CN105530018A - Digital FM receiver threshold expansion system and method - Google Patents
Digital FM receiver threshold expansion system and method Download PDFInfo
- Publication number
- CN105530018A CN105530018A CN201610045949.2A CN201610045949A CN105530018A CN 105530018 A CN105530018 A CN 105530018A CN 201610045949 A CN201610045949 A CN 201610045949A CN 105530018 A CN105530018 A CN 105530018A
- Authority
- CN
- China
- Prior art keywords
- signal
- module
- filtering
- digital
- extended threshold
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/06—Receivers
- H04B1/10—Means associated with receiver for limiting or suppressing noise or interference
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/06—Receivers
- H04B1/10—Means associated with receiver for limiting or suppressing noise or interference
- H04B1/1027—Means associated with receiver for limiting or suppressing noise or interference assessing signal quality or detecting noise/interference for the received signal
- H04B1/1036—Means associated with receiver for limiting or suppressing noise or interference assessing signal quality or detecting noise/interference for the received signal with automatic suppression of narrow band noise or interference, e.g. by using tuneable notch filters
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/06—Receivers
- H04B1/10—Means associated with receiver for limiting or suppressing noise or interference
- H04B1/1027—Means associated with receiver for limiting or suppressing noise or interference assessing signal quality or detecting noise/interference for the received signal
- H04B2001/1054—Means associated with receiver for limiting or suppressing noise or interference assessing signal quality or detecting noise/interference for the received signal by changing bandwidth
Abstract
The invention provides a digital FM receiver threshold expansion system and a method. The digital FM receiver threshold expansion system comprises a simulation front end module, a frequency mixing module, a first filtering module, a threshold expansion module and a demodulation module. The threshold expansion module comprises a first delay module and delays a first filtering signal to obtain a first delay signal; a first frequency spectrum conveying module performs the spectrum conveying on the first delay signal to obtain a first conveying signal; a second filtering module performs filtering on the first conveying signal; a second spectrum conveying module conveys the filtered first conveying signal to the initial position to obtain a threshold expansion signal; the calculation module receives a first filtering signal and calculates a calculation signal according to the first filtering signal; and the calculation module outputs the calculation signal to the first spectrum conveying module and the second delay module. The method is applied to the digital FM receiver threshold expansion system. The invention filters the multicarrier noise, improves the signal to noise ratio of the demodulation signal and prevents the distortion of the sound.
Description
Technical field
The invention belongs to frequency-shift keying field, be specifically related to a kind of for the method and apparatus of digital demodulation shape as the FM signal of stereo broadcasting signal, the particularly extended threshold system and method for frequency-shift keying (FM) receiver.
Background technology
The object of FM receiver is the radio signal according to receiving
restore modulated signals
.Being expressed as of warbled carrier signal
Wherein
it is carrier frequency; D is warble rate, is generally 75KHz;
it is modulated signals.
The structured flowchart of digital FM receiver common at present as shown in Figure 1, analog front-end module 1 is by the RF(RadioFrequency of the FM signal received: radio frequency) be converted to intermediate frequency (IntermediateFrequency: intermediate frequency) and after filtering, obtain IQ two paths of signals, sampled by analog-to-digital conversion module 2 pairs of intermediate-freuqncy signals again, then bandpass filtering modules block 3 is used, i.e. digital band-pass filter RFBPF(IntermediateFrequencyBand-PassFilter) carry out filtering, RFBPF is the complex bandpass filters of frequency centered by RF, in general, the stereophonic signal of 75KHz modulation degree,
bandwidth be approximately ± 100KHz, so in order to ensure that sound is undistorted, the bandwidth of intermediate-frequency filter can not be less than ± 100KHz.And then carry out mixing by frequency mixing module 4, eventually pass the demodulation that demodulation module 5 completes FM signal, demodulation module 5 is transformed into polar algorithm for CORDIC(cartesian coordinate) and differential circuit.But when the signal to noise ratio of the carrier signal received is below FM signalc threshold, the signal to noise ratio of FM restituted signal can sharply worsen, thus causes sensitivity to decline.Therefore need extended threshold technology to improve the sensitivity of digital FM receiver.
In prior art, the method for the signal to noise ratio of common raising FM restituted signal has several as follows:
1. reduce modulation degree, reduce signal bandwidth, thus narrower RFBPF can be used to carry out filtering more multicarrier noise, thus improve restituted signal signal to noise ratio, such as FMFB; But owing to reducing modulation degree, the effect of this method is also bad.
2. if publication number is the phase jump by detecting and remove restituted signal mentioned in the Chinese invention patent application of CN1115833, thus improve restituted signal signal to noise ratio; But this method can only detect the transition of a part, even and if detect that transition also can only weaken transition can not the correct signal of accurate reproduction, the signal noise ratio improve of restituted signal is limited.
3. if publication number is that the use bandwidth varying mentioned in the Chinese invention patent application of CN101420239 carrys out the different carrier signal to noise ratio of self adaptation with the RFBPF of variable attenuation slope, avoid causing the more carrier noise of filtering under the prerequisite of audio distortions, thus improve restituted signal signal to noise ratio; But due to sound will be avoided undistorted, so the attenuation slope of the bandwidth of RFBPF RFBPF while reducing also will become more slow, therefore the final raising to sensitivity is also little.
Summary of the invention
Main purpose of the present invention is to provide a kind of extended threshold system of digital FM receiver.
Another object of the present invention is to provide a kind of extended threshold method of digital FM receiver.
For realizing above-mentioned main purpose, the extended threshold system of digital FM receiver provided by the invention comprises analog front-end module, analog-to-digital conversion module, frequency mixing module, the first filtration module, extended threshold module and demodulation module; Analog front-end module receives FM signal and is intermediate-freuqncy signal by FM signal frequency conversion, and analog front-end module exports intermediate-freuqncy signal to analog-to-digital conversion module; Intermediate-freuqncy signal is carried out analog-to-digital conversion and is obtained digital signal by analog-to-digital conversion module, and analog-to-digital conversion module output digit signals is to frequency mixing module; Digital signal is mixed to direct current and obtains mixed frequency signal by frequency mixing module, and frequency mixing module exports mixed frequency signal to the first filtration module; Noise and the mirror image of the first filtration module filtering mixed frequency signal obtain the first filtering signal, and the first filtration module exports the first filtering signal to extended threshold module; The threshold value that extended threshold module expands the first filtering signal obtains extended threshold signal, and extended threshold module exports thresholding spread signal to demodulation module; Demodulation module demodulation threshold spread signal obtains restituted signal; Wherein, extended threshold module comprises the first Postponement module, the first frequency spectrum shift module, the second filtration module, the second frequency spectrum shift module and computing module; First filtering signal is carried out delay and obtains the first inhibit signal by the first Postponement module, and the first Postponement module exports the first inhibit signal to the first frequency spectrum shift module; First inhibit signal is carried out frequency spectrum shift and is obtained first and move signal by the first frequency spectrum shift module, and the first frequency spectrum shift module exports first and moves signal to the second filtration module; Second filtration module is moved signal by first and is carried out filtering, and after the second filtration module output filtering first moves signal to the second frequency spectrum shift module; Second frequency spectrum shift module is moved signal and is moved and obtain extended threshold signal to origin-location by filtered first; Computing module receives the first filtering signal and calculates according to the first filtering signal the signal that counts, and computing module exports count signal to the first frequency spectrum shift module and the second Postponement module.
From such scheme, extended threshold module provided by the invention is a kind ofly accurately can follow the tracks of the instantaneous frequency of carrier signal and the CTLPF(CarrierTrackingLowPassFilter of narrow bandwidth: carrier track formula low pass filter) carry out the more carrier noise of filtering, thus improve the signal to noise ratio of restituted signal, and audio distortions can not be caused.
A preferred scheme is that extended threshold module comprises the second Postponement module, and the second Postponement module receives to count after signal postpones and obtains the second inhibit signal, and the second Postponement module exports the second inhibit signal to the second frequency spectrum shift module.
Therefore the first Postponement module introduces group delay at the second filtration module; Second Postponement module compensates the group delay introduced at the second filtration module.The IQ two paths of signals of the first filtering signal is through the first Postponement module, the sampling number that IQ two paths of signals postpones is the group delay of the second filtration module, thus guarantee the instantaneous frequency of accurate tracking carrier wave, and can be compensated group delay by the second Postponement module afterwards.
A preferred scheme is that computing module comprises differential module, pulse cancellation module, the 3rd filtration module and cosine and sine signal generation module; Differential module receives to state the first filtering signal and the first filtering signal is carried out process and obtains differential signal, and differential module exports differential signal to pulse cancellation module; The disturbing pulse that pulse cancellation module eliminates differential signal obtains pulse erasure signal, and pulse cancellation module exports pulse erasure signal to the 3rd filtration module; The noise of the 3rd filtration module filtering pulse erasure signal obtains the 3rd filtering signal, and the 3rd filtration module exports the 3rd filtering signal to cosine and sine signal generation module; Cosine and sine signal generation module calculates according to the 3rd filtering signal the signal that counts, and cosine and sine signal generation module exports count signal to the first frequency spectrum shift module and the second Postponement module.
Therefore computing module exports and to count signal to the first frequency spectrum shift module and the second Postponement module, for the shifting frequency of the shifting frequency and the second frequency spectrum shift module that calculate the first frequency spectrum shift module.
A preferred scheme is that pulse cancellation module comprises judge module, multi-path choice module and the 3rd Postponement module, and whether contrast module is greater than or equal to the differential signal of input for contrasting default maximum; Multi-path choice module is used for the pulse erasure signal selecting output according to the result of contrast module; 3rd Postponement module is used for storage pulse erasure signal.
Therefore pulse cancellation module, by the differential signal of input and the maximum preset being compared, judges whether the intermediate-freuqncy signal inputted is normal signal, thus selectively exports pulse erasure signal.
Preferred scheme is that the signal that counts comprises count signal and cosine of sine and to count signal.
Therefore the cosine and sine signal generation module of computing module obtains count signal and cosine of sine respectively to count signal by calculating, and exports the first frequency spectrum shift module and the second Postponement module respectively to.
For realizing another above-mentioned object, the extended threshold method of digital FM receiver provided by the invention comprises AFE (analog front end) step, receives FM signal and be intermediate-freuqncy signal by FM signal frequency conversion; Analog-to-digital conversion step, carries out analog-to-digital conversion by intermediate-freuqncy signal and obtains digital signal; Frequency mixing stages, is mixed to direct current by digital signal and obtains mixed frequency signal; First filter step, the noise of filtering mixed frequency signal and mirror image obtain the first filtering signal; Extended threshold step, the threshold value expanding the first filtering signal obtains extended threshold signal; Demodulation step, demodulation threshold spread signal obtains restituted signal; Wherein, extended threshold step comprises the first delay step, the first frequency spectrum shift step, the second filter step, the second frequency spectrum shift step and calculation procedure successively; First delay step is the step being carried out by the first filtering signal postponing to obtain the first inhibit signal; First frequency spectrum shift step be the first inhibit signal is carried out frequency spectrum shift obtain the step that first moves signal; Second filter step is move first the step that signal carries out filtering; Second frequency spectrum shift step is move signal by filtered first to move the step obtaining extended threshold signal to origin-location; Calculation procedure is reception first filtering signal and calculates the step of the signal that counts according to the first filtering signal.
From such scheme, extended threshold method of the present invention realizes carrier track by carrying out frequency spectrum shift to the intermediate-freuqncy signal after mixing and filtering, first the centre frequency required for intermediate-freuqncy signal is moved direct current, then carry out filtering with fixing low pass filter, after completing filtering, carry out onesize frequency translation to reduce intermediate-freuqncy signal toward rightabout again.
Accompanying drawing explanation
Fig. 1 is the structured flowchart of existing digital FM receiver embodiment.
Fig. 2 is the structured flowchart of the extended threshold system embodiment of digital FM receiver of the present invention.
Fig. 3 is the structured flowchart of extended threshold module in the extended threshold system embodiment of digital FM receiver of the present invention.
Fig. 4 is the structured flowchart of the pulse cancellation module of extended threshold module in the extended threshold system embodiment of digital FM receiver of the present invention.
Fig. 5 is the method flow diagram of the extended threshold embodiment of the method for digital FM receiver of the present invention.
Below in conjunction with drawings and Examples, the invention will be further described.
Embodiment
It is the structured flowchart of the extended threshold system embodiment of digital FM receiver of the present invention see Fig. 2, Fig. 2.Extended threshold system of the present invention comprises analog front-end module 11, analog-to-digital conversion module 12, frequency mixing module 13, first filtration module 14, extended threshold module 15 and demodulation module 16.
Analog front-end module 11, for receiving FM signal and the carrier frequency of the FM signal of reception being converted to intermediate frequency, generates intermediate-freuqncy signal; Analog-to-digital conversion module 12 obtains digital signal for intermediate-freuqncy signal is carried out analog-to-digital conversion; Frequency mixing module 13, i.e. complex mixer, obtain mixed frequency signal for digital signal is mixed to direct current; First filtration module 14, i.e. FIRLPF low pass filter, obtain the first filtering signal for the noise of filtering mixed frequency signal and mirror image, wherein uses LPF to replace the benefit of RFBPF to be without complex filter; Extended threshold module 15 obtains extended threshold signal for the threshold value expanding the first filtering signal; Demodulation module 16 obtains restituted signal for demodulation threshold spread signal, particularly obtains final restituted signal by cordic algorithm and differential circuit.Cordic algorithm is that a kind of cartesian coordinate is transformed into polar algorithm.
The object of the invention is the signal to noise ratio improving the restituted signal of carrier signal to noise ratio below FM signalc threshold.Compared to the prior art, do not need to reduce modulation degree, can not cause audio distortions, the signal to noise ratio of restituted signal is higher.Realize principle as follows:
If the expression formula of warbled carrier signal is:
Wherein
it is carrier frequency; D is warble rate, is generally 75KHz;
it is modulated signals.Suppose
, then the instantaneous frequency of carrier signal is:
Can be known by above formula, the instantaneous frequency of carrier signal be by
instantaneous voltage determine.Again because
instantaneous voltage change can not be too fast, the therefore instant bandwidth of carrier signal
than the total bandwidth that carrier signal occupies
narrow.
For this reason, extended threshold module 15 provided by the invention be a kind of accurately can follow the tracks of carrier signal instantaneous frequency and bandwidth only have
cTLPF(CarrierTrackingLowPassFilter: carrier track formula low pass filter), carry out the more carrier noise of filtering by CTLPF, thus improve the signal to noise ratio of restituted signal, and can not audio distortions be caused.Realize carrier track, then need the centre frequency changing filter, be numerically difficult to realize.One preferably implementation method carries out frequency spectrum shift to signal.Centre frequency required for signal is moved direct current, and then carries out filtering with fixing low pass filter, carry out onesize frequency translation toward rightabout again after completing filtering and carry out recovering signal.
Composition graphs 3, Fig. 3 is the structured flowchart of extended threshold module 15 in the extended threshold system embodiment of digital FM receiver of the present invention.Extended threshold module 15 comprises the first Postponement module 51, first frequency spectrum shift module 52, second filtration module 53, second frequency spectrum shift module 54, second Postponement module 55 and computing module 25.
Digital FM receiver of the present invention is quadrature receiver, and the FM signal namely received by digital FM receiver antenna can be divided into two channels immediately, and one is homophase (I) channel, and another is orthogonal (Q) channel.First filtering signal is divided into IQ two paths of signals to access extended threshold module 15, first obtain the first inhibit signal respectively through the first Postponement module 51, the IQ two paths of signals of the first filtering signal equals the group delay of the second filtration module 53 through the sampled point quantity postponed, this is the instantaneous frequency in order to guarantee accurate tracking carrier wave.
Then, the IQ two paths of signals of the first inhibit signal arrives the first frequency spectrum shift module 52, carry out frequency spectrum shift to obtain first and move signal, the frequency of frequency spectrum shift is determined by the instantaneous frequency of carrier wave, the sine values that this instantaneous frequency is corresponding and cosine values are calculated by cosine and sine signal generation module 59, and wherein the first frequency spectrum shift module 52 is complex mixer.
The first IQ two paths of signals moving signal arrives the second filtration module 53 respectively, second filtration module 53 comprises two IQ two paths of signals that independently FIR low pass filter moves signal to first respectively and carries out filtering, and whether the passband of the second filtration module 53 can according to being monophony and switching between 15KHz and 53KHz.
Then the filtered first IQ two paths of signals moving signal arrives the second frequency spectrum shift module 54, the frequency size moved is calculated by cosine and sine signal generation module 59, and compensate through the second Postponement module 55 group delay that first Postponement module 51 introduces the second filtration module 53, the frequency spectrum that filtered first moves the IQ two paths of signals of signal is reverted on correct position and obtains extended threshold signal, then the IQ two paths of signals of output thresholding spread signal is to outside for demodulation module 16, and wherein the second frequency spectrum shift module 54 is complex mixer.
The shifting frequency of the first frequency spectrum shift module 52 as above and the shifting frequency of the second spectrum block 54 are calculated by computing module 25.Wherein, computing module 25 comprises differential module 56, pulse cancellation module 57, the 3rd filtration module 58 and cosine and sine signal generation module 59, and computational process is as follows:
The IQ two paths of signals of the first filtering signal of input obtains differential signal after differential module 56, and wherein differential module is specially CORDIC and differential circuit, arrives pulse cancellation module 57 afterwards.Composition graphs 4, Fig. 4 is the structured flowchart of the pulse cancellation module 57 of extended threshold module 15 in the extended threshold system embodiment of digital FM receiver of the present invention.Pulse cancellation module 57 comprises contrast module 571, multi-path choice module 572 and the 3rd Postponement module 573, wherein contrast module 571 to compare for the differential signal of maximum that program is preset and input, whether the maximum that determining program is preset is more than or equal to input signal, 1 is exported when being judged as YES, now think that the differential signal inputted is normal signal, multi-path choice module 572 selects the differential signal exporting current input; 0 is exported when being judged as NO, now think that the differential signal inputted is a disturbing pulse, the differential signal of the previous output that multi-path choice module 572 selects output the 3rd Postponement module to preserve, the differential signal namely exported as normal signal will be buffered in the 3rd Postponement module 573.
The differential signal exported by pulse cancellation module 57 at this is all called pulse erasure signal, pulse erasure signal input the 3rd filtration module 58 carries out low-pass filtering, and wherein the passband of the 3rd filtration module 58 can switch between 15KHz and 53KHz according to whether being monophony.The 3rd filtering signal is obtained after the filtering of pulse erasure signal, 3rd filtering signal input sine and cosine signal generating module 59 is carried out accumulation calculating and is obtained the signal that counts by the 3rd filtration module 58, concrete computing formula is as follows, namely first accumulated value is calculated to the 3rd filtering signal of input, then calculates sine value and the cosine value of accumulated value:
Obtain count signal and cosine of sine to count signal, signal and the cosine signal that counts that counted by sine respectively again outputs to the first frequency spectrum shift module 52 and the second Postponement module 55, finally obtains the frequency spectrum shift frequency of the first frequency spectrum shift module 52 and the second frequency spectrum shift module 54.
It is the method flow diagram of the extended threshold embodiment of the method for digital FM receiver of the present invention see Fig. 5, Fig. 5.First perform step S1, the RF radio of the FM signal of reception is converted to intermediate frequency and obtains intermediate frequency (IF) signal by analog front-end module 11, post filtering obtain IQ two paths of signals; Then perform step S2, analog-to-digital conversion module 12 pairs of if signal samplings carry out analog-to-digital conversion and obtain digital signal; Perform step S3, by frequency mixing module 13, namely digital signal is mixed to direct current and obtains mixed frequency signal by complex mixer; Perform step S4 afterwards, by filtration module 14, namely the noise of FIRLPF low pass filter filtering mixed frequency signal and mirror image obtain filtering signal; Perform step S5, utilize extended threshold module 15, i.e. CTLPF(CarrierTrackingLowPassFilter: carrier track formula low pass filter) carry out frequency spectrum shift to filtering signal thus realize extended threshold obtaining extended threshold signal; Finally perform step S6, by demodulation module 16, namely obtained the restituted signal of final FM signal by cordic algorithm and differential circuit.
Therefore, extended threshold module of the present invention is a kind ofly accurately can follow the tracks of the instantaneous frequency of carrier signal and the CTLPF(CarrierTrackingLowPassFilter of narrow bandwidth: carrier track formula low pass filter), can the more carrier noise of filtering by CTLPF, thus improve the signal to noise ratio of restituted signal, and audio distortions can not be caused.
Claims (10)
1. the extended threshold system of digital FM receiver, comprises analog front-end module, analog-to-digital conversion module, frequency mixing module, the first filtration module, extended threshold module and demodulation module;
Described analog front-end module receives FM signal and is intermediate-freuqncy signal by described FM signal frequency conversion, and described analog front-end module exports described intermediate-freuqncy signal to described analog-to-digital conversion module;
Described intermediate-freuqncy signal is carried out analog-to-digital conversion and is obtained digital signal by described analog-to-digital conversion module, and described analog-to-digital conversion module exports described digital signal to described frequency mixing module;
Described digital signal is mixed to direct current and obtains mixed frequency signal by described frequency mixing module, and described frequency mixing module exports described mixed frequency signal to described first filtration module;
Noise and the mirror image of mixed frequency signal described in described first filtration module filtering obtain the first filtering signal, and described first filtration module exports described first filtering signal to described extended threshold module;
The threshold value of described first filtering signal of described extended threshold module expansion obtains extended threshold signal, and described extended threshold module exports described extended threshold signal to described demodulation module;
Described in described demodulation module demodulation, extended threshold signal obtains restituted signal;
It is characterized in that:
Described extended threshold module comprises the first Postponement module, the first frequency spectrum shift module, the second filtration module, the second frequency spectrum shift module and computing module;
Described first filtering signal is carried out delay and obtains the first inhibit signal by described first Postponement module, and described first Postponement module exports described first inhibit signal to described first frequency spectrum shift module;
Described first inhibit signal is carried out frequency spectrum shift and is obtained first and move signal by described first frequency spectrum shift module, and described first frequency spectrum shift module exports described first and moves signal to described second filtration module;
Described second filtration module is moved signal by described first and is carried out filtering, and after described second filtration module output filtering described first moves signal to described second frequency spectrum shift module;
Described second frequency spectrum shift module is moved signal and is moved and obtain described extended threshold signal to origin-location by filtered described first;
Described computing module receives described first filtering signal and calculates according to described first filtering signal the signal that counts, and the signal that counts described in described computing module exports is to described first frequency spectrum shift module and described second Postponement module.
2. the extended threshold system of digital FM receiver according to claim 1, is characterized in that:
Described extended threshold module comprises the second Postponement module, described second Postponement module receives the signal that counts of described computing module input, obtain the second inhibit signal after postponing, described second Postponement module exports described second inhibit signal to described second frequency spectrum shift module.
3. the extended threshold system of digital FM receiver according to claim 1, is characterized in that:
Described computing module comprises differential module, pulse cancellation module, the 3rd filtration module and cosine and sine signal generation module;
Described differential module receives described first filtering signal and described first filtering signal is carried out process and obtains differential signal, and described differential module exports described differential signal to described pulse cancellation module;
The disturbing pulse that described pulse cancellation module eliminates described differential signal obtains pulse erasure signal, and described pulse cancellation module exports described pulse erasure signal to described 3rd filtration module;
Described in described 3rd filtration module filtering, the noise of pulse erasure signal obtains the 3rd filtering signal, and described 3rd filtration module exports described 3rd filtering signal to described cosine and sine signal generation module;
Count described in described cosine and sine signal generation module calculates according to described 3rd filtering signal signal, and the signal that counts described in described cosine and sine signal generation module exports is to described first frequency spectrum shift module and the second Postponement module.
4. the extended threshold system of digital FM receiver according to claim 3, is characterized in that:
Described pulse cancellation module comprises judge module, multi-path choice module and the 3rd Postponement module,
Whether described contrast module is greater than or equal to the described differential signal of input for contrasting default maximum;
Described multi-path choice module is used for the described pulse erasure signal selecting output according to the result of described contrast module;
Described 3rd Postponement module is for storing described pulse erasure signal.
5. the extended threshold system of the digital FM receiver according to Claims 2 or 3, is characterized in that:
The described signal that counts comprises count signal and cosine of sine and to count signal.
6. the extended threshold method of digital FM receiver, the method comprises:
AFE (analog front end) step, receives FM signal be intermediate-freuqncy signal by described FM signal frequency conversion;
Analog-to-digital conversion step, carries out analog-to-digital conversion by described intermediate-freuqncy signal and obtains digital signal;
Frequency mixing stages, is mixed to direct current by described digital signal and obtains mixed frequency signal;
First filter step, the noise of mixed frequency signal described in filtering and mirror image obtain the first filtering signal;
Extended threshold step, the threshold value expanding described first filtering signal obtains extended threshold signal;
Demodulation step, described in demodulation, extended threshold signal obtains restituted signal;
It is characterized in that:
Described extended threshold step comprises the first delay step, the first frequency spectrum shift step, the second filter step, the second frequency spectrum shift step and calculation procedure successively;
Described first delay step is the step being carried out by described first filtering signal postponing to obtain the first inhibit signal;
Described first frequency spectrum shift step be described first inhibit signal is carried out frequency spectrum shift obtain the step that first moves signal;
Described second filter step is move described first the step that signal carries out filtering;
Described second frequency spectrum shift step is move signal by filtered described first to move the step obtaining extended threshold signal to origin-location;
Described calculation procedure is the step receiving described first filtering signal and calculate the signal that counts according to described first filtering signal.
7. the extended threshold method of digital FM receiver according to claim 6, is characterized in that:
Described extended threshold step comprises the second delay step, and described second postpones step performs before described second frequency spectrum shift step, and described second postpones the step that step comprises the signal that to count described in reception.
8. the extended threshold method of digital FM receiver according to claim 6, is characterized in that:
Described calculation procedure comprises differentiation step, pulse removal process, the 3rd filter step and cosine and sine signal generation step successively;
Described differentiation step comprises described first filtering signal of reception and is carried out processing the step obtaining differential signal by described first filtering signal;
Described pulse removal process comprises the step that the disturbing pulse eliminating described differential signal obtains pulse erasure signal;
The noise that described 3rd filter step comprises pulse erasure signal described in filtering obtains the step of the 3rd filtering signal;
Described cosine and sine signal generation step comprise to calculate according to described 3rd filtering signal described in count the step of signal.
9. the extended threshold method of digital FM receiver according to claim 8, is characterized in that:
Described pulse removal process comprises contrast step successively, multi-path choice step and the 3rd postpones step,
Described contrast step is whether the maximum that contrast is preset is greater than or equal to the step of the described differential signal of input;
Described multi-path choice step is select to export the step of pulse erasure signal according to the comparing result of described contrast step;
Described 3rd delay step is the step storing described pulse erasure signal.
10. the extended threshold method of the digital FM receiver according to claim 7 or 8, is characterized in that:
The described signal that counts comprises count signal and cosine of sine and to count signal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610045949.2A CN105530018B (en) | 2016-01-22 | 2016-01-22 | The extended threshold system and method for digital FM receiver |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610045949.2A CN105530018B (en) | 2016-01-22 | 2016-01-22 | The extended threshold system and method for digital FM receiver |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN105530018A true CN105530018A (en) | 2016-04-27 |
| CN105530018B CN105530018B (en) | 2017-06-20 |
Family
ID=55772049
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201610045949.2A Active CN105530018B (en) | 2016-01-22 | 2016-01-22 | The extended threshold system and method for digital FM receiver |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN105530018B (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1134894A (en) * | 1995-01-30 | 1996-11-06 | 精工爱普生株式会社 | Assist device for use in electric vehicle |
| US6512555B1 (en) * | 1994-05-04 | 2003-01-28 | Samsung Electronics Co., Ltd. | Radio receiver for vestigal-sideband amplitude-modulation digital television signals |
| CN102325110A (en) * | 2011-09-20 | 2012-01-18 | 中国空间技术研究院 | Large-modulation index satellite-borne digital frequency modulating receiver |
| CN205490507U (en) * | 2016-01-22 | 2016-08-17 | 建荣集成电路科技(珠海)有限公司 | Digital FM receiver's threshold extend system |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE69902760T2 (en) * | 1998-03-11 | 2003-06-05 | Thomson Licensing Sa | DIGITAL SIGNAL MODULATION SYSTEM |
-
2016
- 2016-01-22 CN CN201610045949.2A patent/CN105530018B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6512555B1 (en) * | 1994-05-04 | 2003-01-28 | Samsung Electronics Co., Ltd. | Radio receiver for vestigal-sideband amplitude-modulation digital television signals |
| CN1134894A (en) * | 1995-01-30 | 1996-11-06 | 精工爱普生株式会社 | Assist device for use in electric vehicle |
| CN102325110A (en) * | 2011-09-20 | 2012-01-18 | 中国空间技术研究院 | Large-modulation index satellite-borne digital frequency modulating receiver |
| CN205490507U (en) * | 2016-01-22 | 2016-08-17 | 建荣集成电路科技(珠海)有限公司 | Digital FM receiver's threshold extend system |
Also Published As
| Publication number | Publication date |
|---|---|
| CN105530018B (en) | 2017-06-20 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP3973725B2 (en) | Receiving machine | |
| US8095095B2 (en) | Band switch control apparatus for intermediate frequency filter | |
| US8804865B2 (en) | Delay adjustment using sample rate converters | |
| US8976969B2 (en) | Delaying analog sourced audio in a radio simulcast | |
| US6907089B2 (en) | Digital demodulation and applications thereof | |
| CN102447516B (en) | Detect the Apparatus and method for of digital radio signals | |
| US10873486B1 (en) | Receiver circuits with blocker attenuating RF filter | |
| US20130003904A1 (en) | Delay estimation based on reduced data sets | |
| US9106299B2 (en) | Audio signal processing circuit | |
| US20130003637A1 (en) | Dynamic time alignment of audio signals in simulcast radio receivers | |
| CN104639190B (en) | The AFE(analog front end) system and its processing method of a kind of FM receiver | |
| KR100273886B1 (en) | Wireless receiving circuit for inducing more than one signal of receiving quality | |
| US6957054B2 (en) | Radio receiver having a variable bandwidth IF filter and method therefor | |
| EP0923272A2 (en) | Signal quality measurement using full-complex FM detector | |
| CN102957642A (en) | Radio data receiving system and receiving method thereof | |
| JPS5934742A (en) | Clock frequency recovering device used for high frequency radio communication in disordered transmission medium | |
| US20080112508A1 (en) | Digital Wireless Receiver | |
| US7548281B2 (en) | Demodulator circuit for digital television and demodulation method | |
| CN205490507U (en) | Digital FM receiver's threshold extend system | |
| WO2014190187A1 (en) | Method and circuit for signal quality estimation and control | |
| EP2747295B1 (en) | A receiver for demodulating a multiplex signal and corresponding method | |
| CN105530018A (en) | Digital FM receiver threshold expansion system and method | |
| US6546237B1 (en) | Differential FM detector for radio receivers | |
| JP2004048397A (en) | Reception system | |
| JP2002232389A (en) | Ofdm receiver |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| TR01 | Transfer of patent right |
Effective date of registration: 20220318 Address after: Rooms 1306-1309, 13 / F, 19 science Avenue West, Hong Kong Science Park, Shatin, New Territories, China Patentee after: BUILDWIN INTERNATIONAL (ZHUHAI) LTD. Address before: 519015 3rd Floor, Stereo Science and Technology Building, 184 Bailian Road, Jida, Zhuhai City, Guangdong Province Patentee before: BUILDWIN INTERNATIONAL (ZHUHAI) Ltd. |
|
| TR01 | Transfer of patent right |