CN201263183Y

CN201263183Y - Integrated multipath radio frequency modulator

Info

Publication number: CN201263183Y
Application number: CNU2008200376363U
Authority: CN
Inventors: 何喜福
Original assignee: DANYANG CITY XINQIAO TOWN XUYANG ELECTRIC APPLIANCE FACTORY
Current assignee: DANYANG CITY XINQIAO TOWN XUYANG ELECTRIC APPLIANCE FACTORY
Priority date: 2008-06-27
Filing date: 2008-06-27
Publication date: 2009-06-24
Anticipated expiration: 2018-06-27

Abstract

The utility model relates to an integrated multi-channel radio-frequency (RF) modulator which comprises a chip circuit that can transform an audio-video signal into an RF signal, a direct current (DC) power supply, an AV signal input terminal and an RF output terminal. The integrated multi-channel RF modulator is characterized in that: the RF output terminal of the chip circuit is connected with a channel filter circuit; a channel filter is connected with a channel mixer; a plurality of channel signals of the RF output terminal are connected with a cable television local area network (LAN) to complete the output. The whole multi-channel RF modulator has low power consumption of 220V/30W and connecting lines of all systems can be connected and debugged in a case by one time. The integrated multi-channel RF modulator is characterized by wholly reliable performance, small size, light weight, convenient use, short line and low attenuation to high-frequency signals and no need of installation and debugging by a professional.

Description

Integrated multi-channel rf modulator

Technical field

The utility model relates to the TV broadcast technical field, especially mixes the cable TV local area network (LAN) that is converted to one road RF output all-channel signal about a kind of AV multi-channel video signal, watches the integrated multi-channel rf modulator of radio and television to the user.

Background technology

Existing video signal mixture modulator, be all the radio-frequency modulator of single channel single supply 220V/20W, unit case, electronic devices and components are many, complex circuit, power consumption is big, the temperature height, wanting the electricity consumption gross power such as 30 monomer radio-frequency modulators is 600W, summer, the machine room cooling that need install an air-conditioner added 30 road mixer channels and a frequency range blender in addition, increased by 2 racks and put.Have more 29 attaching plugs than above integrated 30 road radio-frequency modulators, 29 power lines, numerous electric power plug sockets, channel and frequency range blender need to install 64 F heads of connector, 32 radio frequency lines, need professional's Installation and Debugging, the actual use brought many inconvenience.

Summary of the invention

At above deficiency, the purpose of this utility model is to provide a kind of compact conformation, and Highgrade integration the is integrated AV multi-channel video signal is mixed is converted to the radio-frequency modulator that one road RF exports the all-channel signal.

The technical solution of the utility model is that pass-through mode is realized: integrated multi-channel rf modulator, comprise having sound is looked the chip circuit that conversion of signals becomes radiofrequency signal, DC power supply, AV signal input part, RF output, it is characterized in that: the radio-frequency (RF) output end of described chip circuit is connected with the channel filter circuit, channel filter links to each other with mixer channel, and a plurality of channel signals of RF output are connected with the cable TV local area network (LAN) and finish output.

Above-mentioned channel filter has the branch of high pass filter and low pass filter, and C13, C14, C15, C16, C17, C18 capacitor and L3, L4, L5 inductance are formed high pass filter, and C1, C2, L1, L2 form low band filter.

Above-mentioned frequency band filter is that VHF frequency range below the 470MHZ frequency and the uhf band more than another frequency range 470MHZ frequency are mixed output, circuit VHF frequency range and uhf band blender, C1, C2, L1, L2 form low band filter, and C3, C4, C5 and L3, L4 form the high band filter.

Multi-channel rf modulator of the present utility model, Overall Power Consumption is to the greatest extent the low-power consumption of 220V/30W, the disposable connection tracking examination in cabinet of the connecting line of all systems is finished, has the complete machine dependable performance, volume is little, and is in light weight, need not professional's Installation and Debugging, easy to use, circuit weak point, the characteristics little to front end signal attenuation.It has overcome the prior art medium frequency and can only be " project of "Communication with Every Village" " with squeezing the deficiency of using in low and middle-end, the hotel, and the restaurant, school, factory, it is cheap that public place inside provides, practical closed circuit cable TV local area network (LAN) culture medium equipment.This machine can make full use of frequency resource in 47MHZ-862MHZ frequency range, realize making the television image colour bright-coloured more clear every frequency technical transmission mode, and sound accompaniment might as well.

Description of drawings

Fig. 1 is a process chart of the present utility model.

Fig. 2 is circuit theory diagrams of the present utility model.

Embodiment

Know by Fig. 1, integrated multi-channel rf modulator of the present utility model, comprise having sound is looked the chip circuit that conversion of signals becomes radiofrequency signal, DC power supply, AV signal input part, RF output, the radio-frequency (RF) output end of described chip circuit is connected with the channel filter circuit, and channel filter links to each other with mixer channel, and a plurality of channel signals of RF output are connected with the cable TV local area network (LAN) and finish output; Described channel filter is divided into VHF low band filter and UHF high band filter, wherein this VHF frequency band filter is connected with the mixer channel bus of circuit of 47MHZ-470MHZ scope, and the uhf band filter circuit is connected with 470MHZ-850MHZ scope mixer channel bus of circuit.

Being known by Fig. 2, is circuit theory diagrams of the present utility model.Its operation principle is as follows:

1, many top box of digital machines, the AV signal, many digital satellite receiver AV signals, the AV signal of DVD player, the advertisement of camera head monitor AV signal and the computer photograph managed by oneself, literal, the computer outputting VGA signal changes into the AV signal, is input to integrated multichannel every the corresponding A V of frequency modulator input port, the AV video signal is by the potentiometer of RV1, adjustable damping gains to R1, and R2 divides extrusion 1VPP video signal, guarantees to be consistent in television image brightness in whole system.Video image is capacitively coupled to the IC111 pin by C1, and internal circuit image clamper signal is delivered to the video modulator that signal behind the white level amplitude limit is delivered to next stage.

2, the A audio signal is by the RV2 potentiometer, for regulating the audio signal level, guarantee in whole system, to be consistent at television sound volume, form preemphasis circuit by the C2 capacitor-coupled to resistance R 3 capacitor C 3, it is amplitude for the high fdrequency component that improves audio signal, improved the quality of sound accompaniment, simultaneously audio signal is passed through R4, deliver to IC behind the R5 electric resistance partial pressure, after 16 pin internal circuits cushion amplification, send sound accompaniment frequency conversion FM inner by 14 of IC1,15 pin external capacitor C4 resistance R 6, in the resonant tank formed of all coil L1, the magnetic cap of all coil L1 in the adjusting, the frequency resonance that makes resonant tank on the 6.5MHZ frequency, thereby realized frequency modulation task to the 6.5MHZ sound accompaniment.

3, carrier-frequency oscilaltor is made up of IC1,3,4,5, the peripheral capacitor C 5 of 6 pin, C6, C7, C8, C9, C10, C11, C12 and vibration inductance coil L2, thereby by the number of turns of change L2 inductance coil and the setting of the required channel frequency of pitch realization carrier-frequency oscilaltor, need wider frequency, 47MHZ-850MHZ sets, can be according to inductance coil L2 and the required frequency of C7 capacitance settings.The frequency of carrier-frequency oscilaltor is amplified by the amplifier in the buffering IC integrated circuit, and respectively with image modulation, the sound accompaniment frequency variation signal is loaded on the frequency of oscillator, and by IC1, the image audio signal of 9 pin output radio frequency is sent to channel filter by R7.IC1,7,8,12,13 pin connect power supply and add the 6V end, and C19, C20, C21, C22 capacitor, L7 inductance are formed power-supply filter and connect the 6V positive supply.

4, channel filter has the branch of high pass filter and low pass filter, and natural frequency can be passed through, and the loop total impedance will increase and stops disresonance frequence to pass through during for the frequency that is greater than or less than the loop.According to the channel filter of different frequency use different frequencies, C13, C14, C15, C16, C17, C18 capacitor and L3, L4, L5 inductance are formed high pass filter among the figure.Example is 30 channel filters, and C13, C15, L3 form series resonant circuit, and be very little to 30 channel TV signal impedances, can pass through smoothly, and very big to the signal impedance more than 30 channels, stop by and filter.C16, C14, it is very little to 30 channel TV signal impedance signals that L4 forms series resonant circuit, can pass through smoothly, and very big the following signal impedance of 30 channels, stop by and filter, C17, C18, L5 forms passband, bandwidth filter, guarantee that vision bandwidth is 8MHZ, BG1 is the 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 required electric-level gain of RV3 adjusting by C23, delivers to the next stage mixer channel.

5, mixer channel is the device that the radiofrequency signal that multichannel is different is mixed one tunnel output, is mixer channel, is made up of the band pass filter of a plurality of different frequencies in the circuit.Eliminate the interference beyond the required frequency signal, string signal not mutually between impedance matching and each terminal in the time of also will keeping each channel signals by blender guarantees that channel and channel in the frequency band have the isolation of 25DB.

6, frequency band filter is that VHF frequency range below the 470MHZ frequency and the uhf band more than another frequency range 470MHZ frequency are mixed output.Circuit VHF frequency range and uhf band blender, C1, C2, L1, L2 form low band filter, and it allows 470MHZ, and the following signal of VHF frequency range passes through, and the above signal of 470MHZ frequency range is filtered.C3, C4, C5 and L3, L4 form the high band filter, and it allows the interior signal of the above uhf band of 470MHZ pass through, and VHF frequency signal is filtered.To guarantee that simultaneously the total output port of VHF/UHF (RF) has 80DB gain output.

Because adopt the LC oscillating circuit can make the Frequency point of any TV between 47MHZ-862MHZ, it is comparatively convenient to produce.The LC oscillating circuit at 0-40 ℃ of temperature range drift ± 0.1MHZ and the automatic tracking frequency ± 1.5MHZ of the AFC of TV fully within normal operating range.

Claims

1, integrated multi-channel rf modulator, comprise having sound is looked the chip circuit that conversion of signals becomes radiofrequency signal, DC power supply, AV signal input part, RF output, it is characterized in that: the radio-frequency (RF) output end of described chip circuit is connected with the channel filter circuit, channel filter links to each other with mixer channel, and a plurality of channel signals of RF output are connected with the cable TV local area network (LAN) and finish output.

2, integrated multi-channel rf modulator according to claim 1, it is characterized in that: described channel filter has the branch of high pass filter and low pass filter, C13, C14, C15, C16, C17, C18 capacitor and L3, L4, L5 inductance are formed high pass filter, and C1, C2, L1, L2 form low band filter.

3, integrated multi-channel rf modulator according to claim 1, it is characterized in that: described frequency band filter is that VHF frequency range below the 470MHZ frequency and the uhf band more than another frequency range 470MHZ frequency are mixed output, circuit VHF frequency range and uhf band blender, C1, C2, L1, L2 form low band filter, and C3, C4, C5 and L3, L4 form the high band filter.