the specific implementation of the decoding unit 2, please refer to step S3 in the first embodiment, which is not described herein again.
A low level duration calculation unit 4 for calculating a low level duration of the symbol combination according to the symbol combination and a high level duration; for the specific execution process of the low level duration calculating unit 4, refer to step S4 in the first embodiment, which is not described herein again.
A decoding threshold calculation unit 5, which determines the decoding threshold for the next decoding according to the low level duration; for a specific implementation process of the decoding threshold calculation unit 5, refer to step S5 in the first embodiment, which is not described herein again.
The disclosure above is only one specific embodiment of the present application, but the present application is not limited thereto, and any variations that can be made by those skilled in the art are intended to fall within the scope of the present application.
Claims (8)
1. A modified Miller adaptive decoding method, wherein in decoding a modified Miller data frame, decoding is performed in units of symbol combinations composed of basic symbols, the symbol combinations including a first type of symbol combination including ZZ and XX, a second type of symbol combination including XYZ and ZX, a third type of symbol combination including XYX and ZY, and a fourth type of symbol combination including XYY, the decoding method comprising the steps of:
s1: demodulating the modified Miller data frame signal;
s2: calculating the high level duration of two adjacent low level signal periods of the data frame;
s3: comparing the high level time length with a preset decoding threshold or a decoding threshold determined after the previous decoding to acquire the type of the current symbol combination, determining each symbol of the current symbol combination according to the fact that the first symbol of the current symbol combination is the initial symbol Z of the modified Miller data frame or the last symbol of the previous symbol combination to realize the current decoding, and determining the decoding threshold of the next decoding through the following steps S4 and S5, wherein the decoding threshold comprises a first decoding threshold, a second decoding threshold and a third decoding threshold;
s4: calculating the low level time length of the current code element combination according to the current code element combination and the high level time length, wherein the sum of the high level time length and the low level time length of the first type of code element combination is equal to one basic time unit; the sum of the high level duration and the low level duration of the second type of symbol combination is equal to 3/2 basic time units; the sum of the high level duration and the low level duration of the third type of code element combination is equal to 2 × basic time unit; the sum of the high level duration and the low level duration of the fourth type of code element combination is greater than 2 × basic time unit;
determining the sum of the duration of the high level and the duration of the low level according to the type of the current code element combination, and subtracting the duration of the high level to obtain the duration of the low level of the current code element combination;
s5: determining a decoding threshold for the next decoding according to the low level duration, and repeating steps S2-S5, wherein the decoding threshold for the next decoding is determined according to the low level duration of the current symbol combination, and the specific steps are as follows:
if the low level time length of the current code element is equal to the low level time length of the last code element combination, the method is implemented
The first decoding threshold, the second decoding threshold and the third decoding threshold are unchanged;
if the low level duration of the current code element is greater than or less than the low level duration of the previous code element combination, calculating dynamic adjustment ranges of a first decoding threshold, a second decoding threshold and a third decoding threshold according to the low level duration, and selecting and replacing the optimal decoding threshold with the corresponding first decoding threshold, second decoding threshold and third decoding threshold in the dynamic adjustment range, wherein the adjustment range of the first decoding threshold is [ basic time unit-low level duration, 3/2 [ basic time unit-low level duration ], the adjustment range of the second decoding threshold is [3/2 [ basic time unit-low level duration, 2 [ basic time unit-low level duration ], and the adjustment range of the third decoding threshold is greater than (2 [ basic time unit-low level duration ");
if the low level duration of the current code element exceeds the decodable range, an error signal is generated and the decoding of the data frame is ended.
2. The modified Miller adaptive decoding method of claim 1, wherein the type of the current symbol combination is determined before each symbol of the current symbol combination is determined in step S3, and the method comprises the following specific steps:
if the high level duration of the current code element combination is smaller than the first decoding threshold, the current code element combination is a first type code element combination;
if the high level duration of the current code element combination is greater than the first decoding threshold and less than the second decoding threshold, the current code element combination is a second type code element combination;
if the high level duration of the current code element combination is greater than the second decoding threshold and less than a third decoding threshold, the current code element combination is a third type code element combination;
and if the high level duration of the current code element combination is greater than the third decoding threshold, combining the current code element combination into a fourth type code element combination.
3. The modified Miller adaptive decoding method of claim 1, wherein the step of determining each symbol of the current symbol combination based on whether the first symbol of the current symbol combination is the starting symbol Z of the modified Miller data frame or the last symbol of the previous symbol combination comprises:
if the current code element is combined into the first type code element combination, if the first code element is X, the current code element is XX, and if the first code element is Z, the current code element is ZZ;
if the current code element is combined into the second type code element combination, if the first code element is X, the current code element is XYZ, and if the first code element is Z, the current code element is ZX;
if the current code element is combined into the third type code element combination, if the first code element is X, the current code element is XYX, and if the first code element is Z, the current code element combination is an end signal ZY;
if the current code element is combined into the fourth type code element combination, if the first code element is X, the current code element combination is an ending signal XYY.
4. The modified Miller adaptive decoding method of claim 3, wherein the decoding of the data frame is ended if the current symbol combination is the end signal ZY or XYY.
5. A modified Miller adaptive decoding method as claimed in claim 2 or 3, wherein the step of calculating the low level duration of the symbol combination comprises:
if the current code element is combined into the first code element combination, the corresponding low level time length is the basic time unit-high level time length;
if the current code element is combined into the second type of code element combination, the corresponding low level duration is 3/2 × basic time unit-high level duration;
if the current code element is combined into the third type of code element combination, the corresponding low level time length is 2 × basic time unit-high level time length;
if the current code element combination is the fourth type code element combination, the low level time length does not need to be calculated.
6. The modified Miller adaptive decoding method of claim 1, wherein the optimal value of the first decoding threshold is (5/4 × basic time unit — low level duration).
7. The modified Miller adaptive decoding method of claim 1, wherein the second decoding threshold is optimally (7/4 × basic time unit — low level duration).
8. A modified Miller adaptive decoding apparatus, wherein in decoding a modified Miller data frame, decoding is performed in units of symbol combinations composed of basic symbols, the symbol combinations include a first type of symbol combination including ZZ and XX, a second type of symbol combination including XYZ and ZX, a third type of symbol combination including XYX and ZY, and a fourth type of symbol combination including XYY, the decoding thresholds include a first decoding threshold, a second decoding threshold, and a third decoding threshold, including
A radio frequency receiving unit for demodulating and correcting Miller data frame signals;
the high level duration calculating unit is used for calculating the high level duration of two adjacent low level signal periods of the data frame;
the decoding unit is used for comparing the high-level time length with a preset decoding threshold or a decoding threshold determined after the previous decoding to obtain the type of the current code element combination, and determining each code element of the current code element combination according to the fact that the first code element of the current code element combination is the initial code element Z of the modified Miller data frame or the last code element of the previous code element combination to realize the current decoding;
a low level duration calculation unit, which calculates the low level duration of the code element combination according to the code element combination and the high level duration, wherein the sum of the high level duration and the low level duration of the first type of code element combination is equal to a basic time unit; the sum of the high level duration and the low level duration of the second type of symbol combination is equal to 3/2 basic time units; the sum of the high level duration and the low level duration of the third type of code element combination is equal to 2 × basic time unit; the sum of the high level duration and the low level duration of the fourth type of code element combination is greater than 2 × basic time unit;
determining the sum of the duration of the high level and the duration of the low level according to the type of the current code element combination, and subtracting the duration of the high level to obtain the duration of the low level of the current code element combination;
a decoding threshold calculation unit, configured to determine the decoding threshold for the next decoding according to the low level duration, where the decoding threshold for the next decoding is determined according to the low level duration of the current symbol combination, and the specific steps are as follows:
if the low level time length of the current code element is equal to the low level time length of the last code element combination, the first decoding threshold value, the second decoding threshold value and the third decoding threshold value are unchanged;
if the low level duration of the current code element is greater than or less than the low level duration of the previous code element combination, calculating dynamic adjustment ranges of a first decoding threshold, a second decoding threshold and a third decoding threshold according to the low level duration, and selecting and replacing the optimal decoding threshold with the corresponding first decoding threshold, second decoding threshold and third decoding threshold in the dynamic adjustment range, wherein the adjustment range of the first decoding threshold is [ basic time unit-low level duration, 3/2 [ basic time unit-low level duration ], the adjustment range of the second decoding threshold is [3/2 [ basic time unit-low level duration, 2 [ basic time unit-low level duration ], and the adjustment range of the third decoding threshold is greater than (2 [ basic time unit-low level duration ");
if the low level duration of the current code element exceeds the decodable range, an error signal is generated and the decoding of the data frame is ended.
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Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103065188A (en) * | 2013-01-18 | 2013-04-24 | 无锡中科沃谱瑞科技有限责任公司 | Decoding circuit of non-contact integrated circuit (IC) card |
| CN103297060A (en) * | 2013-06-28 | 2013-09-11 | 上海爱信诺航芯电子科技有限公司 | Decoding circuit suitable for correcting miller code signal at high speed |
| CN103595420A (en) * | 2012-08-13 | 2014-02-19 | 上海华虹集成电路有限责任公司 | Decoder for decoding TYPE A signals transmitted by card reader |
| CN104242952A (en) * | 2013-06-21 | 2014-12-24 | 上海华虹集成电路有限责任公司 | Decoder for 1-out-of-256 mode signal |
| CN105718835A (en) * | 2016-01-14 | 2016-06-29 | 大唐微电子技术有限公司 | Digital shaping circuit |
| CN106437689A (en) * | 2016-09-13 | 2017-02-22 | 中国石油大学(华东) | Method for processing mud-while-drilling positive pulse signal |
| CN108092741A (en) * | 2017-12-12 | 2018-05-29 | 深圳和而泰数据资源与云技术有限公司 | Communication means, terminal and communication equipment based on audio interface |
| CN108418631A (en) * | 2015-11-20 | 2018-08-17 | 王振环 | A kind of information sends, reception device and its maintaining method, system |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6962293B2 (en) * | 2002-09-26 | 2005-11-08 | Samsung Electronics Co., Ltd. | Circuit for generating clock signal and decoding data signal for use in contactless integrated circuit card |
| EP3301876B1 (en) * | 2016-08-05 | 2019-07-24 | Shenzhen Goodix Technology Co., Ltd. | Signal reception method and apparatus |
| EP3337089B1 (en) * | 2016-12-14 | 2020-11-11 | Nxp B.V. | Rf transceiver |
-
2018
- 2018-12-07 CN CN201811500010.6A patent/CN109412757B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103595420A (en) * | 2012-08-13 | 2014-02-19 | 上海华虹集成电路有限责任公司 | Decoder for decoding TYPE A signals transmitted by card reader |
| CN103065188A (en) * | 2013-01-18 | 2013-04-24 | 无锡中科沃谱瑞科技有限责任公司 | Decoding circuit of non-contact integrated circuit (IC) card |
| CN104242952A (en) * | 2013-06-21 | 2014-12-24 | 上海华虹集成电路有限责任公司 | Decoder for 1-out-of-256 mode signal |
| CN103297060A (en) * | 2013-06-28 | 2013-09-11 | 上海爱信诺航芯电子科技有限公司 | Decoding circuit suitable for correcting miller code signal at high speed |
| CN108418631A (en) * | 2015-11-20 | 2018-08-17 | 王振环 | A kind of information sends, reception device and its maintaining method, system |
| CN105718835A (en) * | 2016-01-14 | 2016-06-29 | 大唐微电子技术有限公司 | Digital shaping circuit |
| CN106437689A (en) * | 2016-09-13 | 2017-02-22 | 中国石油大学(华东) | Method for processing mud-while-drilling positive pulse signal |
| CN108092741A (en) * | 2017-12-12 | 2018-05-29 | 深圳和而泰数据资源与云技术有限公司 | Communication means, terminal and communication equipment based on audio interface |
Non-Patent Citations (1)
| Title |
|---|
| 改进密勒编码的解码方法设计与研究;张吉兴，景为平;《微电子学》;20141220;第44卷(第06期);第771-774页 * |
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