CN105634563B - A kind of LF communication system and method for limiting distance - Google Patents
A kind of LF communication system and method for limiting distance Download PDFInfo
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Abstract
The present invention is applied to Near Field Communication technical field, there is provided a kind of LF communication system and method for limiting distance, the system include：Communication transmitting device and communication receiving device, wherein, the communication transmitting device includes transmitting coil, and the communication receiving device includes reception antenna, and the communication transmitting device includes：Coding unit, modulating unit and power amplification unit, the communication receiving device include：Filter unit, amplifying unit and decoding unit.The present invention, circuit structure is simple, configuration is convenient, flexible, and the energy attenuation of transmission is slow, possesses good adaptability and practicality.
Description
Technical field
The invention belongs to Near Field Communication technical field, more particularly to a kind of LF communication system of limiting distance and side
Method.
Background technology
RFID chip is built in by mobile phone radio frequency identification (Radio Frequency Identification, RFID) technology
In mobile phone or mobile phone intelligent card, realize the integrated of cell-phone function and RFID functions, user can brush mobile phone realize mobile payment, finance
Service, by bus purchase and consumption, many closely mobile payment applications such as service, authentication.At present, main flow mobile phone RFID solves
Scheme can be divided into two major classes, i.e. 13.56MHz schemes and 2.4GHz schemes according to working frequency, wherein, based on 2.4GHz's
Radio-frequency technique is integrated into the form for being packaged into SIM card in SIM card together by RFID-SIM, and RFID-SIM had both supported the SIM of standard
Card function, wireless near field communication can be also completed, be the Typical Representative that smart card techniques are combined with non-contact field.
In many mobile payments application, it is thus necessary to determine that payable distance range, and judge mobile phone or pay SIM card to enter
Enter the distance of payment, so as to avoid swiping the card at a distance by mistake.Wherein, a kind of near field communication method of Chinese invention patent and it is
System CN201010166226.0 transmits data using low frequency alternating magnetic field signal, i.e., using default emission parameter transmitting low frequency
Alternating magnetic field signal, preferably the highest frequency f0 of the low frequency alternating magnetic field signal, low frequency alternating magnetic field signal frequency can be
500Hz, 1KHz, 1.5KHz, 2KHz, 2.5KHz, 3KHz, 4KHz, 5KHz, 10KHz, 20KHz or 30KHz.
Existing scheme low frequency alternating magnetic field signal is directly transmitted using baseband signal, and the energy attenuation of transmission is very fast,
It is closer to the distance, and for multiple different transmission rates, it is necessary to produce the alternating magnetic field signal of different frequency, circuit controls more
Complexity, cost are higher.
The content of the invention
The embodiments of the invention provide a kind of LF communication system and method for limiting distance, it is intended to solves prior art and adopts
Be transmitted with baseband signal, the energy attenuation of transmission is very fast, closer to the distance, and for multiple different transmission rates, it is necessary to
The alternating magnetic field signal of different frequency is produced, circuit control is complex, the problem of cost is higher.
On the one hand, there is provided a kind of LF communication system of limiting distance, the system include：Communication transmitting device and communication
Reception device, wherein, the communication transmitting device includes transmitting coil, and the communication receiving device includes reception antenna, described
Communication transmitting device includes：
Coding unit, for carrying out Differential Manchester Encoding to data to be sent, obtain current signal ripple to be sent
Shape；
Modulating unit, it is connected respectively with the coding unit, for using default high-frequency clock, passing through signaling switch control
The pulse width or/and impulse density within the duration of the current signal waveform to be sent are made, obtains preset signals
The current signal of speed；
Power amplification unit, it is connected respectively with the modulating unit and transmitting coil, for passing through the first power amplifier
The current signal is amplified, exports to the transmitting coil and sends afterwards.
Further, the communication receiving device includes：
Filter unit, the current signal for the reception antenna to be received filter out upper frequency by low pass filter
Signal, obtain filtering signal；
Amplifying unit, for being amplified by the second power amplifier to the filtering signal；
Decoding unit, for carrying out Difference Manchester decoding to the filtering signal after amplification, obtain described default
The data of signal rate.
Further, the modulating unit includes modulation circuit, and the modulation circuit includes carrier frequency configuration register；
The carrier clock being connected with the carrier frequency configuration register output end；Piecemeal configuration register；Posted with piecemeal configuration
First counter of storage output end connection；First configuration register；It is connected respectively with the first configuration register output end
The second counter；Second configuration register；The 3rd counter being connected respectively with the second configuration register output end；With
The output level generator of first counter output, the second counter output and the connection of the 3rd counter output,
Second counter output is connected with first counter input, second counter output and the described 3rd
Counter input connects.
Further, the modulating unit specifically includes：
Computation of Period module, for according to the default high-frequency clock and biography configured in the carrier frequency configuration register
The ratio of defeated code check, obtain the carrier cycle numerical value S that the transmission of per bit signal takes；
Pulsewidth acquisition module, number of degrees in the carrier cycle numerical value S taken is transmitted for obtaining the per bit signal
Be worth N number of pulsewidth modulation, the N configurations with the first configuration register and exporting to second counter, N be integer, it is necessary to
The condition N*N of satisfaction is approximately equal to S；
Cycle registration module, for according to continuing carrier cycle R/ level value N, using its quotient as the first numerical value Q and
As third value R, the Q is configured in the piecemeal configuration register and exported to first counter, institute its remainder
State R to be configured in second configuration register and export to the 3rd counter, Q, R are integer；
Cycle division module, for S carrier cycle to be divided into Q+1 fritter, wherein, preceding Q fritter includes N number of clock
Cycle, last fritter include R clock cycle；
Pulse width modulation module, in each fritter, according to block value now, control the high level duty of pulsewidth modulation
There is density linear increase or reduced in high level than either pulse density modulated.
Further, the default high-frequency clock includes 1M, 2M, 4M or 8M.
On the other hand, there is provided a kind of LF communication method of limiting distance, methods described include：
The communication transmitting device carries out Differential Manchester Encoding to data to be sent, obtains current signal to be sent
Waveform；
The communication transmitting device controls the electric current to be sent to believe using default high-frequency clock by signaling switch
The pulse width or/and impulse density within the duration of number waveform, obtain the current signal of preset signals speed；
The communication transmitting device is amplified by the first power amplifier to the current signal, is exported afterwards to institute
State transmitting coil transmission.
Further, methods described includes：
The communication receiving device filters out the current signal that the reception antenna receives by low pass filter higher
The signal of frequency, obtain filtering signal；
The communication receiving device is amplified by the second power amplifier to the filtering signal；
The communication receiving device carries out Difference Manchester decoding to the filtering signal after amplification, obtains described pre-
If the data of signal rate.
Further, the communication transmitting device is controlled described pending using default high-frequency clock by signaling switch
The pulse width or/and impulse density within the duration for the current signal waveform sent, obtain the electric current of preset signals speed
Signal includes：
According to the ratio of default the high-frequency clock and transmission code rate configured in the carrier frequency configuration register, obtain
The carrier cycle numerical value S that the transmission of per bit signal takes；
The N number of pulsewidth modulation of level value in the carrier cycle numerical value S that the per bit signal transmission takes is obtained, it is described
In N configurations and the first configuration register and export to second counter, N is integer, it is necessary to which the condition N*N of satisfaction is approximately equal to S；
According to lasting carrier cycle R/ level value N, using its quotient as the first numerical value Q and its remainder as third value
R, the Q are configured in the piecemeal configuration register and exported to first counter, and the R is configured at described second and matched somebody with somebody
Put in register and export to the 3rd counter, Q, R are integer；
S carrier cycle is divided into Q+1 fritter, wherein, preceding Q fritter includes N number of clock cycle, last fritter
Include R clock cycle；
In each fritter, according to block value now, the high level dutycycle or impulse density for controlling pulsewidth modulation are adjusted
There is density linear increase or reduced in the high level of system.
Further, the default high-frequency clock includes 1M, 2M, 4M or 8M.
The embodiment of the present application includes advantages below：
Communication transmitting device carries out Differential Manchester Encoding to sent bit, obtains the electricity needed for low frequencies end
The current signal waveform sent is flowed, using upper frequency such as 1M, 2M, 4M or 8M clock, passes through the switch of signal, control electricity
The pulse width or impulse density in the duration are flowed, obtains the current signal of a linear change, this signal rate can be with
It is 2K, 4K or 8K, current signal amplifies by power amplifier, the emitted coil of cocurrent, passes through alternation electricity caused by coil
For magnetic coupling on the reception antenna of communication receiving device, reception signal filters out the signal of upper frequency by low pass filter,
And amplify, decode after can obtain 2K, 4K or 8K data-signal, its circuit structure is simple, configuration is convenient, flexible, transmission
Energy attenuation is slow, possesses good adaptability and practicality.
Brief description of the drawings
Fig. 1 is the structural representation of the LF communication system for the limiting distance that the embodiment of the present invention one provides；
Fig. 2 is the Manchester's code and Differential Manchester Encoding schematic diagram that the embodiment of the present invention one provides；
Fig. 3 is the structural representation for the modulation circuit that the embodiment of the present invention one provides；
Fig. 4 is the structural representation for the modulating unit that the embodiment of the present invention one provides；
Fig. 5 is the flow chart of the LF communication method for the communication transmitting device that the embodiment of the present invention two provides；
Fig. 6 is the flow chart of the LF communication method for the communication receiving device that the embodiment of the present invention two provides.
Embodiment
In order to make the purpose , technical scheme and advantage of the present invention be clearer, it is right below in conjunction with drawings and Examples
The present invention is further elaborated.It should be appreciated that the specific embodiments described herein are merely illustrative of the present invention, and
It is not used in the restriction present invention.
It is described in detail below in conjunction with realization of the specific embodiment to the present invention：
Embodiment one
Fig. 1 shows the concrete structure block diagram of the LF communication system for the limiting distance that the embodiment of the present invention one provides, and is
It is easy to illustrate, illustrate only the part related to the embodiment of the present invention.In the present embodiment, the LF communication of the limiting distance
System includes：Communication transmitting device 1 and communication receiving device 2, wherein, communication transmitting device 1 includes transmitting coil, the communication
Reception device 2 includes reception antenna.
Wherein, the communication transmitting device 1 includes：
Coding unit 11, for carrying out Differential Manchester Encoding to data to be sent, obtain current signal to be sent
Waveform；
Wherein, communication transmitting device carries out Differential Manchester Encoding, coding waveforms such as Fig. 2 institutes to data to be sent first
Show.There is a saltus step Manchester's code centre of each, and saltus step from low to high represents 0, and saltus step from high to low represents 1；Also may be used
Opposite definition, from low to high saltus step represent 1, and saltus step from high to low represents 0.Differential Manchester Encoding is compiled based on Manchester
Code, jumped in code stream with previous along in the same direction as data 0, it is reverse for data 1.
Modulating unit 12, it is connected respectively with the coding unit, for using default high-frequency clock, passing through signaling switch
The pulse width or/and impulse density within the duration of the current signal waveform to be sent are controlled, obtains default letter
The current signal of number speed；
Preferably, the default high-frequency clock includes 1M, 2M, 4M or 8M.
In the present embodiment, the modulating unit 12 includes modulation circuit, as shown in figure 3, the modulation circuit includes carrying
Wave frequency rate configuration register；The carrier clock being connected with the carrier frequency configuration register output end；Piecemeal configuration register；
The first counter being connected with the piecemeal configuration register output end；First configuration register；Configured respectively with described first
Second counter of register output end connection；Second configuration register；Connect respectively with the second configuration register output end
The 3rd counter connect；It is connected with first counter output, the second counter output and the 3rd counter output
Output level generator, second counter output is connected with first counter input, and described second counts
Device output end is connected with the 3rd counter input.
Wherein, the clock that the second counter and R are counted is carrier clock, and configuration is configured by N configuration registers and R respectively
Register provides.When system initialization, the value of N and the 3rd counter is 0.After proceeding by signal modulation, whenever second
When the value of counter is changed into Configuration Values N ' from 0, produces a pulse signal and be sent to the first counter；Whenever the 3rd counter
When value is changed into Configuration Values R ' from 0, produces a pulse signal and be sent to the first counter.N and R with setting value according to retouching above
The method stated provides.The value of N and the 3rd counter is input in output level generator.
First counter represents the count value of current piecemeal.In piecemeal configuration register, the Q values of storage are as described in hereafter text
Method provides.During system initialization, Q values are 0.After proceeding by signal modulation, the first counter often receives one second counting
After the pulse that device is sent, the value of the first counter adds 1.When the value of the first counter is equal to piecemeal configuration register preset value Q ',
And after the 3rd counter receives a pulse signal, the saltus step of Q values is 0, and represent that a bit signal is sent.
Output level generator produces the low and high level of output, in each fritter, according to the value of the first counter, accordingly
PWM high level dutycycle or PDM high level is controlled density occur so that in this N carrier cycle, the duty of high level
Than for Q/N.When the value of the first counter is equal to the preset value Q ' of piecemeal configuration register, now high level dutycycle is 1, is held
The continuous carrier cycle time is R.
Further, as shown in figure 4, the modulating unit 12 specifically includes：
Computation of Period module 121, for according to the default high-frequency clock configured in the carrier frequency configuration register
With the ratio of transmission code rate, the carrier cycle numerical value S that the transmission of per bit signal takes is obtained；
Pulsewidth acquisition module 122, grade in the carrier cycle numerical value S taken is transmitted for obtaining the per bit signal
Numerical value of N pulsewidth modulation, N configuration is with the first configuration register and to export to second counter, N be integer, needing
The condition N*N of satisfaction is approximately equal to S；
Cycle registration module 123, continue carrier cycle R/ level value N for basis, using its quotient as the first numerical value Q
With its remainder as third value R, the Q is configured in the piecemeal configuration register and exported to first counter,
The R is configured in second configuration register and exported to the 3rd counter, and Q, R are integer；
Cycle division module 124, for S carrier cycle to be divided into Q+1 fritter, wherein, preceding Q fritter includes N number of
Clock cycle, last fritter include R clock cycle；
Pulse width modulation module 125, in each fritter, according to block value now, control the high level of pulsewidth modulation
There is density linear increase or reduced in the high level of dutycycle either pulse density modulated.
Power amplification unit 13, it is connected respectively with the modulating unit and transmitting coil, for passing through the first power amplification
Device is amplified to the current signal, is exported to the transmitting coil and is sent afterwards.
Wherein, high-frequency clock is preset as carrier wave using 8M, transmitted modulated to describe exemplified by 2K preset signals speed
Journey：
(1) default high-frequency clock and ratio S, the S=16M/2K=4000 of preset signals speed, i.e., 4000 loads are calculated
Wave period transmits a bit signal；
(2) design a pulsewidth modulation (PWM, Pulse Width Modulation) for being total to N number of grade or pulse is close
Degree modulation (PDM, Pulse Density Modulation), N are integer, it is necessary to which the condition N*N of satisfaction is approximately equal to S.According to above-mentioned
Condition, 64 can be equal in the hope of N；
(3) calculate R/N and try to achieve quotient Q and remainder R, Q is 62, R 32 in this example；
(4) the S cycles are divided into Q+1 fritter, wherein, preceding Q fritter includes N number of clock cycle, last fritter bag
Containing R clock cycle.In this row, 4000 cycles are divided into 63 fritters, preceding 62 every piece include 64 clock cycle, it is remaining
Last fritter only includes 32 clock cycle；
(5) in each fritter, according to block value now, the corresponding high level dutycycle for controlling PWM or PDM height electricity
Existing density of clearing does following linear change, from 0/N, 1/N, 2/N, 3/N, 4/N ... ... (N-3)/N, (N-2)/N, (Q-1)/N,
R/R.Wherein, dutycycle or high level density are 0/64,1/64,2/64,3/64 ... ... 61/64,32/32, wherein finally
The full width level of one 32,/32 32 clock cycle of expression；
By the above-mentioned means, the i.e. available electric current that macroscopically current strength gradually linearly increases, similar method, PWM
High level dutycycle or PDM high level there is density R/R in the following order, (Q-1)/N ... ... 1/N, 0/N
Obtain the current signal that current strength linearly reduces.
Further, the communication receiving device 2 includes：
Filter unit 21, the current signal for the reception antenna to be received filter out higher-frequency by low pass filter
The signal of rate, obtain filtering signal；
Amplifying unit 22, for being amplified by the second power amplifier to the filtering signal；
Decoding unit 23, for carrying out Difference Manchester decoding to the filtering signal after amplification, obtain described pre-
If the data of signal rate.
Wherein, jumped in the code stream of Differential Manchester Encoding with previous along in the same direction as data 0, it is reverse for data 1.
Decoding unit 23 can sample according to the default sampling interval to the signal based on Differential Manchester Encoding, then will obtain
The amplitude versus time feature of each sampled point be converted into temporal characteristics；Or level signal is converted using the method for accumulated counts
For triangular signal, by triangular wave gate method, judge crest and trough, obtain clock signal and intermediate data, so as to complete
Into manchester decoder.The signal of communication receiving device 2 is produced by the induced voltage of reception antenna, and induced voltage is proportional to reception
The rate of change of coil flux amount, i.e. V=d Φ/dt.When the timing of receiving coil area one, magnetic flux and magnetic field intensity are directly proportional.It is right
The magnetic field intensity of coil transmissions to space, it is directly proportional with electric current, magnetic field intensity calculates formula for communication transmitting device：H=
N*I/Le, H is magnetic field intensity in formula, unit A/m；N is the number of turn of transmitting antenna coil, and I is exciting current, and Le is measurement sample
The effective magnetic circuit length of product, unit m.According to expression above it was determined that if communication receiving device is sensed such as Fig. 2
Shown low and high level, then communication transmitting device electric current need to meet that V=K*di/dt, wherein K are proportionality constant.Communication is sent
Device coil current linear change can meet to require.
The present embodiment, communication transmitting device carry out Differential Manchester Encoding to sent bit, obtain low frequencies
The current signal waveform that electric current needed for end is sent, using upper frequency such as 1M, 2M, 4M or 8M clock, passes through signal
Switch, pulse width or impulse density in the control electric current duration, obtains the current signal of a linear change, this letter
Number speed can be 2K, 4K or 8K, and current signal amplifies by power amplifier, the emitted coil of cocurrent, produced by coil
Raw alternating electromagnetic field is coupled on the reception antenna of communication receiving device, and reception signal filters out higher-frequency by low pass filter
The signal of rate, and amplify, decode after can obtain 2K, 4K or 8K data-signal, its circuit structure is simple, the convenient spirit of configuration
Living, the energy attenuation of transmission is slow, possesses good adaptability and practicality.
Embodiment two
Fig. 5 shows the implementation process of the LF communication method for the communication transmitting device that the embodiment of the present invention two provides, in detail
State as follows：
What deserves to be explained is the LF communication system of limiting distance includes communication transmitting device and communication receiving device, its
In, the communication transmitting device includes transmitting coil, and the communication receiving device includes reception antenna.
In step S501, communication transmitting device carries out Differential Manchester Encoding to data to be sent, obtains to be sent
Current signal waveform.
In the present embodiment, wherein, communication transmitting device carries out Differential Manchester Encoding to data to be sent first, compiles
Code waveform is as shown in Figure 2.There is a saltus step Manchester's code centre of each, and saltus step from low to high represents 0, jumps from high to low
Become and represent 1；Also definition that can be opposite, from low to high saltus step represent 1, and saltus step from high to low represents 0.Differential Manchester Encoding base
In Manchester's code, jumped in code stream with previous along in the same direction as data 0, it is reverse for data 1.
In step S502, described in the communication transmitting device is controlled using default high-frequency clock, by signaling switch
The pulse width or/and impulse density within the duration of current signal waveform to be sent, obtain preset signals speed
Current signal.
In the present embodiment, the default high-frequency clock includes 1M, 2M, 4M or 8M.The modulating unit includes modulation
Circuit, as shown in figure 3, the modulation circuit includes carrier frequency configuration register；It is defeated with the carrier frequency configuration register
Go out the carrier clock of end connection；Piecemeal configuration register；The first counter being connected with the piecemeal configuration register output end；
First configuration register；The second counter being connected respectively with the first configuration register output end；Second configuration register；
The 3rd counter being connected respectively with the second configuration register output end；With first counter output, the second meter
The output level generator that connect with the 3rd counter output of number device output ends, second counter output and described the
One counter input is connected, and second counter output is connected with the 3rd counter input.
Wherein, the clock that the second counter and R are counted is carrier clock, and configuration is configured by N configuration registers and R respectively
Register provides.When system initialization, the value of N and the 3rd counter is 0.After proceeding by signal modulation, whenever second
When the value of counter is changed into Configuration Values N ' from 0, produces a pulse signal and be sent to the first counter；Whenever the 3rd counter
When value is changed into Configuration Values R ' from 0, produces a pulse signal and be sent to the first counter.N and R with setting value according to retouching above
The method stated provides.The value of N and the 3rd counter is input in output level generator.
First counter represents the count value of current piecemeal.In piecemeal configuration register, the Q values of storage are as described in hereafter text
Method provides.During system initialization, Q values are 0.After proceeding by signal modulation, the first counter often receives one second counting
After the pulse that device is sent, the value of the first counter adds 1.When the value of the first counter is equal to piecemeal configuration register preset value Q ',
And after the 3rd counter receives a pulse signal, the saltus step of Q values is 0, and represent that a bit signal is sent.
Output level generator produces the low and high level of output, in each fritter, according to the value of the first counter, accordingly
PWM high level dutycycle or PDM high level is controlled density occur so that in this N carrier cycle, the duty of high level
Than for Q/N.When the value of the first counter is equal to the preset value Q ' of piecemeal configuration register, now high level dutycycle is 1, is held
The continuous carrier cycle time is R.
Further, the communication transmitting device is controlled described pending using default high-frequency clock by signaling switch
The pulse width or/and impulse density within the duration for the current signal waveform sent, obtain the electric current of preset signals speed
Signal specifically includes：
According to the ratio of default the high-frequency clock and transmission code rate configured in the carrier frequency configuration register, obtain
The carrier cycle numerical value S that the transmission of per bit signal takes；
The N number of pulsewidth modulation of level value in the carrier cycle numerical value S that the per bit signal transmission takes is obtained, it is described
In N configurations and the first configuration register and export to second counter, N is integer, it is necessary to which the condition N*N of satisfaction is approximately equal to S；
According to lasting carrier cycle R/ level value N, using its quotient as the first numerical value Q and its remainder as third value
R, the Q are configured in the piecemeal configuration register and exported to first counter, and the R is configured at described second and matched somebody with somebody
Put in register and export to the 3rd counter, Q, R are integer；
S carrier cycle is divided into Q+1 fritter, wherein, preceding Q fritter includes N number of clock cycle, last fritter
Include R clock cycle；
In each fritter, according to block value now, the high level dutycycle or impulse density for controlling pulsewidth modulation are adjusted
There is density linear increase or reduced in the high level of system.
Wherein, high-frequency clock is preset as carrier wave using 8M, transmitted modulated to describe exemplified by 2K preset signals speed
Journey：
S11, the default high-frequency clock of calculating and preset signals speed ratio S, S=16M/2K=4000, i.e., 4000
Carrier cycle transmits a bit signal；
S12, the pulsewidth modulation (PWM, Pulse Width Modulation) of the common N number of grade of design one or pulse are close
Degree modulation (PDM, Pulse Density Modulation), N are integer, it is necessary to which the condition N*N of satisfaction is approximately equal to S.According to above-mentioned
Condition, 64 can be equal in the hope of N；
S13, calculating R/N try to achieve quotient Q and remainder R, and Q is 62, R 32 in this example；
S14, the S cycles are divided into Q+1 fritter, wherein, preceding Q fritter includes N number of clock cycle, last fritter bag
Containing R clock cycle.In this row, 4000 cycles are divided into 63 fritters, preceding 62 every piece include 64 clock cycle, it is remaining
Last fritter only includes 32 clock cycle；
S15, in each fritter, according to block value now, the height of the corresponding high level dutycycle or PDM for controlling PWM
There is density and does following linear change in level, from 0/N, 1/N, 2/N, 3/N, 4/N ... ... (N-3)/N, (N-2)/N, (Q-1)/
N, R/R.Wherein, dutycycle or high level density are 0/64,1/64,2/64,3/64 ... ... 61/64,32/32, wherein most
The latter 32/32 represents the full width level of 32 clock cycle；
By the above-mentioned means, the i.e. available electric current that macroscopically current strength gradually linearly increases, similar method, PWM
High level dutycycle or PDM high level there is density R/R in the following order, (Q-1)/N ... ... 1/N, 0/N
Obtain the current signal that current strength linearly reduces.
In step S503, described in the communication transmitting device is controlled using default high-frequency clock, by signaling switch
The pulse width or/and impulse density within the duration of current signal waveform to be sent, obtain preset signals speed
Current signal.
Fig. 6 shows the implementation process of the LF communication method for the communication receiving device that the embodiment of the present invention two provides, in detail
State as follows：
In step S503, the current signal that the reception antenna receives is passed through low pass filtered by the communication receiving device
Ripple device filters out the signal of upper frequency, obtains filtering signal.
In step S503, the communication receiving device is put by the second power amplifier to the filtering signal
Greatly.
In step S503, the communication receiving device carries out Difference Manchester solution to the filtering signal after amplification
Code, obtain the data of the preset signals speed.
In the present embodiment, jumped in the code stream of Differential Manchester Encoding with previous along in the same direction as data 0, reverse
For data 1.The signal based on Differential Manchester Encoding can be sampled according to the default sampling interval, then will obtained
The amplitude versus time feature of each sampled point is converted into temporal characteristics.Or level signal is converted into using the method for accumulated counts
Triangular signal, by triangular wave gate method, judge crest and trough, obtain clock signal and intermediate data, so as to complete
Manchester decoder.The signal of communication receiving device is produced by the induced voltage of reception antenna, and induced voltage is proportional to reception line
Enclose the rate of change of magnetic flux, i.e. V=d Φ/dt.When the timing of receiving coil area one, magnetic flux and magnetic field intensity are directly proportional.To logical
Believe for dispensing device, the magnetic field intensity of coil transmissions to space, be directly proportional with electric current, magnetic field intensity calculates formula：H=N*
I/Le, H is magnetic field intensity in formula, unit A/m；N is the number of turn of transmitting antenna coil, and I is exciting current, and Le is measurement sample
Effective magnetic circuit length, unit m.According to expression above it was determined that if communication receiving device is sensed such as Fig. 2 institutes
The low and high level shown, then communication transmitting device electric current need to meet that V=K*di/dt, wherein K are proportionality constant.Communication sends dress
Putting coil current linear change can meet to require.
The present embodiment, communication transmitting device carry out Differential Manchester Encoding to sent bit, obtain low frequencies
The current signal waveform that electric current needed for end is sent, using upper frequency such as 1M, 2M, 4M or 8M clock, passes through signal
Switch, pulse width or impulse density in the control electric current duration, obtains the current signal of a linear change, this letter
Number speed can be 2K, 4K or 8K, and current signal amplifies by power amplifier, the emitted coil of cocurrent, produced by coil
Raw alternating electromagnetic field is coupled on the reception antenna of communication receiving device, and reception signal filters out higher-frequency by low pass filter
The signal of rate, and amplify, decode after can obtain 2K, 4K or 8K data-signal, its circuit structure is simple, the convenient spirit of configuration
Living, the energy attenuation of transmission is slow, possesses good adaptability and practicality.
The LF communication method of limiting distance provided in an embodiment of the present invention can be applied to be implemented in foregoing corresponding system
In example one, details will not be repeated here referring to the description of above-described embodiment one.
It is worth noting that, in said apparatus embodiment, included unit is simply drawn according to function logic
Point, but above-mentioned division is not limited to, as long as corresponding function can be realized；In addition, each functional unit is specific
Title is also only to facilitate mutually distinguish, the protection domain being not intended to limit the invention.
Each embodiment in this specification is described by the way of progressive, what each embodiment stressed be with
The difference of other embodiment, between each embodiment identical similar part mutually referring to.
It should be understood by those skilled in the art that, the embodiment of the embodiment of the present application can be provided as method, controller or meter
Calculation machine program product.Therefore, the embodiment of the present application can use complete hardware embodiment, complete software embodiment or with reference to software
With the form of the embodiment of hardware aspect.Moreover, the embodiment of the present application can use wherein includes computer in one or more
The computer-usable storage medium (including but is not limited to magnetic disk storage, CD-ROM, optical memory etc.) of usable program code
The form of the computer program product of upper implementation.
The embodiment of the present application is with reference to according to the method for the embodiment of the present application, terminal device (system) and computer program
The flow chart and/or block diagram of product describes.It should be understood that can be by computer program instructions implementation process figure and/or block diagram
In each flow and/or square frame and the flow in flow chart and/or block diagram and/or the combination of square frame.These can be provided
Computer program instructions are set to all-purpose computer, special-purpose computer, Embedded Processor or other programmable data processing terminals
Standby processor is to produce a machine so that is held by the processor of computer or other programmable data processing terminal equipments
Capable instruction is produced for realizing in one flow of flow chart or multiple flows and/or one square frame of block diagram or multiple square frames
The controller for the function of specifying.
These computer program instructions, which may be alternatively stored in, can guide computer or other programmable data processing terminal equipments
In the computer-readable memory to work in a specific way so that the instruction being stored in the computer-readable memory produces bag
The manufacture of instruction control unit is included, the instruction control unit is realized in one flow of flow chart or multiple flows and/or block diagram one
The function of being specified in individual square frame or multiple square frames.
These computer program instructions can be also loaded into computer or other programmable data processing terminal equipments so that
Series of operation steps is performed on computer or other programmable terminal equipments to produce computer implemented processing, so that
The instruction performed on computer or other programmable terminal equipments is provided for realizing in one flow of flow chart or multiple flows
And/or specified in one square frame of block diagram or multiple square frames function the step of.
Although having been described for the preferred embodiment of the embodiment of the present application, those skilled in the art once know base
This creative concept, then other change and modification can be made to these embodiments.So appended claims are intended to be construed to
Including preferred embodiment and fall into having altered and changing for the embodiment of the present application scope.
Finally, it is to be noted that, herein, such as first and second or the like relational terms be used merely to by
One entity or operation make a distinction with another entity or operation, and not necessarily require or imply these entities or operation
Between any this actual relation or order be present.Moreover, term " comprising ", "comprising" or its any other variant meaning
Covering including for nonexcludability, so that process, method, article or terminal device including a series of elements are not only wrapped
Those key elements, but also the other element including being not expressly set out are included, or is also included for this process, method, article
Or the key element that terminal device is intrinsic.In the absence of more restrictions, wanted by what sentence "including a ..." limited
Element, it is not excluded that other identical element in the process including the key element, method, article or terminal device also be present.
Above to a kind of LF communication system and method for limiting distance provided herein, it is described in detail,
Specific case used herein is set forth to the principle and embodiment of the application, and the explanation of above example is simply used
Understand the present processes and its core concept in help；Meanwhile for those of ordinary skill in the art, according to the application's
Thought, there will be changes in specific embodiments and applications, in summary, this specification content should not be construed as
Limitation to the application.
Claims (7)
1. a kind of LF communication system of limiting distance, including communication transmitting device and communication receiving device, wherein, the communication
Dispensing device includes transmitting coil, and the communication receiving device includes reception antenna, it is characterised in that the communication transmitting device
Including：
Coding unit, for carrying out Differential Manchester Encoding to data to be sent, obtain current signal waveform to be sent；
Modulating unit, it is connected respectively with the coding unit, for using default high-frequency clock, institute to be controlled by signaling switch
The pulse width or/and impulse density within the duration of current signal waveform to be sent are stated, obtains preset signals speed
Current signal；
Power amplification unit, it is connected respectively with the modulating unit and transmitting coil, for passing through the first power amplifier to institute
State current signal to be amplified, export to the transmitting coil and send afterwards；
Wherein：The modulating unit specifically includes：
Computation of Period module, for according to default the high-frequency clock and transmission code rate configured in carrier frequency configuration register
Ratio, obtain the carrier cycle numerical value S that the transmission of per bit signal takes；
Pulsewidth acquisition module, it is N number of that level value in the carrier cycle numerical value S of occupancy is transmitted for obtaining the per bit signal
Pulsewidth modulation, the N are configured in the first configuration register and exported to the second counter, and N is integer, it is necessary to meet condition N*
N is approximately equal to S；
Cycle registration module, continue carrier cycle R/ level value N for basis, using its quotient as the first numerical value Q and remaining
Number is used as third value R, and the Q, which is configured in piecemeal configuration register and exported to the first counter, the R, is configured at second
In configuration register and export to the 3rd counter, Q, R are integer；
Cycle division module, for S carrier cycle to be divided into Q+1 fritter, wherein, preceding Q fritter includes N number of clock week
Phase, last fritter include R clock cycle；
Pulse width modulation module, in each fritter, according to block value now, control pulsewidth modulation high level dutycycle or
There is density linear increase or reduced in the high level of person's pulse density modulated.
2. the LF communication system of the limiting distance according to the claim 1, it is characterised in that the communications reception dress
Put including：
Filter unit, for the current signal that the reception antenna receives to be filtered out to the letter of upper frequency by low pass filter
Number, obtain filtering signal；
Amplifying unit, for being amplified by the second power amplifier to the filtering signal；
Decoding unit, for carrying out Difference Manchester decoding to the filtering signal after amplification, obtain the preset signals
The data of speed.
3. the LF communication system of the limiting distance according to the claim 1, it is characterised in that the modulating unit bag
Modulation circuit is included, the modulation circuit includes carrier frequency configuration register；With the carrier frequency configuration register output end
The carrier clock of connection；Piecemeal configuration register；The first counter being connected with the piecemeal configuration register output end；First
Configuration register；The second counter being connected respectively with the first configuration register output end；Second configuration register；Respectively
The 3rd counter being connected with the second configuration register output end；With first counter output, the second counter
The output level generator that output end connects with the 3rd counter output, second counter output and the described first meter
The input connection of number device, second counter output are connected with the 3rd counter input.
4. the LF communication system of the limiting distance according to the claim 1, it is characterised in that the default high-frequency
Clock includes 1M, 2M, 4M or 8M.
5. a kind of LF communication method of limiting distance, including communication transmitting device and communication receiving device, wherein, the communication
Dispensing device includes transmitting coil, and the communication receiving device includes reception antenna, it is characterised in that methods described includes：
The communication transmitting device carries out Differential Manchester Encoding to data to be sent, obtains current signal ripple to be sent
Shape；
The communication transmitting device controls the current signal ripple to be sent using default high-frequency clock by signaling switch
The pulse width or/and impulse density within the duration of shape, obtain the current signal of preset signals speed；
The communication transmitting device is amplified by the first power amplifier to the current signal, is exported afterwards to the hair
Ray circle is sent；
Wherein, the communication transmitting device controls the electric current to be sent using default high-frequency clock by signaling switch
The pulse width or/and impulse density within the duration of signal waveform, obtaining the current signal of preset signals speed includes：
According to the ratio of default the high-frequency clock and transmission code rate configured in carrier frequency configuration register, per bit is obtained
The carrier cycle numerical value S that signal transmission takes；
The N number of pulsewidth modulation of level value in the carrier cycle numerical value S that the per bit signal transmission takes is obtained, the N matches somebody with somebody
It is placed in the first configuration register and exports to the second counter, N is integer, it is necessary to which the condition N*N of satisfaction is approximately equal to S；
According to lasting carrier cycle R/ level value N, using its quotient as the first numerical value Q and its remainder as third value R, institute
State Q and be configured in piecemeal configuration register and export to the first counter, the R and be configured in the second configuration register and export
To the 3rd counter, Q, R are integer；
S carrier cycle is divided into Q+1 fritter, wherein, preceding Q fritter includes N number of clock cycle, and last fritter includes
R clock cycle；
In each fritter, according to block value now, the high level dutycycle or pulse density modulated of pulsewidth modulation are controlled
There is density linear increase or reduced in high level.
6. the LF communication method of the limiting distance according to the claim 5, it is characterised in that methods described includes：
The current signal that the reception antenna receives is filtered out upper frequency by the communication receiving device by low pass filter
Signal, obtain filtering signal；
The communication receiving device is amplified by the second power amplifier to the filtering signal；
The communication receiving device carries out Difference Manchester decoding to the filtering signal after amplification, obtains the default letter
The data of number speed.
7. the LF communication method of the limiting distance according to the claim 5, it is characterised in that the default high-frequency
Clock includes 1M, 2M, 4M or 8M.
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| CN106067802B (en) * | 2016-06-24 | 2023-07-07 | 桂林航天电子有限公司 | Microwave isolation solid state relay and operation method thereof |
| JP7003446B2 (en) * | 2017-05-22 | 2022-01-20 | 住友電気工業株式会社 | In-vehicle communication device, in-vehicle communication system, communication control method and communication control program |
| CN107437961A (en) * | 2017-07-03 | 2017-12-05 | 宜昌市瑞磁科技有限公司 | A kind of magnetostatic communication system and its method |
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