CN101442637B - Apparatus and method for identifying television audio standard - Google Patents
Apparatus and method for identifying television audio standard Download PDFInfo
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- CN101442637B CN101442637B CN2007101936413A CN200710193641A CN101442637B CN 101442637 B CN101442637 B CN 101442637B CN 2007101936413 A CN2007101936413 A CN 2007101936413A CN 200710193641 A CN200710193641 A CN 200710193641A CN 101442637 B CN101442637 B CN 101442637B
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Abstract
The invention provides an audio standard identification device, which records frequency bands of carrier waves of a plurality of broadcasting audio format signals in advance. The identification device comprises a carrier wave calculating unit and a switching control unit. An intermediate frequency signal is received through the carrier wave calculating unit; respective first carrier wave energy of the intermediate frequency signal on a plurality of frequency bands is calculated; at least one frequency band with the carrier wave is determined by the switching control unit according to all the first carrier wave energy; a main carrier wave of the frequency band having the carrier wave is analyzed according to at least one threshold to acquire an effective carrier wave; and the effective carrier wave is compared with the frequency band of the carrier waves which are recorded in advance so as to conform a corresponding broadcasting audio format signal. Therefore, the aim of correctly determining the audio standard to support broadcasting systems of each country can be achieved.
Description
Technical field
The present invention relates to television audio standard, particularly relate to a kind of audio standard device for identifying and method that is applied in the analog television broadcast.
Background technology
In television broadcasting signal, about voice signal partly be to define with television audio standard (TV AudioStandard), wherein comprise the definition specification of monophonic broadcasting, stereophonic broadcasting or bilingual broadcasting etc.With at present, the television audio standard in the whole world mainly can be divided into the standard of four kinds of broadcast audio format signals, be respectively: A2, EIAJ, BTSC and NICAM, wherein A2 can divide into FM A2BG, FM A2 DK1, FM A2 DK2, FM A2 DK3, and five kinds of specifications such as FM A2 M again, and NICAM then can divide into AM mono L NICAM, FM mono I NICAM, FM mono BG NICAM, and four kinds of different specifications such as FM mono DK NICAM.In different countries, use the broadcast system of different broadcast audio format signals often, for example: the employed EIAJ standard of Japanese broadcast system; The BTSC standard of using in Taiwan, the American Broadcasting System; And Europe and Chinese employed NICAM and A2 standard etc.
And with present existing TV signal receiver, usually all be to do different circuit design to meet carrier wave and decoded mode thereof at specific broadcast audio format signal, yet this has just caused the function restriction of product itself, only can be confined to particular locality uses, if will when use in other area, just must adopt the product of the specification that meets this area's broadcast system to realize in addition.Thus, not only can cause the chip design manufacturer of television audio control chip to manufacture and design different control chips respectively, also can make TV manufacturer increase the burden on the development and Design and cause puzzlement in the product maintenance at different television audio standards.
Summary of the invention
In view of this, technical problem to be solved by this invention is, by comparing the mode of carrier wave, to compare via the formulation carrier frequency band that calculates the back carrier wave that is obtained and all broadcast audio format signals that write down in advance, and decide the broadcast audio format signal that is consistent to adjust the usefulness of parameter with correct processing and playing audio signal for subsequent conditioning circuit.By this, reaching the purpose that in the single audio frequency coding chip, can correctly judge broadcast audio format signal that various countries are different and be suitable for different broadcast systems, and the usefulness of the chip that is increased and the property applied flexibly.
In order to achieve the above object, according to a scheme proposed by the invention, a kind of audio standard device for identifying is provided, records the frequency band at the carrier wave place of a plurality of broadcast audio format signals in advance, device for identifying comprises: a carrier wave computing unit and switches control unit.Wherein, the carrier wave computing unit receives an intermediate-freuqncy signal, and calculated intermediate-freuqncy signal separately first carrier energy on a plurality of frequency bands, switch control unit is then judged the frequency band that a physical presence has carrier wave in order to the first carrier energy on the foundation frequency band, and resolve the main carrier wave of this frequency band that has carrier wave again according at least one threshold value (Threshold), and then obtain an effective carrier wave, so switch control unit is compared the frequency band at the carrier wave place of writing down in advance to switch the broadcast audio format signal that output meets according to effective carrier wave.
In order to achieve the above object, according to another program proposed by the invention, a kind of audio standard discrimination method is provided, wherein write down the frequency band at the carrier wave place of a plurality of broadcast audio format signals in advance, and be fundamental frequency signal with the intermediate-freuqncy signal frequency conversion that is received according to a plurality of frequency bands, and the step of this discrimination method comprises: at first, on these frequency bands, scan the carrier wave of fundamental frequency signal respectively and calculate separately and produce a first carrier energy, then, count the frequency band that at least one physical presence has carrier wave according to these first carrier energy, moreover, resolve the main carrier wave of frequency band that this physical presence has carrier wave obtaining an effective carrier wave by a threshold value, with effective carrier wave ratio to the frequency band at this carrier wave place of writing down in advance to determine the broadcast audio format signal that is consistent.By this, supported the broadcast system that various countries are different, and provide corresponding broadcast audio format signal to adjust the usefulness of parameter with correct processing and playing audio signal to subsequent conditioning circuit.
Above general introduction and ensuing detailed description and accompanying drawing all are to reach mode, means and the effect that predetermined purpose is taked in order to further specify the present invention.And relevant other purpose of the present invention and advantage will be set forth in follow-up explanation and accompanying drawing.
Description of drawings
Fig. 1 is the carrier wave schematic diagram of audio standard;
Fig. 2 is the embodiment calcspar of audio standard device for identifying of the present invention;
Fig. 3 is the embodiment calcspar of carrier wave computing unit of the present invention;
Fig. 4 is the frequency spectrum sampling schematic diagram of the present invention in NICAM broadcast audio format signal;
Fig. 5 is the embodiment flow chart of audio standard discrimination method of the present invention;
Fig. 6 A-B is the embodiment flow chart that the present invention determines the broadcast audio format signal;
Fig. 7 A is first schematic diagram of broadcast audio format signal;
Fig. 7 B is second schematic diagram of broadcast audio format signal; And
Fig. 7 C is the 3rd schematic diagram of broadcast audio format signal.
The reference numeral explanation
Device for identifying 1
Carrier wave computing unit 10
Intermediate-freuqncy signal 101
Second carrier energy 102 '
The converting unit 110 of rotation of coordinate digital calculator
The vector location 130 of rotation of coordinate digital calculator
Switch control unit 20
Amplitude orthogonal component I, Q
The amplitude orthogonal component I ' of sampling rate, Q '
Embodiment
The audio standard (Audio Multi-Standard) that the present invention's (comprising claim) is mentioned comprises the broadcast audio format signal (totally 11 kinds) of the employed broadcast system in present all parts of the world, just shown in the carrier wave schematic diagram of Fig. 1 audio standard, comprising FM A2 BG, FM A2 DK1, FM A2 DK2, FM A2 DK3, FM A2 M, EIAJ, BTSC, AM mono L NICAM, FM monoI NICAM, FM mono BG NICAM, and 11 kinds of broadcast audio format signals such as FM mono DK NICAM.It should be noted that at this carrier wave of above-mentioned broadcast audio format signal can be formed at 4.5MHz, 4.72MHz, 5.5MHz, 5.74MHz, 5.85MHz, 6MHz, 6.25MHz, 6.4MHz, 6.5MHz, 6.552MHz, 6.6MHz, and 6.74MHz etc. on the one or more frequency bands in the middle of totally 12 frequency bands.
By also learning among the figure, in the carrier wave of different broadcast audio format signals, in order to reach sound effect such as bilingual or stereo, can on two frequency bands, have carrier wave simultaneously, and represent main carrier wave with the horizontal stripe that fills up among the figure, represent attached carrier wave with the horizontal stripe of blank, and the present invention carries out identification by the frequency band at main carrier wave place when carrying out identification.In addition, in all broadcast audio format signals, have only NICAM broadcast audio format signal to comprise simulation and two kinds of carrier waves of numeral, remaining broadcast audio format signal then all belongs to analog carrier, and wherein analog carrier has the strong characteristic of energy; The then common more weak and frequency range broad of energy of digital carrier.
Therefore, for the broadcast audio format signal can correctly be provided, the frequency band at the carrier wave place of above-mentioned various broadcast audio format signals is just write down in the design of device for identifying of the present invention in advance, which kind of frequency band detects its carrier wave of audio signal that is received into afterwards again is positioned on, and testing result and the aforementioned carrier frequency band of various broadcast audio format signals of record in advance compared the broadcast audio form that is consistent with the audio signal that is received into decision.
Please refer to Fig. 2, Fig. 2 is the embodiment calcspar of audio standard device for identifying of the present invention, as shown in the figure, the invention provides a kind of audio standard device for identifying 1, comprises that a carrier wave computing unit 10, switches control unit 20, reaches a phase generator 30.In general, audio standard device for identifying 1 is one of composition assembly of the audio-frequency function part of a television system (TV system), is used for detecting automatically and judging the audio standard that audio signal was suitable for that is received into.Wherein, carrier wave computing unit 10 is in order to receive the intermediate-freuqncy signal 101 via harmony device (Tuner) (figure does not show) and analog/digital converter (ADC) (figure does not show) output of changing, wherein said intermediate-freuqncy signal 101 is via the SIF sound intermediate frequency after the digital translation (Sound Intermediate Frequency, SIF) signal.Then carrier wave computing unit 10 calculates the energy size (Magnitude) of the first carrier 102 of intermediate-freuqncy signal 101 respectively on above-mentioned 12 frequency bands, and because the phase place and the angle of frequency signal are different because of waveform change, therefore the carrier energy at carrier wave is to calculate with amplitude among the present invention, that is to say before calculating first carrier energy 102, earlier the intermediate-freuqncy signal 101 that receives is converted to an amplitude orthogonal component in order to the energy that calculates carrier wave, and first carrier energy 102 of the present invention is to average and produced more representative first carrier energy 102 with the sampling value at a plurality of (for example 4096) carrier energy.
And be the computing that further specifies first carrier energy 102, please also refer to the embodiment calcspar of Fig. 3 carrier wave computing unit of the present invention, as shown in the figure, in carrier wave computing unit 10, also include a rotation of coordinate digital calculator (Coordinate Rotation Digital Computer, the vector location 130 of converting unit 110 CORDIC), a frequency reducing unit 120, a rotation of coordinate digital calculator, an and numerical operation unit 140.Wherein the converting unit 110 of CORDIC is according to the present frequency band that scans and intermediate-freuqncy signal 101 is carried out the quadrature frequency conversion is fundamental frequency signal, and further be converted to the amplitude orthogonal component again, this amplitude orthogonal component includes baseband I component and Q component, and for whole device for identifying 1 can be operated under power saving and operation efficiency condition with higher, therefore have I, the amplitude orthogonal component of Q component can be again imposes the restriction of band territory with the amplitude orthogonal component that produces a sampling rate (I ' and Q ') via frequency reducing unit 120, for example with analog/digital converter the 24.576MHz sampling rate of specific output be restricted to the amplitude orthogonal component (I ' and Q ') of the sampling rate of 384KHz by frequency reducing unit 120.
The vector location 130 of CORDIC then is again the amplitude orthogonal component of sampling rate (I ' and Q ') to be scaled second carrier energy 102 ' according to the polar coordinates value of each component, and by one first counter 1410 in the numerical operation unit 140 count and the number of accumulating second carrier energy 102 ' to reach first number of samples (4096) afterwards, average computing to export the first carrier energy 102 of present institute scan band by numerical operation unit 140 again.
And the phase generator 30 among Fig. 2 in order to define above-mentioned in the fixed frequency of 12 frequency bands, and provide frequency band transformation to carrier wave computing unit 10 to finish the first carrier energy 102 that calculates each frequency band in regular turn, band count device 210 in the switch control unit 20 then is the frequency band transformation that is provided by phase generator 30 in order to counting carrier wave computing unit 10, to confirm to have produced all first carrier energy 102 separately on all frequency bands.Afterwards, switch control unit 20 is just added up first carrier energy 102 on all frequency bands physical presence is had carrier wave on which frequency band to obtain.And it is as discussed previously, each broadcast audio format signal all comprises a main carrier wave at least, and device for identifying 1 of the present invention mainly is that the frequency band of judging main carrier wave place comes the identification audio standard, therefore whether the switch control unit 20 main carrier wave of further resolving in the detected frequency band that has carrier wave according at least one threshold value (Threshold) 201 is an effective carrier wave, with the frequency band of confirming that main carrier wave is positioned at.
Because the main carrier wave that different broadcast audio format signals is comprised may be the carrier wave of simulation and/or numeral, therefore at different main carrier waves, switch control unit 20 must utilize different analysis modes to resolve the frequency band at main carrier wave place, for example: the frequency band that comes the main carrier wave place of analytic simulation by sluggish mode; And utilize ralocatable mode to come the frequency band at the main carrier wave place of resolution digital.Wherein sluggish mode promptly is to utilize two threshold values to repeat to screen the main carrier wave of this simulation, when the main carrier wave of simulation judges that then this main carrier wave is invalid carrier wave during less than wherein a first threshold, this main carrier wave of ability decidable was effective carrier wave when perhaps the main carrier wave of this simulation must be greater than wherein another second threshold value.Wherein, invalid carrier wave may just be noise promptly or be disturbed the surging that is produced, be not the carrier signal for the broadcast audio format signal, and effective carrier wave that passing threshold parsed just be the carrier signal of broadcast audio format signal.
In addition, analysis mode for convenience of description floats, referring again to the frequency spectrum sampling schematic diagram of Fig. 4 the present invention in NICAM broadcast audio format signal, because NICAM broadcast audio format signal includes the main carrier wave of numeral and simulation, and unsteady analysis mode is described by digital carrier wherein, as shown in the figure, the frequency band at the main carrier wave place of numeral is positioned on the frequency band of 5.85MHz, and its frequency range broad (falling between the 5.74MHz-6MHz approximately), yet in fact the frequency curve that is obtained by spectrum analyzer (Spectrum) is a dashed curve as shown in FIG., wherein resolve as threshold value 201 if directly get the high and minimum level difference value i of the carrier wave on the 5.85MHz frequency band, then tend to consequently can't accurately calculate threshold value 201 and resolve because digital carrier causes the situation of waveform shake easily because of interference of noise.So design by ralocatable mode, selection must not have one of NICAM carrier wave and (for example: 6.35MHz) as benchmark float frequency band, the level difference value j of frequency band 5.85MHz at frequency band and the main carrier wave place of numeral of will floating again is set at threshold value 201, to finish the parsing to the frequency band at the main carrier wave place of numeral.In other words, at this unsteady analysis mode, promptly be as threshold value with unsteady noise floor (noise floor).
Therefore, switch control unit 20 just can obtain the above-mentioned frequency band that effective carrier wave was positioned at that parses, and then the carrier frequency band of all broadcast audio format signals that it comparison is write down in advance, to determine the broadcast audio form that is consistent with the audio signal that is received into.
In order to further specify the present invention, please refer to Fig. 5, Fig. 5 is the embodiment flow chart of audio standard discrimination method of the present invention, as shown in the figure, present embodiment provides discrimination method performed in the audio standard device for identifying 1.Identical, wherein device for identifying 1 records the frequency band at the carrier wave place of all broadcast audio format signals in advance, and the step of discrimination method comprises: at first, provide the carrier wave computing unit 10 receiving intermediate frequency signals 101 (S501), and then the frequency band transformation by phase generator 30 loads in regular turn as 12 frequency bands in Fig. 1 explanation, and the frequency band that foundation is scanned is fundamental frequency signal (S503) with intermediate-freuqncy signal 101 frequency conversions, then, converting unit 110 by the CORDIC in the carrier wave computing unit 10 to be scanning (S505) at the carrier wave on the frequency band at present place, and calculates second carrier energy 102 ' (S507) of the frequency band at present place by the vector location 130 of CORDIC.
In addition, the representativeness of the carrier energy that calculates in order to increase, therefore design of the present invention is that the number of samples of choosing 4096 second carrier energies 102 ' averages computing, wherein be to judge by first counter 1410 whether the quantity of second carrier energy 102 ' that calculates at this frequency band reaches first number of samples of setting (4096) (S509), if judged result then repeats to carry out carrier scanning for not on present frequency band; Otherwise if judged result is for being, i.e. the quantity of second carrier energy 102 ' that expression is accumulated has reached 4096, therefore just averages computing with generation first carrier energy 102 (S511) by numerical operation unit 140.And then, for example start one first buffer (figure does not show) again and be stored in the first carrier energy 102 (S512) that is calculated on the present frequency band.Certainly, those skilled in the art should understand, and the average calculating operation described in the present embodiment only is an example, and the quantity of sampling also need not to be defined in 4096 points, also can adopt other average strategy or weighted average strategy; Even and do not average computing, the direct benchmark that is used as judging with second carrier energy, also not having can not.
And in step (S512) afterwards, just judge whether to finish all frequency scans (S513) by band count device 210, to determine on each frequency band, all having calculated first carrier energy 102, if the judged result of step (S513) is for denying, the scanning of all frequency bands is not finished in i.e. expression as yet, therefore just provide frequency band transformation to enter next frequency band (S515) with indication by phase generator 30, and repeated execution of steps (S503) flow process afterwards, scanning all finished up to 12 frequency bands.
If the judged result of step (S513) promptly represents to finish the scanning of all frequency bands for being, so switch control unit 20 just counts according to the first carrier energy 102 of all storages in first buffer physical presence has carrier wave (S519) on which frequency band.In addition, the present invention has the frequency band of carrier wave to carry out the identification of main carrier wave at physical presence, and may be that actual voice signal also might be the waveform that noise produces in the main carrier wave, therefore further again passing threshold 201 is resolved main carrier wave (S521), and then can obtain the definite frequency band that effective carrier wave was positioned at, the frequency band that effective carrier wave the was positioned at comparison that will obtain again afterwards is the carrier frequency band of all broadcast audio format signals of record in advance, just can determine the broadcast audio form (S523) that is consistent with the audio signal that is received into and adjust the usefulness of parameter with correct processing and group playback frequency signal for subsequent conditioning circuit.In addition, if the frequency band that effective carrier wave is positioned at is after the carrier frequency band of the broadcast audio format signal that comparison is write down in advance, the broadcast audio form that generation is consistent reaches one when above, then provide the broadcast audio form, and come other broadcast audio form that meets of selective switching in the mode that candidate item is provided simultaneously according to preferential power and position.And preferential power and position wherein refers to and in advance different broadcast audio forms is set order and be stored among one second buffer (figure do not show), and when last when producing a plurality of broadcast audio form that is consistent, just inspected default order in second buffer and come foundation as preferential power and position.
Refer again to Fig. 6 A-B, Fig. 6 A-B determines the embodiment flow chart of broadcast audio format signal for the present invention, and present embodiment is further describing of being done of step in the corresponding diagram 5 (S519)-step (S523).And at first be noted that, present embodiment is for example 11 kinds of broadcast audio format signals among Fig. 1 to be divided into different systems with the difference of the frequency band at carrier wave place own, thereby is broadly divided into M/N system (EIAJ, BTSC, FM A2 M), BG system (FM A2 BG, FM mono BG NICAM), I system (FM_mono I NICAM, AM_mono L NICAM) and four kinds of systems such as (FM A2 DK1, FM A2DK2, FM A2 DK3, FM mono DK NICAM, AM_mono L NICAM) of L/DK system.The frequency band of distinguishing above-mentioned these systems then is respectively to be set at 4.5MHz, 5.5MHz, 6MHz and 6.5MHz.
Therefore, in obtaining first buffer, after the first carrier energy (S601) of all frequency bands, then there is the frequency band of carrier wave to indicate (S603) physical presence in the frequency band of 4.5MHz, 5.5MHz, 6MHz and 6.5MHz.Then, confirm in the frequency band of 4.5MHz, 5.5MHz, 6MHz and 6.5MHz whether have only one of them frequency band (S605) of sign.If the affirmation result of step (S605) promptly represent to confirm system (S607), and this may be to have a plurality of frequency band physical presence that carrier wave is arranged simultaneously, thereby have a plurality of frequency bands to be labeled, so can't confirm system for not; Also or may carrier wave be arranged, thereby there is not frequency band to be labeled, so can't confirm system equally without any the frequency band physical presence.
If the affirmation result of step (S605) then represents to have only one of them frequency band physical presence that carrier wave is arranged and be labeled for being, therefore just can carry out follow-up step according to the frequency band that is labeled.Wherein, in the affirmation result of step (S605) for after being, if the frequency band of 4.5MHz is labeled, then be expressed as the M/N system, so further judge that in sluggish mode whether the frequency band of 4.72MHz is greater than default threshold value (S609) again, if judged result is for being, the frequency band that then can obtain 4.5MHz and 4.72MHz is to have effective carrier wave, therefore behind the frequency band at the carrier wave place that comparison is write down in advance, just can confirm to provide the broadcast audio form (S611) of the stereo format of FM A2M, and, just be stereosonic form therefore owing to there are two frequency bands to have effective carrier wave.Opposite, if the judged result of step (S609) is for denying, represent that then the frequency band that only can obtain 4.5MHz has effective carrier wave, therefore behind the frequency band at the carrier wave place that comparison is write down in advance, can confirm to provide the broadcast audio form (S613) of the monophony form of EIAJ, BTSC or FM A2 M, and the mode with preferential power and position provides the broadcast audio form, provides to switch in the candidate item mode again and selects.
And in the affirmation result of step (S605) for after being, if when the frequency band of 5.5MHz is labeled, then be expressed as the BG system.And after being judged as the BG system, can be simultaneously with reference to shown in the figure 7A, further passing threshold judges with ralocatable mode whether the frequency band of 5.85MHz has digital carrier (S615).If judged result is for being, the frequency band that can obtain 5.5MHz and 5.85MHz is to have effective carrier wave, and the frequency band of 5.85MHz is a digital carrier, therefore behind the carrier frequency band at the place that comparison is write down in advance, can confirm to provide the broadcast audio format signal (S617) of FM mono BG NICAM.
Opposite, if the judged result of step (S615) for not the time, then can judge that in sluggish mode whether the frequency band of 5.74MHz is greater than default threshold value (S619) shown in Fig. 7 B and Fig. 7 C.If the judged result of step (S619) is for being, then the expression frequency band that can obtain 5.5MHz and 5.74MHz is to have effective carrier wave, therefore in comparison in advance behind the frequency band at the carrier wave place of record, can confirm to provide the broadcast audio format signal (S621) of the stereo format of FM A2 BG.And if the judged result of step (S619) is not, represent that then the carrier wave on the frequency band of 5.74MHz may be the waveform of noise merely, thereby the frequency band that only can obtain 5.5MHz is to have effective carrier wave, therefore in comparison in advance behind the frequency band at the carrier wave place of record, can confirm to provide the broadcast audio format signal (S623) of the monophony form of FM A2 BG.
And in the affirmation result of step (S605) for after being, if when the frequency band of 6MHz is labeled, then be expressed as the I system, and then same passing threshold judges with ralocatable mode whether the frequency band of 6.552MHz has digital carrier (S625).If judged result is for being, the frequency band that then can obtain 6MHz and 6.552MHz is to have effective carrier wave, and the frequency band of 6.552MHz is a digital carrier, therefore behind the frequency band at the carrier wave place that comparison is write down in advance, can confirm to provide the broadcast audio format signal (S627) of FM mono I NICAM.Otherwise if the judged result of step (S625) is not for the time, then the expression frequency band that only obtains 6MHz has effective carrier wave, therefore in advance behind the frequency band at the carrier wave place of record, can confirm to provide the broadcast audio format signal (S629) of AM mono L NICAM in comparison.
And in the affirmation result of step (S605) for after being, if when the frequency band of 6.5MHz is labeled, then be expressed as the L/DK system, and then passing threshold judges with ralocatable mode whether the frequency band of 5.85MHz has digital carrier (S631).If the judged result of step (S631) is when being, then the expression frequency band that can obtain 6.5MHz and 5.85MHz is to have effective carrier wave, and the frequency band of 5.85MHz is a digital carrier, therefore behind the frequency band at the carrier wave place that comparison is write down in advance, can confirm to provide the broadcast audio format signal (S633) of FM mono DK NICAM or AM_mono L NICAM, and both provide the broadcast audio format signal in the mode of preferential power and position equally, provide selection in the candidate item mode again.
And if the judged result of step (S631) for not the time, then judge that in sluggish mode whether the frequency band of 6.25MHz is greater than preset threshold value (S635), if the judged result of step (S635) is for being, then the expression frequency band that can obtain 6.5MHz and 6.25MHz is to have effective carrier wave, therefore behind the frequency band at the carrier wave place that comparison is write down in advance, can confirm to provide the stereosonic broadcast audio format signal (S637) of FM A2 DK1.
And if the judged result of step (S635) for not the time, then continue to judge that in sluggish mode whether the frequency band of 6.74MHz is greater than preset threshold value (S639), if the judged result of step (S637) is for being, then the expression frequency band that can obtain 6.5MHz and 6.74MHz is to have effective carrier wave, therefore behind frequency band, can confirm to provide the broadcast audio format signal (S641) of the stereo format of FM A2 DK2 than the carrier wave place that should write down in advance.
Moreover, if the judged result of step (S639) is not for the time, further judge that in sluggish mode whether the frequency band of 5.74MHz is greater than preset threshold value (S643) again, if the judged result of step (S643) is for being, then the expression frequency band that can obtain 6.5MHz and 5.74MHz is to have effective carrier wave, therefore in comparison in advance behind the frequency band at the carrier wave place of record, can confirm to provide the broadcast audio format signal (S645) of the stereo format of FM A2 DK3.At last, if the judged result of step (S643) is for denying, then the expression frequency band that only can obtain 6.5MHz is to have effective carrier wave, and owing to can not have digital carrier, therefore in comparison in advance behind the carrier frequency band of record, can confirm to be provided as the broadcast audio format signal (S647) of the monophony form of any FM A2 DK.
Subsidiary one what carry is that above-described threshold value is adjustable threshold value, and is to can be different threshold value for the parsing of different frequency bands, mainly is to set in response to the different designs situation, and is not in order to restriction the present invention.
In sum, the present invention calculates affiliated carrier wave by the carrier energy of statistics sound if signal, and the frequency band at the carrier wave place of all broadcast audio format signals of record in advance of comparing, obtain the broadcast audio format signal that correct effective carrier wave decides to be consistent with activation, this can not only more accurately judge the broadcast audio format signal that the different digital sound if signal is arranged in pairs or groups and offer subsequent conditioning circuit and adjusts the usefulness of parameter with correct processing and playing audio signal, also can reach the purpose that just can support various countries' broadcast system by design single audio frequency coding chip, increase the property applied flexibly of chip significantly, and do not need to save development resources because of repeatedly developing similar products.
The above, only be the detailed description and the accompanying drawing of specific embodiments of the invention, be not in order to restriction the present invention, all scopes of the present invention should be as the criterion with claim of the present invention, those skilled in the art can think easily and variation or modify the scope that claim defined all can be encompassed in the application.
Claims (16)
1. audio standard device for identifying records the frequency band at the carrier wave place of a plurality of broadcast audio format signals in advance, comprising:
One carrier wave computing unit receives an intermediate-freuqncy signal, and by being that a baseband signal is calculated this intermediate-freuqncy signal separately first carrier energy on a plurality of frequency bands according to a plurality of frequency bands with this intermediate-freuqncy signal frequency conversion; And
One switches control unit, the first carrier energy of adding up on these frequency bands is obtained at least one frequency band that has carrier wave, and resolve the frequency band that this has carrier wave according at least one threshold value again, and then obtain at least one effective carrier wave, and this switch control unit is confirmed in these broadcast audio format signals one according to this effective carrier wave again;
Wherein, the broadcast audio format signal of confirming through this switch control unit is to there being this effective carrier wave.
2. audio standard device for identifying as claimed in claim 1, wherein this intermediate-freuqncy signal is the digital audio intermediate-freuqncy signal.
3. audio standard device for identifying as claimed in claim 1, wherein calculating this first carrier energy is to calculate with an amplitude orthogonal component, and this carrier wave computing unit further comprises:
The converting unit of one rotation of coordinate digital calculator is that to carry out the quadrature frequency conversion be a fundamental frequency signal and be converted to this amplitude orthogonal component with this intermediate-freuqncy signal;
One frequency reducing unit is in order to this amplitude orthogonal component is imposed the restriction of band territory, to produce the amplitude orthogonal component of a sampling rate;
The vector location of one rotation of coordinate digital calculator is converted to one second carrier energy with the amplitude orthogonal component of this sampling rate; And
One numerical operation unit in order to accumulate this second carrier energy when reaching one first number of samples, averages computing to export this first carrier energy.
4. audio standard device for identifying as claimed in claim 3, wherein this amplitude orthogonal component comprises baseband I component and Q component.
5. audio standard device for identifying as claimed in claim 1, wherein this exists carrier wave to comprise a main carrier wave at least, and this threshold value is resolved this main carrier wave by sluggishness or ralocatable mode.
6. audio standard device for identifying as claimed in claim 5 wherein should the sluggishness mode utilize two these threshold values to resolve the main carrier wave of a simulation.
7. audio standard device for identifying as claimed in claim 5, wherein this ralocatable mode utilization and is floated the computing of frequency band producing this threshold value, and then resolves the main carrier wave of a numeral.
8. audio standard device for identifying as claimed in claim 1 also comprises a phase generator, in order to defining the fixed frequency of these frequency bands, and provides frequency band transformation to this carrier wave computing unit.
9. audio standard device for identifying as claimed in claim 1, wherein this switch control unit further comprises a band count device, in order to whether counting this carrier wave computing unit, and on these frequency bands, produce this first carrier energy separately by the frequency band transformation that this phase generator provided.
10. audio standard discrimination method records the frequency band at the carrier wave place of a plurality of broadcast audio format signals in advance, in order to receiving an intermediate-freuqncy signal, and is a fundamental frequency signal according to a plurality of frequency bands with this intermediate-freuqncy signal frequency conversion, and the step of this discrimination method comprises:
On these frequency bands, scan the carrier wave of this fundamental frequency signal respectively, and calculate a first carrier energy separately;
According to these first carrier energy, count at least one frequency band that has carrier wave;
Resolve this frequency band that has carrier wave to obtain at least one effective carrier wave by at least one threshold value; And
This effective carrier wave ratio is exported one of them broadcast audio format signal to the frequency band at this carrier wave place of writing down in advance to switch;
Wherein, the broadcast audio format signal of this switching output is to there being this effective carrier wave.
11. audio standard discrimination method as claimed in claim 10, wherein calculating this first carrier energy is to calculate with an amplitude orthogonal component, makes the carrier wave of this fundamental frequency signal be converted to this amplitude orthogonal component.
12. audio standard discrimination method as claimed in claim 11, wherein this amplitude orthogonal component comprises baseband I component and Q component.
13. audio standard discrimination method as claimed in claim 10, wherein this exists carrier wave to comprise a main carrier wave at least, and this threshold value is resolved this main carrier wave by sluggishness or ralocatable mode.
14. audio standard discrimination method as claimed in claim 10, wherein if this effective carrier wave and carrier wave that this writes down in advance compare obtain a plurality of when corresponding broadcast audio format signal is arranged, then provide a candidate item with select these broadcast audio format signals that correspondence is arranged one of them to export.
15. audio standard discrimination method as claimed in claim 10, further provide one first counter to judge with accumulative total whether one second carrier energy that each these frequency band is taken a sample reaches one first number of samples, and then averaged computing and obtain this first carrier energy.
16. audio standard discrimination method as claimed in claim 10, further provide a band count device to count frequency band transformation judging whether have this first carrier energy on these frequency bands separately, if judged result is for being then to store these first carrier energy to have carrier wave to count this.
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| MAHARATNA K ET AL.《A 16-bit cordic rotator for high-speed wireless lan》.《PIMRC 2004，15 TH IEEE INTERNATIONAL SYMPOSIUM ON BARCELONA》.2004,1747-1751. * |
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