CN2653791Y - Precision synchronous covering system for FM broadcast - Google Patents
Precision synchronous covering system for FM broadcast Download PDFInfo
- Publication number
- CN2653791Y CN2653791Y CN 03278721 CN03278721U CN2653791Y CN 2653791 Y CN2653791 Y CN 2653791Y CN 03278721 CN03278721 CN 03278721 CN 03278721 U CN03278721 U CN 03278721U CN 2653791 Y CN2653791 Y CN 2653791Y
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- broadcast
- synchronous
- vibration source
- gps
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Abstract
A precise and synchronous covering system for FM broadcast of the utility model belongs to the technical field of FM broadcast and the system of FM synchronous broadcast. The technical problem to be solved is to provide an FM broadcast system which can make the common frequency protective rate of the FM synchronous broadcast approach 0Db and realize the FM broadcast system with precise and synchronous FM broadcast and seamless covering. The utility model is characterized in that an FM modulator, a local vibration source of the engine tracked by GPS synchronously, a frequency mixer and a frequency changer consisting of a band filter are positioned between the audio system and the signal transmission system, and the FM modulator and the output end of the local vibration source of the engine tracked by GPS synchronously are connected with the input end of the frequency mixer; a digital time delayer, a local vibration source of the engine tracked by GPS synchronously, a frequency mixer and a frequency inverse transform device consisting of a band filter are positioned between the power amplifier of each sending machine in the system and the signal transmission system, and the digital time delayer and the output end of the local vibration source of the engine tracked by GPS synchronously are connected with the input end of the frequency mixer. The utility model has the advantage of precise and synchronous frequency deviation, carrier frequency and time delay.
Description
Technical field: the utility model relates to a kind of FM broadcasting and synchronous frequency-modulating broadcast system, the accurate covering system synchronously of particularly a kind of FM broadcasting.
Background technology: FM broadcasting is the main mode that broadcasting covers that realizes at present.FM broadcasting realizes that the synchronized broadcasting operation is the networking general layout of improving FM broadcasting, the important measures of saving frequency resource, the effective coverage rate of expansion.So-called synchronous frequency-modulating broadcast, promptly the carrier frequency of transmitter, instantaneous frequency modulation, modulation signal time delay must keep synchronous.But; what existing synchronous frequency-modulating broadcast system adopted is the scheme of the independent frequency modulation modulation of each transmitter (5); because the characterisitic parameters such as tracking inertia of each transmitter modulation sensitivity, Modulation and Nonlinear, modulation phase-locked loop is discrete; in theory; can't guarantee under current intelligence the synchronously accurate of carrier frequency and frequency deviation between each transmitting station, so that still need the radio-frequency protection ratio of 6dB in the equifield intensity district at all.So still there is appreciable co-channel interference distorted region in existing synchronous frequency-modulating broadcast at the intersection area of coverage.
Summary of the invention: technical problem to be solved in the utility model is: provide a kind of same frequency protective rate of synchronous frequency-modulating broadcast that can make to be tending towards 0Db, thereby can realize really that the FM broadcasting precision is synchronous, the frequency modulation broadcast system of seamless covering.Its technical scheme is: the accurate covering system synchronously of a kind of FM broadcasting, comprise each transmitter in audio system, signal transmission system and the system, it is characterized in that: the frequency changer that is provided with frequency interleaved modulation modulator between described audio system and the signal transmission system and constitutes by local vibration source, frequency mixer and the band pass filter of the synchronous tracking engine of GPS, the output of the frequency interleaved modulation modulator and the local vibration source of the synchronous tracking engine of GPS is connected with the input of frequency mixer; The frequency inverse transformer that is respectively equipped with digital time delayer in the system between the power amplifier of each transmitter and the signal transmission system and is made of local vibration source, frequency mixer and the band pass filter of the synchronous tracking engine of GPS, the output of the digital time delayer and the local vibration source of the synchronous tracking engine of GPS is connected with the input of frequency mixer.Its technique effect is: because each transmitter in the whole system is only before signal transmission system, be provided with a frequency interleaved modulation modulator and carry out frequency modulation(FM), thereby signal transmission system is transferred to that the signal of each transmitter is actually a modulated standard FM signal in the system, thereby the instantaneous frequency deviation that can guarantee each transmitter in the system is definitely consistent; Simultaneously, because the local vibration source of set frequency mixer locks by the GPS synchronization engine in the local vibration source of shared frequency interleaved modulation modulator of whole system and frequency mixer and each transmitter, thus the high level of synchronization of each transmitter transmitting carrier frequency in can the realization system; In addition, owing to be provided with digital time delayer between frequency mixer in each transmitter and the signal transmission system, thus can effectively control the time-delay of each transmitter, eliminate " echo " effect of equifield intensity overlapping coverage area.Therefore, native system has frequency deviation, carrier frequency, the accurate synchronous characteristics of time-delay, makes the same frequency protective rate of FM broadcasting be tending towards 0dB, has really realized the accurate synchronous seamless covering of FM broadcasting.
The drawing explanation:
Fig. 1 connects block diagram for the utility model.
Embodiment:
As shown in Figure 1, the frequency changer that is provided with frequency interleaved modulation modulator between audio system and the signal transmission system and constitutes by local vibration source, frequency mixer and the band pass filter of the synchronous tracking engine of GPS.The audio signal that audio system is sent via frequency interleaved modulation modulator encode, after the frequency modulation modulation, the fm broadcast signal of outputting standard, in frequency converter, carry out mixing with output signal from the local vibration source of the synchronous tracking engine of GPS, after the band pass filter frequency-selecting, obtain the intermediate frequency signal of a suitable signal transmission system transmission.This intermediate frequency signal is actually a modulated standard FM signal.The transmission means that adopts according to signal transmission system as: the difference of microwave link, optical fiber link or satellite link, intermediate frequency can have different selections.Simultaneously, in order to ensure the accuracy and the stability of intermediate frequency, the phase-locked loop of frequency interleaved modulation modulator also locks the synchronization engine with GPS.The long-term synchronization accuracy of system under lock-out state can reach 5EXP-12.
The frequency inverse transformer that is provided with digital time delayer in the system between the power amplifier of each transmitter and the signal transmission system and is made of local vibration source, frequency mixer and the band pass filter of the synchronous tracking engine of GPS is to replace the frequency interleaved modulation modulator that is provided with in the original transmitter.It is synchronous that the effect of digital time delayer is to control the modulation signal time delay in equifield intensity district.The structure of frequency inverse transformer is similar to above-mentioned frequency changer, and just its effect is just in time opposite, and it is with the intermediate frequency signal tranmitting frequency broadcasted frequently of conversion readjustment again.After amplifying by power amplifier again, export antenna to and launch, can realize accurate carrier frequency synchronization, instantaneous frequency deviation synchronously and the programme signal time-delay synchronously.Be that the accurate of FM broadcasting covers synchronously.
Because the carrier-to-noise ratio of satellite link is lower, thereby when using satellite link to carry out the signal transmission, need before the satellite link transmission, carry out the frequency modulation processing of a high modulation index again, exchange the raising of terminal signal to noise ratio with the increase peak frequency deviation for the intermediate frequency signal of band pass filter output.After satellite-signal lands, then at first need to carry out fm demodulation and could obtain intermediate frequency signal.
Optical fiber link also can directly be connected to the transmission of line TV optical networking with modulator output with signal, download signal optical receiver demodulation primary frequency signal.
Claims (2)
1, the accurate covering system synchronously of a kind of FM broadcasting, comprise each transmitter in audio system, signal transmission system and the system, it is characterized in that: the frequency changer that is provided with frequency interleaved modulation modulator between described audio system and the signal transmission system and constitutes by local vibration source, frequency mixer and the band pass filter of the synchronous tracking engine of GPS, the output of the frequency interleaved modulation modulator and the local vibration source of the synchronous tracking engine of GPS is connected with the input of frequency mixer; The frequency inverse transformer that is respectively equipped with digital time delayer in the system between the power amplifier of each transmitter and the signal transmission system and is made of local vibration source, frequency mixer and the band pass filter of the synchronous tracking engine of GPS, the output of the digital time delayer and the local vibration source of the synchronous tracking engine of GPS is connected with the input of frequency mixer.
2, the accurate covering system synchronously of a kind of FM broadcasting according to claim 1 is characterized in that: the phase-locked loop of described frequency interleaved modulation modulator and the locking of GPS synchronization engine.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 03278721 CN2653791Y (en) | 2003-09-20 | 2003-09-20 | Precision synchronous covering system for FM broadcast |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 03278721 CN2653791Y (en) | 2003-09-20 | 2003-09-20 | Precision synchronous covering system for FM broadcast |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN2653791Y true CN2653791Y (en) | 2004-11-03 |
Family
ID=34332111
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 03278721 Expired - Fee Related CN2653791Y (en) | 2003-09-20 | 2003-09-20 | Precision synchronous covering system for FM broadcast |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN2653791Y (en) |
-
2003
- 2003-09-20 CN CN 03278721 patent/CN2653791Y/en not_active Expired - Fee Related
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C19 | Lapse of patent right due to non-payment of the annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |