CN102224710B - Dynamic multi-path detection device and method - Google Patents
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Abstract
In one embodiment of the present invention, a dynamic multi-path detection device is disclosed to include at least one narrow-band signal metric estimator responsive to input signal. Each of the at least one estimators measures a particular characteristic of the input signal in a frequency band that is narrower than the overall signal bandwidth and is operative to generate a signal parameter estimate signal. The dynamic multi-path detection device is further disclosed to include a signal metric comparison device responsive to the signal parameter estimate signal(s) and operative to generate a dynamic multi-path indication signal for detecting dynamic multi-path.
Description
Technical field
Relate generally to receiver of the present invention, and particularly, relate to the receiver with the ability that detects Dynamic Multi-Pathing effect.
Background technology
In communication system, send information from transmitter to receiver by channel, this introduces various impairments.The impairment of one type generally running in radio communication is known as multipath.Multipath is to adopt multiple paths to arrive receiver place due to the multiple copies that transmitted or " echo " by wireless medium by like this name.In the simulated television system of the NTSC such as North America and European PAL, multipath impairment causes multiple images or " ghost image " beyond master image.In radio digital communication system, comprise such as by with undefined digital land television system: known standard A/53 of 1) being adopted by Advanced Television Systems Committee (ATSC); 2) the known standard EN 300744 of being adopted by ETSI European Telecommunications Standards Institute (ETSI); Or the known standard for Digital Television land multimedia broadcasting (DTMB) of 3) adopting in China, be conventionally necessary to weaken multipath in receiver in case zero defect the input signal of decoding.
As known in prior art, multipath impairment can be classified as " flat decline " or " frequency selective fading ".Conventionally, flat decline refers to that the whole frequencies place in signal band causes the multipath of approximately equal decay to detract.This type of decline can be compensated by simple multipath mitigation equipment (such as automatic gain control (AGC)).On the other hand, frequency selective fading is greater than the decay to other frequencies to the decay of some frequency.It is necessary to use more complicated multipath mitigation equipment, such as equalizer.Conventionally, receiver is not known the definite decay of each frequency in advance, so necessary use adaptive multi-path weakening equipment (such as, adaptive equalizer), this adaptive multi-path weakens equipment and must be adapted to allow the error-free recovery of data.Initial adaptation occurs in the beginning that signal receives.This type of adaptation can comprise programming initial coefficients, based on blind formula standard or certainty standard update coefficient, or other adaptive approachs.After initial equalizer adaptation completes, suppose that multipath is static, this adaptation can slow down or stop.
But, if multipath is dynamic, such as being in the situation of motion when receiver, the dependent attenuation of unlike signal frequency changed along with the time, and need to by Dynamic Multi-Pathing weaken equipment (such as, train continuously adaptive equalizer) follow the tracks of.
As known in the art, design Dynamic Multi-Pathing weaken equipment (such as, train continuously adaptive equalizer) a challenge be, for equalizer is selected suitable adaptation speed.But conventionally, adaptive causing improves the susceptibility of noise faster, exists thus compromise between noiseproof feature and tracking velocity.In prior art, consider that the whole bag of tricks is for automatically adjusting the adaptation speed of adaptive equalizer.Multiple error levels that depend on after equilibrium in these methods, the bit error based on for example being carried out as Reed-Solomon decoder by forward error correction (FEC) module is proofreaied and correct or constellation range measurement.For example, in a prior art, the successive value of mean square deviation (MSE) is for adjusting the adaptation speed of equalizer.Other prior aries are adjusted the adaptation speed of equalizer in a direction, to reduce packet error rate and be also like this in Reed-Solomon decoder.
Be for the problem that depends on the error level of adjusting adaptation speed, be difficult to the source of finding out that error level raises.The source of also, not knowing the error level raising be whether due to Dynamic Multi-Pathing, need faster adaptation speed or due to random noise, need slower adaptation speed.The problem being associated with the source that can not accurately identify experienced error level rising obviously causes variety of issue.For example, the adjustment that may lead to errors, and the more important thing is and fail to weaken Dynamic Multi-Pathing.
Some prior art does not solve the problem that detects the error level source raising, and other prior aries depend on trial-and-error method type method.In addition, other method is by adjusting adaptation speed by equalizer coefficients gradient.For example, in an art methods, adjust equalizer step sizes based on coefficient gradients.But coefficient gradients is responsive to random noise, thus, the method may cause adaptation speed unnecessary and undesirably increase.
In signal processing technology field, being known that as testing goal is used multiple filters with different time constant, is not known but be applied to Dynamic Multi-Pathing detection.In known prior art, in detection speech activity, fast filter and slow filter are used for distinguishing real speech signal and noise signal, and filter is not used in the signal metric of measuring the frequency band that is less than input signal bandwidth for measuring the power of whole signal.Use the method to be for the problem of Dynamic Multi-Pathing detection, Dynamic Multi-Pathing causes the marked change in signal metric in special frequency band in many cases, but the maintenance of whole signal power is identical.Thus, by maintenance, detected and Dynamic Multi-Pathing will can not weaken the variation in signal metric.
For eliminating simulation land TV phantom, improve for the performance requirement of digital television receiver.Specific domain of interest is that wherein digital television receiver is the performance in the Dynamic Multi-Pathing environment of mobile device.In addition, a demand of existence is, as cost in the situation that, not improving Dynamic Multi-Pathing performance taking additional noise sensitivity in improving for static channel.
Under enlightenment above, need a kind of method and apparatus for detection of Dynamic Multi-Pathing, and weaken the adaptation speed of equipment (such as continuous training adaptive equalizer) for configuring Dynamic Multi-Pathing.
Summary of the invention
Briefly, in an embodiment of the invention, a kind of dynamic multi-path detection device comprises at least one narrow band signal tolerance estimator, and it is in response to input signal.Each in described at least one estimator is measured than the special characteristic of the input signal in the frequency band of overall signal narrow bandwidth, and can operate to generate signal parameter estimated signal.Dynamic multi-path detection device is further open to comprise signal metric compare facilities, and it is in response to one or more signal parameter estimated signal, and can operate to generate Dynamic Multi-Pathing index signal for detecting Dynamic Multi-Pathing.
In multiple illustrated detailed description of the preferred embodiment from hereinafter with reference accompanying drawing, above and other object of the present invention, feature and advantage will be easily shown in.
Brief description of the drawings
Fig. 1 shows the dynamic multi-path detection device according to one embodiment of the present invention, and it comprises N narrow band signal tolerance estimator and signal metric compare facilities;
Fig. 2 shows according to the further details of the signal metric compare facilities of Fig. 1 of one embodiment of the present invention;
Fig. 3 shows the further details of the signal metric compare facilities of Fig. 1 of another execution mode according to the present invention;
Fig. 4 shows according to the high level block diagram of the example application of dynamic multi-path detection device one embodiment of the present invention, in the television receiver of digital land; And
Fig. 5 to Fig. 7 shows the diagram of the behavior of the Dynamic Multi-Pathing detection signal in the example implementation of ATSC A/53 receiver (such as the receiver 400 in Fig. 4).
Embodiment
What in the situation that reading and understand this specification, easily see is, in order to overcome above-mentioned restriction of the prior art and to overcome other restrictions, the invention discloses a kind of apparatus and method for detection of the rate of change in multipath, for making the speed of correspondingly adjusting adaptive equalizer effectively to weaken Dynamic Multi-Pathing.
In an embodiment of the invention, the present invention is by providing a kind of method and apparatus to solve above-mentioned one or more problem, the method and device to be to detect the rate of change of the selected feature (or parameter or tolerance) of input signal with the rate of change that detects multipath (distortion) for weakening the consistent mode of Dynamic Multi-Pathing, thereby reduce error level and improve systematic function.It should be noted that term " multipath ", " multipath distortion " and " multipath impairment " use interchangeably, thereby any the quoting for " multipath " is intended to identify multipath distortion or multipath effect at this.
In the claims that invest this, illustrated especially novel features and these and various other advantages of describing feature of the present invention, and these claims form a part of the present invention.But, for its advantage and the object understanding better the present invention, obtain by its use, with reference to forming the accompanying drawing of another part of the present invention and the description content of following, at accompanying drawing with describe shown in content and described the concrete example of embodiment of the present invention.
Referring now to Fig. 1,, wherein show dynamic multi-path detection device 10 to comprise N narrow band signal tolerance estimator 102, wherein N is integer, according to an embodiment of the invention, each narrow band signal parameter (or tolerance or feature) estimator 102 is depicted as and is coupled to signal metric compare facilities 104, and this signal metric compare facilities 104 is depicted as and generates Dynamic Multi-Pathing index signal 105.Each estimator 102 generates signal parameter estimated signal 103, and this signal parameter estimated signal 103 is received by equipment 104.
" arrowband " refers to the bandwidth that is less than whole signal bandwidth.Although signal metric compare facilities 104 is depicted as to the input receiving from estimator 102, but in other embodiments, this signal metric compare facilities 104 can receive the input from other sources, includes but not limited to " broadband " or " signal band " signal metric estimator.
Equipment 10 receives signal input 101, and in an embodiment of the invention, a part for receiver system receives the input from antenna, and wherein signal 101 is for example generated by carrier recovery circuit.The exemplary application of equipment 10 is Digital Television, will further discuss in detail hereinafter.Estimator 102 is and each feature of signal correction connection or the estimator of parameter, such as, but not limited to absolute signal level, signal power or other signal statistics data.Such as the signal characteristic of reflection in signal 103.
Although figure 1 illustrates N estimator 102, can use the estimator of arbitrary number.In fact,, by the meticulousr detectability of crossing over frequency spectrum is provided, additional estimator can produce improved Dynamic Multi-Pathing and detect.
In an embodiment of the invention, especially when just measured parameter is direct current (DC) level, each estimator 102 is low pass filter (LPF), and wherein each filter has unique bandwidth and the scope different from another filter.For example, one of estimator 102 has than all the other N-1 the bandwidth that estimator is narrow, and another estimator has larger but than the little bandwidth of all the other N-1 estimator, by that analogy than the former.Different bandwidth ranges allows the output of different estimators 102 to change with different rates.Different and the unique bandwidth support being associated from estimator 102 detects the rate of change in multi-path signal 102.Thus, in the situation that each estimator is being estimated DC level, for the given rate of change in the multipath of signal 101, rate of change in the DC level of each estimator 102 is different due to different bandwidth, and rate of change in the multipath of signal 101 can detect by the output of comparison (deducting) different estimators 102.
Each estimator 102 is estimated prearranged signals frequency signal parameter or tolerance around, and wherein the bandwidth of each estimator 102 (or estimated bandwidth) is less than overall signal bandwidth, is also the bandwidth of signal 101.For this reason, estimator 102 is known as " arrowband ".In one embodiment, estimator 102 has unique bandwidth separately, and in another embodiment, estimator 102 all has identical bandwidth but has different centre frequencies.In another execution mode, estimator 102 all has identical bandwidth and centre frequency, but measures separately different signal parameters or tolerance.Can conceive other execution modes, the various combinations of estimator 102 utilized bandwidths, centre frequency and signal parameter or tolerance in these other execution modes.
More specifically, signal metric compare facilities 104 receives the signal metric estimated signal 103 from estimator 102, and in response to the variation in the signal metric estimation occurring in time.In alternate embodiment of the present invention, except receiving the input from one or more estimator 102, signal metric compare facilities 104 can receive input beyond estimator 102, such as receiving from the source that is similar to broadband or signal band signal tolerance estimator, wherein estimated bandwidth is greater than or equal to the bandwidth of input signal 101.Signal metric compare facilities 104 generates Dynamic Multi-Pathing index signal 105, has Dynamic Multi-Pathing impairment in these signal 105 index signals.Dynamic Multi-Pathing index signal 105 can be boolean's (true or false) signal, and this boolean signal instruction exists or do not exist Dynamic Multi-Pathing impairment in signal; Or can be many level digitals or analog signal, the degree of the multipath impairment in amplitude and the signal of this signal be proportional; Or can be some other instruction that is relevant to multipath impairment.Although not shown in Fig. 1, but as example, Dynamic Multi-Pathing index signal 105 can weaken equipment (or other equipment) by the Dynamic Multi-Pathing in receiver and use, to control such as the adaptation of adaptive equalizer or the parameter of tracking velocity.
Fig. 2 show according to one embodiment of the present invention, the further details of signal metric compare facilities 104 in Fig. 1.The execution mode of Fig. 2 is particularly useful in the time there is two narrow band signals tolerance estimator 102, and each narrow band signal tolerance estimator 102 is configured for measures same frequency signal metric or parameter around, and the bandwidth difference for estimating only.In an illustrative embodiments, two narrow band signal tolerance estimators 102 use the filter with different time constant.
In Fig. 2, summation device 203 illustrates to receive two tolerance and estimates input signal 201 and 202, and further illustrates to generate metric difference signal 204.Absolute value equipment 205 receives metric difference signal 204, and generates absolute signal metric difference signal 206.Threshold value compare facilities 207 receives absolute signal metric difference signal 206 and generates Dynamic Multi-Pathing index signal 208.
In operation, equipment 203 is added (or subtracting each other) to generate signal 204 by signal 201 and 202.The absolute value of signal 204 calculates to generate signal 206 by equipment 205, and this signal 206 uses to determine the polarity of signal 206 with respect to predetermined threshold by equipment 207.Also, in an embodiment of the invention, in the time that signal 206 is confirmed as exceeding predetermined threshold, signal 208 is logically in "True" state; And in the time that signal 206 is considered to lower than predetermined threshold, signal 208 is logically in " vacation " state.Identical with signal 105, first rate or the second speed that the "True" of signal 208 and " vacation " state indicate respectively multipath to change.Thus, in the execution mode of Fig. 2, the detection limit of Dynamic Multi-Pathing is in detecting two speed, and this does not cause quick Dynamic Multi-Pathing to detect in the time processing following problem.
Two known problems in dynamic multi-path detection device are that vacation detects and detection speed.False test example is as appeared at following situation: if narrow band signal tolerance estimator 102 (in Fig. 1) is too responsive for noise, if or the threshold value using in threshold value compare facilities 207 (in Fig. 2) too small.A method that reduces false detection probability is to increase time requirement, for example, before concluding Dynamic Multi-Pathing index signal 207, require absolute signal metric difference signal 206 higher than threshold value special time amount.But this has reduced the probability of false detection has also reduced detection speed.
Fig. 3 illustrates the further details of the signal metric compare facilities 104 another execution mode, Fig. 1 according to the present invention.In Fig. 3, signal metric compare facilities 104 is depicted as and comprises summation device 303, absolute value equipment 305, first threshold compare facilities 307, Second Threshold compare facilities 309, time-measurement device 311, the 3rd threshold value comparison signal 314 and logical device 315.Equipment illustrates to generate Dynamic Multi-Pathing index signal 316.
Equipment 303 illustrates to receive the first tolerance and estimates input signal 301 and the second tolerance estimation input signal 302, and these two signals are provided by the signal 103 in Fig. 1.Equipment 303 is added signal 301 and 302 (or subtracting each other) and generates the metric difference signal 304 that serves as the input to equipment 305.Equipment 305 is carried out absolute value operation to generate absolute measure difference signal 306 to signal 304, and this signal provides to equipment 307 and 309 as input.Equipment 307 is signal 306 and first threshold comparison, and to provide comparative result to equipment 311 be first threshold comparison signal 308.Equipment 309 compares signal 306 and Second Threshold, and to provide comparative result to equipment 315 be Second Threshold comparison signal 310.Equipment 311 use signals 308 detect that in multipath the time durations of variation counts.Avoid in this way the vacation in multipath to change, this is because as visible at once, and the variation in multipath is further detected after scheduled time slot.Also, equipment 311 provides relatively time signal 312 of threshold value to equipment 313, its comparison signal 312 and the 3rd threshold value, and provide its comparative result to equipment 315.In this way, because exist (or not existing) multipath to change waits for some time and then carries out another threshold value comparison before in statement, the variation stated is unlikely false statement, this is to have some time because the variation in multipath has been detected as, and is not effectively if changed thus, and this variation can not keep in time.
The execution mode of Fig. 3 exists two or more narrow band signal tolerance estimator (such as estimator 102) in the situation that to be particularly useful, this narrow band signal tolerance estimator can be configured for separately measures same frequency single tolerance around, and wherein each estimator is only different for the bandwidth of estimating.
Although it should be noted that and show two threshold value compare facilitieses (such as equipment 307 and 309), can use this kind equipment of other numbers.Additional threshold compare facilities can produce equalizer adaptation time and improved Dynamic Multi-Pathing distortion tracking faster.
In operation, equipment 303 receives signal 301 and 302, and generates signal 304.Equipment 305 receives signal 304 and generates signal 306.Equipment 307 receives signal 306 and generates signal 308.In an embodiment of the invention, signal 308 in the time that signal 306 exceedes first threshold in logic "True" state.Equipment 309 receives signal 306 and generates signal 310.In an embodiment of the invention, signal 310 in the time that signal 306 exceedes Second Threshold in logic "True", this Second Threshold is greater than first threshold.Use two threshold value compare facilitieses 307 and 309, equipment 311 and the 3rd threshold value compare facilities 313 allow fast detecting to change soon multipath, and permission can error detection not arrived variation in the situation that there is slow variation multipath.At this point, the adaptive equalizer that makes to be coupled to equipment 10 in Fig. 1 is triggered to change multipath and adaptive fast soon in response to existing, and in the time there is the slow multipath changing, enters slow adaptively, reduces thus error level and improves systematic function.
Equipment 311 is depicted as and receives signal 308, and measuring-signal 308 for example generates the time quantum of signal 312 under logic "True" state.In an illustrative embodiments, equipment 311 can be realized by usage counter, this counter increases progressively with fixed rate during in logic "True" state at signal 308, and for example whenever signal 308 is during in logic " vacation " state or after the scheduled time, the value of resetting to " 0 ".
In an exemplary embodiment of the present invention, after certain scheduled time, counter 311 is reset as " 0 ", so that counter 311 is similar to measurement window operation, and the percentage of time that in definite measurement window, state is "True", instead of continuous "True" state.
Equipment 313 is relatively time and the 3rd threshold value of the threshold value of reflection in signal 312 relatively, to generate signal 314.Equipment 315 receives signal 310 and signal 314, and generates signal 316.In an illustrative embodiments, equipment 315 make signal 316 whenever signal 310 in logic "True" state or signal 314 during in logic "True" state in logic "True" state, to indicate multipath to change; Whenever signal 314 and 310 both during all in " vacation " state, equipment 315 makes signal 316 in " vacation " state, does not exist multipath to change to indicate.Although various types of logic states have been discussed at this for accompanying drawing, it should be noted that the state that can expect the other types that join with signal correction discussed herein, and state discussed herein is only as example.
As previously mentioned, the execution mode of Fig. 1 application is digital land TV.In the TV applications of digital land, the A/53 standard of digital land TV signal based on being adopted by Advanced Television Systems Committee (ATSC) broadcasted.In A/53 system, digital television signal comprises the pilot signal that is positioned at preset frequency place (also from band edge genesis 310kHz).In typical receiver, pilot signal by carrier wave demodulation equipment moving to DC.Due to the existence of pilot signal, the signal level near DC after carrier wave demodulation is useful signal metric, parameter or feature.In addition, Dynamic Multi-Pathing detects and can on average realize with long-term DC by comparing short-term.Thus advantageously, after the carrier wave demodulation equipment of ATSC A/53 receiver, realize the equipment 10 of Fig. 1 and whole other execution modes thereof.Refer again to Fig. 1, by the base exemplary application of the present invention of describing for ATSC A/53 receiver.Those skilled in the art are to be understood that, without departing from the scope of the invention, can expect equipment 10 other application for ATSC A/53 receiver, comprise and use narrow band signals tolerance estimator more than two narrow band signals tolerance estimators (such as estimator 102) or still less, and come for signal metric comparison by DC level signal metric and various criterion in addition.
In the exemplary digital land TV applications of execution mode that uses Fig. 1, there are two signal metric estimators 102 (N=2), wherein each measurement is near the signal level of DC.The time constant of two estimators 102 is selected different, and an estimator uses slower estimation, and another estimator use is comparatively fast estimated.Each in two estimators 102 generates tolerance estimated signal 103, and this signal 103 obtains from the estimation of average signal level.Signal metric compare facilities 104 receives two signal metrics and estimates 103, and estimates over time in response to described signal metric.Described signal metric compare facilities 104 generates Dynamic Multi-Pathing index signal 105, the existence of Dynamic Multi-Pathing impairment in these signal 105 index signals.The digital land TV applications of equipment 10 is discussed with further reference to Fig. 4 now.
Referring now to Fig. 4,, according to an embodiment of the invention, the high level block diagram of an example application of equipment 10 has been shown in digital land television receiver 400.Receiver 400 illustrates to comprise dynamic multi-path detection device 409, and this equipment 409 is similar to the equipment 10 of Fig. 1 and whole other checkout equipments of the various execution modes of the present invention.
As example, receiver 400 is for receiving according to the digital land TV signal of Advanced Television Systems Committee (ATSC) standard A/53 broadcast.Show demodulator integrated circuit (IC) 402 that comprise, that be coupled to tuner 401, received RF (RF) input in receiver 400.
According to an embodiment of the invention, IC 402 illustrates to comprise analog digital (A/D) transducer 403, base band mixer 404, carrier recovery circuit 405, timing recovery apparatus 406, adaptive equalizer 407, decoder 408 and according to dynamic multi-path detection device 409 of the present invention.IC 402 illustrates to be coupled to tuner 401, and it provides intermediate frequency (IF) signal to IC 402, and inputs as it from communication channel received RF (RF) signal.A/D converter 403 illustrates to be coupled to frequency mixer 404, and this frequency mixer is depicted as and is coupled to carrier recovery circuit 405.Frequency mixer 404 and carrier recovery circuit 405 are depicted as and are coupled to timing recovery apparatus 406, and this timing recovery apparatus 406 is then depicted as and is coupled to adaptive equalizer 407.Adaptive equalizer 407 is depicted as and is coupled to decoder 408, and the latter provides output transport stream (TS).Dynamic multi-path detection device 409 be depicted as be coupled to timing recovery apparatus 406 and adaptive equalizer 407 both.
Still with reference to figure 4, tuner 401 illustrates to receive RF signal for this RF signal being downconverted to intermediate frequency (IF) signal, and this IF signal serves as the input of IC 402, and illustrates to be coupled to the A/D converter 403 of IC 402.In other execution modes of the present invention, IC 402 needs not to be the chip, semiconductor or the integrated circuit that are relevant to Fig. 4 and illustrate and discuss.On the contrary, IC 402 can comprise the part of a more than IC or system or realize with software.
In operation, IC 402 processes IF signal to produce digital video transport stream (TS).A/D converter 403 with asynchronous in the speed sampled analog IF of distance transmitter signal (this distance transmitter is not shown in Fig. 4), to produce digital IF signal and this numeral IF signal is provided to base band mixer 404.Digital IF signal is down-converted to base band by base band mixer 404, and the baseband signal through down-conversion is provided to timing recovery apparatus 406.Base band mixer 404 is synchronized to IF carrier wave by carrier recovery circuit 405.Timing recovery apparatus 406, to be synchronized with the speed resampling of distance transmitter through the baseband signal of down-conversion, upgrades its resampling speed automatically to keep synchronous.Adaptive equalizer 407 is removed multipath distortion and other forms of intersymbol interference (ISI) from signal.Decoder 408 is carried out grid (trellis) decoding, deinterleaving, forward error correction, solution randomization and other functions to produce digital video TS.
Equipment 409 had previously been discussed the pattern consistent with accompanying drawing to meet at this, received the output signal of timing recovery apparatus 406, and in response to the Dynamic Multi-Pathing distortion in received signal.Equipment 409 provides Dynamic Multi-Pathing detection signal to adaptive equalizer 407, makes adaptive equalizer 407 adjust its adaptation rate according to the multipath distortion rate of change in signal.Should be appreciated that and can use the configuration of other receivers IC 402 is interior, comprise that A/D sampling rate is wherein synchronized with those of distance transmitter.It is also understood that and can comprise other processing blocks shown in Fig. 4 IC 402 is interior, such as, but not limited to automatic gain control (AGC), digital filter and various synchronous circuit.It is also understood that equipment 409 can receive other signals beyond the output of timing recovery apparatus 406 as input, such as the signal of other circuit evolvings by IC 402.Foregoing example is the output of base band mixer 404, and the output of the output of base band mixer 404 instead of timing recovery apparatus 406 is provided to equipment 409 as input thus.It is also understood that embodiments of the present invention are applicable to the communication system of other types and Fig. 4 other receivers configurations beyond illustrating.
Fig. 5, Fig. 6 and Fig. 7 illustrate the diagram of the behavior of the Dynamic Multi-Pathing detection signal in the example implementation of ATSC A/53 receiver (such as the receiver 400 of Fig. 4).In this example, Dynamic Multi-Pathing detector is used for utilizing two signal metric estimators.All DC level of estimated signal of two signal metric estimators.Two signal metric estimators all comprise polar digital infinite impulse response (IIR) filter, follow thereafter accumulation and empty circuit.Two iir filters can be described by following discrete time equation, wherein x (n) is the input signal at time index n place, dc (n) is at the signal DC of the estimation at time index n place level, and y (n) is the output signal at time index n place, remove at DC place or near the composition of DC:
Y (n)=x (n)-dc (n-1) equation 1
Dc (n)=y (n)/8192 equation 2
Filter is with the ATSC A/53 character rate operation of about 10.76 hundred ten thousand symbol/seconds.Accumulate and empty average dc (n) value of N symbol of circuit calculating, wherein for a signal metric estimator (" soon " estimator) N=4096 (2
12), and for another (" slowly " estimator) N=2,097,152 (2
21).
In this example, use according to the signal metric compare facilities of Fig. 3 execution mode.Fig. 5 estimates 301 and 302 diagrams in time for two DC of the ATSC signal of institute's emulation, this ATSC signal has the emulation multipath impairment that comprises single echo, all has 5 microsecond delays, the 5dB that decays, has 10Hz Doppler shift with respect to main signal.The x axle of Fig. 5 is thereby that standardized nominal A/53 pilot tone level is 1.0.Fig. 6 is the diagram of absolute DC difference signal 306 with respect to the threshold value (about 0.056 and 0.224) being used by two threshold value compare facilitieses 307 and 309.In this example, time-measurement device is counter, if a DC estimate on first threshold, this counter every 4096 (2
12) individual symbol increases progressively.Every 2,097,152 (2
21) individual symbol, counter is latching to the relatively time 312 of threshold value, and being then reset is 0.Fig. 7 is threshold value comparison time 312 and the threshold value (128) that used by the 3rd threshold value compare facilities 313.In this execution mode of the present invention, the output of dynamic multi-path detection device is Boolean logic signal, just (is determined by three threshold values) when changing faster than special speed when multipath, and this is output as very.For above-mentioned simulate signal, it is true that output is always, because threshold value compares the time 312 always higher than threshold value.
Although with the formal description of specific implementations the present invention, of the present invention alternative and amendment is easily shown in for those skilled in the art beyond doubt.Appended claims is intended to be interpreted as and covers whole these type of the alternative and amendments that drop in true spirit of the present invention and scope thus.
Claims (10)
1. a dynamic multi-path detection device, comprising:
At least one narrow band signal tolerance estimator, in response to the input signal with input signal bandwidth, each measurement at least one estimator is less than the special characteristic of the described input signal in the bandwidth of described input signal bandwidth, and can operate to generate parameter Estimation signal; And
Signal metric compare facilities, in response to parameter Estimation signal described in one or more and can operate to generate Dynamic Multi-Pathing index signal for detect Dynamic Multi-Pathing, wherein said signal metric compare facilities comprises:
Summation device, for suing for peace to described parameter Estimation signal and can operating to generate metric difference signal;
Absolute value equipment, in response to described metric difference signal and can operate to generate absolute measure difference signal; And
First threshold compare facilities and Second Threshold compare facilities, described first threshold compare facilities and described Second Threshold compare facilities are all coupled to receive described absolute measure difference signal, described first threshold compare facilities can operate to generate first threshold comparison signal, and described Second Threshold compare facilities can operate to generate Second Threshold comparison signal, and described signal metric compare facilities further comprises counter, described counter is in response to described Second Threshold comparison signal, and can operate to generate relatively time signal of threshold value, and
The 3rd threshold value compare facilities, coupling is compared time signal to receive described threshold value, and can operate to generate the 3rd threshold value comparison signal.
2. dynamic multi-path detection device according to claim 1, wherein said Dynamic Multi-Pathing index signal, for changing and carry out adaptive multipath tracking velocity according to multipath, makes to weaken Dynamic Multi-Pathing and improve systematic function thus.
3. dynamic multi-path detection device according to claim 1, wherein said signal metric compare facilities further comprises logical device, it is in response to described Second Threshold comparison signal and described the 3rd threshold value comparison signal, and can operate to generate described Dynamic Multi-Pathing index signal.
4. dynamic multi-path detection device according to claim 1, wherein said dynamic multi-path detection device in response to described parameter Estimation signal over time.
5. dynamic multi-path detection device according to claim 1, wherein said input signal is the output of carrier recovery circuit.
6. a dynamic multi-path detection device, comprising:
Estimator means, for measuring the special characteristic of input signal of reception, the residing bandwidth of input signal bandwidth of the input signal of described reception is less than input signal bandwidth, and can operate to generate parameter Estimation signal; And
Signal metric compare facilities, in response to described signal parameter estimated signal and can operate to generate the Dynamic Multi-Pathing index signal for detection of Dynamic Multi-Pathing, wherein said signal metric compare facilities comprises:
Summation device, for suing for peace to described parameter Estimation signal and can operating to generate metric difference signal;
Absolute value equipment, in response to described metric difference signal and can operate to generate absolute measure difference signal; And
First threshold compare facilities and Second Threshold compare facilities, described first threshold compare facilities and described Second Threshold compare facilities are all coupled to receive described absolute measure difference signal, described first threshold compare facilities can operate to generate first threshold comparison signal, and described Second Threshold compare facilities can operate to generate Second Threshold comparison signal, and described signal metric compare facilities further comprises counter, described counter is in response to described first threshold comparison signal, and can operate to generate relatively time signal of threshold value, and
The 3rd threshold value compare facilities, coupling is compared time signal to receive described threshold value, and can operate to generate the 3rd threshold value comparison signal.
7. dynamic multi-path detection device according to claim 6, wherein said Dynamic Multi-Pathing index signal, for changing and carry out adaptive multipath tracking velocity according to multipath, makes to weaken Dynamic Multi-Pathing and improve systematic function thus.
8. dynamic multi-path detection device according to claim 6, wherein said signal metric compare facilities further comprises logical device, it is in response to described Second Threshold comparison signal and described the 3rd threshold value comparison signal, and can operate to generate described Dynamic Multi-Pathing index signal.
9. dynamic multi-path detection device according to claim 6, wherein said dynamic multi-path detection device in response to described parameter Estimation signal over time.
10. dynamic multi-path detection device according to claim 6, wherein said input signal is the output of carrier recovery circuit.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PCT/US2008/076439 WO2010030294A1 (en) | 2008-09-15 | 2008-09-15 | Dynamic multi-path detection device and method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN102224710A CN102224710A (en) | 2011-10-19 |
| CN102224710B true CN102224710B (en) | 2014-08-20 |
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| CN200880131752.4A Expired - Fee Related CN102224710B (en) | 2008-09-15 | 2008-09-15 | Dynamic multi-path detection device and method |
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| WO (1) | WO2010030294A1 (en) |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1147742A (en) * | 1995-09-23 | 1997-04-16 | 三星电子株式会社 | Circuit for detecting completion of carrier recovery and symbol timing recovery, method thereof, and high definition television adapting the same |
| US6249757B1 (en) * | 1999-02-16 | 2001-06-19 | 3Com Corporation | System for detecting voice activity |
| CN1127813C (en) * | 1996-12-20 | 2003-11-12 | 艾利森电话股份有限公司 | Double talk and echo path change detection in telephony system |
| CN1677877A (en) * | 2004-03-31 | 2005-10-05 | 清华大学 | Assembly structure of time-domain synchronous orthogonal frequency-division multiplex receiver |
| US7181184B1 (en) * | 2000-08-22 | 2007-02-20 | Lucent Technologies Inc. | Band edge amplitude reduction system and method |
| US7343143B2 (en) * | 2003-06-10 | 2008-03-11 | Alpine Electronics, Inc. | Radio receiver with operation state setting unit |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8964912B2 (en) * | 2005-05-31 | 2015-02-24 | Telefonaktiebolaget Lm Ericsson (Publ) | Adaptive timing recovery via generalized RAKE reception |
| US8077821B2 (en) * | 2006-09-25 | 2011-12-13 | Zoran Corporation | Optimized timing recovery device and method using linear predictor |
-
2008
- 2008-09-15 CN CN200880131752.4A patent/CN102224710B/en not_active Expired - Fee Related
- 2008-09-15 WO PCT/US2008/076439 patent/WO2010030294A1/en active Application Filing
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1147742A (en) * | 1995-09-23 | 1997-04-16 | 三星电子株式会社 | Circuit for detecting completion of carrier recovery and symbol timing recovery, method thereof, and high definition television adapting the same |
| CN1127813C (en) * | 1996-12-20 | 2003-11-12 | 艾利森电话股份有限公司 | Double talk and echo path change detection in telephony system |
| US6249757B1 (en) * | 1999-02-16 | 2001-06-19 | 3Com Corporation | System for detecting voice activity |
| US7181184B1 (en) * | 2000-08-22 | 2007-02-20 | Lucent Technologies Inc. | Band edge amplitude reduction system and method |
| US7343143B2 (en) * | 2003-06-10 | 2008-03-11 | Alpine Electronics, Inc. | Radio receiver with operation state setting unit |
| CN1677877A (en) * | 2004-03-31 | 2005-10-05 | 清华大学 | Assembly structure of time-domain synchronous orthogonal frequency-division multiplex receiver |
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| Publication number | Publication date |
|---|---|
| CN102224710A (en) | 2011-10-19 |
| WO2010030294A1 (en) | 2010-03-18 |
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