CN103905800A - Rapid blind-searching method insensitive to adjacent channel interference - Google Patents
Rapid blind-searching method insensitive to adjacent channel interference Download PDFInfo
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Abstract
The invention brings forward a rapid blind-searching method insensitive to adjacent channel interference. A parameter index is firstly initialized so that a block of frequency spectrum is captured. Then existence of a signal with high frequency spectrum amplitude in the captured block of frequency spectrum and whether frequency distance between the signal with high frequency spectrum amplitude and a starting point index is greater than a first frequency distance threshold value are judged. If the judgment result is no, a full frequency range channel is judged. If the judgment result is yes, signal detection and parameter capturing are performed, and frequency of the starting point index is arranged to be a second crossover point. After that, a difference value of frequency of the starting point index and frequency of a terminal point index is less than a second frequency distance threshold value is judged. If the judgment result is no, a carrier frequency index is arranged so that the next block of frequency spectrum is captured by a tuner. When a situation of an idle channel or a partial frequency range channel occurs, frequency of the starting point index and the carrier frequency index are also arranged so that the next block of frequency spectrum is captured by the tuner.
Description
Technical field
The present invention relates to the technical field of satellite digital TV transmission, espespecially one disturbs insensitive Fast Blind to sweep (Blind Scan) method to adjacent channel, is applicable in DVB-S or DVB-S2 system.
Background technology
Digital Television is wanted can be flourish, and top priority is set up digital platform exactly.What digital platform referred to is not, and simple hardware device similarly is box on machine (Set-Top Box), further comprises digital channel and digital content.
The main specifications of current global Digital Television can be divided into several large fields, comprise taking American market as main ATSC(Advanced Television Systems Committee) system, European market is main DVB(Digital Video Broadcasting) system, and market, China's Mainland is main DTMB(DigitalTerrestrial Multimedia Broadcasting) system, also have taking Japanese market as main ISDB-T system etc.Wherein, DVB system more can be subdivided into DVB-C/C2(Cable), DVB-S/S2(Satellite) and DVB-T/T2(Terrestrial).So-called DVB-C/C2 refers to cable TV standard, and DVB-S/S2 refers to satellite television standard, and DVB-T/T2 refers to the radiovision standard on ground.
By the satellite in more than 32000 kilometers high-altitude, CMTS dealer can, by DVB-S/S2 signal, be sent to the satellite antenna on household's building, utilizes kind of a transmission means, carrys out transmitting MPEG 2 data.Because the position (carrier frequency) of each channel on frequency spectrum and symbol rate (frequency range) be not all by clear and definite specification, receiving terminal can be selected prestore position (carrier frequency) and the symbol rate (frequency range) thereof of all known channels, so that can high-speed receiving program.
But, in the time of the carrier frequency of channel and symbol rate change, the above-mentioned mode that prestores just possibly cannot correctly receive the channel of new settings more.Therefore, in the application such such as satellite television (DVB-S/S2) receiver, total blindness's channel search is a necessary and indispensable function, it provides a kind of easy operator scheme, can make user not need to know in advance the information of received satellite channel and can automatically all channel parameters be scanned out.Wherein, sweep speed and correctness are to weigh one of blind most important index of sweeping algorithm performance, and also, quick and correct search can be saved user's stand-by period.
Fig. 1 is the calcspar of existing receiving terminal.Its operation principle is first to set a carrier frequency (Carrier Frequency to tuner (tuner) 12 by control device 11, CF), then start bank of filters (filter bank) (not shown) and timing recovery loop (timing recovery loop) (not shown) in base band demodulating chip 13, start computing from minimum symbol rate (SR), if timing loop cannot be restrained, strengthen symbol rate.The never convergence if symbol rate exceedes possible maximum, representing does not have signal on this frequency.So next just need to upgrade the carrier frequency of tuner, on original basis, add a step-length (Step), repeat above step until timing loop is restrained, and then detect signal and parameter thereof.
The shortcoming of this method is that search speed is very slow, because the possible range of symbol rates using in DVB-S/S2 system is very large, from 1M baud to 45M bauds all likely.Moreover the shared frequency spectrum of satellite-signal is also very wide, has 950MHz ~ 2150MHz at the input range of Ku or C-band tuner.The a lot of possibilities of both combination results, blind sweeping will all be searched for these possibilities one time, by search time very long cost.In addition, the carrier frequency that changes tuner 12 is a process consuming time, and stepping carrier frequency frequently can obviously extend search time.In addition, the stepping resolution of tuner is quite limited, and its representative value only has hundreds of MHz conventionally, is therefore inaccurate with detected carrier frequency only according to the frequency that changes tuner.Meanwhile, the convergence of timing loop is also very slow, utilizes timing loop to carry out back ring type ground search symbol rate quite slow and time-consuming.
About blind another problem of sweeping, be the sensitiveness that will reduce adjacent channel interference strength.In frequency spectrum, each adjacent signals power differs greatly, and still has the possibility of being disturbed by other system or strong signal source.Have only and reduce the sensitiveness that adjacent channel is disturbed, just can reach quick and correct channel search target." for the blind system and method for sweeping of DVB-S system " (open case of the corresponding U.S. 2011/0135042) of China's number of patent application 98141858 is the relevant case that the inventor applies for before, although this invention improves and proposed the efficient blind method of sweeping, but still cannot bear the strong and weak difference of violent adjacent signal.
Therefore, in prior art, still have it to be improved for the blind system and method for sweeping of DVB-S/S2 system.
Summary of the invention
Object of the present invention is mainly to provide one to disturb insensitive Fast Blind to sweep method to adjacent channel.Be applicable in DVB-S or DVB-S2 system.Can prevent the interference to the little signal of contiguous spectral amplitude of signal that spectral amplitude is large, thus can correctly detect signal weak in DVB-S/S2 system, and can accelerate the speed of the signal scanning in DVB-S/S2 system.
According to object of the present invention, the present invention proposes a kind of Fast Blind for DVB-S/S2 system and sweeps method, and it comprises step: (A) initiation parameter index; (B) set a tuner in order to capture a block frequency spectrum; (C) judge whether to have in this block frequency spectrum signal that signal that a spectral amplitude is large and this spectral amplitude are large and the frequency distance of a starting point index to be greater than a first frequency distance threshold value (BW_th1); (D) in this block frequency spectrum, do not have signal that signal that a spectral amplitude is large or this spectral amplitude are large and the frequency distance of a starting point index to be greater than this first frequency distance threshold value (BW_th1) if judge, then determine whether a full frequency band passage (full-bandchannel); (E) if full frequency band passage (full-band channel) carries out input and parameter acquisition; (F) frequency of setting this starting point index (SP) is one second crossover point (CP2); (G) whether the difference that judges the frequency of this starting point index (SP) and the frequency of a terminal index (EP) is less than a second frequency distance threshold value (BW_th2); (H) if judge the non-second frequency distance threshold value (BW_th2) that is less than of the difference of the frequency of this starting point index (SP) and the frequency of a terminal index (EP), set a carrier frequency index (CF), and execution step (B) is to be captured next block frequency spectrum by this tuner.While meeting sky passage or band segment passage, also set respectively frequency and the carrier frequency index (CF) of starting point index, to be captured next block frequency spectrum by tuner.So complete Fast Blind and sweep method.
Brief description of the drawings
Fig. 1 is the calcspar of existing receiving terminal.
Fig. 2 is that the present invention is a kind of for DVB-S/S2 system blind system block diagrams of sweeping method fast.
Fig. 3 is that the present invention is a kind of for the DVB-S/S2 system blind flow chart of sweeping method fast.
Fig. 4 is the schematic diagram of one embodiment of the invention, (S1): (| CP1-SP|>BW_th1) & (M>8m) → EP=CP1.
Fig. 5 is the schematic diagram of one embodiment of the invention, (S2): SP<CP1<CP2<EP → detection and parameter acquisition.
Fig. 6 is the schematic diagram of one embodiment of the invention, (PT): capture next block frequency spectrum by tuner.
Fig. 7 is the schematic diagram of one embodiment of the invention, (S1): (| CP1-SP|>BW_th1) & (M>8m) → EP=CP1.
Fig. 8 is the schematic diagram of one embodiment of the invention, (PT): capture next block frequency spectrum by tuner.
Fig. 9 is the schematic diagram of one embodiment of the invention, (PT): capture next block frequency spectrum by tuner.
Figure 10 is the schematic diagram of one embodiment of the invention, (S2): SP<CP1<CP2<EP → detection and parameter acquisition.
Figure 11 is the schematic diagram of one embodiment of the invention, (PT): capture next block frequency spectrum by tuner.
Figure 12 is the schematic diagram of one embodiment of the invention, (S3): CP2>EP → SP=CP1.
Figure 13 is the schematic diagram of one embodiment of the invention, (PT): capture next block frequency spectrum by tuner.
Figure 14 is the schematic diagram of one embodiment of the invention, (S2): SP<CP1<CP2<EP → detection and parameter acquisition.
Figure 15 is the schematic diagram of one embodiment of the invention, (PT): capture next block frequency spectrum by tuner.
Figure 16 is the schematic diagram of one embodiment of the invention, (S4): (CP1=SP_org) and(CP2=EP_org) → SP=EP.
Figure 17 is the schematic diagram of one embodiment of the invention, (PT): capture next block frequency spectrum by tuner.
Figure 18 is the schematic diagram of one embodiment of the invention, (S1): (| CP1-SP|>BW_th1) & (M>8m) → EP=CP1.
Figure 19 is the schematic diagram of one embodiment of the invention, (S2): SP<CP1<CP2<EP → detection and parameter acquisition.
Figure 20 is the schematic diagram of one embodiment of the invention, (S5): | SP-EP|<BW_th2 → SP=EP.
Figure 21 is the schematic diagram of one embodiment of the invention, (PT): capture next block frequency spectrum by tuner.
Figure 22 is the schematic diagram of one embodiment of the invention, (S2): SP<CP1<CP2<EP → detection and parameter acquisition.
Figure 23 is the schematic diagram of one embodiment of the invention, (S6): | CF>CF_max| → EP (end of program).
Figure 24 is that the present invention schemes compared with the prior art.
Main element symbol description:
Base band demodulating chip 13
The blind system 200 of sweeping
Tuner (tuner) 205 analog-to-digital converters 210
Tuner automatic gain control equipment 215
Digital AGC 230 digital matched filters 235
Frequency spectrum calculation element 240 frequency spectrum parameter capture devices 245
Step (A) ~ step (O).
Embodiment
Fig. 2 is that a kind of Fast Blind for DVB-S/S2 system of the present invention is swept method system 200 calcspars, comprise: a tuner (tuner) 205, one analog-to-digital converter (Analog to digital converter, ADC) 210, one tuner automatic gain control equipment (AGC) 215, one digital mixer (Digital Mixer) 220, one interpolation device (Interpolation Device) 225, one digital AGC (DAGC) 230, one digital matched filter (Digital Matched Filter, DMF) 235, one frequency spectrum calculation element 240, one frequency spectrum parameter capture device 245, an and control device 250.
" for the blind system and method for sweeping of DVB-S system " (open case of the corresponding U.S. 2011/0135042) of China's number of patent application 98141858 is the relevant case that inventor applies for.The present invention is the blind method of sweeping of improving in this patent application case, and the present invention uses identical hardware element with this patent application case, therefore aforementioned components of the present invention is found in China's number of patent application 98141858 that inventor applies for, does not repeat them here.
Fig. 3 is that a kind of Fast Blind for DVB-S/S2 system of the present invention is swept the flow chart of method.First in step (A), initiation parameter index.This parameter index comprises this starting point index (SP), this terminal index (EP), a carrier frequency index (CF), a starting point original index (SP_org), a terminal original index (EP_org).
Frequency band in DVB-S/S2 system is 950MHz ~ 2150MHz.Each frequency range is 1MHz ~ 45MHz.Therefore suppose that required minimum sampling rate is 90MHz.In the time of initialization, numeral mixer (Digital Mixer) 220 and interpolation device (Interpolation Device) 225 neither move, and only allow signal pass through, wherein this starting point index (SP) and this starting point original index (SP_org) can be made as to 950MHz, this terminal index (EP) and this terminal original index (EP_org) are made as 995MHz(950+45), and this carrier frequency index (CF) is made as 972.5MHz(950+45/2).
With regard to physical significance, now at the digital signal frequency spectrum of interpolation device (Interpolation Device) 225 outputs, its direct current composition corresponds to the carrier frequency index (CF) that tuner (tuner) 205 sets, and poor (being also the poor of EP_org and SP_org) of terminal index (EP) and this starting point index (SP) is the half of sampling rate.And as digital mixer and interpolation device (Digital Mixer) 220(Interpolation Device) 225 whens action, just can adjust equivalently according to need these two values in order to detection signal.This is that the exposure of those skilled in the art based on the present invention and prior art can complete, and repeats no more.
In step (B), set a tuner 205 in order to capture a block frequency spectrum.
In step (C), judge whether to have in this block frequency spectrum signal that signal that a spectral amplitude is large and this spectral amplitude are large and the frequency distance of a starting point index (SP) to be greater than a first frequency distance threshold value (BW_th1).Also be that the available mathematical formulae of step (C) is expressed as: (| CP1-SP|>BW_th1) & (M>8m).
In step (C), for detection of the large signal of spectral amplitude, it can use mathematical formulae to represent: M>8m, and central M is peak in this block frequency spectrum, m is minimum in this block frequency spectrum.Also, in step (C), detect whether the octuple that signal peak (M) that spectral amplitude is large is minimum (m) occurs in this block frequency spectrum.
The frequency distance of the signal that this spectral amplitude is large and a starting point index is greater than a first frequency distance threshold value (BW_th1) and can uses mathematical formulae to represent: (| CP1-SP|>BW_th1).In the middle of CP1 for the frequency that is greater than for the first time an amplitude threshold (amp_th) in this block frequency spectrum and locates be this first crossover point (CP1), SP is this starting point index (SP), BW_th1 is this frequency distance threshold value (BW_th1).
As shown in Figure 4, between this starting point index (SP) and this terminal index (EP), there are three signals, are respectively signal 1, signal 2 and signal 3.Wherein, signal 3 is than signal 1 and signal 2, and signal 3 is the signal that a spectral amplitude is large, therefore peak M is the amplitude of signal 3 in this block frequency spectrum.In the time that signal amplitude is little, be that signal whichever is noise owing to cannot distinguishing whichever, therefore in this block frequency spectrum minimum m be noise (noisefloor).
Can calculate this amplitude threshold (amp_th) by peak M and minimum m, wherein, this amplitude threshold (amp_th) is:
amp_th=(M-m)×η+m，
In the middle of, M is peak (M) in this block frequency spectrum, and m is minimum (m) in this block frequency spectrum, and η is an adjustment factor.Preferred example is adjusted factor η and be can be 0.3.
As shown in Figure 4, the frequency that is less than for the first time this amplitude threshold (amp_th) in this block frequency spectrum is this second crossover point (CP2).
In this block frequency spectrum, do not have signal that signal that a spectral amplitude is large or this spectral amplitude are large and the frequency distance of a starting point index (SP) to be greater than this first frequency distance threshold value (BW_th1) if judge, then in step (D), determine whether a full frequency band passage (full-band channel).
In step (D), full frequency band passage (full-band channel) refers to that the frequency of this terminal index (EP) is greater than the frequency of this second crossover point (CP2), the frequency of this second crossover point (CP2) is greater than the frequency of this first crossover point (CP1), the frequency of this first crossover point (CP1) is greater than the frequency of this starting point index (SP), is also that the available mathematical formulae of step (D) is expressed as SP<CP1<CP2<EP.
In step (E), if full frequency band passage (full-band channel) carries out input and parameter acquisition.
In step (F), the frequency of setting this starting point index (SP) is one second crossover point (CP2).The available mathematical formulae of step (F) is expressed as SP=CP2.
In step (G), judge whether the difference of the frequency of this starting point index (SP) and the frequency of a terminal index (EP) is less than a second frequency distance threshold value (BW_th2).The available mathematical formulae of step (G) represents: | SP-EP|<BW_th2.
In step (H), when judging the non-second frequency distance threshold value (BW th2) that is less than of difference of the frequency of this starting point index (SP) and the frequency of a terminal index (EP) in step (G), set this carrier frequency index (CF), and execution step (N).
In step (N), judge whether been scanned of a search area frequency spectrum, if so, finish this blind method of sweeping, if not, in step (O), set this starting point index (SP), this terminal index (EP).Perform step again (B), to be captured next block frequency spectrum by this tuner.
In step (I), have in this block frequency spectrum signal that a spectral amplitude is large and the large signal of this spectral amplitude and the frequency distance of a starting point index be greater than this frequency distance threshold value when judging in step (C), the frequency of setting this terminal index (EP) is one first crossover point (CP1).The available mathematical formulae of step (I) represents: EP=CP1.
In step (J), judge in the step (D) non-ly during as full frequency band passage (full-band channel), then determine whether passage (empty channel).Step (J) hollow channel (empty channel) refers to that the frequency of this first crossover point (CP1) equals the frequency of this starting point original index (SP_org), and the frequency of this second crossover point (CP2) equals the frequency of this terminal original index (EP_org).The available mathematical formulae of step (J) represents: (CP1=SP_org) & (CP2=EP_org)
In step (K), when being judged to be sky passage (empty channel) in step (J), set the frequency of this starting point index (SP) for the frequency of this terminal index (EP).The available mathematical formulae of step (K) represents: SP=EP.
In step (L), be empty passage (empty_channel) when judging non-in step (J), then determine whether a part of frequency range passage (partial-band channel).Wherein, in step (L), band segment passage (partial-band channel) refers to that the frequency of this second crossover point (CP2) is greater than the frequency of this terminal index (EP).The available mathematical formulae of step (L) represents: (CP2>EP).
In step (M), when being judged to be band segment passage (partial-band channel) in step (L), the frequency of setting this starting point index (SP) is one first crossover point (CP1).The available mathematical formulae of step (M) represents: SP=CP1.When judging in step (L) that non-is band segment passage (partial-band channel), resumes step (B).
In step (N), judge whether been scanned of a search area frequency spectrum, if so, finish this blind method of sweeping.The available mathematical formulae of step (N) represents: CF>CF_max, in the middle of, because the frequency band in DVB-S/S2 system is 950MHz ~ 2150MHz, CF_max can be redefined for 2150MHz.In other embodiments, in order to detect more signal, CF_max can be redefined for 2172.5MHz(2150+22.5).
If in step (N), judge on this search area frequency spectrum to be been scanned, in step (O), set this starting point index (SP), this terminal index (EP), then perform step (B).The available mathematical formulae of step (O) represents: SP=SP_org, EP=EP_org.
When the difference of judging the frequency of this starting point index (SP) and the frequency of this terminal index (EP) in step (G) is less than this second frequency distance threshold value (BW_th2), execution step (K).
Fig. 4 to Figure 23 is the schematic diagram of one embodiment of the invention.Please coordinate the flow chart of Fig. 3.As shown in Figure 4, signal 3 is the signal that a spectral amplitude is large, easily signal 1 and signal 2 is masked.In prior art, normal because of the large signal of spectral amplitude, and signal 1 and signal 2 cannot correctly be detected.
Therefore peak M is the amplitude of signal 3 in this block frequency spectrum.In the time that signal amplitude is little, be that signal whichever is noise owing to cannot distinguishing whichever, therefore in this block frequency spectrum minimum m be noise (noise floor).
The signal 3 large due to spectral amplitude exists, therefore this amplitude threshold (amp_th) can be drawn high, this first crossover point (CP1) and this second crossover point (CP2) can be crossing with signal 3.At scanned frequency spectrum of the left side frequency spectrum designation of this starting point index (SP), the present invention scans the right frequency spectrum of this starting point index (SP) to the frequency spectrum of this terminal index (EP).
As shown at Fig. 4 to Figure 23, two round dots crossing with this amplitude threshold (amp_th), the round dot on the left side is this first crossover point (CP1), the round dot on the right is the second crossover point (CP2).
As shown in Figure 4, this first crossover point (CP1) from this starting point index (SP) too away from, owing to there being the signal 3 that spectral amplitude is large to exist, the present invention wishes the frequency spectrum between this starting point index (SP) and this first crossover point (CP1) to scan, but not directly neglect, therefore in step (I), the frequency of setting this terminal index (EP) for this first crossover point (CP1) (EP=CP1).
Have one to be false when the judgment formula in step (C) (| CP1-SP|>BW_th1) or (M>8m), execution step (D).As shown in Figure 5, M is not greater than 8m, now the frequency spectrum between this starting point index (SP) and this terminal index (EP) does not have the signal that spectral amplitude is large, simultaneously, judgment formula SP<CP1<CP2<EP also sets up, the frequency spectrum being illustrated between this starting point index (SP) and this terminal index (EP) has full frequency band passage (full-band channel), and therefore execution step (E) is carried out input and parameter acquisition.
As shown in Figure 6, when after execution of step (E), represent that signal 1 is detected and capture parameter, set this tuner 205 in order to capture the correlation step such as next block frequency spectrum (Programming Tunner, PT) therefore carry out.Therefore in step (F), the frequency of setting this starting point index (SP) is one second crossover point (CP2).The correlation technique of the input in step (E) and parameter acquisition is found in the open case of the corresponding U.S. 2011/0135042 of China number of patent application 98141858(that inventor applies for) in.
In step (G), in the time that the difference of the frequency of this starting point index (SP) and the frequency of this terminal index (EP) is less than a second frequency distance threshold value (BW_th2), represent that the frequency spectrum between frequency and this terminal index (EP) of this starting point index (SP) is too little, may there is no signal, can directly skip over the frequency between frequency and this terminal index (EP) of this starting point index (SP), so execution step (K).As shown in Figure 6, the frequency spectrum between the frequency of this starting point index (SP) and this terminal index (EP) can too little (not being greater than BW_th2), and the signal that expressed possibility exists, therefore execution step (H), setting carrier frequency index (CF) is CF+SP-SP_org.
In step (N), judge whether been scanned of a search area frequency spectrum, when been scanned (CF>CF_max is false) not yet, execution step (O), setting this starting point index (SP) is that SP_org, this terminal index (EP) are EP_org, and execution step (B) is to be captured next block frequency spectrum, as shown in Figure 7 by this tuner.
In Fig. 8, due to the frequency spectrum between this starting point index (SP) and this terminal index (EP), there is the signal 3 that spectral amplitude is large, thus execution step (I), taking the frequency of setting this terminal index (EP) as this first crossover point (CP1).
Afterwards, via step (D), step (E), signal 2 is detected and acquisition parameter.As shown in Figure 9, therefore in step (F), the frequency of setting this starting point index (SP) is one second crossover point (CP2).As shown in Figure 9, frequency spectrum between the frequency of this starting point index (SP) and this terminal index (EP) can too little (not being greater than BW_th2), the signal that expressed possibility exists, thus perform step (H), step (N), step (O), and capture next block frequency spectrum.
As shown in figure 10, the frequency spectrum between this starting point index (SP) and this first crossover point (CP1) is too not large, therefore judgment formula in step (C) (| CP1-SP|>BW_th1) be false, execution step (D).Simultaneously, judgment formula SP<CP1<CP2<EP in step (D) also sets up, the frequency spectrum being illustrated between this starting point index (SP) and this terminal index (EP) has full frequency band passage (full-band channel), therefore execution step (E), carry out that signal 3 detects and parameter acquisition, and be this second crossover point (CP2) by the frequency setting of this starting point index (SP), as shown in figure 11.Due to the non-second frequency distance threshold value (BW_th2) that is less than of difference of the frequency of this starting point index (SP) and the frequency of this terminal index (EP), therefore execution step (H), step (N), step (O), to capture next block frequency spectrum, as shown in figure 12.
As shown in figure 12, after execution step (C), because CP2 is greater than EP, therefore the judgement formula SP<CP1<CP2<EP in step (D) is also false, represent in block frequency spectrum, be not full frequency band passage (full-bandchannel), and may be empty passage (empty channel), therefore judge CP1=SP_org and CP2=EP_org again in step (J).As shown in figure 12, and be false, so execution step (L).
In step (L), judge whether CP2 is greater than EP.Because CP2 is greater than EP, therefore execution step (M), taking by the frequency setting of this starting point index (SP) as this first crossover point (CP1), as shown in figure 13, perform step again (H), step (N), step (O) to capture next block frequency spectrum, as shown in figure 14.
As shown in figure 14, after execution step (C), step (D), signal 4 detects and captures parameter in step (E).Again in step (F), the frequency setting of this starting point index (SP) is this second crossover point (CP2), as shown in figure 15, due to the non-second frequency distance threshold value (BW_th2) that is less than of difference of the frequency of this starting point index (SP) and the frequency of this terminal index (EP), therefore execution step (H), step (N), step (O), to capture next block frequency spectrum, as shown in figure 16.
In Figure 16, owing to not having signal between this starting point index (SP) and this terminal index (EP), therefore this amplitude threshold (amp_th) is about noise (noise floor).So now, this first crossover point (CP1) is this starting point index (SP), and this second crossover point (CP2) is this terminal index (EP).So after step (C), step (D), determine whether sky passage (empty channel) in step (J).Judgement formula by step (J): (CP1=SP_org) & (CP2=EP_org) sets up, therefore execution step (K), taking by the frequency setting of this starting point index (SP) as this terminal index (EP), thereby skip over the frequency spectrum between this starting point index (SP) and this terminal index (EP), as shown in figure 17.Afterwards, then perform step (H), step (N), step (O), to capture next block frequency spectrum, as shown in figure 18.
As shown in figure 18, because the amplitude frequency distance large and signal 6 and this starting point index (SP) of signal 6 is greater than this first frequency distance threshold value (BW_th1), therefore the judgement formula of step (C) is set up, and perform step (I), taking the frequency as this second crossover point (CP2) by the frequency setting of this terminal index (EP), as shown in figure 19.Afterwards, via step (C), step (D), and in step (E), signal 5 is detected and acquisition parameter.As shown in figure 19, therefore in step (F), the frequency of setting this starting point index (SP) is one second crossover point (CP2).As shown in figure 20.
As shown in figure 20, in step (G), because the difference of the frequency of this starting point index (SP) and the frequency of this terminal index (EP) is less than a second frequency distance threshold value (BW_th2), represent that the frequency spectrum between frequency and this terminal index (EP) of this starting point index (SP) is too little, may there is no signal, can directly skip over the frequency between frequency and this terminal index (EP) of this starting point index (SP), so execution step (K), setting SP is EP, as shown in figure 21.Afterwards, then perform step (H), step (N), step (O), to capture next block frequency spectrum, as shown in figure 22.
As shown in figure 22, after execution of step (C), step (D), step (E), step (F), step (G), step (H), as shown in figure 23.Judge whether been scanned of a search area frequency spectrum in step (N) again.Because CF is greater than carrier frequency preset value (CF_max), so finish this blind method of sweeping.
Figure 24 is that the present invention schemes compared with the prior art.It all uses the tuner (tuner) of Sharp company: Sharp7306, and measures the blind method of sweeping and produce screen-picture required service time.950MHz ~ 2150MHz frequency band of DVB-S/S2 system is divided into C(22k) and Ku(non22k) two frequency bands, before 600MHz be 22k, after 600MHz be non22k.Each frequency band can be divided into again perpendicular polarization (Vertical polarization) and horizontal polarization (Horizontal polarization) simultaneously.As shown in figure 24, under 22k perpendicular polarization, the present invention spends 1 point of 16 seconds (1'16 "), and 2 points of 01 second (2'1 ") of prior art need.Under non22k perpendicular polarization, the present invention spend 12 seconds (12 "), and prior art need 35 seconds (35 ").Under 22k horizontal polarization, the present invention spends 1 point of 7 seconds (1'7 "), and 1 point of 27 seconds (1'27 ") of prior art need.Under non22k horizontal polarization, the present invention spends 1 point of 58 seconds (1'58 "), and 3 points of 55 seconds (3'55 ") of prior art need.
From above stated specification, the present invention is by the judgement formula of step (C), in order to prevent the interference to the little signal of contiguous spectral amplitude of signal that spectral amplitude is large, therefore can correctly detect the little signal of amplitude in DVB-S/S2 system.Meanwhile, the judgement formula of step (G) and step (J) can be accelerated the speed of the signal scanning in DVB-S/S2 system, therefore all have compared with prior art and better detect usefulness in actual measurement.Simultaneously, the present invention uses this analog tuner, adopt larger step (step size) to capture and scan whole frequency spectrum, use and in simulation field, capture a new frequency spectrum block, and use digital mixer in digital field, to support follow-up channel and the detection of parameter.Thereby the blind speed of sweeping method of significantly lifting entirety, the present invention can be according to the frequency spectrum of observing in each calculating loop, dynamically adjust this adjustment factor η, adapt to ground and determine this amplitude threshold (amp_th), and then the channel that height is different in frequency spectrum, detected as much as possible, thereby reduce channel by the probability of drain sweep.Moreover, because the reformed number of times of tuner 12 its carrier frequency has been minimized, can reach quick and correct channel search target eventually.
From the above, the present invention, no matter with regard to object, means and effect, all shows that it is totally different in the feature of prior art, has practical value.But it should be noted, above-mentioned many embodiment only give an example for convenience of explanation, the interest field that the present invention advocates should be as the criterion with described in claims certainly, but not only limits to above-described embodiment.
Claims (16)
1. disturb insensitive Fast Blind to sweep a method for DVB-S/S2 system to adjacent channel, it comprises step:
A) initiation parameter index;
B) set a tuner in order to capture a block frequency spectrum;
C) judge and in described block frequency spectrum, whether have signal that a spectral amplitude is large and the large signal of described spectral amplitude and the frequency distance of a starting point index be greater than a first frequency distance threshold value;
D) in described block frequency spectrum, do not have signal that signal that a spectral amplitude is large or described spectral amplitude are large and the frequency distance of a starting point index not to be greater than described first frequency distance threshold value if judge, then determine whether a full frequency band passage;
E) if full frequency band passage carries out input and parameter acquisition;
F) frequency of setting described starting point index is one second crossover point;
Whether the difference that G) judges the frequency of described starting point index and the frequency of a terminal index is less than a second frequency distance threshold value;
H) if judge the non-second frequency distance threshold value that is less than of the difference of the frequency of described starting point index and the frequency of a terminal index, set a carrier frequency index, and perform step B) in order to be captured next block frequency spectrum by described tuner.
2. the method for eliminating illiteracy fast according to claim 1, it further comprises:
I) as step C) in judge have in described block frequency spectrum signal that a spectral amplitude is large and the large signal of described spectral amplitude and the frequency distance of described starting point index be greater than described frequency distance threshold value, the frequency of setting described terminal index is one first crossover point.
3. Fast Blind according to claim 2 is swept method, and it further comprises:
J) as step D) in judge that described block frequency spectrum is non-during as described full frequency band passage, then determined whether passage.
4. Fast Blind according to claim 3 is swept method, and it further comprises:
K) as step J) in be judged to be sky passage, the frequency of setting described starting point index is the frequency of described terminal index.
5. Fast Blind according to claim 4 is swept method, and it further comprises:
L) as step J) in to judge non-be empty passage, then determine whether a part of frequency range passage.
6. Fast Blind according to claim 5 is swept method, and it further comprises:
M) as step L) in be judged to be described band segment passage, the frequency of setting described starting point index is one first crossover point.
7. Fast Blind according to claim 5 is swept method, wherein, as step L) in judge non-ly as described band segment passage, perform step B).
8. Fast Blind according to claim 7 is swept method, and it further comprises:
N) judge whether been scanned of a search area frequency spectrum, if so, finish the described blind method of sweeping, if not, at step O) in set described starting point index, and described terminal index, then perform step B).
9. Fast Blind according to claim 8 is swept method, wherein, as step G) in judge that the difference of the frequency of described starting point index and the frequency of described terminal index is less than described second frequency distance threshold value, performs step K).
10. Fast Blind according to claim 9 is swept method, wherein, step C) described in block frequency spectrum have the signal that described spectral amplitude is large to refer to the octuple that in described block frequency spectrum, peak is minimum.
11. Fast Blinds according to claim 9 are swept method, wherein, step D) in full frequency band passage refer to that the frequency of described terminal index is greater than the frequency of described the second crossover point, the frequency of described the second crossover point is greater than the frequency of described the first crossover point, and the frequency of described the first crossover point is greater than the frequency of described starting point index.
12. Fast Blinds according to claim 8 are swept method, wherein, the frequency that is greater than for the first time described amplitude threshold in described block frequency spectrum is described the first crossover point, and the frequency that is less than for the first time described amplitude threshold in described block frequency spectrum is described the second crossover point.
13. Fast Blinds according to claim 12 are swept method, and wherein, described amplitude threshold amp_th is:
amp_th=(M-m)×η+m，
In the middle of, M is peak in described block frequency spectrum, and m is minimum in described block frequency spectrum, and η is an adjustment factor.
14. Fast Blinds according to claim 13 are swept method, wherein, step J) in described empty passage refer to that the frequency of described the first crossover point equals the frequency of a starting point original index, the frequency of described the second crossover point equals the frequency of a terminal original index.
15. Fast Blinds according to claim 14 are swept method, wherein, step L) in band segment passage refer to that the frequency of described the second crossover point is greater than the frequency of described terminal index.
16. Fast Blinds according to claim 14 are swept method, wherein, step N) in search area frequency spectrum been scanned refer to that described carrier frequency index is greater than a carrier frequency preset value.
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| CN201210575074.9A CN103905800A (en) | 2012-12-26 | 2012-12-26 | Rapid blind-searching method insensitive to adjacent channel interference |
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| TWI779363B (en) * | 2020-09-30 | 2022-10-01 | 瑞昱半導體股份有限公司 | Blind scan method, non-transitory computer-readable medium and control circuit thereof |
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