CN110598498B - Method for improving signal identification capability of non-contact card reader - Google Patents
Method for improving signal identification capability of non-contact card reader Download PDFInfo
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- CN110598498B CN110598498B CN201910870211.3A CN201910870211A CN110598498B CN 110598498 B CN110598498 B CN 110598498B CN 201910870211 A CN201910870211 A CN 201910870211A CN 110598498 B CN110598498 B CN 110598498B
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- 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
- G06K7/10019—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 resolving collision on the communication channels between simultaneously or concurrently interrogated record carriers.
- G06K7/10029—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 resolving collision on the communication channels between simultaneously or concurrently interrogated record carriers. the collision being resolved in the time domain, e.g. using binary tree search or RFID responses allocated to a random time slot
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Abstract
The embodiment of the invention relates to a method for improving the signal identification capability of a non-contact card reader, which is characterized by comprising the following steps: acquiring a first frame signal; generating a first time threshold, a second time threshold, a first energy parameter and a first count; initializing a first check bit, a second check bit and a third check bit; sequentially extracting unit waveforms of a first frame signal, carrying out half-waveform time check on the extracted unit waveforms according to a first time threshold and a first count, and setting a first check bit; sequentially extracting unit waveforms of a first frame signal, carrying out half-waveform energy check on the extracted unit waveforms according to the first energy parameter and the first count, and setting a second check bit; sequentially extracting 2 continuous half waveforms of the first frame signal, carrying out subcarrier signal continuous double-half waveform time check on the extracted 2 half waveforms according to a second time threshold and the first count, and setting a third check bit; when the first, second and third check bits are all 1, the first frame signal is marked as a valid signal.
Description
Technical Field
The invention relates to the technical field of near field communication, in particular to a method for improving signal identification capability of a non-contact card reader.
Background
Contactless integrated circuit cards (abbreviated as contactless cards) based on International Organization for Standardization (abbreviated as ISO)/International electrotechnical Commission (abbreviated as IEC) 14443 family of specifications are currently widely used in various industries. The corresponding card reading device is called a non-contact card reader. In practical application, because signal receiving and signal sending of the non-contact card reader are integrated, under the condition that the transmitting field intensity is overlarge, a receiving end has larger power interference, and the specific embodiment is that the receiving end can receive continuous interference signals to cause the non-contact card reader to generate mistaken receiving and mistaken decoding on the signals.
Disclosure of Invention
The present invention provides a method for improving the signal recognition capability of a contactless card reader, which aims at the technical defects. By using the method, the identification degree of the deformation signal is improved, and the signal identification capability of the non-contact card reader is improved.
In order to achieve the above object, the present invention provides a method for improving signal recognition capability of a contactless card reader, comprising:
the non-contact card reader carries out wireless signal receiving processing through a signal receiving antenna, acquires and generates a first frame signal, wherein the first frame signal comprises a plurality of unit waveforms, and the unit waveforms comprise: the first half waveform and the second half waveform;
the non-contact card reader acquires a subcarrier signal half-waveform duration reference threshold value from a system area to generate a first time threshold value, acquires a subcarrier signal full-waveform duration reference threshold value to generate a second time threshold value, acquires a subcarrier signal half-waveform energy reference value to generate a first energy parameter, acquires a single-frame signal effective waveform lower limit to generate a first count;
the non-contact card reader initializes the value of the first check bit to be 0, initializes the value of the second check bit to be 0 and initializes the value of the third check bit to be 0;
the non-contact card reader sequentially performs unit waveform extraction operation from the initial unit waveform to the last unit waveform of the first frame signal according to the first frame signal, performs subcarrier signal half-waveform time check operation on the extracted unit waveform according to the first time threshold and the first count, and sets the first check bit;
the non-contact card reader sequentially performs unit waveform extraction operation from the initial unit waveform to the last unit waveform of the first frame signal according to the first frame signal, performs sub-carrier signal half-waveform energy check operation on the extracted unit waveform according to the first energy parameter and the first count, and sets the second check bit;
the non-contact card reader sequentially performs continuous 2 half-waveform extraction operations from the first half waveform of the initial unit waveform of the first frame signal to the first half waveform of the last unit waveform according to the first frame signal, performs subcarrier signal continuous double-half-waveform time check operation on the extracted 2 half waveforms according to the second time threshold and the first count, and sets the third check bit;
when the values of the first check bit, the second check bit and the third check bit are all 1, the non-contact card reader performs effective signal marking operation on the first frame signal mark and sends the first frame signal to a decoding unit of the non-contact card reader for decoding operation.
Further, the method further comprises:
and when the value of the first check bit is 2, the half-waveform time check execution of the subcarrier signal fails, and the non-contact card reader performs invalid signal marking operation on the first frame signal mark and exits the signal processing flow.
When the value of the second check bit is 2, the sub-carrier signal half-waveform energy check fails to be executed, and the non-contact card reader performs invalid signal marking operation on the first frame signal mark and exits the signal processing flow.
When the value of the first check bit is 2, the subcarrier signal full-waveform time check fails to be executed, and the non-contact card reader conducts invalid signal marking operation on the first frame signal mark and exits the signal processing flow.
Further, the non-contact card reader sequentially performs unit waveform extraction operations from a starting unit waveform to a last unit waveform of the first frame signal according to the first frame signal, performs a subcarrier signal half-waveform time check operation on the extracted unit waveforms according to the first time threshold and the first count, and sets the first check bit, specifically including:
step 31, initializing a value of a first index to be 1 and initializing a value of a first counter to be 0 by the non-contact card reader;
step 32, the non-contact card reader acquires the total number of unit waveforms of the first frame signal according to the first frame signal to generate a first total number;
step 33, the non-contact card reader extracts the first index unit waveform of the first frame signal to generate a first waveform, extracts the first half waveform of the first waveform to generate a first front half waveform, and extracts the second half waveform of the first waveform to generate a first rear half waveform according to the first frame signal;
step 34, the non-contact card reader acquires the waveform duration of the first half waveform to generate a first half waveform time, and acquires the waveform duration of the first second half waveform to generate a first second half waveform time;
step 35, the contactless card reader performs a first half waveform time qualification check operation on the first half waveform time according to the first time threshold, and after the first half waveform time qualification check is successfully performed, the contactless card reader adds 1 to the value of the first counter;
step 36, the contactless card reader performs a second half-waveform time qualification check operation on the first half-waveform time according to the first time threshold, and after the second half-waveform time qualification check is successfully performed, the contactless card reader adds 1 to the value of the first counter;
step 37, the non-contact card reader adds 1 to the value of the first index;
step 38, the contactless reader determines whether the value of the first index is greater than the value of the first total number, if so, go to step 39, and if not, go to step 33;
step 39, the non-contact card reader generates a first half waveform count according to the product of the value of the first count multiplied by 2;
and step 40, when the value of the first counter is greater than or equal to the value of the first half waveform count, the non-contact card reader sets the value of the first check bit to 1.
Preferably, the method further comprises:
when the value of the first counter is smaller than the value of the first half waveform count, the non-contact card reader sets the value of the first check bit to 2.
Preferably, the non-contact card reader performs a first half-waveform time qualification check operation on the first half-waveform time according to the first time threshold, and specifically includes:
the non-contact card reader acquires a lower threshold limit of the first time threshold value to generate a first lower limit, and acquires an upper threshold limit of the first time threshold value to generate a first upper limit according to the first time threshold value;
when the first front half waveform time is less than or equal to the first upper limit and the first front half waveform time is greater than or equal to the first lower limit, the first half waveform time qualification check is successful.
Further, the non-contact card reader sequentially performs unit waveform extraction operations from a starting unit waveform to a last unit waveform of the first frame signal according to the first frame signal, performs a subcarrier signal half-waveform energy check operation on the extracted unit waveforms according to the first energy parameter and the first count, and sets the second check bit, specifically including:
step 61, initializing a value of a second index to be 1 and initializing a value of a second counter to be 0 by the non-contact card reader;
step 62, the non-contact card reader acquires the total number of unit waveforms of the first frame signal according to the first frame signal to generate a second total number;
step 63, the non-contact card reader extracts the second index unit waveform of the first frame signal to generate a second waveform according to the first frame signal, extracts the first half waveform of the second waveform to generate a second first half waveform, and extracts the second half waveform of the second waveform to generate a second half waveform;
step 64, the non-contact card reader performs carrier energy calculation operation on the second front half waveform to generate second front half waveform energy, and performs carrier energy calculation operation on the second rear half waveform to generate second rear half waveform energy;
step 65, when the second front half waveform energy is greater than or equal to the first energy parameter, the non-contact card reader adds 1 to the value of the second counter;
step 66, when the energy of the second front-back waveform is greater than or equal to the first energy parameter, the non-contact card reader adds 1 to the value of the second counter;
step 67, the non-contact card reader adds 1 to the value of the second index;
step 68, the contactless reader determines whether the value of the second index is greater than the value of the second total number, if the value of the second index is greater than the value of the second total number, go to step 69, and if the value of the second index is less than or equal to the value of the second total number, go to step 63;
step 69, the contactless card reader generates a second half waveform count according to the product of the value of the first count multiplied by 2;
and step 70, when the value of the second counter is greater than or equal to the value of the second half waveform count, the non-contact card reader sets the value of the second check position to 1.
Preferably, the method further comprises:
when the value of the second counter is less than the value of the second half waveform count, the contactless reader sets the value of the second check bit to 2.
Further, the non-contact card reader sequentially performs continuous 2 half-waveform extraction operations from a first half waveform of a starting unit waveform of the first frame signal to a first half waveform of a last unit waveform of the first frame signal according to the first frame signal, performs continuous double-half-waveform time check operation on the extracted 2 half waveforms according to the second time threshold and the first count, and sets the third check bit, specifically including:
step 81, initializing a value of a third index to be 1 and initializing a value of a third counter to be 0 by the non-contact card reader;
step 82, the non-contact card reader acquires the total number of unit waveforms of the first frame signal according to the first frame signal, and generates a third total number according to the product of the total number of unit waveforms multiplied by 2 and then the difference of 1;
step 83, the non-contact card reader extracts the third index half waveform of the first frame signal to generate a third waveform and extracts the next half waveform of the third index half waveform of the first frame signal to generate a fourth waveform according to the first frame signal;
step 84, the non-contact card reader acquires the waveform duration of the third waveform to generate a third waveform time, acquires the waveform duration of the fourth waveform to generate a fourth waveform time, and generates a first double-half waveform time according to the sum of the third waveform time and the fourth waveform time;
step 85, the contactless card reader performs a first double half waveform time qualification check operation on the first double half waveform time according to the second time threshold, and after the first double half waveform time qualification check is successfully executed, the contactless card reader adds 1 to the value of the third counter;
step 86, the contactless card reader adds 1 to the value of the third index;
step 87, the contactless reader determines whether the value of the third index is greater than the value of the third total number, if so, go to step 88, and if not, go to step 83;
step 88, the non-contact card reader generates a first double-half waveform count according to the product of the value of the first count multiplied by 2 and then subtracting the difference of 1;
and step 89, when the value of the third counter is greater than or equal to the value of the first double half waveform count, the contactless card reader sets the value of the third check digit to 1.
Preferably, the method further comprises:
when the value of the third counter is less than the value of the first double-half waveform count, the contactless reader sets the value of the third check bit to 2.
The invention provides a method for improving the signal identification capability of a non-contact card reader, which comprises the steps of carrying out subcarrier signal half-waveform time check on a received frame signal according to a subcarrier signal half-waveform duration reference threshold value, carrying out subcarrier signal half-waveform energy check on the received frame signal according to a subcarrier signal half-waveform energy reference value, carrying out subcarrier signal continuous double-half-waveform time check on the received frame signal according to a subcarrier signal full-waveform duration reference threshold value, carrying out interference signal discrimination on the received frame signal through the three checks, further decoding operation is carried out by considering the checked waveform as an effective waveform, and abandoning the invalid signal if the checked waveform is not the effective waveform.
Drawings
Fig. 1 is a schematic diagram of a method for improving signal recognition capability of a contactless card reader according to an embodiment of the present invention.
Fig. 2 is a schematic diagram of a method for improving signal recognition capability of a contactless card reader according to a second embodiment of the present invention.
Fig. 3 is a schematic diagram of a waveform of a frame signal according to an embodiment of the present invention.
Detailed Description
To make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the accompanying drawings. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.
The subcarrier unit time period and unit waveform signal energy of a standard effective signal are defaulted on the premise that a given communication frequency and subcarrier modulation mechanism are known. The method of the invention subdivides the time threshold value according to the unit time period of the standard subcarrier, and divides the time threshold value into two time intervals of a half-waveform time threshold value and a continuous double-half-waveform time threshold value, and judges the time of all unit waveforms of the received frame signal according to the two time intervals, and the unit waveforms which do not conform to the threshold value range are regarded as invalid signals. And performing half waveform energy subdivision according to the standard subcarrier unit waveform signal energy, and judging the energy of all unit waveforms of the received frame signal according to the half waveform energy subdivision, wherein the unit waveforms which do not conform to the threshold range are regarded as invalid signals.
In conventional applications, the signal received by the contactless reader at the receiving end can be roughly understood as: a standard valid signal, a distorted valid signal, a persistent interference signal. The above determination method must be able to pass for a standard valid signal; for deformed effective signals, although the judgment is based on half-waveform strict judgment, a threshold space is provided, so that the deformed effective signals cannot be judged as noise by mistake and can be further identified; for the continuous interference signal, even if the signal is continuous and has enough energy, the stability of the unit waveform cannot be guaranteed, and the requirement cannot be met when the half-waveform determination is performed. Therefore, the method not only improves the identification of the deformation signal, but also enhances the discrimination of the interference signal.
In a first embodiment of the present invention, as shown in fig. 1, which is a schematic diagram of a method for improving signal recognition capability of a contactless card reader provided in the first embodiment of the present invention, the method includes the following steps:
step 1, a non-contact card reader receives and processes wireless signals through a signal receiving antenna, acquires and generates a first frame signal, wherein the first frame signal comprises a plurality of unit waveforms, and the unit waveforms comprise: the first half waveform and the second half waveform, as shown in fig. 3.
And 2, the non-contact card reader acquires a reference threshold value of the half waveform duration of the subcarrier signal from the system area to generate a first time threshold value, acquires a reference threshold value of the full waveform duration of the subcarrier signal to generate a second time threshold value, acquires a reference value of the half waveform energy of the subcarrier signal to generate a first energy parameter, and acquires a lower limit of the effective waveform of the single-frame signal to generate a first count.
And 3, initializing the value of the first check bit to be 0, initializing the value of the second check bit to be 0 and initializing the value of the third check bit to be 0 by the non-contact card reader.
Step 4, the non-contact card reader sequentially performs unit waveform extraction operation from the initial unit waveform to the last unit waveform of the first frame signal according to the first frame signal, performs subcarrier signal half-waveform time check operation on the extracted unit waveform according to a first time threshold and a first count, and sets a first check bit,
the method specifically comprises the following steps: step 41, initializing the value of the first index to be 1 and initializing the value of the first counter to be 0 by the non-contact card reader;
step 42, the non-contact card reader acquires the total unit waveform number of the first frame signal according to the first frame signal to generate a first total number;
step 43, the non-contact card reader extracts the first index unit waveform of the first frame signal to generate a first waveform, extracts the first half-wave of the first waveform to generate a first half-wave, and extracts the second half-wave of the first waveform to generate a first second half-wave according to the first frame signal;
step 44, the non-contact card reader acquires the waveform duration of the first half waveform to generate a first half waveform time, and acquires the waveform duration of the first second half waveform to generate a first second half waveform time;
step 45, the non-contact card reader performs a first half-waveform time qualification check operation on the first half-waveform time according to a first time threshold, after the first half-waveform time qualification check is successfully performed, the non-contact card reader adds 1 to the value of the first counter,
the method specifically comprises the following steps: step 451, the non-contact card reader obtains a lower threshold of the first time threshold to generate a first lower limit, and obtains an upper threshold of the first time threshold to generate a first upper limit;
step 452, when the first half waveform time is less than or equal to the first upper limit and the first half waveform time is greater than or equal to the first lower limit, the first half waveform time qualification check is successful;
step 453, after the first half-waveform time qualification check is successfully performed, the contactless card reader increments the value of the first counter by 1;
and step 46, the non-contact card reader performs a second half-waveform time qualification check operation on the first half-waveform time according to the first time threshold, and after the second half-waveform time qualification check is successfully performed, the non-contact card reader adds 1 to the value of the first counter,
the method specifically comprises the following steps: step 461, the non-contact card reader obtains a lower threshold of the first time threshold to generate a second lower limit, and obtains an upper threshold of the first time threshold to generate a second upper limit according to the first time threshold;
462, when the first half waveform time is less than or equal to the second upper limit and the first half waveform time is greater than or equal to the second lower limit, the second half waveform time qualification check is successful;
step 463, after the second half waveform time qualification check is successfully performed, the contactless card reader adds 1 to the value of the first counter;
step 47, the non-contact card reader adds 1 to the value of the first index;
step 48, the contactless card reader determines whether the value of the first index is greater than the value of the first total number, and goes to step 49 if the value of the first index is greater than the value of the first total number, or goes to step 43 if the value of the first index is less than or equal to the value of the first total number;
step 49, the non-contact card reader generates a first half waveform count according to the product of the value of the first count multiplied by 2;
and step 50, when the value of the first counter is greater than or equal to the value of the first half waveform count, the value of the first check position is set to 1 by the non-contact card reader.
Step 5, the non-contact card reader sequentially performs unit waveform extraction operation from the initial unit waveform to the last unit waveform of the first frame signal according to the first frame signal, performs subcarrier signal half-waveform energy check operation on the extracted unit waveform according to the first energy parameter and the first count, and sets a second check bit,
the method specifically comprises the following steps: step 51, initializing the value of the second index to be 1 and initializing the value of the second counter to be 0 by the non-contact card reader;
step 52, the non-contact card reader acquires the total unit waveform number of the first frame signal according to the first frame signal to generate a second total number;
step 53, the non-contact card reader extracts a second index unit waveform of the first frame signal to generate a second waveform according to the first frame signal, extracts a first half waveform of the second waveform to generate a second first half waveform, and extracts a second half waveform of the second waveform to generate a second half waveform;
step 54, the non-contact card reader calculates the carrier energy of the second front half waveform to generate second front half waveform energy, and calculates the carrier energy of the second rear half waveform to generate second rear half waveform energy;
step 55, when the second first half waveform energy is larger than or equal to the first energy parameter, the non-contact card reader adds 1 to the value of the second counter;
step 56, when the energy of the waveform before and after the second time is larger than or equal to the first energy parameter, the non-contact card reader adds 1 to the value of the second counter;
step 57, the non-contact card reader adds 1 to the value of the second index;
step 58, the contactless card reader determines whether the value of the second index is greater than the value of the second total number, if the value of the second index is greater than the value of the second total number, the step 59 is executed, and if the value of the second index is less than or equal to the value of the second total number, the step 53 is executed;
step 59, the non-contact card reader generates a second half-waveform count according to the product of the value of the first count multiplied by 2;
and step 60, when the value of the second counter is greater than or equal to the value of the second half waveform count, the non-contact card reader sets the value of the second check position to 1.
Step 6, the non-contact card reader sequentially performs continuous 2 half-wave extraction operations from the first half wave form of the initial unit wave form of the first frame signal to the first half wave form of the last unit wave form according to the first frame signal, performs continuous double-half-wave time check operation on the extracted 2 half-wave unit wave forms according to a second time threshold and a first count, and sets a third check bit,
the method specifically comprises the following steps: step 61, initializing the value of a third index to be 1 and initializing the value of a third counter to be 0 by the non-contact card reader;
step 62, the non-contact card reader obtains the total number of unit waveforms of the first frame signal according to the first frame signal, and generates a third total number according to the product of the total number of unit waveforms multiplied by 2 and then subtracting the difference of 1;
step 63, the non-contact card reader extracts a third index half waveform of the first frame signal to generate a third waveform and extracts a next half waveform of the third index half waveform of the first frame signal to generate a fourth waveform according to the first frame signal;
step 64, the non-contact card reader acquires the waveform duration of a third waveform to generate a third waveform time, acquires the waveform duration of a fourth waveform to generate a fourth waveform time, and generates a first double-half waveform time according to the sum of the third waveform time and the fourth waveform time;
step 65, the non-contact card reader performs a first double half-waveform time qualification check operation on the first double half-waveform time according to a second time threshold, and after the first double half-waveform time qualification check is successfully executed, the non-contact card reader adds 1 to the value of the third counter;
step 66, the non-contact card reader adds 1 to the value of the third index;
step 67, the non-contact card reader judges whether the value of the third index is larger than the value of the third total number, if the value of the third index is larger than the value of the third total number, the step 68 is switched, and if the value of the third index is smaller than or equal to the value of the first total number, the step 63 is switched;
step 68, the non-contact card reader generates a first double-half waveform count according to the product of the value of the first count multiplied by 2 and the difference of 1 subtracted;
in step 69, when the value of the third counter is greater than or equal to the value of the first double-half waveform count, the contactless card reader sets the value of the third check bit to 1.
And 7, when the values of the first check bit, the second check bit and the third check bit are all 1, the non-contact card reader performs effective signal marking operation on the first frame signal mark and sends the first frame signal to a decoding unit of the non-contact card reader for decoding operation.
In the second embodiment of the present invention, as shown in fig. 2, which is a schematic diagram of a method for improving the signal recognition capability of a contactless card reader provided in the second embodiment of the present invention, the method includes the following steps:
102, the non-contact card reader acquires a reference threshold of half waveform duration of a subcarrier signal from a system area to generate a first time threshold, acquires a reference threshold of full waveform duration of the subcarrier signal to generate a second time threshold, acquires a reference value of half waveform energy of the subcarrier signal to generate a first energy parameter, and acquires a lower limit of an effective waveform of a single-frame signal to generate a first count.
the method specifically comprises the following steps: step 1041, initializing the value of the first index to 1 and the value of the first counter to 0 by the non-contact card reader;
step 1042, the non-contact card reader acquires the total unit waveform number of the first frame signal according to the first frame signal to generate a first total number;
step 1043, the non-contact card reader extracts the first index unit waveform of the first frame signal to generate a first waveform, extracts the first half waveform of the first waveform to generate a first front half waveform, and extracts the second half waveform of the first waveform to generate a first rear half waveform according to the first frame signal;
step 1044, the non-contact card reader acquires the waveform duration of the first half waveform to generate a first half waveform time, and acquires the waveform duration of the first second half waveform to generate a first second half waveform time;
in step 1045, the contactless card reader performs a first half-waveform time qualification check operation on the first half-waveform time according to a first time threshold, and after the first half-waveform time qualification check is successfully performed, the contactless card reader adds 1 to the value of the first counter,
the method specifically comprises the following steps: step 10451, the non-contact card reader obtains a lower threshold of the first time threshold to generate a first lower limit, and obtains an upper threshold of the first time threshold to generate a first upper limit according to the first time threshold;
step 10452, when the first half waveform time is less than or equal to the first upper limit and the first half waveform time is greater than or equal to the first lower limit, the first half waveform time qualification check is successful;
step 10453, after the first half waveform time qualification check is successfully performed, the contactless card reader adds 1 to the value of the first counter;
step 1046, the contactless card reader performs a second half-waveform time qualification check operation on the first half-waveform time according to the first time threshold, and after the second half-waveform time qualification check is successfully performed, the contactless card reader adds 1 to the value of the first counter,
the method specifically comprises the following steps: step 10461, the non-contact card reader obtains a lower threshold of the first time threshold to generate a second lower limit, and obtains an upper threshold of the first time threshold to generate a second upper limit according to the first time threshold;
step 10462, when the first half waveform time is less than or equal to the second upper limit, and the first half waveform time is greater than or equal to the second lower limit, the second half waveform time qualification check is successful;
step 10463, after the qualification check is successfully performed in the second half waveform time, the contactless card reader adds 1 to the value of the first counter;
step 1047, the contactless card reader adds 1 to the value of the first index;
step 1048, the contactless card reader determines whether the value of the first index is greater than the value of the first total number, if the value of the first index is greater than the value of the first total number, go to step 1049, and if the value of the first index is less than or equal to the value of the first total number, go to step 1043;
step 1049, the contactless card reader generates a first half waveform count according to the product of the value of the first count multiplied by 2;
in step 1050, when the value of the first counter is greater than or equal to the value of the first half waveform count, the contactless card reader sets the value of the first check bit to 1.
the method specifically comprises the following steps: step 1051, the non-contact card reader initializes the value of the second index to 1 and initializes the value of the second counter to 0;
step 1052, the non-contact card reader acquires the total unit waveform number of the first frame signal to generate a second total number according to the first frame signal;
step 1053, the non-contact card reader extracts the second index unit waveform of the first frame signal to generate a second waveform, extracts the first half waveform of the second waveform to generate a second first half waveform, and extracts the second half waveform of the second waveform to generate a second half waveform according to the first frame signal;
step 1054, the non-contact card reader calculates the carrier energy of the second front half waveform to generate a second front half waveform energy, and calculates the carrier energy of the second back half waveform to generate a second back half waveform energy;
step 1055, when the second first half waveform energy is greater than or equal to the first energy parameter, the contactless card reader adds 1 to the value of the second counter;
step 1056, when the energy of the second front and back waveform is greater than or equal to the first energy parameter, the non-contact card reader adds 1 to the value of the second counter;
step 1057, the contactless card reader adds 1 to the value of the second index;
step 1058, the contactless card reader determines whether the value of the second index is greater than the value of the second total number, if the value of the second index is greater than the value of the second total number, go to step 1059, and if the value of the second index is less than or equal to the value of the second total number, go to step 1053;
step 1059, the contactless card reader generates a second half waveform count according to the product of the value of the first count multiplied by 2;
in step 1060, when the value of the second counter is greater than or equal to the value of the second half waveform count, the contactless card reader sets the value of the second check digit to 1.
the method specifically comprises the following steps: step 1061, initializing the value of the third index to be 1 and initializing the value of the third counter to be 0 by the non-contact card reader;
step 1062, the non-contact card reader obtains the total number of unit waveforms of the first frame signal according to the first frame signal, and generates a third total number according to the product of the total number of unit waveforms multiplied by 2 and then subtracting the difference of 1;
step 1063, the non-contact card reader extracts a third index half-waveform of the first frame signal to generate a third waveform and extracts a next half-waveform of the third index half-waveform of the first frame signal to generate a fourth waveform according to the first frame signal;
step 1064, the non-contact card reader acquires the waveform duration of the third waveform to generate a third waveform time, acquires the waveform duration of the fourth waveform to generate a fourth waveform time, and generates the first double-half waveform time according to the sum of the third waveform time and the fourth waveform time;
step 1065, the non-contact card reader performs a first double half waveform time qualification check operation on the first double half waveform time according to the second time threshold, and after the first double half waveform time qualification check is successfully performed, the non-contact card reader adds 1 to the value of the third counter;
step 1066, the contactless card reader adds 1 to the value of the third index;
step 1067, the contactless card reader determines whether the value of the third index is greater than the value of the third total number, if the value of the third index is greater than the value of the third total number, go to step 1068, and if the value of the third index is less than or equal to the value of the first total number, go to step 1063;
step 1068, the contactless card reader generates a first double-half waveform count according to the product of the value of the first count multiplied by 2 and then subtracting the difference of 1;
in step 1069, when the value of the third counter is greater than or equal to the value of the first double-half waveform count, the contactless card reader sets the value of the third check bit to 1.
step 110, the contactless card reader determines whether the third check bit value is 2, if the third check bit value is 2, it indicates that the execution of the subcarrier signal full waveform time check fails, and the next step should go to step 410, and if the third check bit value is not 2, the next step goes to step 420;
and step 111, the non-contact card reader performs effective signal marking operation on the first frame signal mark and sends the first frame signal to a decoding unit of the non-contact card reader for decoding operation.
In step 410, the first frame signal flag is subjected to an invalid signal flag operation and the signal processing flow is exited.
Here, such errors generally occur because the signal is found to be not in accordance with the preset requirements when the half-waveform time, the continuous dual-waveform time, and the half-waveform energy are respectively determined for the signal.
And step 420, checking that the bit parameters are wrong, exiting the signal processing flow and restarting the non-contact card reader.
Here, generally, the cause of such an error may be rewriting of the memory data by the host system of the contactless card reader.
The invention provides a method for improving the signal identification capability of a non-contact card reader, which comprises the steps of carrying out subcarrier signal half-waveform time check on a received frame signal according to a subcarrier signal half-waveform duration reference threshold value, carrying out subcarrier signal half-waveform energy check on the received frame signal according to a subcarrier signal half-waveform energy reference value, carrying out subcarrier signal continuous double-half-waveform time check on the received frame signal according to a subcarrier signal full-waveform duration reference threshold value, carrying out interference signal discrimination on the received frame signal through the three checks, further decoding operation is carried out by considering the checked waveform as an effective waveform, and abandoning the invalid signal if the checked waveform is not the effective waveform. By using the method, the effective identification of the deformation signal is improved, the discrimination of the interference signal is enhanced, and the working stability of the non-contact card reader is ensured.
Those of skill would further appreciate that the various illustrative components and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both, and that the components and steps of the various examples have been described above generally in terms of their functionality in order to clearly illustrate this interchangeability of hardware and software. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.
The steps of a method or algorithm described in connection with the embodiments disclosed herein may be embodied in hardware, a software module executed by a processor, or a combination of the two. A software module may reside in Random Access Memory (RAM), memory, read Only Memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.
The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are merely exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (9)
1. A method of improving signal recognition capabilities of a contactless reader, the method comprising:
the non-contact card reader carries out wireless signal receiving processing through a signal receiving antenna, acquires and generates a first frame signal, wherein the first frame signal comprises a plurality of unit waveforms, and the unit waveforms comprise: the first half waveform and the second half waveform;
the non-contact card reader acquires a subcarrier signal half-waveform duration reference threshold value from a system area to generate a first time threshold value, acquires a subcarrier signal full-waveform duration reference threshold value to generate a second time threshold value, acquires a subcarrier signal half-waveform energy reference value to generate a first energy parameter, acquires a single-frame signal effective waveform lower limit to generate a first count;
the non-contact card reader initializes the value of the first check bit to be 0, initializes the value of the second check bit to be 0 and initializes the value of the third check bit to be 0;
the non-contact card reader sequentially performs unit waveform extraction operation from the initial unit waveform to the last unit waveform of the first frame signal according to the first frame signal, performs subcarrier signal half-waveform time check operation on the extracted unit waveform according to the first time threshold and the first count, and sets the first check bit;
the non-contact card reader sequentially performs unit waveform extraction operation from the initial unit waveform to the last unit waveform of the first frame signal according to the first frame signal, performs sub-carrier signal half-waveform energy check operation on the extracted unit waveform according to the first energy parameter and the first count, and sets the second check bit;
the non-contact card reader sequentially performs continuous 2 half-waveform extraction operations from the first half waveform of the initial unit waveform of the first frame signal to the first half waveform of the last unit waveform according to the first frame signal, performs subcarrier signal continuous double-half-waveform time check operation on the extracted 2 half waveforms according to the second time threshold and the first count, and sets the third check bit;
when the values of the first check bit, the second check bit and the third check bit are all 1, the non-contact card reader performs effective signal marking operation on the first frame signal mark and sends the first frame signal to a decoding unit of the non-contact card reader for decoding operation.
2. The method of claim 1, further comprising:
when the value of the first check bit is 2, the half waveform time check execution of the subcarrier signal fails, and the non-contact card reader performs invalid signal marking operation on the first frame signal mark and exits a signal processing flow;
when the value of the second check bit is 2, the execution of the subcarrier signal half-waveform energy check fails, and the non-contact card reader performs invalid signal marking operation on the first frame signal mark and exits the signal processing flow;
when the value of the third check bit is 2, the subcarrier signal full-waveform time check fails to be executed, and the non-contact card reader performs invalid signal marking operation on the first frame signal mark and exits the signal processing flow.
3. The method according to claim 1, wherein the contactless card reader sequentially performs unit waveform extraction operations from a starting unit waveform to a last unit waveform of the first frame signal according to the first frame signal, performs a subcarrier signal half-waveform time check operation on the extracted unit waveform according to the first time threshold and the first count, and sets the first check bit, specifically comprising:
step 31, initializing the value of a first index to be 1 and initializing the value of a first counter to be 0 by the non-contact card reader;
step 32, the non-contact card reader acquires the total number of unit waveforms of the first frame signal according to the first frame signal to generate a first total number;
step 33, the non-contact card reader extracts the first index unit waveform of the first frame signal to generate a first waveform, extracts the first half waveform of the first waveform to generate a first front half waveform, and extracts the second half waveform of the first waveform to generate a first rear half waveform according to the first frame signal;
step 34, the non-contact card reader acquires the waveform duration of the first half waveform to generate a first half waveform time, and acquires the waveform duration of the first second half waveform to generate a first second half waveform time;
step 35, the contactless card reader performs a first half waveform time qualification check operation on the first half waveform time according to the first time threshold, and after the first half waveform time qualification check is successfully performed, the contactless card reader adds 1 to the value of the first counter;
step 36, the contactless card reader performs a second half-waveform time qualification check operation on the first half-waveform time according to the first time threshold, and after the second half-waveform time qualification check is successfully performed, the contactless card reader adds 1 to the value of the first counter;
step 37, the non-contact card reader adds 1 to the value of the first index;
step 38, the contactless reader determines whether the value of the first index is greater than the value of the first total number, if the value of the first index is greater than the value of the first total number, the step 39 is performed, and if the value of the first index is less than or equal to the value of the first total number, the step 33 is performed;
step 39, the non-contact card reader generates a first half waveform count according to the product of the value of the first count multiplied by 2;
and step 40, when the value of the first counter is greater than or equal to the value of the first half waveform count, the non-contact card reader sets the value of the first check digit to 1.
4. The method of claim 3, further comprising:
when the value of the first counter is smaller than the value of the first half waveform count, the non-contact card reader sets the value of the first check bit to 2.
5. The method according to claim 3, wherein the contactless reader performs a first half waveform time qualification check operation on the first half waveform time according to the first time threshold, specifically comprising:
the non-contact card reader acquires a lower threshold limit of the first time threshold value to generate a first lower limit, and acquires an upper threshold limit of the first time threshold value to generate a first upper limit according to the first time threshold value;
when the first front half waveform time is less than or equal to the first upper limit and the first front half waveform time is greater than or equal to the first lower limit, the first half waveform time qualification check is successful.
6. The method according to claim 1, wherein the contactless card reader sequentially performs unit waveform extraction operations from a starting unit waveform to a last unit waveform of the first frame signal according to the first frame signal, and performs a subcarrier signal half-waveform energy check operation on the extracted unit waveforms according to the first energy parameter and the first count and sets the second check bit, specifically comprising:
step 61, initializing the value of a second index to be 1 and initializing the value of a second counter to be 0 by the non-contact card reader;
step 62, the non-contact card reader acquires the total number of unit waveforms of the first frame signal according to the first frame signal to generate a second total number;
step 63, the non-contact card reader extracts the second index unit waveform of the first frame signal to generate a second waveform, extracts the first half waveform of the second waveform to generate a second first half waveform, and extracts the second half waveform of the second waveform to generate a second half waveform according to the first frame signal;
step 64, the non-contact card reader performs carrier energy calculation operation on the second front half waveform to generate second front half waveform energy, and performs carrier energy calculation operation on the second rear half waveform to generate second rear half waveform energy;
step 65, when the second front half waveform energy is greater than or equal to the first energy parameter, the non-contact card reader adds 1 to the value of the second counter;
step 66, when the energy of the second front-back waveform is greater than or equal to the first energy parameter, the non-contact card reader adds 1 to the value of the second counter;
step 67, the non-contact card reader adds 1 to the value of the second index;
step 68, the contactless reader determines whether the value of the second index is greater than the value of the second total number, if the value of the second index is greater than the value of the second total number, go to step 69, and if the value of the second index is less than or equal to the value of the second total number, go to step 63;
step 69, the non-contact card reader generates a second half waveform count according to the product of the value of the first count multiplied by 2;
and step 70, when the value of the second counter is greater than or equal to the value of the second half waveform count, the contactless card reader sets the value of the second check digit to 1.
7. The method of claim 6, further comprising:
and when the value of the second counter is smaller than the value of the second half waveform count, the non-contact card reader sets the value of the second check bit to 2.
8. The method according to claim 1, wherein the contactless card reader sequentially performs 2 consecutive half-waveform extraction operations from a first half waveform of a starting unit waveform of the first frame signal to a first half waveform of a last unit waveform according to the first frame signal, performs a subcarrier signal consecutive double-half-waveform time check operation on the 2 extracted half-waveforms according to the second time threshold and the first count, and sets the third check bit, specifically comprising:
step 81, initializing a value of a third index to be 1 and initializing a value of a third counter to be 0 by the non-contact card reader;
step 82, the non-contact card reader acquires the total number of unit waveforms of the first frame signal according to the first frame signal, and generates a third total number according to the product of the total number of unit waveforms multiplied by 2 and then the difference of 1;
step 83, the non-contact card reader extracts the third index half waveform of the first frame signal to generate a third waveform and extracts the next half waveform of the third index half waveform of the first frame signal to generate a fourth waveform according to the first frame signal;
step 84, the non-contact card reader acquires the waveform duration of the third waveform to generate a third waveform time, acquires the waveform duration of the fourth waveform to generate a fourth waveform time, and generates a first double-half waveform time according to the sum of the third waveform time and the fourth waveform time;
step 85, the contactless card reader performs a first double half waveform time qualification check operation on the first double half waveform time according to the second time threshold, and after the first double half waveform time qualification check is successfully executed, the contactless card reader adds 1 to the value of the third counter;
step 86, the non-contact card reader adds 1 to the value of the third index;
step 87, the contactless reader determines whether the value of the third index is greater than the value of the third total number, if so, go to step 88, and if not, go to step 83;
step 88, the non-contact card reader generates a first double-half waveform count according to the product of the value of the first count multiplied by 2 and then subtracting the difference of 1;
and step 89, when the value of the third counter is greater than or equal to the value of the first double half waveform count, the contactless card reader sets the value of the third check digit to 1.
9. The method of claim 8, further comprising:
when the value of the third counter is less than the value of the first double-half waveform count, the contactless reader sets the value of the third check bit to 2.
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