CN107231204B - Frequency modulation broadcasting multi-path digital modulating system - Google Patents
Frequency modulation broadcasting multi-path digital modulating system Download PDFInfo
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- CN107231204B CN107231204B CN201710355630.4A CN201710355630A CN107231204B CN 107231204 B CN107231204 B CN 107231204B CN 201710355630 A CN201710355630 A CN 201710355630A CN 107231204 B CN107231204 B CN 107231204B
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04H—BROADCAST COMMUNICATION
- H04H20/00—Arrangements for broadcast or for distribution combined with broadcast
- H04H20/44—Arrangements characterised by circuits or components specially adapted for broadcast
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- 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
- H04B1/02—Transmitters
- H04B1/04—Circuits
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- 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
- H04B1/02—Transmitters
- H04B1/04—Circuits
- H04B1/0475—Circuits with means for limiting noise, interference or distortion
-
- 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
- H04B1/02—Transmitters
- H04B1/04—Circuits
- H04B2001/0408—Circuits with power amplifiers
-
- 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
- H04B1/02—Transmitters
- H04B1/04—Circuits
- H04B2001/0491—Circuits with frequency synthesizers, frequency converters or modulators
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- Engineering & Computer Science (AREA)
- Signal Processing (AREA)
- Computer Networks & Wireless Communication (AREA)
- Transmitters (AREA)
Abstract
Frequency modulation broadcasting multi-path digital modulating system, it is related to broadcasting television technology field, every suit broadcast program for solving existing frequency modulation broadcasting requires to correspond to a set of transmitting equipment, DA converter circuit is also needed using the program that driver is modulated, it also occur that technology of more the problems such as being distorted using modulation twice, the method that can modulate and emit more set frequency modulation broadcasting programs simultaneously with circuit kit device in transformation and modulated process.Broadcast program transport stream is obtained from derived digital signal by Data Input Interface circuit, demultiplexing obtains specified forwarding program data stream, after being compressed using digital solution, this several programs is modulated to together within a midband with frequency-shift keying circuit and add circuit；Using a single sideband modulation circuit, the intermediate-freuqncy signal of these programs is moved frequency modulation broadcasting frequency range together, after amplifying using a power amplifier, all programs can launched together with an antenna, realizes efficient frequency modulation broadcasting program covering.
Description
Technical field
The present invention relates to broadcasting television technology fields, and in particular to the method for modulation circuit in broadcast transmitter, with this
Kind method can be designed that a kind of frequency-modulated broadcast transmitter of small multi-channel.
Background technique
Pocket radio set is easy to carry, and listening to radio broadcasting does not influence job in hand also, and frequency modulation broadcasting program sound quality is good, deep
It is welcome by users.Because frequency modulation broadcasting uses VHF band modulate emission, high-frequency electric wave line-of-sight propagation, so overlay area
It is small.In outlying district, there are many covering blind spots.In order to solve the broadcast covering problem in these areas, need to build very much
Program launch website, then many transmitters are installed.
The radio program signal that radio receives is emitted by the antenna of transmitter.Sound programme baseband signal needs
It first to be modulated with driver, programs of a plurality of channels is synthesized together through power amplifier and then with multiplexer, finally altogether
Antenna is sent to feedback pipe to launch.Therefore every suit broadcast program requires to correspond to a set of transmitting equipment, while emitting more sets
The equipment cost and volume and the quantity of program of program are almost directly proportional.
Because broadcast program contents have realized Digital Transmission, it is sent into the program that driver is modulated and also needs digital mould
Quasi- translation circuit, and it also occur that more distortions in transformation and modulated process.
Summary of the invention
The present invention is to solve every suit broadcast program of existing frequency modulation broadcasting to require to correspond to a set of transmitting equipment, using swashing
It encourages the program that device is modulated and also needs DA converter circuit, it also occur that more distortions in transformation and modulated process
The problems such as, a kind of frequency modulation broadcasting multi-path digital modulating system is provided.
Frequency modulation broadcasting multi-path digital modulating system, including Data Input Interface circuit, de-multiplexing circuitry, digital solution compression electricity
Road, frequency-shift keying circuit, add circuit, power amplifier and single sideband modulation circuit obtain number by Data Input Interface circuit
The program transport streams of word, and pass through the data information of de-multiplexing circuitry separation program transport streams；Obtain program data stream；It is described
Digital solution compressor circuit unzips it the program data stream of acquisition, and the broadcast sounds data after decompression are input to number
Word FM circuit；
The frequency-shift keying circuit counting goes out the corresponding modulating frequency of voice data, and every programs are individually modulated, real
Existing different programme signal modulation are over different frequencies；After modulated signal is overlapped using add circuit, it is distributed in
On identical medium-frequency band signal；The single sideband modulation circuit is used to medium-frequency band signal moving frequency modulation broadcasting frequency range,
Obtain Polymera composite signal total in frequency modulation broadcasting frequency range；The power amplifier is used to the Polymera composite signal carry out
Amplification, and emitted using antenna, realize that covering is listened in the frequency modulation broadcasting of Polymera.
Beneficial effects of the present invention: digital modulation system of the invention can use a set of electricity using the technology of modulation twice
Road device is modulated simultaneously and emits the method for more set frequency modulation broadcasting programs.It is obtained by Data Input Interface circuit from derived digital signal
Broadcast program transport stream, demultiplexing obtain specified forwarding program data stream, after compressing using digital solution, use frequency-shift keying
Circuit and add circuit are together modulated to this several programs within one midband；Using a single sideband modulation circuit,
The intermediate-freuqncy signal of these programs moves frequency modulation broadcasting frequency range together, after amplifying using a power amplifier, with a day
Line together can launch all programs, realize efficient frequency modulation broadcasting program covering.
Present invention employs the methods that number is directly modulated, and the digital program data of input is directly modulated to high frequency, in
Between there is no analog converting process, so broadcast sounds distortion is small, because a set of digital circuit can more set sections of modulation parallel simultaneously
Mesh is simultaneously superimposed, and then shares a set of transmit circuit and launches, so emitting simultaneously compared with legacy transmission machine equipment
When multiple programs, that is, multiple drivers are not needed, and do not need multiple power amplifiers, less there is multiplexer.So being obviously reduced
The volume and power consumption of equipment, reduce costs.
Detailed description of the invention
Fig. 1 is the functional block diagram of frequency modulation broadcasting multi-path digital modulating system of the present invention；
Fig. 2 is by several program modulations using frequency modulation broadcasting multi-path digital modulating system of the present invention later in intermediate frequency
Distribution Principle figure on frequency band；
Fig. 3 is to be passed through using the intermediate-freuqncy signal of all programs in frequency modulation broadcasting multi-path digital modulating system of the present invention
After amplitude-modulating modulation, the spectrogram after shifting as frequency spectrum is realized.
Specific embodiment
Specific embodiment one illustrates present embodiment, frequency modulation broadcasting multi-path digital modulating system, packet in conjunction with Fig. 1 to Fig. 3
Include Data Input Interface circuit 1, de-multiplexing circuitry 2, digital solution compressor circuit 3, frequency-shift keying circuit 4, add circuit 5, frequency displacement
Circuit 6, side frequency filter circuit 7, power amplifier 8 and antenna 9；
Broadcast program digitlization, which is transferred, generallys use wired coaxial cable, optical fiber, microwave, satellite and network several ways,
Digitized program can be obtained using corresponding data interface circuit 1 and transfer stream, wherein include multiple program data streams and
Relevant programme information.Each program data packets can be identified using programme information by de-multiplexing circuitry 2, pass through mask data
The identification code of packet, the available one or several program data streams wherein specified.
Since every programs are all just transferred after being compressed, so the data flow at this moment obtained needs to decompress
Actual programme content can just be obtained.The selected one or more program data streams for needing to emit, utilize digital solution compressor circuit 3
True broadcast sounds content PCM data is restored, frequency-shift keying circuit is then inputted.
The frequency-shift keying circuit directly to calculate the corresponding modulating frequency of sound-content with digital circuit, realizes section
The frequency modulation of mesh sound is modulated.Substantially linear V/F translation circuit, its size according to program PCM data V, correspondent transform
The frequency F exported at oscillator difference.According to national standard " metric wave frequency modulation broadcasting technical specification ", maximum frequency deviation is no more than 75KHz.
Every programs are required individually to be modulated, and different programs need to be modulated in respectively different frequencies.
The modulation fundamental frequency of that minimum programs can use 200KHz, and crosstalk between each programs in order to prevent needs adjacent a program to carry
The difference of wave fundamental frequency is greater than 400KHz.This function can easily be realized using FPGA, DSP or singlechip chip；
It being modulated to after signal after multiple programs are modulated is superimposed with adder while all one and is no more than several million
In the IF frequency of hertz (generally 8,000,000).
In conjunction with Fig. 2, Fig. 2 is distribution of several program modulations later on medium-frequency band.1st program is modulated onto F1 frequency
In rate, the 2nd program is modulated onto F2 frequency, and until n-th program is modulated onto FN frequency, several frequency intervals need
Greater than 400KHz.And amplitude modulation fundamental frequency angular frequency will be carried out much smaller than next step.Use amplitude modulation fundamental frequency angular frequency for ω's
Amplitude-modulating modulation circuit moves high frequency band as frequency shift circuit 6, this medium-frequency band, produces two sideband signals.Such as
The angular frequency of fruit input signal is F, and amplitude modulation fundamental frequency angular frequency is ω.So amplitude modulation process are as follows:
(U+1) COS (ω t)=[COS (Ft)+1] COS (ω t)=COS (ω t)+COS [(ω+F) t]/2+COS [(ω-
F)t]/2
In formula, modulated signal U=COS (Ft), COS (ω t) are amplitude modulation fundamental frequency, and COS [(ω+F) t]/2 is upper side frequency, COS
[(ω-F) t]/2 is lower side frequency.
Embodiment is described with reference to Fig. 3, and Fig. 3 is the spectrogram after shifting as frequency spectrum.The signal mirror image of each program point
Cloth forms lower two sideband signals x1, x2 ... xN and upper side band signal f1, f2 ... fN in ω frequency two sides.On the two sides
In band signal, each frequency carries the acoustic information of corresponding broadcast program, if receiving demodulation to it may listen to.But
It is to select to retain upper side band signal f1, f2 ... fN as the signal for being finally amplified and emitting in order not to interfere air communications,
The signal of its frequency is all filtered out from x1, x2 ... xN and ω.
According to national standard " metric wave frequency modulation broadcasting technical specification " provide, the tranmitting frequency of frequency modulation broadcasting from 87MHz to 108MHz,
The successive bands of higher frequency are allocated to navigation and aviation is conversed.Top may be chosen to the influence of flight safety in order to prevent
Band signal is as output band.If modulation lowest frequency is FL, most high frequency is FH, then the value of the fundamental frequency of amplitude-modulating modulation circuit
Minimum range is 87MHz-FL, is up to 108MHz-FH.
Amplitude modulation fundamental frequency and lower side frequency are filtered out using side frequency filter circuit 7, only retains upper side frequency signal, it is wide just to obtain this several set
It broadcasts program while being modulated to Polymera composite signal total in frequency modulation broadcasting frequency range, the resultant signal that Polymera synthesizes is sent to one
Power amplifier 8 can directly be launched, so that it may realize this few set broadcast program after amplification using an antenna 9
Covering is listened in nigh frequency modulation broadcasting.
In present embodiment, other method of Single Side Band Module can also be used, FM circuit can be modulated using analog circuit
Mode.
Claims (3)
1. frequency modulation broadcasting multi-path digital modulating system, including Data Input Interface circuit (1), de-multiplexing circuitry (2), digital decompression
Contracting circuit (3), frequency-shift keying circuit (4), add circuit (5), power amplifier (8) and single sideband modulation circuit, it is characterized in that；
Digitized program transport streams are obtained by Data Input Interface circuit (1), and separate program by de-multiplexing circuitry (2)
The data information of transport stream；Obtain program data stream；
The digital solution compressor circuit (3) unzips it the program data stream of acquisition, and by the broadcast sounds after decompression
Data are input to frequency-shift keying circuit；
The frequency-shift keying circuit (4) calculates the corresponding modulating frequency of voice data, and every programs are individually modulated, and realizes
Different programme signal modulation are over different frequencies；After modulated signal is overlapped using add circuit, it is distributed in phase
On same medium-frequency band signal；
The single sideband modulation circuit is used to moving medium-frequency band signal into frequency modulation broadcasting frequency range, obtains in frequency modulation broadcasting frequency range
Total Polymera composite signal；
The power amplifier (8) is emitted for the Polymera composite signal to be amplified, and using antenna (9), is realized more
Covering is listened in the frequency modulation broadcasting of program；
The frequency-shift keying circuit (4) directly to calculate the corresponding modulating frequency of sound-content with digital circuit, realizes section
The frequency modulation of mesh sound is modulated, substantially linear V/F translation circuit, its size according to program PCM data V, correspondent transform
The frequency F exported at oscillator difference.
2. frequency modulation broadcasting multi-path digital modulating system according to claim 1, which is characterized in that the single sideband modulation electricity
Route frequency shift circuit (6) and side frequency filter circuit (7) composition；The frequency shift circuit (6) is for moving medium-frequency band signal
High frequency band signal, while two side frequency signals are produced, using upper side frequency signal as output band signal；
The side frequency filter circuit (7) is used to filter out the amplitude modulation fundamental frequency signal and lower side frequency signal in output band, retains top
Frequency signal obtains Polymera and is modulated to Polymera composite signal total in frequency modulation broadcasting frequency range simultaneously.
3. frequency modulation broadcasting multi-path digital modulating system according to claim 2, which is characterized in that the frequency shift circuit (6)
Amplitude modulation process using following formula indicate are as follows:
(U+1) COS (ω t)=[COS (Ft)+1] COS (ω t)=COS (ω t)+COS [(ω+F) t]/2+COS [(ω-F) t]/
In 2 formulas, F is the angular frequency of input signal, and ω is amplitude modulation fundamental frequency angular frequency, and modulated signal U=COS (Ft), COS (ω t) are to adjust
Width fundamental frequency, COS [(ω+F) t]/2 are upper side frequency, and COS [(ω-F) t]/2 is lower side frequency.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710355630.4A CN107231204B (en) | 2017-05-19 | 2017-05-19 | Frequency modulation broadcasting multi-path digital modulating system |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201710355630.4A CN107231204B (en) | 2017-05-19 | 2017-05-19 | Frequency modulation broadcasting multi-path digital modulating system |
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| CN107231204A CN107231204A (en) | 2017-10-03 |
| CN107231204B true CN107231204B (en) | 2019-10-29 |
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Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN109617639A (en) * | 2018-11-16 | 2019-04-12 | 安徽帆扬通信电子技术有限公司 | Multiplex broadcasting digital modulation device based on FPGA |
| CN109687926A (en) * | 2018-12-04 | 2019-04-26 | 安徽省广播电视设备器材有限责任公司 | A kind of broadcasting engineering transmitting antenna frequency modulation system |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201369798Y (en) * | 2009-03-28 | 2009-12-23 | 桂林市思奇通信设备有限公司 | Ground digital TV transmitting system |
| CN204598198U (en) * | 2015-04-14 | 2015-08-26 | 北京北广科技股份有限公司 | A kind of multi channel signals modulator |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US9432063B2 (en) * | 2013-01-16 | 2016-08-30 | Huawei Technologies Co., Ltd. | Radio frequency signal transceiving and processing method, device, and base station system |
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Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201369798Y (en) * | 2009-03-28 | 2009-12-23 | 桂林市思奇通信设备有限公司 | Ground digital TV transmitting system |
| CN204598198U (en) * | 2015-04-14 | 2015-08-26 | 北京北广科技股份有限公司 | A kind of multi channel signals modulator |
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