CN106571836A - Frequency-modulated radio transmitting system and frequency-modulated radio transmitting method - Google Patents
Frequency-modulated radio transmitting system and frequency-modulated radio transmitting method Download PDFInfo
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- CN106571836A CN106571836A CN201610947976.9A CN201610947976A CN106571836A CN 106571836 A CN106571836 A CN 106571836A CN 201610947976 A CN201610947976 A CN 201610947976A CN 106571836 A CN106571836 A CN 106571836A
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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
- H04H—BROADCAST COMMUNICATION
- H04H20/00—Arrangements for broadcast or for distribution combined with broadcast
- H04H20/53—Arrangements specially adapted for specific applications, e.g. for traffic information or for mobile receivers
- H04H20/59—Arrangements specially adapted for specific applications, e.g. for traffic information or for mobile receivers for emergency or urgency
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- Engineering & Computer Science (AREA)
- Signal Processing (AREA)
- Computer Networks & Wireless Communication (AREA)
- Business, Economics & Management (AREA)
- Emergency Management (AREA)
- Transmitters (AREA)
Abstract
The invention discloses a frequency-modulated radio transmitting system and a frequency-modulated radio transmitting method. The system comprises a digital processing unit and a radio frequency unit. The radio frequency unit comprises a central processing module, a high-speed DAC module, an oscillator and mixer module, and a radio-frequency power amplifier module. The digital processing unit and the central processing module are connected via a USB interface. The central processing module is connected with the high-speed DAC module and the oscillator and mixer module. The high-speed DAC module is connected with the oscillator and mixer module. The oscillator and mixer module is connected with the radio-frequency power amplifier module. The radio-frequency power amplifier module is connected with a transmitting antenna. According to the invention, the structure of a transmitter is simplified greatly, complex multi-frequency modulation is realized in a way of SDR, and any normal radio can receive signals transmitted by the transmitter without tuning as long as the radio is turned on. The equipment cost and maintenance cost are low. The system and the method can be widely used in information transfer in an electromagnetic shielding space, and has popularization and application value in the aspect of disaster prevention and mitigation.
Description
Technical field
The invention belongs to communication technique field, is related to a kind of frequency modulation broadcast system and method, and in particular to a kind of frequency modulation is wide
Broadcast and penetrate system and method；Can be used for the occasions such as emergency disaster relief broadcast.
Background technology
Since broadcast technology comes out, through development for many years and improvement, a kind of important media means are had become,
Play an important role in various aspects such as Information Communication, amusement, messages meant, spins.Broadcast receiver is received
Sound machine principle is simple, and with low cost, effect is easily guaranteed that, therefore until the Internet highly developed today, its owning rate is still
It is at a relatively high, or even into the indispensability configuration on automobile and mobile phone.
Common radio transmitting device, based on AM (amplitude modulation(PAM)) or FM (frequency modulation(PFM)) technology, audio signal is adjusted
Make, traditional transmitter can only work with a frequency.Different
Broadcasting station use different radio wave frequencies, radio only be tuned to the broadcasting station identical frequency on when,
The signal in the radio station can just be listened to.
The broadcast occupied bandwidth narrow (9Khz or so) of AM modes, (200Khz is left for the broader bandwidth of the broadcast occupancy of FM modes
It is right), therefore its audio signal quality of broadcast of FM modes is significantly better than the broadcast of AM modes.In addition, general AM broadcasting frequencys
Scope is 522Khz-1620Khz, and total bandwidth is 1098Khz, and wavelength is hundreds of meters, generally requires magnetic antenna and can just obtain
Preferable reception, its reception device are difficult miniaturization modularity；And FM broadcasting frequency scopes are 88Mhz-108Mhz, total band
A width of 20Mhz, wavelength are 3 meters or so, the easy miniaturization modularity of its reception device.Current city broadcast is main by the way of
For FM modes.
Due to due to electric wave propagation characteristic, under basement, tunnel, bridge, bomb shelter or because natural disaster is made
Into put under house arrest under the masking such as space environment, radio wave decay is serious, and broadcast signal quality is deteriorated, the people
It is many to be also just difficult to obtain rescue information or traffic, Weather information.For example, driver obtains traffic by FM broadcast
Information, after automobile sails tunnel into, driver just cannot obtain transport information again, if now front occurs emergency, public
Information just cannot be timely transmitted to driver by peace department.Although broadcasting station can be set up in tunnel to broadcast out message
Go, but be because that the broadcasting station listened to before into tunnel by each driver is not the same, its frequency cannot be known, therefore pass
The broadcast transmitter of system is difficult to be competent at, because according to general radio performance, the signal of 250Khz bandwidth can be received, if
Need to allow every radio all to receive signal, then need to set up 80 broadcast transmitters, every transmitter works in different
Frequency.Its installation cost and maintenance cost are all at a relatively high.
Same situation, it may occur however that be take precautions against natural calamities and disaster relief work in.After the condition of a disaster prevents stage or calamity, radio
It is the important means of common people's acquisition announcement information, but on the one hand, in case of emergency, the common people is probably due to cannot tune in a hurry
To broadcast station signal, on the other hand, victims of the disaster's location may be already in electromagnetic wave shielding environment, it is impossible to receive wide
Broadcast radio signals.
The content of the invention
In order to solve above-mentioned technical problem, the invention provides a kind of frequency modulation broadcast emission system and method.
The technical scheme that adopted of system of the present invention is：A kind of frequency modulation broadcast emission system, it is characterised in that：Including number
Word processing unit and radio frequency unit, the digital processing element include the computer for being provided with GNU Radio；The radio frequency unit
Including central processing module, high-speed DAC module, vibration and mixer module and radio frequency power amplification module；Computer is with
Centre processing module is connected by USB interface, and central processing module is connected with high-speed DAC module, vibration and mixer module respectively,
High-speed DAC module is connected with vibration and mixer module, and vibration and mixer module are connected with radio frequency power amplification module, radio frequency
Power amplifier module is connected with transmitting antenna.
The technical scheme adopted by the method for the present invention is：A kind of frequency modulation broadcasting launching technique, it is characterised in that include with
Lower step：
Step 1：Audio signal is carried out into FM modulation, the narrow-band digital intermediate frequency after FM modulation is generated, by narrow-band digital intermediate frequency
It is divided into N roads with allotter, while generating from X1Mhz starts, to X2What Mhz terminated, with xKhz as the N-1 digital local oscillator at interval
Signal, this N-1 digital local oscillator signal is mixed with N-1 roads narrow-band digital intermediate-freuqncy signal respectively, and through Digital High Pass Filter,
To realize Digital Up Convert, narrow-band digital intermediate-freuqncy signal of the N-1 roads positioned at different frequent points is obtained；
Step 2：By N-1 railway digitals intermediate-freuqncy signal and remaining one is multiplied by often without the zero intermediate frequency signals of mixing all the way
Number system number, to adjust amplitude, in case next step addition process；
Step 3：N railway digitals intermediate-freuqncy signal after adjustment amplitude is added by adder, wideband digital intermediate frequency is obtained；
Step 4：Wideband digital intermediate frequency feeding DAC is carried out into digital-to-analogue conversion, broadband analogue intermediate-freuqncy signal is obtained；
Step 5：Separately produce the simulation local oscillation signal of a YMhz, itself and broadband analogue intermediate-freuqncy signal be mixed, generate with
The signal of the mirror image each other of two centered on local oscillation signal：
cos(flocal_osc*t)*cos(fif* t)=
((cos(flocal_osc*t+fif*t))+(cos(flocal_osc*t-fif*t)))/2
Wherein, flocal_oscFor the frequency of local oscillation signal, fifFor the frequency of intermediate-freuqncy signal, t is the time；
cos(flocal_osc*t+fif* t) and cos (flocal_osc*t-fif* two are with f t)local_oscCentered on mirror
As signal.
Step 6：By the signal obtained in step 5 through flatness adjust and power amplification, most after Jing antennas launch.
Compared with prior art, the present invention adopts SDR (software radio) technology, will be the structure of transmitter greatly simplified,
Complicated multi-frequency modulation is realized with SDR modes, it is only necessary to one (require to reduce equipment performance, it would however also be possible to employ 2 or
The modes such as person 4) transmitter can complete the FM broadcast all standings of 20Mhz bandwidth, any radio working properly, only
Start shooting, need not tune, you can receive the signal of this transmitter transmitting.And its equipment cost and maintenance cost are low, can be with
The information for being widely used in being electromagnetically shielded space is passed on, and has application value at aspect of preventing and reducing natural disasters.
Description of the drawings
System structure sketches of the Fig. 1 for the embodiment of the present invention；
Radio frequency unit structure charts of the Fig. 2 for the embodiment of the present invention；
Method flow schematic diagrams of the Fig. 3 for the embodiment of the present invention.
Specific embodiment
Understand for the ease of those of ordinary skill in the art and implement the present invention, below in conjunction with the accompanying drawings and embodiment is to this
It is bright to be described in further detail, it will be appreciated that enforcement example described herein is merely to illustrate and explains the present invention, not
For limiting the present invention.
Ask for an interview Fig. 1 and Fig. 2, a kind of frequency modulation broadcast emission system that the present invention is provided, including digital processing element and radio frequency
Unit, digital processing element include the computer for being provided with GNU Radio；The radio frequency unit includes central processing module (ARM
Core CPU-LPC1850), high-speed DAC module (high-speed DAC-MAX5184), vibration and mixer module (agitator and frequency mixer
RFFC5072 the radio frequency power amplification module for), and by 2sc3355 and 2sc1970 constituting；Computer passes through USB with LPC1850
Interface connects, and LPC1850 is connected with MAX5184, RFFC5072 respectively, and MAX5184 is connected with RFFC5072, RFFC5072 with penetrate
Frequency power amplifier module connects, and radio frequency power amplification module is connected with transmitting antenna.
GNU Radio are the SDR design platforms increased income, wherein there is a graphic programming instrument grc, it is possible to achieve quick
Modularity SDR.To realize the digital processing of the present invention, coding is needed to realize the generation of digital local oscillator, FM modulation, multiplier
The function such as (up-conversion), adder, finally gives wideband digital intermediate-freuqncy signal.
From the sound or the audio files being stored in inside computer of computer microphone, after the calculating of gnu radio,
Obtain digital broadband intermediate-freuqncy signal.
In fig. 2, LPC1850 is connected with the USB interface of computer, receives the digital broadband intermediate-freuqncy signal from computer, and
Data form is carried out into plural number-real number conversion and bit width conversion (8bit-10bit), while also needing to control rffc5072, is made
The local oscillator of rffc5072 is 87Mhz, and data are issued high-speed DAC MAX5184 according to constant speed then, and MAX5184 is by number
Word intermediate-freuqncy signal is converted to analog if signal, and is sent to the IF ends of rffc5072, inside rffc5072, has now produced
The local oscillation signal of 87Mhz is given birth to, the local oscillation signal is mixed with the intermediate-freuqncy signal from IF ends, obtains 88Mhz-107.75Mhz's
Radiofrequency signal, while also generating image signal, therefore needs the filter network through LC compositions to carry out high pass network, filtered
Signal transmission is amplified to the two-stage radio-frequency amplifier being made up of two audions of 2sc3355 and 2sc1970, obtains general power
The radiofrequency signal of about 1W, last emitted antenna are transmitted in the air.As bandwidth has 20Mhz, therefore in the work(of each frequency
Rate is all smaller, can only receive for the radio within hundreds of rice, and the impact to normal broadcasting station is smaller.
The present embodiment is hence set up in common computer and runs GNU just to the exploitativeness of the fast verification present invention
On the basis of Radio softwares, therefore cost can be slightly higher, and reliability can be lower slightly.If necessary to produce in batches, can be by GNU
The digital processing work completed by Radio is completed by FPGA or ASIC design (special integrated circuit).
Fig. 3 is asked for an interview, a kind of frequency modulation broadcasting launching technique that the present invention is provided is comprised the following steps：
Step 1：Audio signal is carried out into FM modulation, the narrow-band digital intermediate frequency (being now zero intermediate frequency) after FM modulation is generated,
Narrow-band digital intermediate frequency allotter is divided into into 40 tunnels, while generating from the beginning of 0.25Mhz, is terminated to 9.75Mhz, with 250Khz
For 39 digital local oscillator signals at interval, this 39 digital local oscillator signals are mixed with 39 road narrow-band digital intermediate-freuqncy signals respectively,
And through Digital High Pass Filter, to realize Digital Up Convert, obtain narrow-band digital intermediate-freuqncy signal of 39 tunnels positioned at different frequent points；
Step 2：By 39 railway digital intermediate-freuqncy signals and remaining one is multiplied by often without the zero intermediate frequency signals of mixing all the way
Number system number (is less than 1, such as 0.02), to adjust amplitude, in case next step addition process；
Step 3：40 railway digital intermediate-freuqncy signals after adjustment amplitude are added by adder, wideband digital intermediate frequency is obtained；
Step 4：Wideband digital intermediate frequency feeding DAC is carried out into digital-to-analogue conversion, broadband analogue intermediate-freuqncy signal is obtained；
Step 5：The simulation local oscillation signal of a 98Mhz is separately produced, which is mixed with broadband analogue intermediate-freuqncy signal, due to mixed
Frequency device is substantially multiplier, and in local oscillation signal, (hypothesis frequency is flocal_osc) (hypothesis frequency is f with intermediate-freuqncy signalif) mixing
Afterwards, actually generate the signal of two centered on local oscillation signal mirror images each other：
cos(flocal_osc*t)*cos(fif* t)=
((cos(flocal_osc*t+fif*t))+(cos(flocal_osc*t-fif*t)))/2
Therefore it is so far, generate covering 88.25Mhz to 107.75Mhz, whole FM broadcast bands, interval
The broadcast singal of 250Khz, but due to device and the characteristic of circuit, inband flatness is not fine, needs device after filtering,
Adjustment flatness；
Step 6：By this wide band radio-frequency broadcast singal through radio-frequency power amplifier amplify, most after Jing antennas launch
Go.
Now, on radio, no matter tuned frequency is how many, can receive the signal.
In the step of the present embodiment 1,40 set tunnels and interval 250Khz are according to most of wireless intermediate frequencies
The numeral taken by bandwidth, in fact, taking other close intervals can also obtain similar effect, for example, is spaced 200Khz, point
Into 50 tunnels, or interval 300Khz, it is divided into 34 tunnels.Can be determined according to selected hardware performance when being embodied as.
The present invention is ingenious to make use of the mirror image for being typically considered interference signal or invalid signals in the radio communication
Signal (can try every possible means to eliminate image signal in common radio communication), therefore the complexity of broadband broadcast equipment is dropped
Half lower, saves cost, improves exploitativeness.
It should be appreciated that the part that this specification is not elaborated belongs to prior art.
It should be appreciated that the above-mentioned description for preferred embodiment is more detailed, therefore can not be considered to this
The restriction of invention patent protection scope, one of ordinary skill in the art are being weighed without departing from the present invention under the enlightenment of the present invention
Under the protected ambit of profit requirement, replacement can also be made or deformed, be each fallen within protection scope of the present invention, this
It is bright scope is claimed to be defined by claims.
Claims (3)
1. a kind of frequency modulation broadcast emission system, it is characterised in that：Including digital processing element and radio frequency unit；The radio frequency unit
Including central processing module, high-speed DAC module, vibration and mixer module and radio frequency power amplification module；Digital processing list
Unit be connected by USB interface with central processing module, central processing module respectively with high-speed DAC module, vibrate and frequency mixer mould
Block connects, and high-speed DAC module is connected with vibration and mixer module, and vibration and mixer module are connected with radio frequency power amplification module
Connect, radio frequency power amplification module is connected with transmitting antenna.
2. frequency modulation broadcast emission system according to claim 1, it is characterised in that：The digital processing element is to be provided with
The computer of GNU Radio, FPGA or ASIC.
3. a kind of frequency modulation broadcasting launching technique, it is characterised in that comprise the following steps：
Step 1：Audio signal is carried out into FM modulation, the narrow-band digital intermediate frequency after FM modulation is generated, narrow-band digital intermediate frequency is used and is divided
Orchestration is divided into N roads, while generating from X1Mhz starts, to X2What Mhz terminated, with xKhz as the N-1 digital local oscillator signal at interval,
This N-1 digital local oscillator signal is mixed with N-1 roads narrow-band digital intermediate-freuqncy signal respectively, and through Digital High Pass Filter, with reality
Existing Digital Up Convert, obtains narrow-band digital intermediate-freuqncy signal of the N-1 roads positioned at different frequent points；
Step 2：By N-1 railway digitals intermediate-freuqncy signal and it is remaining all the way without mixing zero intermediate frequency signals be multiplied by a constant system
Number, to adjust amplitude, in case next step addition process；
Step 3：N railway digitals intermediate-freuqncy signal after adjustment amplitude is added by adder, wideband digital intermediate frequency is obtained；
Step 4：Wideband digital intermediate frequency feeding DAC is carried out into digital-to-analogue conversion, broadband analogue intermediate-freuqncy signal is obtained；
Step 5：The simulation local oscillation signal of a YMhz is separately produced, which is mixed with broadband analogue intermediate-freuqncy signal, generated with local oscillator
The signal of the mirror image each other of two centered on signal：
cos(flocal_osc*t)*cos(fif* t)=
((cos(flocal_osc*t+fif*t))+(cos(flocal_osc*t-fif*t)))/2
Wherein, flocal_oscFor the frequency of local oscillation signal, fifFor the frequency of intermediate-freuqncy signal, t is the time；
cos(flocal_osc*t+fif* t) and cos (flocal_osc*t-fif* two are with f t)local_oscCentered on mirror image letter
Number；
Step 6：By the signal obtained in step 5 through flatness adjust and power amplification, most after Jing antennas launch.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610947976.9A CN106571836A (en) | 2016-10-26 | 2016-10-26 | Frequency-modulated radio transmitting system and frequency-modulated radio transmitting method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610947976.9A CN106571836A (en) | 2016-10-26 | 2016-10-26 | Frequency-modulated radio transmitting system and frequency-modulated radio transmitting method |
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| CN106571836A true CN106571836A (en) | 2017-04-19 |
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| CN201610947976.9A Pending CN106571836A (en) | 2016-10-26 | 2016-10-26 | Frequency-modulated radio transmitting system and frequency-modulated radio transmitting method |
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101132382A (en) * | 2006-08-22 | 2008-02-27 | 捷顶微电子（上海）有限公司 | Frequency modulation transmitter |
| CN201369737Y (en) * | 2009-03-13 | 2009-12-23 | 谭大勋 | Wired frequency-modulation broadcasting transmit-receive system |
| CN105610450A (en) * | 2016-03-08 | 2016-05-25 | 武汉大学 | Broadband broadcasting transmission method and system |
-
2016
- 2016-10-26 CN CN201610947976.9A patent/CN106571836A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101132382A (en) * | 2006-08-22 | 2008-02-27 | 捷顶微电子（上海）有限公司 | Frequency modulation transmitter |
| CN201369737Y (en) * | 2009-03-13 | 2009-12-23 | 谭大勋 | Wired frequency-modulation broadcasting transmit-receive system |
| CN105610450A (en) * | 2016-03-08 | 2016-05-25 | 武汉大学 | Broadband broadcasting transmission method and system |
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| PB01 | Publication | ||
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Application publication date: 20170419 |