CN201178415Y - U waveband mobile phone television signal forwarding device inhibiting adjacent frequency interference - Google Patents

Abstract

The invention provides a U wave band mobile television signal transponder for inhibiting adjacent channel interference, which comprises a preamplifier,an AGC, a down converter, an intermediate frequency processor, an up converter, a final amplifier and a frequency synthesis source. The signal transponder adopts the converter technique for twice, namely the down conversion and the up conversion. A local oscillation signal of a frequency mixer is provided by the frequency synthesis source. An antenna receives mobile radio-frequency signals that need forwarding; after amplified through the preamplifier, the mobile radio-frequency signals are changed into intermediate signals through the down converter; after processed through intermediate frequency, the intermediate signals are again changed into radio-frequency signals through the up converter; the radio-frequency signals are amplified through the final amplifier, and are sent through a radio-frequency power amplifier. The signal transponder has the advantages that : after processed through intermediate frequency, signals can be effectively prevented from the adjacent channel interference from up and down channels to the transponder, thereby enabling the transponder to output useful signals under the maximal power; the service performance is good; the service occasions are wide.

Description

A kind of U wave band mobile TV signal repeater that suppresses adjacent frequency interference

Technical field

The utility model relates to a kind of mobile TV signal forwarding equipment, and particularly a kind of mobile TV that is used for is with the power intensifier of transmitting frequently.

Background technology

Under the situation that mobile TV is promoted day by day,,, will be unthinkable if there is not the covering of mobile TV signal in dense population areas such as some markets, underground parking, subway, tunnel, skyscraper, public places of entertainment.In conjunction with the characteristics of mobile TV transmitter, can not all set up a transmitting station at zone or signal blind zone that each digital television signal covers difference, so all set up mobile TV signal forwarding apparatus usually in these zones.Signal repeater is to utilize reception antenna that the mobile TV signal is introduced, and the mobile TV signal filtering is amplified, and utilizes transmitting antenna that signal is forwarded to the shadow region with frequency again.Vast territory and abundant resources in China, and the transmitting channel of a lot of broadcast television signals is the modes that adopt the adjacent channel emission under the frequency resource condition of limited of broadcast television signal.Mobile TV signal repeater signal can with the adjacent channel mutual interference mutually that transmits.

The utility model content

Technical problem of the present utility model is the adjacent U wave band mobile TV signal repeater that disturbs frequently of inhibition that will provide a kind of effective inhibition adjoining channel signal that transponder is disturbed.

In order to solve above technical problem, the utility model provides a kind of adjacent U wave band mobile TV signal repeater that disturbs frequently that suppresses, comprise preamplifier, AGC, low-converter, intermediate frequency processor, upconverter, final amplifier, frequently combine the source, adopt the double conversion technology, be respectively down-conversion and up-conversion, the local oscillation signal of frequency mixer provides by combining the source frequently, antenna receives the mobile phone radio frequency signal that needs forwarding, after the preamplifier amplification, change to intermediate-freuqncy signal through low-converter, after the intermediate frequency process, change to radiofrequency signal again, amplify by final amplifier through upconverter, the radio-frequency power amplifier emission.

Described intermediate frequency processor adopts the intermediate frequency Surface Acoustic Wave Filter, leaches the signal of lower sideband adjacent channel.

Superior effect of the present utility model is:

1) signal has suppressed the interference of the adjoining channel signal of upper and lower channel to transponder effectively through after the intermediate frequency process, make the output useful signal of transponder maximum power, signal is transmitted in same frequency, be suitable for mobile TV with the different channel of frequency repeating power booster, different bandwidth, different power output;

2) serviceability is good, guarantees the mobile TV quality of signals, and the signal in blind area and weak district covers, and makes the mobile TV signal constantly extend forward;

3) application of suitable various ways mobile TV signal repeater inside comprises various power grades, channel, bandwidth, indoor or outdoors type etc., so use occasion is very extensive.

Description of drawings

Fig. 1 is a schematic block circuit diagram of the present utility model;

Fig. 2 is the circuit diagram that frequency of the present utility model is combined source (PLL);

Fig. 3 is the circuit diagram of MCU of the present utility model;

Fig. 4 is the circuit diagram of detector amplifier of the present utility model;

Fig. 5 is the circuit diagram of agc circuit of the present utility model and amplifying circuit;

Fig. 6 is specific embodiment of the utility model figure;

The number in the figure explanation

The 1-preamplifier; 2-AGC;

The 3-low-converter; The 4-intermediate frequency processor;

The 5-upconverter; The 6-final amplifier;

7-combines the source frequently; The 8-detection is amplified.

Embodiment

See also shown in the accompanying drawing, the utility model will be further described.

As shown in Figure 1, the utility model provides a kind of adjacent U wave band mobile TV signal repeater that disturbs frequently that suppresses, comprise preamplifier 1, AGC2, low-converter 3, intermediate frequency processor 4, upconverter 5, final amplifier 6, frequently combine source 7, adopt the double conversion technology, be respectively down-conversion and up-conversion, the local oscillation signal of frequency mixer provides by combining source 7 frequently, antenna receives the mobile phone radio frequency signal that needs forwarding, after preamplifier 1 amplification, change to intermediate-freuqncy signal through low-converter 3, after the intermediate frequency process, change to radiofrequency signal again, amplify by final amplifier 6 through upconverter 5, the radio-frequency power amplifier emission.

Pre-low-noise amplifier 1 amplifies faint aerial radiofrequency signal, is converted to intermediate frequency through low-converter 3, after amplifying through intermediate frequency processor 4 filtering, be converted to radiofrequency signal through upconverter 5, this device has the AGC2 circuit simultaneously, as shown in Figure 5, has automatic gain control function.

Described intermediate frequency processor 4 adopts the intermediate frequency Surface Acoustic Wave Filter, leaches the signal of lower sideband adjacent channel.The mode of intermediate frequency process is an amplifying signal after the filtering of employing intermediate frequency Surface Acoustic Wave Filter, suppresses adjacent signal frequently.

As shown in Figures 2 and 3, combine the control in source 7 (PLL) frequently and finish by universal serial bus, carry out various settings easily by MCU.Frequently combine the reference frequency in source 7 (PLL) and the clock signal of MCU and come from high-precision temperature-compensating crystal oscillator, the output of combining source 7 (PLL) frequently is divided into the usefulness of two-way for frequency mixer after low noise amplifier amplifies.

As shown in Figure 4, the source signal of detector amplifier 8 is from carrying out the amplification of radiofrequency signal after the primary path of radiofrequency signal is obtained a less component earlier, after carry out the stack of the direct voltage of signal voltage again, and then enter diode detection, the voltage signal that obtains after the detection is being represented the intensity of the radiofrequency signal of this moment, form negative feedback loop through feeding back to AGC2 after the processing of operational amplifier again, thereby realize Gain Automatic regulation and control.

As shown in Figure 6, the existing TV programme signal frequency of using with Shanghai City is example, and 32 channels are that the mobile TV frequency band power is the about 53dBm of 200W, and adjacent 33 channels frequently are that the simulated television frequency band power is the about 75dBm of 30KW.

The emission of two signal common transmitting antennas, the available signal power that the receiving terminal of mobile TV power enhanced system receives (the mobile TV signals of 32 channels to be transmitted) is 1: 150 with the power ratio of unwanted signal power (other spacing wave beyond the mobile TV signal band), be available signal power only account for total power signal 1% less than, represent that with logarithm promptly useful signal and unwanted signal differ 22dB.Owing in the space electromagnetic environment of reality, also exist other power signal except that adjacent frequency, useful signal is in fact also smaller than the value of calculating.If to the neighbour frequently unwanted signal do not suppress, then the use power of mobile TV power enhanced system will be by a large amount of the taking of useless power, a large amount of unwanted signal that made device forwards disturbs thereby form, useful signal also can't normally broadcast simultaneously.The utility model can have the good restraining effect frequently to the neighbour, and the outer inhibition degree of band is up to 43dB.Adjacent signal frequently after suppressing via the utility model has been attenuated 43dB, promptly adjacent signal frequently has been attenuated nearly 20000 times, useful signal has differed 23dB relatively, the ratio of available signal power and unwanted signal power is about 130: 1, the ratio that useful signal accounts for gross output is 99.2%, be with outer unwanted signal only to account for 0.8% of gross output, the interference of adjacent signal frequently is very faint, and drawing the utility model thus has very desirable effect to neighbour's inhibition frequently.

Area is wide in Chinese region, and frequency resource is limited, and the radio and television in most areas are to adopt the adjacent mode that takes place frequently and penetrate, adjacent interference problem between frequently that the utility model has solved the power enhanced system well.

Claims (2)

1, a kind of U wave band mobile TV signal repeater that suppresses adjacent frequency interference comprises preamplifier, AGC, low-converter, intermediate frequency processor, upconverter, final amplifier, combines the source frequently, it is characterized in that:

Adopt the double conversion technology, be respectively down-conversion and up-conversion, the local oscillation signal of frequency mixer provides by combining the source frequently, antenna receives the mobile phone radio frequency signal that needs forwarding, after the preamplifier amplification, change to intermediate-freuqncy signal through low-converter, after the intermediate frequency process, change to radiofrequency signal again through upconverter, by final amplifier amplification, radio-frequency power amplifier emission.

2, by the described a kind of adjacent U wave band mobile TV signal repeater that disturbs frequently that suppresses of claim 1, it is characterized in that:

Described intermediate frequency processor adopts the intermediate frequency Surface Acoustic Wave Filter, leaches the signal of lower sideband adjacent channel.

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