CN2148446Y - Cable transmission device for antenna far away from TV set - Google Patents

Abstract

The utility model relates to a cable transmission device for an antenna far away from a TV, which is designed for solving the problem that the individual householder in mountain area has difficulty in receiving TV programs. The utility model provides with a cable frequency converting transmission system between the antenna and the TV, and the channel selection and frequency conversion are realized through cable remote control method. Through the elaborate design of a tuner voltage generator 1-3 and a frequency converting voltage generator 1-4 in a downconverter, and a control voltage generator 2-3 in an upper converter, the function of using one transmission line to transmit TV signal and inversely transmit the control voltage and the service voltage is achieved. The utility model both simplifies the transmission line and reduces the cost.

Description

Cable transmission device for antenna far away from TV set

The utility model belongs to a kind of small-sized TV receiving system.

In the mountain area, general resident family mostly lives in the corrie place and since the mountain stop that the TV signal field intensity at corrie place is very weak, make television set normally not receive.In prior art, in order to solve the television reception problem in mountain area, the way that adopts is that radio parallax switching receipts system is set usually.This system is arranged on the stronger position of TV signal with antenna, and the signal of a certain channel that antenna is received becomes intermediate-freuqncy signal, after amplifying, intermediate frequency becomes another channel TV signal that is different from receiving channels again, again after power amplification, be sent to the space by transmitting antenna, then near television set gets final product reliable reception.A transposer once can only be transmitted the signal of a television channel.The above-mentioned poor receipts system wide coverage of transferring, and can guarantee that television set receives reliably.But it is a kind of relatively large equipment, is unsuitable for individual the installation.In the mountain area,, there are a lot of areas that this equipment is installed and are still very difficult owing to the restriction that is subjected to economically.In addition, there is the transmitting-receiving interference problem in this equipment radio frequency that need take up room, makes its installation also be subjected to certain restriction.

At present, many resident families in mountain area wish to have and are suitable for the individual micro television receiver of installing very much, solving the individual resident family in the mountain area difficult problem that televiews, and wish that its price is not too expensive, can allow the individual resident family in mountain area afford.The micro television receiver that is suitable for the installation of individual resident family public in prior art is a kind of antenna amplifier antennafire.This technical scheme is that signal amplifier is arranged on antenna end, and the signal that antenna is received directly amplifies, and is sent to television set by transmission line then.Because the output signal of this signal amplifier is identical with the signal frequency that antenna receives, form self-excitation so very easily produce positive feedback, for fear of self-excitation, must force down Amplifier Gain, the output signal level of amplifier is limited on certain degree, therefore, the signal transmission distance of this receiver is very short, generally is no more than 100 meters.This transmission range can not satisfy the mountain area and require, because in the mountain area, antenna generally is erected on the mountain top, and the distance of resident family is arrived generally all about 300-500 rice in the mountain top, this distance is considerably beyond 100 meters, so this receiver can not guarantee to receive reliably.In prior art, the television set that Chinese patent CN2105814 provides a kind of fuselage to be connected with the tuner split.Its design philosophy is that the tuner of television set is separated in television body, tuner is installed in antenna end, utilize the frequency conversion amplification system of television set self to solve problem of signal attenuation on the transmission line,, in fact be difficult for realizing though this scheme is practicable from principle.Because the line of tuner and television set has many, can be described as the moustache line, the expense of every line is added up and is made that the expense of whole transmission line is higher, and simultaneously, the moustache line also is difficult for setting up.In addition, to carry out above-mentioned repacking be unpractical to the general television set of having bought for mountain area resident family.In sum, also there is not at present a kind of comparatively ideal scheme can solve the individual resident family in the mountain area difficult problem that televiews.

The purpose of this utility model is that the situation at prior art provides a kind of and is suitable for individual the installation, and can guarantee the wired transmission device of the television antenna of mountain area resident family reliable reception away from television set.

Solution of the present utility model is as follows: referring to Fig. 1, be provided with a low-converter 1 in antenna end, be provided with a upconverter 2 in TV set terminal, be provided with a transmission line 3 between upper and lower frequency converter, this root transmission line can be coaxial cable or balanced feeder line.Comprise in the described low-converter that an a certain channel signals that desire is received becomes the electronic tuning unit 1-1 and the intermediate frequency amplifier 1-2 of intermediate-freuqncy signal.Electronic tuning unit is commonly called as tuner, is provided with a control voltage U that upconverter oppositely is sent to low-converter at the tuning end of its channel selection _KCarry out the tuning voltage generator 1-3 of conversion, be provided with one to the control voltage U at its wave band end of convert _KThe frequency range conversion voltage generator 1-4 that changes also is provided with one to the control voltage U in low-converter _KCarry out voltage stabilizing and export the pressurizer of low-converter working power.Comprise intermediate frequency amplifier 2-1 that an intermediate-freuqncy signal that low-converter is sent is amplified in the described upconverter and intermediate-freuqncy signal is become the frequency converter 2-2 and the control voltage generator 2-3 of the receivable a certain channel signals of television set.

In order to guarantee reliable reception, this device has adopted wired frequency conversion transmission system, because system has carried out frequency-conversion processing, has avoided the self-excitation problem of signal amplifier in the system, so amplifier gain can design according to transmission range.Simultaneously, system becomes intermediate-freuqncy signal with TV signal to be transmitted, and because of frequency is low, so loss of signal is little, therefore, the transmission range of system can reach km.In addition, this device carries out wired transmission, and the radio frequency that do not take up room settles and set up to have independence.Consider the problem that reduces cost, the key measure that this device adopts is by tuning voltage generator, frequency range conversion voltage generator being set in low-converter and the control voltage generator being set in upconverter, realized the function of wired remote control channel selection and frequency range conversion, and transmitted TV signal simultaneously and oppositely transmit the function of controlling voltage and operating voltage with a transmission line by well-designed realization to above-mentioned each voltage generator.Therefore, make the structure of this device, the transmission line between the particularly upper and lower frequency converter is simplified greatly.The cost and the installation cost of this device self decrease.Promptly one retail price (transmission line that comprises 300-500 rice) is about about 400 yuan.

In sum, superiority of the present utility model is low price, be fit to individual resident family and install, and the own dependable performance of device simultaneously, Installation And Construction is convenient, can thoroughly solve the individual resident family in the mountain area difficult problem that televiews.

Describe in detail according to embodiment below.

Fig. 1, functional-block diagram of the present utility model.

Fig. 2, the physical circuit figure that the remote control channel selection is tuning and frequency range is changed.

Fig. 3, contour structures schematic diagram of the present utility model.

Fig. 4, two of tuning voltage generator physical circuit.

Referring to Fig. 1, constitute the TV signal transmission channel by electronic tuning unit 1-1, intermediate frequency amplifier 1-2, transmission line 3, intermediate frequency amplifier 2-1 and frequency converter 2-2.Its conversion transmission course is as follows: the TV signal that antenna 4 receives is sent to electronic tuning unit, it is transformed to intermediate frequency with the TV signal that desire receives, deliver to intermediate frequency amplifier 1-2, be sent to the input of intermediate frequency amplifier 2-1 then at a distance by transmission line, after intermediate frequency amplifier 2-1 amplifies once again signal delivered to frequency converter 2-2, this frequency converter becomes the signal of a certain channel that television set can receive to give television set 5 conversion of signals.C on the transmission line ₁, C ₂It is capacitance.Constitute the tuning and frequency range conversion and control line of remote control channel selection by control voltage generator 2-3, transmission line 3, tuning voltage generator 1-3 and frequency range conversion voltage generator 1-4.Wherein control voltage generator and can also provide operating voltage V for intermediate frequency amplifier 2-1 and frequency converter 2-2 ₅, V ₆The control voltage U of control voltage generator output _KThrough inductance L ₂, transmission line, inductance L ₁Deliver to tuning voltage generator, frequency range conversion voltage generator and pressurizer 1-5 respectively, wherein pressurizer 1-5 is to U _KProvide operating voltage V for frequency range conversion voltage generator, tuning voltage generator, electronic tuning unit, intermediate frequency amplifier 1-2 after the voltage stabilizing ₁, V ₂, V ₃, V ₄Inductance L on the control line ₁, L ₂Work to cut off TV signal.

Physical circuit according to control line illustrates the control procedure that the remote control channel selection is tuning and the remote control frequency range is changed below.

Referring to Fig. 2, the BT of electronic tuning unit 1-1 end is the tuning control end of channel selection, and BL, BH end is frequency range conversion and control end.When the BL end is high level, when the BH end is low level, the adjustable voltage of 0-30V is sent into the BT end, then electronic tuning unit can be exported the TV signal of each channel in the VHF low-frequency range (1-5 channel) successively along with BT holds the change of input voltage; When BL is a low level, and BH in like manner regulates the BT terminal voltage when being high level, and electronic tuning unit is exported the TV signal of each channel of VHF high band (6-12 channel) successively.This device by tuning voltage generator to control voltage U _KProcessing, the tuning voltage of output 0-30 volt is sent into the BT end.Tuning voltage generator is made of negative feedback operational amplifier 1-3.1, and the negative input end of this amplifier is by resitstance voltage divider 1-3.2 and operating voltage V ₂Join, its positive input terminal is by resitstance voltage divider 1-3.3 and control voltage U _KJoin its power supply termination U _KWant the supply power voltage of double as pressurizer 1-5, so U _KLower limit can not be equal to or less than voltage stabilizing value (+12 volts).Therefore, U _KLower limit be limited at about 15 volts, its adjustable range is defined as 15-30 volt.U _KOppositely be sent at a distance in this amplifier by transmission line 3, because V ₂Be stable operating voltage,, work as U so the maintenance of A point current potential is constant _KDuring for lower limit, B point current potential is higher than A point current potential, and then this amplifier is output as zero, and the variable resistor 2-3.1 that regulates in the control voltage generator in TV set terminal makes U _KWhen lower limit rose to higher limit continuously, then B point current potential was higher than A point current potential, and the difference of 2 current potentials is with U _KRising and increase gradually, along with this amplifier output of variation of input variable from the zero tuning voltage value that rises to continuously about 30 volts.Thereby realized the tuning function of remote control channel selection.

This device passes through the frequency range conversion voltage generator to U _KProcessing export the control signal of above-mentioned high and low two frequency ranges conversion.Again referring to Fig. 2, the frequency range conversion voltage generator comprises that a positive feedback operational amplifier 1-4.1 and one connect feedback operational amplifier 1-4.1 and a conversion output circuit that is connected into by triode 1-4.2,1-4.3,1-4.4,1-4.5 by triode 1-4.2,1-4.3,1-4.4,1-4.5.When needs are watched the low-frequency range TV programme, pass through potentiometer 2-3.1 earlier with U _KBe adjusted downward to lower limit, and then energized, because of the instantaneous charging effect of electric capacity 1-4.6, make the F point in the amplifier be higher than E point current potential, then amplifier is output as zero, and keeps.At this moment, triode 1-4.2,1-4.3 end, and triode 1-4.4,1-4.5 conducting promptly provide the BL end and be low level low-frequency range control signal for high level, BH end; When needs are watched the TV programme of high band, earlier with U _KTransfer to lower limit, disconnect normally closed switch 2-3.2 then, at this moment, U _KFrom the lower limit hop to higher limit, charging effect because of electric capacity 1-4.7, make in the amplifier E point current potential moment be higher than F point current potential, amplifier output high level, because the positive feedback effect of amplifier, its output keeps high level output, then triode 1-4.2,1-4.3 conducting, and triode 1-4.4,1-4.5 end, and promptly provide the BL end and are low level, and the BH end is the high band control signal of high level.If in the time of will changing the tremendously low frequency section again, need shutdown, press the start of aforesaid operations rules again and get final product.Thereby realized the function of remote control frequency range conversion.

Referring to Fig. 1, the intermediate frequency amplifier 2-1 in the electronic tuning unit 1-1 in the low-converter, intermediate frequency amplifier 1-2 and pressurizer 1-5 and the upconverter, frequency converter 2-2 all adopt existing conventional element circuit again.Fig. 3 illustrates the contour structures of Fig. 1.

Referring to Fig. 4, tuning voltage generator also can constitute with resolution element, promptly is connected into direct-coupled dual-stage amplifier with a PNP triode 6 and a NPN triode 7, and it is tuning stable to guarantee that second utmost point amplifier is connected into negative feedback amplifier.Negative feedback operational amplifier 1-4.1's among its input-output characteristic and Fig. 2 is identical.This circuit possesses good property equally, and cost is also lower.

Claims (3)

1, television antenna is characterized in that away from the wired transmission device of television set:

A. be provided with a low-converter 1 in antenna end, be provided with a upconverter 2, between upper and lower frequency converter, be provided with a transmission line 3 in TV set terminal,

B. comprise in the described low-converter that an a certain channel signals that desire is received becomes the electronic tuning unit 1-1 and the intermediate frequency amplifier 1-2 of intermediate-freuqncy signal, is provided with a control voltage U that upconverter oppositely is sent to low-converter at the tuning end of the channel selection of electronic tuning unit _KCarry out the tuning voltage generator 1-3 of conversion, be provided with one to the control voltage U at its wave band end of convert _KThe frequency range conversion voltage generator 1-4 that changes also is provided with one to the control voltage U in low-converter _KCarry out voltage stabilizing and export the pressurizer of low-converter working power,

C. comprise the intermediate frequency amplifier 2-1 that an intermediate-freuqncy signal that low-converter is transmitted is amplified in the described upconverter and intermediate-freuqncy signal is become the frequency converter 2-2 and the control voltage generator 2-3 of the receivable a certain channel signals of television set.

2, wired transmission device as claimed in claim 1 is characterized in that: described tuning voltage generator is made of negative feedback operational amplifier 1-3, and the negative input end of this amplifier is by resitstance voltage divider 1-3.2 and operating voltage V ₂Join, the positive input terminal of this amplifier is by resitstance voltage divider 1-3.3 and control voltage U _KJoin its power supply termination U _K

3, as claim 1,2 described wired transmission devices, it is characterized in that: described frequency range conversion voltage generator comprises a positive feedback operational amplifier 1-4.1 and a conversion output circuit that is connected into by triode 1-4.2,1-4.3,1-4.4,1-4.5.

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