CN106612441A - Radio frequency modulator for television systems - Google Patents
Radio frequency modulator for television systems Download PDFInfo
- Publication number
- CN106612441A CN106612441A CN201510684796.1A CN201510684796A CN106612441A CN 106612441 A CN106612441 A CN 106612441A CN 201510684796 A CN201510684796 A CN 201510684796A CN 106612441 A CN106612441 A CN 106612441A
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- CN
- China
- Prior art keywords
- frequency
- channel
- filter
- circuit
- mixer
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- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
- H04N21/20—Servers specifically adapted for the distribution of content, e.g. VOD servers; Operations thereof
- H04N21/23—Processing of content or additional data; Elementary server operations; Server middleware
- H04N21/238—Interfacing the downstream path of the transmission network, e.g. adapting the transmission rate of a video stream to network bandwidth; Processing of multiplex streams
- H04N21/2383—Channel coding or modulation of digital bit-stream, e.g. QPSK modulation
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- Engineering & Computer Science (AREA)
- Multimedia (AREA)
- Signal Processing (AREA)
- Transmitters (AREA)
- Details Of Television Systems (AREA)
- Two-Way Televisions, Distribution Of Moving Picture Or The Like (AREA)
Abstract
A radio frequency modulator for television systems comprises a channel carrier frequency oscillator, an aural modulator, a video modulator, a channel filter, a buffer amplifier circuit, an AV, an RF adjustable-level attenuation circuit, a radio frequency matcher, a channel mixer, a band mixer, a DC power supply, a power switch, an LED indicator lamp, and a case. A chip circuit is arranged on an electronic circuit board. The radio frequency output end of the chip circuit is connected with a channel filter circuit. The channel filter is connected with the channel mixer. The radio frequency modulator is characterized in that the output port of the band filter and the output port of the channel mixer are connected to be an RF output end, and the port of the RF output end outputs the signals of 30 channels to be connected with a cable television local area network. Frequency resources within the frequency range from 47MHz and 862MHz are fully utilized. A frequency-isolating transmission mode is realized. The color of television images is brighter and clearer, and the accompanying sound is good.
Description
Technical field
The present invention relates to a kind of AV multi-channel video signals switch to the manipulator for exporting all-channel signal all the way, belong to TV broadcast technology.
Background technology
The progress of CMOS complementary metal-oxide-semiconductor CMOS fabrication technology, promotes the parts density of integrated circuit to improve, and relative to the transistor of small size, its reaction rate is improved therewith.For 0.8 μm of CMOS processing procedures, its most fast reaction rate can reach 200MHz.Therefore in TV very high frequency(VHF) VHF frequency band, radio-frequency modulator of the frequency range in 50MHz to 100MHz.Can be completed with CMOS technology.
Traditional radio-frequency modulator, with bipolar (bipolar) fabrication techniques.Product on the market, has the bipolar integrated circuit IC of SONY CX20138, and the MDMT2A of similar Fu Hua electronics corporation (Forward Electronics Co., Ltd.s), with bipolar bipolar electric crystals and the product of RLC assembling parts at present.They there are common shortcoming.For example, expensive instrument is needed during its production, make the adjustment of multi-step, cause production not convenient, improve cost.On the other hand, its radio frequency Modulation and Amplitude Modulation, with bipolar nonlinear characteristic, is produced with product effect.With respect to its signal, with the presence of nonlinear chromatic distortion and the problem of difference frequency interference.
The content of the invention
The technical problem to be solved, is to provide the television system radio-frequency modulator of a kind of compact conformation, Highgrade integration.
The technical scheme is that what is be accomplished by：Television system radio-frequency modulator, include channel carrier-frequency oscilaltor, audio modulator, video modulation, channel filter, buffer amplifier circuit, AV, RF adjustable level attenuator circuit, radio-frequency match, mixer channel, frequency band mixer, DC source, on and off switch, LED light and casing, chip circuit is located on electronic circuit board, the RF output end of the chip circuit is connected with channel filter circuit, channel filter is connected with mixer channel, it is characterised in that：Described frequency band filter delivery outlet is connected with mixer channel delivery outlet and is connected into RF outfans, and RF outfans port exports the signal of 30 channels and is connected with cable television LAN.
Described channel carrier-frequency oscilaltor has IC1, 3, 4, 5, 6 feet periphery electric capacity C5, C6, C7, C8, C9, C10, C11, C12 and vibration inductance coil L2 compositions, by changing the number of turns and pitch of L2 inductance coils so as to realize the setting of channel frequency needed for carrier-frequency oscilaltor, frequency according to needed for inductance coil L2 and C7 capacitance settings, the frequency of carrier-frequency oscilaltor is amplified by the amplifier buffered in IC integrated circuits, respectively by image modulation, sound accompaniment frequency variation signal is loaded in the frequency of agitator, by IC1, the image audio signal of 9 feet output radio frequency is sent to channel filter by R7.IC1,7,8,12,13 feet connection power supply add 6V ends, C19, C20, C21, C22 capacitor, L7 inductance composition power-supply filter to connect 6V positive supplies.
Described channel filter have high pass filter and low pass filter point, natural frequency can pass through, for during frequency more than or less than loop, loop total impedance will increase prevention disresonance frequence and pass through, according to the channel filter of different frequency usage different frequencies, C13, C14, C15, C16, C17, C18 capacitors and L3, L4, L5 inductance composition high pass filter., C13, C15, L3 composition series resonant circuit to 30 channel television signal impedance very littles, can pass through, and very big to signal impedances more than 30 channels, prevent by and filter；C16, C14, L4 constitute series resonant circuit to 30 channel television signal impedance signal very littles, can pass through, and very big to 30 channel signals below impedances, prevent by and filter, C17, C18, L5 composition passbands, bandwidth filter, it is ensured that vision bandwidth is 8MHZ.
The present invention, makes full use of frequency resource in 47MHZ -862MHZ frequency ranges, realizes every frequency technical transmission mode, makes television image colored more bright-coloured clear, and sound accompaniment might as well.Practical closed circuit cable television LAN culture medium equipment, due to short, little to the front end signal attenuation advantage of circuit.
Description of the drawings
Fig. 1 is the circuit diagram of the present invention.
Specific embodiment
Known by Fig. 1, television system radio-frequency modulator, include channel carrier-frequency oscilaltor, audio modulator, video modulation, channel filter, buffer amplifier circuit, AV, RF adjustable level attenuator circuits, radio-frequency match, mixer channel, frequency band mixer, DC source, on and off switch, LED light and casing, chip circuit is located on electronic circuit board, the RF output end of the chip circuit is connected with channel filter circuit, channel filter is connected with mixer channel, described frequency band filter delivery outlet is connected with mixer channel delivery outlet and is connected into RF outfans, RF outfans port exports the signal of 30 channels and is connected with cable television LAN.
Overall Power Consumption is to the greatest extent the energy-conserving product of the low-power consumption of 220V/30W, and the disposable connection system debugging in factory in cabinet of the systematic connecting line of institute is completed, with overall performance reliability, small volume, it is lightweight, without the need for professional's installation and debugging, 30 road radio-frequency modulator of integration easy to use.
UHF high-frequency band filters：The uhf band filter circuit is connected with 470MHZ -850MHZ scope mixer channel circuit bus.
VHF frequency band filters delivery outlet is connected with uhf band wave filter delivery outlet and is connected into RF outfans.
The signal of 30 channels of RF ports output is connected with cable television LAN and completes.
Being briefly described for the course of work of the present invention of technical scheme given above be, multiple stage top box of digital machine, AV signals, multiple stage digital satellite receiver AV signals, the AV signals of DVD player, the advertisement of camera head monitor AV signals and the computer photograph managed by oneself, word, computer outputting VGA signal changes into AV signals, is input to the corresponding A V input port of the radio-frequency modulator on integrated 30 tunnel.Signal impedance above is very big, prevents by and filters.C16, C14, L4 constitute series resonant circuit to 30 channel television signal impedance signal very littles, can pass through, and very big to 30 channel signals below impedances, prevent by and filter, C17, C18, L5 composition passbands, bandwidth filter, it is ensured that vision bandwidth is 8MHZ.
BG1 is buffered hf amplifier, and signal gain is amplified, and improves the load-carrying ability of circuit.It is 100DB that signal is coupled to the electric-level gain needed for RV3 is adjusted by C23, is sent to next stage mixer channel.
Mixer channel, is the device for exporting multichannel different radiofrequency signal mixing all the way, is mixer channel, is made up of the band filter of multiple different frequencies in circuit.Interference needed for eliminating beyond frequency signal, mutual not string signal between impedance matching and each terminal when will also keep each channel signals to pass through blender, it is ensured that in frequency band, channel and channel have the isolation of 25DB.
Frequency band filter is that the VHF frequency ranges below 470MHZ frequencies are mixed output with uhf band more than another frequency range 470MHZ frequency.Circuit VHF frequency ranges and uhf band blender, C1, C2, L1, L2 composition low pass filter, it allows 470MHZ, VHF frequency range signals below to pass through.
Claims (3)
1. television system radio-frequency modulator, include channel carrier-frequency oscilaltor, audio modulator, video modulation, channel filter, buffer amplifier circuit, AV, RF adjustable level attenuator circuit, radio-frequency match, mixer channel, frequency band mixer, DC source, on and off switch, LED light and casing, chip circuit is located on electronic circuit board, the RF output end of the chip circuit is connected with channel filter circuit, channel filter is connected with mixer channel, it is characterised in that：Described frequency band filter delivery outlet is connected with mixer channel delivery outlet and is connected into RF outfans, and RF outfans port exports the signal of 30 channels and is connected with cable television LAN.
2. television system radio-frequency modulator according to claim 1, it is characterised in that：Described channel carrier-frequency oscilaltor has IC1,3,4,5,6 feet periphery electric capacity C5,C6,C7,C8,C9,C10,C11,C12 and vibration inductance coil L2 compositions，By changing the number of turns and pitch of L2 inductance coils so as to realize the setting of channel frequency needed for carrier-frequency oscilaltor，Frequency according to needed for inductance coil L2 and C7 capacitance settings，The frequency of carrier-frequency oscilaltor is amplified by the amplifier buffered in IC integrated circuits，Respectively by image modulation，Sound accompaniment frequency variation signal is loaded in the frequency of agitator，By IC1,The image audio signal of 9 feet output radio frequency is sent to channel filter by R7，IC1,7,8,12,13 feet connection power supply adds 6V ends，C19,C20,C21,C22 capacitors，L7 inductance composition power-supply filter connects 6V positive supplies.
3. television system radio-frequency modulator according to claim 1, it is characterised in that：Described channel filter have high pass filter and low pass filter point, natural frequency can pass through, for during frequency more than or less than loop, loop total impedance will increase prevention disresonance frequence and pass through, according to the channel filter of different frequency usage different frequencies, C13, C14, C15, C16, C17, C18 capacitors and L3, L4, L5 inductance constitutes high pass filter, C13, C15, L3 constitutes series resonant circuit, to 30 channel television signal impedance very littles, can pass through, and it is very big to signal impedances more than 30 channels, prevent by and filter；C16, C14, L4 constitute series resonant circuit to 30 channel television signal impedance signal very littles, can pass through, and very big to 30 channel signals below impedances, prevent by and filter, C17, C18, L5 composition passbands, bandwidth filter, it is ensured that vision bandwidth is 8MHZ.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510684796.1A CN106612441A (en) | 2015-10-22 | 2015-10-22 | Radio frequency modulator for television systems |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510684796.1A CN106612441A (en) | 2015-10-22 | 2015-10-22 | Radio frequency modulator for television systems |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN106612441A true CN106612441A (en) | 2017-05-03 |
Family
ID=58611981
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201510684796.1A Pending CN106612441A (en) | 2015-10-22 | 2015-10-22 | Radio frequency modulator for television systems |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN106612441A (en) |
-
2015
- 2015-10-22 CN CN201510684796.1A patent/CN106612441A/en active Pending
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| WD01 | Invention patent application deemed withdrawn after publication |
Application publication date: 20170503 |
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| WD01 | Invention patent application deemed withdrawn after publication |