CN101060509B - Symbol timing detector and wireless terminal - Google Patents
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- CN101060509B CN101060509B CN2007100966498A CN200710096649A CN101060509B CN 101060509 B CN101060509 B CN 101060509B CN 2007100966498 A CN2007100966498 A CN 2007100966498A CN 200710096649 A CN200710096649 A CN 200710096649A CN 101060509 B CN101060509 B CN 101060509B
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Abstract
A wireless terminal detects the symbol timing in a received modulated signal and demodulates the signal. Symbol timing can be stably controlled, even when frequency deviation occurs in the wireless communication frequencies. Sampling means samples signal values of the modulated signals at a period that is shorter than the symbol period. An extraction means extracts, from a plurality of sampling points, what are taken to be signal values at symbol timing points, and sampling point demodulation means performs demodulation with respect to signal values at each sampling point. A value detection means is used to detect the power value at each sampling point resulting from the demodulation. Symbol timing control means are used to control the timing taken to be symbol timing by the extraction means, based on the power values at the sampling points.
Description
Invention field
The present invention relates to a kind of wireless device, be specifically related to a kind of synchronizing symbol wireless device regularly.Particularly, under the situation of digital modulation signals demodulation, the present invention relates to a kind of detected symbol method regularly that is used for setting up sign synchronization.
Background technology
The receiver of digital modulation system need be realized timing synchronization, signal that arrives with demodulate reception and accurate picked up signal information.Remove asynchronous symbol timing and receiver the symbol timing here, otherwise the receiver demodulated information will comprise error in transmitter this side.
For the synchronizing symbol timing, under the situation of π/4-phase shift QPSK system, for example, detected symbol method regularly comprises that the Differential Detection of the baseband signal that receives and the zero passage of base band quadrature component (Q component) and in-phase component (I component) regularly detect and pass through to use the method for this method detected symbol timing.Day patent application 2003-234791 of the present disclosure (reference paper 1) has described the example of this system.
As an example, in the wireless device of mobile communication system, the digital demodulation system by receiver carry out the signal demodulation and accurately picked up signal information based on the hypothesis of having set up sign synchronization.As mentioned above, if there is not sign synchronization between transmitter and receiver, the signal message of receiver one end demodulation will comprise error.In π/4-phase shift QPSK modulation, use the zero passage method.Particularly, the received signal that is transformed into digital signal is converted to two components by quadrature, homophase I component and quadrature Q component, and from the zero crossing detected symbol regularly.Reference paper 1 is described the example of such wireless communication system.
Yet, above the problem of conventional art be that it is subject to the influence of receiver frequency departure inherently.The remarkable deviation of receiving frequency signals make determine symbol regularly put become impossible, make obtain regularly very difficult synchronously.Another problem is, when the phase amplitude of I and Q component is used to regularly synchronously, because it regularly is very necessary can accurately obtaining the zero passage of I component, impossible if phase place or other such factors regularly become the zero passage that obtains I component, it is regularly impossible synchronously to cause.
For example, the symbol method regularly that comprises in the demodulation process with the receiver that is used for detecting mobile radio station is an example.Because conventional art uses the zero crossing in the amplitude of I or Q component to detect, frequency departure may make phase point experience transformation on I or the Q axle after Differential Detection, make correctly detect zero passage regularly become impossible.
As another example, the frequency departure between the transmitter and receiver produces difference at the phase point that is obtained by the Differential Detection received signal.In the I component zero crossing is surveyed, for example, the frequency departure that makes phase point rotate concussion on the Q axle will hinder and detect zero crossing, thereby hinder the symbolic point timing detection.
Even if the purpose of this invention is to provide a kind ofly in employed wireless communication frequency during the occurrence frequency deviation, also stably detected symbol is regularly and this synchronous wireless terminal regularly.
Summary of the invention
In order to reach above-mentioned target, the invention provides and detect modulation signal symbol symbol timing detector regularly, this detector comprises: sampling apparatus is used to sample at the signal value than the modulation signal of the time internal modulation of symbol period section; The sampled point demodulating equipment, it carries out demodulation to the signal value at the sampled point of being sampled by sampling apparatus; Value detection device detects performance number or range value at the sampled point demodulation gained that obtains by the sampled point demodulating equipment; With symbol timing checkout gear,, detect as symbol timing regularly based on the value of the sampled point that detects by value detection device.
In other words, be worth detected symbol regularly, even if for example, in the wireless communication frequency that uses, produce frequency departure, also detected symbol timing stably and regularly synchronous to this by power (or amplitude) at each sampled point demodulation gained.
Can use different modulation, for example, π/4-phase shift QPSK modulation.Similarly, can use different corresponding demodulation methods, for example under π/4-phase shift QPSK modulation case, use Differential Detection.The signal that uses can be the complex signal that comprises I and Q component.About being used for sampling period of sampled modulated signal, can use the different cycles.For example, can use over-sampling, promptly use the symbol period N cycle doubly.
Different models can be used to power (or amplitude) the value detected symbol timing based on each sampled point.For example, can use as drag, in this model, use power (or amplitude) value the highest in regularly based on the amplitude of the power (amplitude) of each sampled point value, and come detected symbol regularly at two adjacent-symbols minimum signal subsection of intermediate point regularly at symbol.
In configuration example according to symbol timing detector of the present invention, the skew removal device at value detection device detected a plurality of (for example, N) power of sampled point or range value produce and move, and the minimum value of a symbol period becomes zero (or approaching zero) thus.Equilibration device is averaged power or the range value by the sampled point that moves of skew removal device.Based on the result who averages with equilibration device, symbol regularly checkout gear detects as symbol timing regularly.
Therefore, after the skew of removing each sampled point power (or amplitude) value, average one by one and the result is used as the basis of detected symbol timing at sampled point sampled point.Therefore, when implementing on average for example, can to remove skew when reducing noise, improve the accuracy that symbol regularly detects like this.
For skew removal pattern, can use different patterns.For example, can use as drag, wherein, at power (or amplitude) value of a plurality of (for example, N) sampled point, the minimum value that detects in the symbol period deducts as deviant and from power (or amplitude) value.Similarly, different mode can be used for averaging, for example integration.
The present invention also provide detect the modulation signal that receives symbol regularly and the wireless terminal of restituted signal, this terminal comprises: sampling apparatus, at the signal value that is shorter than the described modulation signal of sampling in the time of symbol period; Extraction element extracts from the signal value by a plurality of sampled points of described sampling apparatus sampling as the signal value that is positioned at the signal value that symbol regularly puts; Demodulating equipment carries out demodulation at the signal value of described extraction; The sampled point demodulating equipment carries out demodulation at the signal value by each sampled point of described sampling apparatus sampling; Value detection device detects by carrying out performance number or the range value that demodulation produces in the sample point that obtains by described sampled point demodulating equipment; And the symbol timing control apparatus, based on power or the range value by detected each sampled point of described value detection device, control is got as symbol timing regularly by described extraction element.
Therefore, by control based on regularly from the symbol of power (or amplitude) value of the demodulation of each sampled point, control character that can be stable regularly and regularly synchronously, even if if for example, in the wireless communication frequency that uses, produce frequency departure.
Wireless terminal may further include the skew removal device, and the power or the range value of a plurality of sampled points that detect at described value detection device move, and the minimum value of a symbol period becomes zero or approach zero thus; Equilibration device, the on average value of each sampled point that is moved by described skew removal device; Wherein based on by described equilibration device averaged result, described symbol timing control apparatus control is got as symbol timing regularly by described extraction element.
Therefore, after removing skew, be that the basis is implemented average and the result is used as control character basis regularly with the sampled point at sampled point at power (or amplitude) value of each sampled point.Therefore, when implementing on average for example, to remove skew when reducing noise, improve the time-controlled accuracy of symbol.
Wireless terminal also can dispose the controlling of sampling device, and therefore this device control improve symbol accuracy regularly by the timing of the sampling of sampling apparatus enforcement.
Different models can be used to control sampling timing.For example, can use as drag, therein, sampling timing is adjusted the minimum value (or by equilibration device averaged result) that makes by the detected symbol period of value detection device and (for example is lowered, to minimum value), or make maximum (or by equilibration device averaged result) be increased (for example, to maximum) by the detected symbol period of value detection device.
As previously mentioned, because according to the present invention, (demodulation) signal that receives is sampled in the cycle of symbol period and comes detected symbol regularly based on power (or amplitude) value that obtains in each sampled point demodulation being shorter than, even if so if, for example, produce frequency departure on the wireless communication frequency that uses, detected symbol that also can be stable regularly.
Equally according to the present invention, after removing skew at power (or amplitude) value of each sampled point, being the basis with the sampled point implements average and the result is used as detected symbol basis regularly at sampled point.Therefore, when implementing on average for example, can to remove skew when reducing noise, improve the accuracy that symbol regularly detects.The present invention also can improve the accuracy that symbol regularly detects by the control sampling timing.
Description of drawings
Fig. 1 is the schematic diagram according to demodulation part in the wireless device of first specific embodiment of the present invention.
Fig. 2 is the schematic diagram according to demodulation part in the wireless device of second specific embodiment of the present invention.
Fig. 3 is the example that the processing of part enforcement is removed in skew.
Embodiment
With reference now to drawings clear, explanation specific embodiments of the invention.The symbol timing detector that provides by demodulation part at the wireless device of wireless terminal come detected symbol regularly structure and use testing result to control the process structure regularly of demodulation part.For example, wireless device is made up of transmitter and receiver, and receiver is furnished with the demodulation part.Can use dissimilar wireless terminals.For example, can be the wireless terminal that carries by the people, for example hand-held phone terminal, or the individual wireless terminal that is installed in ideal position.
The digital modulation system of Shi Yonging is π/4-phase shift QPSK modulating system in an embodiment.In the modulation based on π/4-phase shift QPSK of Shi Yonging,, next phase point is set in an embodiment by the phase point that an angle in 45 degree, 135 degree ,-45 degree ,-135 degree is added to previous symbol according to the QPSK graphical diagram.In demodulating process, detect poor between the angle of current sign phase point and the previous symbol phase point angle, and detected differential seat angle is used for defining corresponding QPSK symbolic point information (data).
Signal of communication is made up of preamble and data.For example, preamble is made up of the QPSK symbolic point that obtains by π/4-phase shift QPSK modulated process (comprise and repeat " 01 " alternately (+135 degree) and " 10 " (45 degree)).In this case, ideally, two the continuous symbol points " 01 " that demodulation obtains and the intermediate point of " 10 " are by the initial point (zero passage) on IQ plane, and this regularly can be as detecting (deduction) symbolic point basis regularly.At data division, desirable equally, because the signal that is obtained by demodulation always has zero crossing, can detect this regularly also as detecting (deduction) symbolic point basis regularly.For example, the timing between adjacent-symbol (symbol period) is set in advance in the transmitter and receiver.
A specific embodiment of the present invention is described now.
Fig. 1 is the schematic diagram according to the wireless device of wireless communication system of the present invention.With reference to figure 1, the 101st, the demodulation process part, the 102nd, the synchronization gain part, the 103rd, A/D (analog to digital) transducer, the 104th, baseband-converted part, the 105th, LPF (low pass filter), the 106th, receiving filter, the 107th, Differential Detection part, 108 is-symbol determining sections, the 109th, S/P (serial/parallel) conversion portion, the 110th, the Differential Detection part, the 111st, amplitude calculating section, the 112nd, integral processing part, the 113rd, minimum value test section, the 114th, reference value deducts part, the 115th, RWF (random walk (Random Walk) filter), the 116th, timing controlled part and 117 is samplers.
The signal that is received by the antenna (not shown) passes through IF (intermediate frequency) part to A/D converter 103, and here analog signal is converted into digital signal.Sample frequency is arranged to N times (N is a positive integer) of symbol frequency.The conversion of signals that receives like this becomes digital signal, carries out baseband-converted by the baseband-converted part in the demodulation process part 101 104, is demodulated into homophase I component and quadrature Q component thus.LPF 105 removes unnecessary frequency subsequently.To be input to receiving filter 106 and synchronization gain part 102 from the data of LPF 105 outputs.The data experience waveform that is input to receiving filter 106 forms and removes the noise element.Afterwards, sampler 117 extracts the signal value that symbol is regularly put, and enter data into Differential Detection part 107 subsequently, the signal conjugate complex number that wherein has a symbol of delay multiply by current input signal to obtain decoded signal, is output as decoded bits through signal determining section 108 then.
The over-sampling that will be input to the data serial signal (being N signal here) of synchronization gain part 102 by S/P conversion portion 109 partly converts parallel signal to.In Differential Detection part 110, each in Zhuan Huan the N signal is multiplied by the conjugate complex number of the delayed data of a symbol like this, and symbol is stored in the memory that Differential Detection part 110 provides, and is input to amplitude calculating section 111.At amplitude calculating section 111, obtain Differential Detection part 110 detected complex data range values and be entered into integral processing part 112.Integral processing part 112 obtains the mean value of N range value of input by N range value being carried out partial integration.
The data of integral processing part 112 are input to minimum value test section 113, and it is found out, and which has minimum value in N the data.Minimum value test section 113 and integral processing part 112 all have buffer.From being 0 sequence number (index value), a word of buffer finds the index value of the buffer of storage minimum value.
Deduct part 114 in reference value, the intermediate buffer index value is arranged to reference value, and reference value is deducted poor with the index value of the buffer that calculates the storage minimum value and reference value from detected index value.The difference that deducts the reference value that part 114 calculates with reference value is imported into RWF 115, and it subdues the error in the difference between the same reference value that is produced by the influence that is included in noise in the received signal or decline.Difference between the same reference value of thus obtained gained is delivered to timing controlled part 116, and it is regularly poor to reduce this to change therein, and sampled signal is delivered to A/D converter 103.Based on the input from RWF 115, timing controlled part 116 control characters are point regularly, therefrom extracts signal value at this point sampling device 117.
Thereby, detect by the minimum amplitude value of using baseband signal IQ component in symbol regularly detects, during promptly convenient occurrence frequency deviation, the present invention makes and stablizes acquisition and become possibility synchronously.According to the present invention, a kind of wireless device is provided, when promptly convenient frequency departure occurred in the frequency that radio communication uses, detected symbol that also can be stable was regularly and obtain regularly synchronously.Simultaneously, after the synchronization gain process, can verify synchronously and set up.Can verify synchronously by the predetermined angle of phase place rotation, and the frequency departure that calculates by synchronous checking also can be used for FREQUENCY CONTROL.
The present invention also provides the wireless device that is used for carrying out radio communication, and wireless device comprises: the demodulating equipment that is used for restituted signal; Be used to obtain synchronous synchronization gain device; With the timing control apparatus that is same as the adjustment signal timing; Wherein the synchronization gain device calculates with the difference and the realization clock phase of reference value and proofreaies and correct.
The present invention also provides the method for detecting symbol timing in the wireless device that is used for carrying out radio communication, wireless device has at least: demodulating equipment is used for restituted signal, with the synchronization gain device, be used for obtaining synchronously, described detection method comprises: detect detection step with the difference between the reference value, and based on detecting the detected aligning step of proofreading and correct with the clock phase of the difference between the reference value of step.
Second specific embodiment of the present invention now will be described.
This specific embodiment has been described an example of symbol synchronization system in the receiving signal demodulation processing.The modulating system that uses is π/4-phase shift QPSK system, two bits of each symbol transmission.
Fig. 2 has provided the structure of the demodulation part of wireless device.As shown in the figure, provide A/D (analog to digital) transducer 103, demodulation process part 101 and timing controlled part 116 for the demodulation part.Demodulation process part 101 has synchronization gain part 102, baseband-converted part 104, LPF (low pass filter) 105, receiving filter 106, sampler 117, Differential Detection part 107 and symbol determining section 108.Synchronization gain part 102 has S/P (serial/parallel) conversion portion 109, Differential Detection part 110, power calculation part 201, skew and removes part 202, integral processing part 112, minimum value test section 113, reference value and deduct part 114 and RWF (random walk filter) 115.
Now introduce the work of demodulation part.The signal that receives by the antenna (not shown) arrives A/D converter 103 through IF (intermediate frequency) part.In this case, the signal that receives is modulated through π/4-phase shift QPSK in emitting side.In A/D converter 103, analog signal is converted into digital signal and outputs to baseband-converted part 104.The sample frequency of A/D converter 103 is arranged to N times (N is a positive integer) of symbol frequency.In baseband-converted part 104, change through quadrature from the digital signal of A/D converter 103 inputs, signal is become demodulation homophase I component and quadrature Q component.The result of this conversion is output to LPF 105, and it is removed for I and the unnecessary frequency of Q component signal, and outputs results to receiving filter 106 and synchronization gain part 102.The I and the Q component signal experience waveform that are input to receiving filter 106 form and the removal noise component(s), and output results to sampler 117.Sampler 117 extracts the signal value (I and Q component value) that symbol is regularly put, and dateout is to Differential Detection part 107.In sampler 117, symbol period is stored in the memory in advance, and timing controlled part 116 control characters timing point.
At importing I and Q component signals from sampler 117, the signal conjugate complex number that Differential Detection part 107 will have a symbol delay (is stored in the memory of 107 parts, i.e. signal before symbol) multiply by the decoded signal that current input signal obtains to output to symbol determining section 108, carry out determining of decoded signal in the symbol determining section to obtain decoded bits, subsequently this decoded bits is outputed to, for example, signal codec (CH-CODEC) processing section.
The signal that is input to synchronization gain part 102 from LPF 105 is imported into S/P conversion portion 109, and signal is converted to N the parallel signal that is output to Differential Detection part 110 from serial signal in S/P conversion portion 109.In this example, N parallel signal forms the signal of a symbol period corresponding to N the signal that is obtained by A/D converter 103 samplings.
At each I and the input of Q component parallel signal from S/P conversion portion 109, the signal conjugate complex number that Differential Detection part 110 will have a symbol delay (is stored in the memory of 110 parts, i.e. signal before symbol) multiply by current input signal, multiplication result outputs to power calculation part 201.
Based on the value that Differential Detection part 110 is calculated, power calculation part 201 is calculated the quadratic sum (I of I and Q component
2+ Q
2) obtaining complex power (in this example, being the data of N power), it is output to skew and removes part 202.Common, obtain the power square root and mean, when determining to be magnitude relationship, obtain identical value in fact at the amplitude of power calculation part 201 shown in Figure 1 and amplitude calculating section 111.
In this specific embodiment, demodulation is applied to the π/4-phase shift QPSK modulation of received signal by Differential Detection part 110 and the power of demodulation result obtains by power calculation part 201.Demodulation result is corresponding QPSK symbolic point under symbol timing situation, and the corresponding in other cases arbitrary symbolic point that links on the line that faces the QPSK symbolic point mutually.Under preamble (wherein the QPSK symbolic point of demodulation is to repeat " 01 " and " 10 " alternately) situation of received signal part, for example, power is the highest in the symbol timing, and the intermediate point between adjacent symbols point is minimum.At the data division of non-preamble, same, " 01 " and " 10 ", or " 11 " (+45 degree) and " 00 " (135 spend) be adjacent, power is minimum on its intermediate point.
Performance number (being N performance number in this example) based on the parallel signal of importing from power calculation part 201, skew removal part 202 finds the minimum value as the performance number of deviant, from each parallel signal performance number, deduct deviant so that minimal power values becomes zero, and the output parallel signal deducts the result to integral processing part 112.
Fig. 3 (a) is at when existing little power fluctuation, provided skew remove before and the example of the performance number of parallel signal afterwards, Fig. 3 (b) is at when exist big power fluctuation, provided skew remove before with the example of the performance number of parallel signal afterwards.In each figure, the left end of the curve of expression power and right-hand member correspondence and are closed on symbolic point, and the mid point correspondence of each curve and closed on intersymbol mid point.Each curve is represented a symbol period.
Shown in Fig. 3 (b), in the time of near symbolic point passes through contiguous initial point, power fluctuation is very big, helps the symbol timing detection.Yet, because frequency departure or noise etc., when symbolic point by near the initial point time, for example under the situation of Fig. 3 (a), it is very low to think that signal is used for the reliability that symbol regularly detects.Therefore, in this specific embodiment, skew removal part 202 usefulness remove skew makes minimal power values become zero, thereby increases power fluctuation.
Here, preferred integral model is that partial integration is handled.Carry out partial integration when handling at the signal value to a plurality of 0＜α＜1, the result of the integration formerly that has obtained multiply by (1-α) and the result is joined with α and multiply by among the result of current demand signal value, and the result of addition is used as new integral result.
Minimum value test section 113 will be from integral processing part 112 (this example, the average power content of each parallel signal input N average power content) stores in each buffer, find the minimum value in a plurality of average power contents, detection of stored the index value corresponding to the buffer of the average power content of minimum value, and transmission testing result (index value) deducts part 114 to reference value.In this example, index value is that a word of buffer is 0 sequence number, and index value 1 to N is assigned in N the parallel signal first to N.
Index value information (storing index value) based on 113 inputs corresponding to the buffer of the average power content of minimum value from the minimum value test section, by deducting reference value and output subtraction result to RWF 115 from index value, reference value deducts part 114 and calculates poor between the index value of the buffer of storing the minimum average B configuration performance number and the default reference value.In this example, an intermediate buffering index value is set to reference value.Particularly, when using the 0th during to N index value, when N is even number, with N/2 as with reference to value with when N is odd number, with (N+1)/2 or (N-1)/2 be worth as reference.
115 couples of RWF carry out filtering from the value that reference value deducts part 114 inputs, and output results to timing controlled part 116.This filtering removed by noise or since in the received signal that causes of phase place effect with the error in the difference between reference value.Subsequently, input value is added into by storing register into.When register value surpass default positive threshold value (+L), the value (for example ,+1) of this effect of indication is outputed to timing controlled part 116 and register is eliminated, the zero clearing register value.If register value (L), outputs to timing controlled part 116 and register is eliminated, the zero clearing register value with the value (for example ,-1) of this effect of indication in the predetermined negative threshold value.
Based on the input from RWF 115, timing controlled part 116 control characters are point regularly, is sampled device 117 at these signal values and extracts.Timing controlled part 116 is also controlled numbering and the buffer index value (by the index value of minimum value test section 113 uses) that is deducted the reference value of part 114 uses by reference value, so that getting enough, opens figure blank, with the timing of the symbol in the interval sampling device 117 point.
As such example, on basis from the input of RWF 115, when by from the index value of the buffer of storing the minimum average B configuration performance number, deduct difference that reference value obtains when positive direction increases (for example, when from RWF 115 input+1), timing controlled part 116 is the amount of a sampling of symbol constant time lag in the sampler 117, and also reference value deducted the amount (so that the index value of described buffer is more near reference value) that reference value that part 114 uses postpones a sampling.Similarly, on basis from the input of RWF 115, when by from the index value of the buffer of storing the minimum average B configuration performance number, deduct difference that reference value obtains when negative direction increases (for example, when from RWF 115 input-1), timing controlled part 116 makes that symbol regularly quickens the amount of a sampling in the sampler 117, and also makes by reference value and deduct the amount (so that the index value of described buffer is more near reference value) that reference value that part 114 uses is quickened a sampling.In this case, if be set as consistent at the initial value that reference value deducts the timing of the reference value that part 114 uses with the mid point of adjacent symbols between regularly in the sampler 117, because timing afterwards is also with unanimity, be controlled at the suitable symbol timing of setting in the sampler by utilization, the index value that makes the buffer of storing the minimum average B configuration performance number is to more near reference value (that is to say, difference is reduced).
Timing controlled part 116 also can be by A/D converter 103 control sampling timing, and the signal that shows sampling timing by output is to A/D converter 103.As such example, timing controlled part 116 can be carried out symbol meticulous adjusting regularly by the sampling timing of control A/D converter 103, further to reduce by minimum value test section 113 detected minimum average B configuration performance numbers.
As mentioned above, use method for detecting symbol timing of the present invention, in the receiver that meets π/4-phase shift QPSK modulation, at with symbol frequency N doubly (N is a positive integer) the sample frequency over-sampling and through each sampled point of the received signal x (n) of the generation of S/P conversion, calculate v as a result (n)=x (n) x of the Differential Detection of received signal x (n)
*(n-N), based on Differential Detection result's (real part)
2+ (imaginary part)
2And come rated output | V (n) |
2Remove skew so that minimal power values is zero, and (in this example at the mean value that obtains power signal in the past, pass through integration), detect minimal power values in N the sampled point (it is ideally at the adjacent symbols zero crossing of mid point regularly), and adjust regularly based on the difference between sampled point that is detected in minimal power values and the reference value, thereby set up sign synchronization.
Be convenient frequency departure when occurring in the wireless communication frequency of use, this makes the stable detection symbol regularly and obtain sign synchronization and become possibility.
In this specific embodiment, for example, employed value (being power in this case) reflection I and Q component that power calculation part 201 is calculated so frequency departure does not bring the change on the power, make correct detected symbol regularly become possibility.Simultaneously, skew removal part 202 deducts deviant so that minimal power values becomes zero from the performance number of each parallel signal.Therefore, when having big power fluctuation, the value that is input to integral processing part 112 can increase, and the symbol that increases signal regularly detects validity, and thereby increase detection accuracy.In addition, implementing skew before average removes.
Although introduced synchronization gain part 102 at a structure, mid point by using minimum value test section 113 to find between two adjacent-symbols are regularly put in this structure, to find minimum value in N the average power content, still also can use other structures.For example, replace minimum value test section 113, also can be by detecting the maximum in N the average power content, use the maximum test section detected symbol timing point of assigning to.If use the maximum test section, based on input from RWF 115, with the symbol timing point in the timing controlled part 116 control samplers 117, and symbol regularly put deduct the reference value that part 114 uses with reference value and aim at, so that the index value of buffer of storing the maximum average power value is more near reference value.As an example, timing controlled part 116 can realize symbol accurate adjustment regularly by the sampling timing of control A/D converter 103, with further increase by the detected maximum average power value in maximum test section (in this example, being N average power content).
The demodulation part of wireless device comprises sampling apparatus, is made up of the sampling function of A/D converter 103; Extraction element is made up of the function of the sampler 117 that extracts the signal value of regularly putting as symbol; And demodulating equipment, form by the function of the Differential Detection part 107 of the demodulation (in the present embodiment, being Differential Detection) of extracting signal value; The sampled point demodulating equipment is made up of the function of the Differential Detection part 110 of the demodulation (in the present embodiment, Differential Detection) of each sampled point signal value; Value detection device is made up of the function in the power calculation part 201 (or amplitude calculating section 111 as shown in Figure 1) of each sampled point detection power value (or range value); The skew removal device is removed the function of part 202 and is formed by the skew of removing the performance number skew; Equilibration device is carried out the function of the integral processing part 112 of integral processing (average example) and forms by performance number (or range value) after removing at skew; Symbol is checkout gear regularly, and the function of the symbol timing controlled part 116 that is regularly detected by the symbol that deducts the result of part 114 or RWF 115 based on minimum value test section 113, reference value is formed; The symbol timing control apparatus is by forming based on the function of symbol timing testing result control character timing controlled part 116 regularly in the sampler 117; And the controlling of sampling device is made up of the function of the timing controlled part 116 of the timing of control A/D converter 103 sampling.
Be not limited to the statement of front according to the structure of system of the present invention and equipment, other multiple structures also are possible.The present invention can be provided as the program that realizes processing method of the present invention, or records the program on the recording medium.In addition, application of the present invention need not be confined to the description of front, and it also is possible applying the present invention to other multiple fields.
In addition, the various process of implementing in the system or equipment of the present invention can for example be implemented in the hardware resource of equipment processor and memory or the like, and described processor and memory are by implementing to be stored in the processor control of the control program among the ROM (read-only memory).The different functional method that is used to implement this processing also can be made up of the separate hardware circuit.
In addition, the present invention also can be understood as and stores top control program in floppy disk, CD (compact disk)-ROM or other computer readable recording medium storing program for performing invention, make by described control program and realize treatment in accordance with the present invention, program is input to computer and is carried out by processor from recording medium.
Claims (9)
1. detect the symbol symbol timing detector regularly of modulation signal, described detector comprises:
Sampling apparatus is used at the signal value that is shorter than the described modulation signal of sampling in the time of symbol period;
The sampled point demodulating equipment carries out demodulation at the signal value in the sample point of being sampled by described sampling apparatus;
Value detection device, detection is by the performance number or the range value of the demodulation generation of the sample point of described sampled point demodulating equipment acquisition; And
Symbol is checkout gear regularly, in detected a plurality of values, detect the minimum value of a symbol period by described value detection device, and, based on the time difference between the reference sample point of setting in the sampled point of described minimum value and the described symbol period, detect as symbol timing regularly.
2. according to the symbol timing detector of claim 1, further comprise:
The skew removal device, the value of a plurality of sample point that detect at described value detection device moves, and the minimum value of a symbol period becomes zero or approach zero thus; And
Equilibration device, the on average value of each sample point that is moved by described skew removal device;
Wherein based on by described equilibration device averaged result, described symbol regularly checkout gear detects as symbol timing regularly.
3. according to the symbol timing detector of claim 1 or 2, described symbol timing detector uses π/4-phase shift QPSK digital modulation system.
4. detect the symbol timing of the modulation signal that receives and the wireless terminal of the described signal of demodulation, described terminal comprises:
Sampling apparatus is at the signal value that is shorter than the described modulation signal of sampling in the time of symbol period;
Extraction element extracts from the signal value by a plurality of sampled points of described sampling apparatus sampling as the signal value that is positioned at the signal value that symbol regularly puts;
Demodulating equipment carries out demodulation at the signal value of described extraction;
The sampled point demodulating equipment carries out demodulation at the signal value by each sampled point of described sampling apparatus sampling;
Value detection device, detection is by the performance number or the range value of the demodulation generation of the sample point of described sampled point demodulating equipment acquisition; And
The symbol timing control apparatus, in detected a plurality of values, detect the minimum value of a symbol period by described value detection device, and, based on the time difference between the reference sample point of setting in the sampled point of described minimum value and the described symbol period, control is got as symbol timing regularly by described extraction element.
5. according to the wireless terminal of claim 4, further comprise:
The skew removal device, the power or the range value of a plurality of sampled points that detect at described value detection device move, and the minimum value of a symbol period becomes zero or approach zero thus; And
Equilibration device, the on average value of each sampled point that is moved by described skew removal device;
Wherein based on by described equilibration device averaged result, described symbol timing control apparatus control is got as symbol timing regularly by described extraction element.
6. according to the wireless terminal of claim 4 or 5, described wireless terminal is equipped with the control device of the sampling timing of the described sampling apparatus of control.
7. according to the wireless terminal of claim 5, it is equipped with and is used for controlling of sampling device that the sampling timing of described sampling apparatus is controlled, wherein said controlling of sampling device is controlled the sampling timing of described sampling apparatus, with the minimum value of a symbol period of the mean value of the described value that reduces to detect or described equilibration device, or increase the maximum of a symbol period of the mean value of the described value that detects by described value detection device or described equilibration device by described value detection device.
8. according to the wireless terminal of claim 4 or 5, described wireless terminal uses π/4-phase shift QPSK digital modulation system.
9. detect the symbol method for detecting symbol timing regularly of modulation signal, described method comprises the steps:
At the signal value that is shorter than the described modulation signal of sampling in the time of symbol period;
Signal value in each sampled point demodulation sampling;
Detection is by the performance number or the range value of the described demodulation generation of each sample point of described demodulation acquisition; And
In detected a plurality of values, detect the minimum value of a symbol period, and, based on the time difference between the reference sample point of setting in the sampled point of described minimum value and the described symbol period, detect timing as the symbol timing.
Applications Claiming Priority (4)
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| JP116206/2006 | 2006-04-19 | ||
| JP2006116206 | 2006-04-19 | ||
| JP259869/2006 | 2006-09-26 | ||
| JP2006259869A JP4268180B2 (en) | 2006-04-19 | 2006-09-26 | Symbol timing detection device and wireless terminal device |
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| CN101060509A CN101060509A (en) | 2007-10-24 |
| CN101060509B true CN101060509B (en) | 2011-12-21 |
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| WO2012106866A1 (en) * | 2011-07-05 | 2012-08-16 | 华为技术有限公司 | Signal demodulation method and receiving device |
| JP5853196B2 (en) * | 2011-12-19 | 2016-02-09 | パナソニックＩｐマネジメント株式会社 | Synchronization system and receiving apparatus including the same |
| CN103561460B (en) * | 2013-11-13 | 2016-04-20 | 中国科学院微电子研究所 | Symbol synchronization method |
| JP6223873B2 (en) | 2014-03-14 | 2017-11-01 | 株式会社荏原製作所 | Polishing apparatus and polishing method |
| WO2020075319A1 (en) * | 2018-10-09 | 2020-04-16 | 国立研究開発法人宇宙航空研究開発機構 | Observation device, observation method, and program |
| JP6797428B2 (en) * | 2018-10-09 | 2020-12-09 | 国立研究開発法人宇宙航空研究開発機構 | Observation equipment, observation methods and programs |
| JP7177676B2 (en) * | 2018-12-04 | 2022-11-24 | 旭化成エレクトロニクス株式会社 | demodulator |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN1310903A (en) * | 1999-05-24 | 2001-08-29 | 皇家菲利浦电子有限公司 | Differentiate and multiply based timing recovery in a quadrature demodulator |
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| CN1310903A (en) * | 1999-05-24 | 2001-08-29 | 皇家菲利浦电子有限公司 | Differentiate and multiply based timing recovery in a quadrature demodulator |
Non-Patent Citations (5)
| Title |
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| JP特开2001-237905A 2001.08.31 |
| JP特开2003-234791A 2003.08.22 |
| JP特开2005-117199A 2005.04.28 |
| JP特开平8-116344A 1996.05.07 |
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