CN103856278A - Implementing method and device for FM digital-analog simulcasting - Google Patents
Implementing method and device for FM digital-analog simulcasting Download PDFInfo
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Abstract
The invention relates to an implementing method and device for FM digital-analog simulcasting. The method comprises the steps that an analog audio signal and a digital audio signal are received; digital quantification is performed on the analog audio signal so that an audio signal after the digital quantification can be acquired; analog FM baseband modulation is performed on the audio signal after the digital quantification, baseband modulation is performed on the digital audio signal, and therefore an analog FM channel I signal, an analog FM channel Q signal, a digital audio channel I signal and a digital audio channel Q signal are acquired; signal combination is performed on the analog FM channel I signal, the analog FM channel Q signal, the digital audio channel I signal and the digital audio channel Q signal on a baseband to generate a composite baseband signal I and a composite baseband signal Q, wherein the composite baseband signals are orthogonal; RF modulation is performed on the composite baseband signals. According to the implementing method and device for FM digital-analog simulcasting, occupation of RF channel resources in the implementing process of FM digital-analog simulcasting is effectively reduced.
Description
Technical field
The present invention relates to broadcast technology, particularly relate to a kind of frequency modulation digital-to-analogue with the implementation method of broadcasting and the same implement device of broadcasting of frequency modulation digital-to-analogue.
Background technology
Frequency modulation (Frequency Modulation, FM) is broadcasted tonequality and the interference free performance with its high-quality, and becomes a kind of application that liked by user in society.
In order to improve the program quality of FM broadcasting, FM broadcasting is developed to digital frequency modulation broadcast by traditional analog fm broadcast.Compared with broadcasting with traditional analog fm, digital frequency modulation broadcast, owing to having adopted digital transmission technology, therefore, can be eliminated the phenomenons such as multipath effect, doppler shift effect and burst noise interference effectively; Aspect tonequality, digital frequency modulation broadcast can reach the tonequality that approaches CD; Aspect business, digital frequency modulation broadcast can provide high-quality audio broadcasting program, and expands new data service.In future, analog fm broadcast will be substituted by digital audio broadcasting.
But, although digital frequency modulation broadcast is compared with the broadcast of traditional analog fm, there is more advantage, but, owing to there is at present the restriction of the condition such as frequency spectrum resource and digitizer shortage, therefore, analog fm broadcast meeting within a period of time with digital frequency modulation broadcast and deposit.
At analog fm broadcast and digital frequency modulation broadcast and during depositing, transmitting terminal can adopt digital-to-analogue with broadcasting technology conventionally.So-called digital-to-analogue is with broadcasting, refer to and do not needing to apply under the clear condition of new frequency spectrum resource, traditional analog transmissions program making and speech amplifier are carried out to digital improvement, at existing audio broadcasting frequency range (88-108MHz) upper launching simulation program and digital program simultaneously, thereby realize the smooth excessiveness of analog fm broadcast to digital frequency modulation broadcast.
At present, existing frequency modulation digital-to-analogue with the implementation of broadcasting is: FM modulation system receives digital audio and video signals (Audio Engineering Society/European Broadcast Union, audio engineer association/European Broadcasting Union, or simulated audio signal AES/EBU), by DSP(Digital Signal Processing, digital signal processor) digital audio and video signals receiving is carried out to Audio Signal Processing and stereo coding processing, DSP exports stereo composite signal, this stereo composite signal is through D/A(D/A) transducer is converted into the composite signal that simulates stereo, system can utilize this signal to press cavity oscillations device to VCO() carry out frequency modulation modulation.That is to say, before producing stereo composite signal, the digital audio and video signals that system docking is received carries out digitized processing, and after stereo composite signal is converted into the composite signal that simulates stereo, system adopts the mode of existing analog fm modulation to process.This implementation can be referred to as " DSP+PLL(phase-locked loop) " mode.
Inventor finds realizing in process of the present invention: because existing frequency modulation digital-to-analogue is first digital audio modulation signal to be modulated to radio frequency with the implementation of broadcasting, then, carrying out power with analog signal again synthesizes, carry out modulus with synthesizing of broadcasting in radio frequency domains, therefore, this implementation needs two radio-frequency channels, has taken limited radio-frequency channel resource.
Because the problem that existing frequency modulation digital-to-analogue exists with the implementation of broadcasting, practical experience and the professional knowledge of the inventor based on being engaged in this type of product design manufacture and enriching for many years, and the utilization of cooperation scientific principle, actively research and innovation in addition, to founding a kind of new frequency modulation digital-to-analogue with implementation method and the device broadcast, can overcome the problem that existing frequency modulation digital-to-analogue exists with the implementation of broadcasting, make it have more practicality.Through continuous research and design, and through repeatedly studying sample and improvement, finally create the present invention who has practical value.
Summary of the invention
Main purpose of the present invention is, overcome the problem that existing frequency modulation digital-to-analogue exists with the implementation of broadcasting, and the implementation method and the device that provide a kind of new frequency modulation digital-to-analogue to broadcast together, technical problem to be solved is to reduce taking radio frequency channel resource in frequency modulation digital-to-analogue is broadcast implementation procedure together.
Object of the present invention and solve its technical problem and can adopt following technical scheme to realize.
A kind of frequency modulation digital-to-analogue proposing according to the present invention, with the implementation method of broadcasting, comprising: receive simulated audio signal and digital audio and video signals; Described simulated audio signal is carried out to digital quantization processing, to obtain digital quantization audio signal after treatment; Described digital quantization audio signal after treatment is carried out to the processing of analog fm baseband modulation, and described digital audio and video signals is carried out to baseband modulation processing, to obtain analog fm I road signal, analog fm Q road signal, digital audio I road signal and digital audio Q road signal; Described analog fm I road signal, analog fm Q road signal, digital audio I road signal and digital audio Q road signal are carried out to the synthetic processing of signal in base band, generate I, the orthogonal compound baseband signal of Q two-way; Described compound baseband signal is carried out to rf modulations processing.
Aforesaid frequency modulation digital-to-analogue is with the implementation method of broadcasting, wherein saidly described digital quantization audio signal after treatment is carried out to the processing of analog fm baseband modulation comprise: described digital quantization audio signal after treatment is carried out to level conditioning, to adjust the amplitude of audio signal; Audio signal after level is nursed one's health is carried out phase-accumulated as frequency control word and the phase information of process phase register delay process, to obtain the current phase information that described frequency control word is corresponding; Described current phase information is stored in phase register; From described phase register, read current phase information, and intercept the information of predetermined length; The address of searching by the information of described intercepting as one in analog fm I road signal and analog fm Q road signal, and by the phase-accumulated result of the information of described intercepting and phase control words as in analog fm I road signal and analog fm Q road signal another search address; According to the described lookup result of address in sine lookup table of searching, export mutually orthogonal analog fm I road signal and analog fm Q road signal.
Aforesaid frequency modulation digital-to-analogue is with the implementation method of broadcasting, the information of wherein said intercepting is the address of searching of described analog fm I road signal, and the phase-accumulated result of carrying out 90 ° of phase shifts of the information of described intercepting and phase control words is the address of searching of analog fm Q road signal; Or the information of described intercepting is the address of searching of described analog fm Q road signal, the phase-accumulated result of carrying out 270 ° of phase shifts of the information of described intercepting and phase control words is the address of searching of analog fm I road signal.
Aforesaid frequency modulation digital-to-analogue is with the implementation method of broadcasting, and wherein the degree of depth of sine lookup table is: 2^N
p, wherein, N
pfor the bit wide of described phase control words.
Aforesaid frequency modulation digital-to-analogue is with the implementation method of broadcasting, and the synthetic treatment step of the analog fm baseband modulation treatment step in wherein said method, the baseband modulation treatment step of digital audio and video signals and signal is realized by on-site programmable gate array FPGA.
A kind of frequency modulation digital-to-analogue proposing according to the present invention is with the implement device of broadcasting, and this device comprises: receiver module, for receiving simulated audio signal and digital audio and video signals; Digital quantization module, for simulated audio signal is carried out to digital quantization processing, to obtain digital quantization audio signal after treatment; Analog fm baseband modulation module, for described digital quantization audio signal after treatment is carried out to the processing of analog fm baseband modulation, to obtain analog fm I road signal and analog fm Q road signal; Digital audio and video signals baseband modulation module, carries out baseband modulation processing for the digital audio and video signals that described receiver module is received, to obtain digital audio I road signal and digital audio Q road signal; Baseband signal synthesis module, for described analog fm I road signal, analog fm Q road signal, digital audio I road signal and digital audio Q road signal are carried out in base band, signal is synthetic to be processed, and generates I, the orthogonal compound baseband signal of Q two-way; Rf modulations processing module, for carrying out rf modulations processing to described compound baseband signal.
Aforesaid frequency modulation digital-to-analogue is with the implement device of broadcasting, and wherein said analog fm baseband modulation module comprises: level conditioning unit, for described digital quantization audio signal after treatment is carried out to level conditioning, to adjust the amplitude of described audio signal; The first phase-accumulated unit, phase-accumulated for the audio signal of described level conditioning unit output is carried out as frequency control word and the phase information of process phase register delay process, to obtain the current phase information that described frequency control word is corresponding; Phase register, for storing the current phase information of described the first phase-accumulated unit output; Interception unit, for reading current phase information from described phase register, and intercepts the information of predetermined length; The second phase-accumulated unit, phase-accumulated for by the information of described intercepting and phase control words; Sine lookup table unit, store sine lookup table, sine lookup table unit is for the address of searching as analog fm I road signal and analog fm Q road signal by the information of described interception unit output, and by the information of described the second phase-accumulated unit output as in analog fm I road signal and analog fm Q road signal another search address, export mutually orthogonal analog fm I road signal and analog fm Q road signal according to searching the lookup result of address in sine lookup table described in two.
By technique scheme, frequency modulation digital-to-analogue of the present invention at least has following advantages and beneficial effect with the implementation method of broadcasting and device: the present invention is by carrying out digital quantization processing to the simulated audio signal receiving, and audio signal after base band is to digital quantification treatment is carried out the processing of analog fm baseband modulation, like this, analog fm signal and digital audio modulation signal can carry out signal in base band completely and synthesize, and carry out rf modulations in radio frequency domains again after synthetic, thereby the present invention can realize frequency modulation digital-to-analogue with broadcasting in the situation that only taking a radio-frequency channel, in addition, technical scheme provided by the invention is convenient to system debug, and the good stability of system, final the present invention has reduced frequency modulation digital-to-analogue with broadcasting implementation procedure to the taking of radio frequency channel resource, and has reduced the cost of realizing of product.
In sum, the present invention has significant progress technically, and has significantly positive technique effect, is really a new and innovative, progressive, practical new design.
Above-mentioned explanation is only the general introduction of technical solution of the present invention, in order to better understand technological means of the present invention, and can be implemented according to the content of specification, and for above and other object of the present invention, feature and advantage can be become apparent, below especially exemplified by preferred embodiment, and coordinate Figure of description, be described in detail as follows.
Brief description of the drawings
Fig. 1 is that frequency modulation digital-to-analogue of the present invention is with the principle schematic that realizes of broadcasting;
Fig. 2 is the flow chart of frequency modulation digital-to-analogue of the present invention with the implementation method of broadcasting;
Fig. 3 is the specific implementation schematic diagram of analog fm baseband modulation of the present invention processing;
Fig. 4 is the spectrum diagram of compound baseband signal of the present invention;
Fig. 5 is that frequency modulation digital-to-analogue of the present invention is with the implement device schematic diagram of broadcasting.
Embodiment
Technological means and effect of taking for reaching predetermined goal of the invention for further setting forth the present invention, below in conjunction with accompanying drawing and preferred embodiment, the frequency modulation digital-to-analogue proposing according to the present invention, with the implementation method of broadcasting and embodiment, structure, feature and actual effect of device, is described in detail as follows.
The principle that realizes of the present invention comprises: make analog fm signal and digital audio modulation signal complete modulus in base band synthetic with what broadcast, afterwards, in radio frequency domains, above-mentioned synthetic signal is carried out to rf modulations processing again, thus mutually orthogonal I road signal and the Q road signal of output radio frequency domains.This realizes schematic diagram as shown in Figure 1.
In Fig. 1, carry out the processing of analog fm baseband modulation through the simulated audio signal of digital quantization processing in base band, output two-way analog fm signal, i.e. analog fm I road signal and analog fm Q road signal; Meanwhile, digital audio and video signals carries out the processing of digital audio and video signals baseband modulation in base band, output two-way digital audio and video signals, i.e. digital audio I road signal and digital audio Q road signal; Zhe Si road signal carries out the synthetic processing of baseband signal at base band place, thereby generate and export the mutually orthogonal compound baseband signal of two-way, be I, the orthogonal compound baseband signal of Q two-way, the orthogonal compound baseband signal of this two-way can utilize a radio-frequency channel to carry out rf modulations processing in radio frequency domains.
Although the above-mentioned processing procedure shown in Fig. 1 is at FPGA(Field Programmable Gate Array, field programmable gate array) in realize, but, in actual applications, also can utilize other data processing devices to realize, as microprocessor etc.
The feasibility that realizes of the present invention being carried out to the processing of analog fm baseband modulation in base band is below proved explanation.
Frequency modulation is a kind of mode that the control of the signal modulated by the needs instantaneous frequency to radio-frequency carrier signal realizes modulation, the amplitude size of the signal of the frequency of radio-frequency carrier signal and needs modulation is the relation of linear change, and this relation can be explained by following formula (1):
S
fM(t)=Acos[ω
ct+K
fM∫ f (t) dt+ θ
0] formula (1)
In above-mentioned formula (1), the amplitude that A is FM signal, ω
cfor the angular frequency of frequency modulated carrier; F (t) is for needing the audio signal of modulation; K
fMfor frequency deviation constant; ω
0for initial phase.
Analog fm baseband modulation processing in the present invention is actually carries out frequency modulation(FM) by simulated audio signal after treatment process digital quantization at zero-frequency, i.e. above-mentioned ω
c=0, above-mentioned formula (1) is changed to following formula (2):
S
fM(t)=Acos[K
fM∫ f (t) dt+ θ
0] formula (2)
Thereby have instantaneous angular frequency ω to be:
ω=K
fMf (t)+θ
0formula (3)
Like this, the present invention by designing one and the direct akin processing module of frequency synthesis (DDS) algorithm in FPGA or other data handling components, the variation of momentary angular frequencies omega can be converted into the control that frequency control word is changed, meanwhile, can export the orthogonal analog fm I road signal of two-way and analog fm Q road signal completely by the employing mode such as table look-up simultaneously.
Below in conjunction with accompanying drawing, two embodiment of the present invention are described.
Embodiment mono-, frequency modulation digital-to-analogue are with the implementation method of broadcasting, and the flow process of the method as shown in Figure 2.
In Fig. 2, S100, reception simulated audio signal and digital audio and video signals.This simulated audio signal and digital audio and video signals are need to carry out frequency modulation digital-to-analogue with the signal of broadcasting.
S110, the above-mentioned simulated audio signal receiving is carried out to digital quantization processing, thereby can obtain digital quantization audio signal after treatment.
Concrete, can carry out timing sampling to simulated audio signal, and the signal of sampling is carried out to analog-to-digital conversion process.In actual applications, can adopt analog to digital converter to carry out analog-to-digital conversion process to simulated audio signal.
S120, the audio signal after digital quantification treatment is carried out to the processing of analog fm baseband modulation, thereby can obtain analog fm I road signal and analog fm Q road signal; The above-mentioned digital audio and video signals receiving is carried out to baseband modulation processing, thereby can obtain digital audio I road signal and digital audio Q road signal.
Concrete, can adopt to be similar to direct frequency synthesis algorithm and to realize above-mentioned analog fm baseband modulation processing.A concrete example is as shown in Figure 3: first, to carrying out level conditioning through digital quantization audio signal after treatment, amplitude with the audio signal to after digital quantification treatment is adjusted, thereby in the time that simulated audio signal is input as the input of nominal audio frequency, total modulation degree of baseband signal can be 100% modulation left and right; Secondly, level is nursed one's health to audio signal after treatment and carry out phase-accumulated processing as frequency control word and the phase information of process phase register delay process, as utilized phase accumulator to realize aforesaid phase-accumulated process, thereby can obtain the current phase information that frequency control word is corresponding; The current phase information of aforementioned acquisition is stored in phase register; The width of this phase register can be 12-14 bit; The current phase information of storing in this phase register can be used for aforesaid phase-accumulated on the one hand, on the other hand can be as the address of searching of sine lookup table; The phase information reading out from this phase register is intercepted predetermined length (as intercepted high N bit), and the information of what this was intercepted have predetermined length is searched address as of sine lookup table; Another searches the phase-accumulated result that address is the above-mentioned information with predetermined length being intercepted and phase control words; If the information with predetermined length being intercepted is the address of searching of analog fm I road signal, and the information with predetermined length being intercepted and phase control words phase-accumulated carries out the address of searching that 90 ° of phase shift results are analog fm Q road signals; For another example, the information with predetermined length being intercepted is the address of searching of analog fm Q road signal, and phase-accumulated 270 ° of phase shift results of the information with predetermined length being intercepted and phase control words are the addresses of searching of analog fm I road signal; Afterwards, search the lookup result that search in sine lookup table address, output analog fm I road signal and analog fm Q road signal according to above-mentioned two.The degree of depth of above-mentioned sine lookup table can be set to: 2^N
p, wherein, N
pfor the bit wide of phase control words.
The frequency f of this analog fm baseband modulation signal (being analog fm I road signal and analog fm Q)
outfor:
In above-mentioned formula (4), Δ ω is that analog fm baseband modulation signal changes in the phase place of two adjacent clock cycle, i.e. the analog fm I road signal of a clock cycle output of every mistake and the phase change of analog fm Q, f
clkfor system clock frequency, W
ffor frequency control word, N
ffor the bit wide of frequency control word.
In this step, digital audio and video signals is carried out to baseband modulation processing and can adopt existing baseband modulation processing mode, as can be " be with outer digital broadcast channel frame structure according to the part 1 of existing frequency modulation frequency range Chinese Digital audio broadcasting technical specification, Channel Coding and Modulation " in regulation, by exciter, the business datum from upper strata is carried out to scrambling, LDPC coding, constellation mapping, sub-carrier interleaving processing, after business description information scrambler, adopt 1/4 convolution code with system information, Bit Interleave and constellation mapping processing, and carry out OFDM modulation together with scattered pilot, thereby generation baseband signal, be digital audio I road signal and digital audio Q road signal.The present invention does not limit the specific implementation of digital audio and video signals being carried out to baseband modulation processing.
S130, the analog fm I road signal of above-mentioned acquisition, analog fm Q road signal, digital audio I road signal and digital audio Q road signal are carried out in base band to signal is synthetic to be processed, thereby generation compound baseband signal, i.e. mutually orthogonal I road baseband modulation signal and the Q road baseband modulation signal of two-way.
In this step, because analog fm modulation signal and digital audio modulation signal are baseband modulation signal, therefore, can adopt the synthetic processing mode of existing signal to generate compound baseband signal.
A concrete example, according to analog-and digital-audio frequency FM broadcasting principle, baseband signal (being analog fm I road signal and analog fm Q road signal) and digital audio FM signal (being digital audio I road signal and digital audio Q road signal) that analogue audio frequency frequency modulation is generated superpose, generate needed modulus with the baseband signal of broadcasting, the spectrogram of this baseband signal as shown in Figure 4.
S140, the orthogonal baseband modulation signal of the orthogonal baseband modulation signal in above-mentioned I road and Q road is carried out to rf modulations processing in radio frequency domains.
In this step, can, in the situation that using a radio-frequency channel, utilize existing rf modulations processing mode to carry out rf modulations processing to compound baseband signal.
In above-described embodiment one, S120 and S130 can be realized by FPGA, certainly, also can be realized by the data handling component of other types.
Utilize technical scheme that the present embodiment provides can obtain the frequency modulation modulating baseband signal of better quality completely, its analysis of causes is as follows:
If system clock frequency is f
clk, phase control words is W
p, the bit wide of phase control words is N
p, frequency control word is W
f, the bit wide of frequency control word is N
f, the degree of depth of sine look up table is 2^N
p, in the situation that phase control words is constant, system clock cycle of every mistake, the phase change of the frequency modulation modulating baseband signal of the present embodiment output is:
Thereby the frequency of the frequency modulation modulating baseband signal of the present embodiment output is:
In the time that frequency control word changes, the output frequency of the frequency modulation modulating baseband signal of the present embodiment output can change thereupon, thus the frequency modulation(FM) of settling signal; If fclk=3.264MHz and Nf=32, the frequency resolution of the present embodiment is:
Seen from the above description, the frequency modulation modulating baseband signal of the present embodiment output can meet the requirement of system to modulating signal of frequency modulation completely.
Embodiment bis-, frequency modulation digital-to-analogue are with the implement device of broadcasting.The structure of this device as shown in Figure 5.
In Fig. 5, frequency modulation digital-to-analogue comprises with the implement device of broadcasting: receiver module 1, digital quantization module
2, analog fm baseband modulation module 3, digital audio and video signals baseband modulation module 4, baseband signal synthesis module 5 and rf modulations processing module 6.Receiver module 1 is connected respectively with digital quantization module 2 and digital audio and video signals baseband modulation module 4, digital quantization module 2 is also connected with analog fm baseband modulation module 3, and baseband signal synthesis module 5 is connected respectively with analog fm baseband modulation module 3, digital audio and video signals baseband modulation module 4 and rf modulations processing module 6.Above-mentioned analog fm baseband modulation module 3, digital audio and video signals baseband modulation module 4 and baseband signal synthesis module 5 can be realized in FPGA.
What receiver module 1 was mainly used in receiving outside input need to carry out frequency modulation digital-to-analogue with simulated audio signal and the digital audio and video signals broadcast.
The simulated audio signal that digital quantization module 2 is mainly used in receiver module 1 to receive carries out digital quantization processing, and to analog fm baseband modulation module 3 its digital quantization of output audio signal after treatment.Digital quantization module 2 can be carried out timing sampling to simulated audio signal, and the signal of sampling is carried out to analog-to-digital conversion process.Digital quantization module 2 can be existing analog to digital converter.
The digital quantization audio signal after treatment that analog fm baseband modulation module 3 is mainly used in digital quantization modules 2 to export is carried out the processing of analog fm baseband modulation, and exports analog fm I road signal and analog fm Q road signal to baseband signal synthesis module 5.
Analog fm baseband modulation module 3 can comprise: level conditioning unit, the first phase-accumulated unit, phase register, interception unit, the second phase-accumulated unit and sine lookup table unit.
Wherein, level conditioning unit is connected with the first phase-accumulated unit, and the first phase-accumulated unit is also connected with phase register, and phase register is also connected with interception unit, and interception unit is also connected with the second phase-accumulated unit and sine lookup table unit.
The digital quantization audio signal after treatment that level conditioning unit is mainly used in digital quantization modules 2 to export is carried out level conditioning, to adjust the amplitude of its audio signal receiving.Amplitude adjustment by level conditioning module to audio signal, this device can be 100% modulation left and right to total modulation degree of baseband signal.
The first phase-accumulated unit is mainly used in the audio signal of level conditioning unit output to carry out phase-accumulated as frequency control word and the phase information of process phase register delay process, produce current phase information corresponding to frequency control word, and export this current phase information to phase register.
Phase register is mainly used in the current phase information of buffer memory first phase-accumulated unit output.The width of this phase register can be 12-14 bit; The current phase information of storing in this phase register can be used for aforesaid phase-accumulated on the one hand, on the other hand can be as the address of searching of sine lookup table.
Interception unit is mainly used in reading current phase information from phase register, and from this frequency information, intercepts the information (as intercepted high N bit) of predetermined length, afterwards, by the communication of predetermined length intercepting to sine lookup table unit.
The second phase-accumulated unit is mainly used in phase-accumulated by the information of interception unit output and phase control words, and exports accumulation result to sine lookup table unit.
In sine lookup table unit, be provided with sine lookup table, the degree of depth of this sine lookup table can be set to: 2^N
p, wherein, N
pfor the bit wide of phase control words.
Sine lookup table unit is mainly used in the address of searching as in analog fm I road signal and analog fm Q road signal by the information of interception unit output, and by the phase-accumulated result of the second phase-accumulated unit output as in analog fm I road signal and analog fm Q road signal another search address, and utilize these two to search address searching in the sine lookup table of its storage, according to the mutually orthogonal signal of lookup result output two-way, i.e. analog fm I road signal, analog fm Q road signal.
The digital audio and video signals that digital audio and video signals baseband modulation module 4 is mainly used in receiver module 1 to receive carries out baseband modulation processing, and to baseband signal synthesis module 5 outputting digital audio I road signals and digital audio Q road signal.Digital audio and video signals baseband modulation module 4 can adopt existing baseband modulation processing mode to carry out corresponding operation, as the exciter in digital audio signal baseband modulation module 4 can " be with outer digital broadcast channel frame structure according to the part 1 of existing frequency modulation frequency range Chinese Digital audio broadcasting technical specification, Channel Coding and Modulation " in regulation, business datum from upper strata is carried out to scrambling, LDPC coding, constellation mapping, sub-carrier interleaving processing, after business description information scrambler, adopt 1/4 convolution code with system information, Bit Interleave and constellation mapping processing, and carry out OFDM modulation together with scattered pilot, thereby produce digital audio I road signal and digital audio Q road signal.
Baseband signal synthesis module 5 is mainly used in digital audio I road signal that analog fm I road signal that analog fm baseband modulation module 4 is exported and analog fm Q road signal and digital audio and video signals baseband modulation module 4 export and digital audio Q road signal and carries out in base band that signal is synthetic to be processed, to generate compound baseband signal, be I, the orthogonal compound baseband signal of Q two-way, and to frequency modulation modulation treatment module 6 its synthetic I of output, the orthogonal compound baseband signal of Q two-way.Baseband signal synthesis module 5 can adopt the synthetic processing mode of existing signal to generate compound baseband signal.
The orthogonal compound baseband signal of I, Q two-way that rf modulations processing module 6 is mainly used in baseband signal synthesis module 5 to export carries out rf modulations processing.Rf modulations processing module 6 can, in the situation that using a radio-frequency channel, utilize existing rf modulations processing mode to carry out rf modulations processing to compound baseband signal.
The above is only preferred embodiment of the present invention, not the present invention is done to any pro forma restriction, although the present invention discloses as above with preferred embodiment, but not in order to limit technology of the present invention, any those skilled in the art are not departing within the scope of technical solution of the present invention, when can utilizing the technology contents of above-mentioned announcement to make a little change or being modified to the equivalent embodiment of equivalent variations, in every case be the content that does not depart from technical solution of the present invention, any simple modification of above embodiment being done according to technical spirit of the present invention, equivalent variations and modification, all still belong in the scope of technical solution of the present invention.
Claims (10)
1. frequency modulation digital-to-analogue, with an implementation method of broadcasting, is characterized in that, comprising:
Receive simulated audio signal and digital audio and video signals;
Described simulated audio signal is carried out to digital quantization processing, to obtain digital quantization audio signal after treatment;
Described digital quantization audio signal after treatment is carried out to the processing of analog fm baseband modulation, and described digital audio and video signals is carried out to baseband modulation processing, to obtain analog fm I road signal, analog fm Q road signal, digital audio I road signal and digital audio Q road signal;
Described analog fm I road signal, analog fm Q road signal, digital audio I road signal and digital audio Q road signal are carried out to the synthetic processing of signal in base band, generate I, the orthogonal compound baseband signal of Q two-way;
Described compound baseband signal is carried out to rf modulations processing.
2. frequency modulation digital-to-analogue as claimed in claim 1, with the implementation method broadcast, is characterized in that, describedly described digital quantization audio signal after treatment is carried out to the processing of analog fm baseband modulation comprises:
Described digital quantization audio signal after treatment is carried out to level conditioning, to adjust the amplitude of described audio signal;
Audio signal after level is nursed one's health is carried out phase-accumulated as frequency control word and the phase information of process phase register delay process, to obtain the current phase information that described frequency control word is corresponding;
Described current phase information is stored in phase register;
From described phase register, read current phase information, and intercept the information of predetermined length;
The address of searching by the information of described intercepting as one in analog fm I road signal and analog fm Q road signal, and by the phase-accumulated result of the information of described intercepting and phase control words as in analog fm I road signal and analog fm Q road signal another search address;
According to the described lookup result of address in sine lookup table of searching, export mutually orthogonal analog fm I road signal and analog fm Q road signal.
3. frequency modulation digital-to-analogue as claimed in claim 2, with the implementation method of broadcasting, is characterized in that:
The information of described intercepting is the address of searching of described analog fm I road signal, and the phase-accumulated result of carrying out 90 ° of phase shifts of the information of described intercepting and phase control words is the address of searching of analog fm Q road signal; Or
The information of described intercepting is the address of searching of described analog fm Q road signal, and the phase-accumulated result of carrying out 270 ° of phase shifts of the information of described intercepting and phase control words is the address of searching of analog fm I road signal.
4. frequency modulation digital-to-analogue as claimed in claim 2, with the implementation method of broadcasting, is characterized in that, the degree of depth of described sine lookup table is: 2^N
p, wherein, N
pfor the bit wide of described phase control words.
5. frequency modulation digital-to-analogue is as claimed in claim 1 or 2 or 3 or 4 with the implementation method of broadcasting, it is characterized in that, the synthetic treatment step of the analog fm baseband modulation treatment step in described method, the baseband modulation treatment step of digital audio and video signals and signal is realized by on-site programmable gate array FPGA.
6. frequency modulation digital-to-analogue, with an implement device of broadcasting, is characterized in that, this device comprises:
Receiver module, for receiving simulated audio signal and digital audio and video signals;
Digital quantization module, for described simulated audio signal is carried out to digital quantization processing, to obtain digital quantization audio signal after treatment;
Analog fm baseband modulation module, for described digital quantization audio signal after treatment is carried out to the processing of analog fm baseband modulation, to obtain analog fm I road signal and analog fm Q road signal;
Digital audio and video signals baseband modulation module, carries out baseband modulation processing for the digital audio and video signals that described receiver module is received, to obtain digital audio I road signal and digital audio Q road signal;
Baseband signal synthesis module, for described analog fm I road signal, analog fm Q road signal, digital audio I road signal and digital audio Q road signal are carried out in base band, signal is synthetic to be processed, and generates I, the orthogonal compound baseband signal of Q two-way;
Rf modulations processing module, for carrying out rf modulations processing to described compound baseband signal.
7. frequency modulation digital-to-analogue as claimed in claim 1, with the implement device of broadcasting, is characterized in that, described analog fm baseband modulation module comprises:
Level conditioning unit, for carrying out level conditioning to described digital quantization audio signal after treatment, to adjust the amplitude of described audio signal;
The first phase-accumulated unit, phase-accumulated for the audio signal of described level conditioning unit output is carried out as frequency control word and the phase information of process phase register delay process, to obtain the current phase information that described frequency control word is corresponding;
Phase register, for storing the current phase information of described the first phase-accumulated unit output;
Interception unit, for reading current phase information from described phase register, and intercepts the information of predetermined length;
The second phase-accumulated unit, phase-accumulated for by the information of described intercepting and phase control words;
Sine lookup table unit, store sine lookup table, sine lookup table unit is for the address of searching as analog fm I road signal and analog fm Q road signal by the information of described interception unit output, and by the information of described the second phase-accumulated unit output as in analog fm I road signal and analog fm Q road signal another search address, export mutually orthogonal analog fm I road signal and analog fm Q road signal according to searching the lookup result of address in sine lookup table described in two.
8. frequency modulation digital-to-analogue as claimed in claim 7, with the implement device of broadcasting, is characterized in that:
The information of described intercepting is the address of searching of described analog fm I road signal, and the phase-accumulated result of carrying out 90 ° of phase shifts of the information of described intercepting and phase control words is the address of searching of analog fm Q road signal; Or
The information of described intercepting is the address of searching of described analog fm Q road signal, and the phase-accumulated result of carrying out 270 ° of phase shifts of the information of described intercepting and phase control words is the address of searching of analog fm I road signal.
9. frequency modulation digital-to-analogue as claimed in claim 7, with the implement device of broadcasting, is characterized in that, the degree of depth of described sine lookup table is: 2^N
p, wherein, N
pfor the bit wide of described phase control words.
10. the frequency modulation digital-to-analogue as described in claim 6 or 7 or 8 or 9 is with the implement device of broadcasting, it is characterized in that, described analog fm baseband modulation module, digital audio and video signals baseband modulation module and baseband signal synthesis module are realized by on-site programmable gate array FPGA.
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| CN112968851B (en) * | 2021-04-22 | 2022-07-19 | 吉林省广播电视研究所(吉林省广播电视局科技信息中心) | Multi-channel stereo FM broadcast modulator |
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| CN103856278B (en) | 2016-12-21 |
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