Summary of the invention:
In view of the deficiency that above-mentioned prior art exists, the purpose of this utility model provides low, the effective adjustable choosing band of the mobile communication bandwidth repeater of a kind of price.
The purpose of this utility model is to realize like this, it comprises two duplexers that link to each other with donor antenna and domestic aerial respectively and places between two duplexers and is connected in series down link and the up link that constitutes mutually by low noise amplifier, filter, power amplifier respectively, it is characterized in that: be connected in series two frequency range selectors on down link and up link respectively, the filter on down link and the up link places between two frequency range selectors.The GSM repeater receives the base station down signal by donor antenna, after sending downstream signal descending low noise amplifier to amplify, duplexer send the band downlink selector, the low side frequency and the high-end frequency of two frequency range selector difference frequency-selecting bands, filter in the middle of the choosing band device is used for filtering clutter and interference, adjusting filter makes it reach the complete machine flatness index, power amplifier carries out the frequency-selecting section and amplifies, be sent to cable and distribution system through low-loss, high-isolation duplexer, through domestic aerial to area of coverage radiation.Domestic aerial receives the mobile phone upward signal and serves line frequency segment selector choosing band after duplexer is delivered to up low noise amplifier amplification, carry out the amplification of wideband section through frequency-selecting Duan Houzai ingoing power amplifier, and the upward signal of amplification is delivered to the base station by donor antenna again through duplexer.
The utility model has the advantages that will choosing band scope narrow down to minimum, the carrier frequency of required usefulness is included in selects in the band scope, the result who does like this, effective more a lot of than common choosing band repeater, and price is cheap again more a lot of than overloading frequency selecting repeater frequently.
Below in conjunction with accompanying drawing the utility model is explained.
Embodiment:
By accompanying drawing as can be known, the utility model comprises 2 duplexers, 1 descending low noise amplifier, 1 up low noise amplifier, 2 band downlink selectors (frequency range selector 1 and frequency range selector 2), 2 uplink band selectors (frequency range selector 1 and frequency range selector 2), 1 downlink power amplifier, 1 ascending power amplifier, 1 downstream filter, 1 upstream filter.Constitute down link by 1 descending low noise amplifier, 1 downstream filter and 2 band downlink selectors, downstream filter places between 2 band downlink selectors; Constitute up link by 1 up low noise amplifier, 1 upstream filter and 2 uplink band selectors, upstream filter places between 2 band downlink selectors.
Frequency range selector 1 and frequency range selector 2 series connection are used, and so Shi Ji bandwidth of operation is the common factor of 2 bandwidth of operation, and as shown in Figure 2, establishing the working frequency range initial frequency is F1, and the termination frequency is F2, and then working frequency range is 890-909MHz.
Frequency range selector 1 is used for suppressing the low side frequency, then centre frequency F
C1=F1+ bandwidth/2;
Frequency range selector 2 is used for suppressing high-end frequency, then centre frequency F
C2=F2-bandwidth/2;
Band downlink is identical with the uplink band operation principle.
The frequency range selector (see figure 3) is made up of high-end selections device and low side selections device, and two selections devices are controlled respectively by signal high-end by frequency and low side by frequency, and two is selected frequency range by the frequency intermediate bands.Each selections device has two ports, is respectively RF
INAnd RF
OUT.Frequency is F
CRadio frequency frequently signal from RF
INPort input selections device, 2SC2351 carries out preposition amplification by the radio-frequency (RF) power amplification pipe, gains to be 11dB.Signal after the amplification mates the brachium pontis 1 that the back signal enters electric bridge by Л type network, brachium pontis 4,6 ends of electric bridge connect PIN pipe BAP64-05, change the supply power voltage of PIN pipe and then change the power output of the resistance control brachium pontis 3 of 4,6 arms by potentiometer, thereby realize the gain controlling of selections device.Frequency mixer is a nonlinear device, can produce new frequency component, and frequency mixer is made up of chip 004E and peripheral circuit, 1 terminal input signal carrier frequency F of frequency mixer
C, 3 terminals inputs local frequency F
L, after the 2 terminals output frequency conversion with frequently and difference frequency.Local oscillation signal is produced by VCO and phase-locked loop circuit, and its local frequency can arbitrarily be adjusted in the scope of application by Single-chip Controlling, and stepping is 100KHz.Local oscillation signal is divided into two-way by electric bridge, is respectively applied for down-conversion to guarantee the output signal frequency error.In the practical application, high-end selections device high-end by frequency F
C1With selections device centre frequency F
CHThe pass be: F
CI=F
CH+ bandwidth/2; The low side of low side selections device is by frequency F
C2With selections device centre frequency F
CLThe pass be: F
C2=F
CL-bandwidth/2, wherein bandwidth is the repeater operational frequency bandwidth.Radiofrequency signal in frequency mixer with the local oscillation signal mixing, the generation frequency is F
IIntermediate-freuqncy signal, in the up selections device, F
I=F
C-F
L, in the descending selections device, F
I=F
L-F
CLocal oscillation signal frequency F is set
LWith the pass of selections device centre frequency be F
LH-F
CH=F
LL-F
CL=90MHz (descending) or F
CH-F
LH=F
CL-F
LL=90MHz (up), the intermediate-freuqncy signal frequency after the input signal down-conversion is near 90MHz like this.Intermediate-freuqncy signal after the frequency conversion is amplified network through the intermediate frequency of being made up of intermediate frequency power tube 2SC2053 and peripheral circuit thereof and is amplified to compensate the decay of frequency mixer, and gaining is 15dB.Amplified IF signal enters Frequency Band Selection intermediate frequency SAW (Surface Acoustic Wave) filter.SAW (Surface Acoustic Wave) filter is a kind of electroacoustic transduction element, the signal of telecommunication of input converts surface acoustic wave to by interdigital transducer and propagates along the element Piezoelectric Substrates, interdigital transducer by output is reduced into the signal of telecommunication, finish bandpass filtering treatment, the centre frequency of intermediate frequency SAW (Surface Acoustic Wave) filter is 90MHz, the bandpass filtering bandwidth equals the repeater operational frequency bandwidth, and squareness factor is very good, has only F
IIn the time of in the passband of intermediate frequency sound table, signal could normally pass through.In high-end selections device if F
C>F
CH, F then
I>90MHz+ bandwidth/2, intermediate-freuqncy signal will be by filterings outside filter passband.In low side selections device if F
C<F
CL, F then
I<90MHz-bandwidth/2, intermediate-freuqncy signal also will be by filterings outside filter passband.Be the loss of passing through of compensation sound table 22dB, add the one-level intermediate frequency amplifier circuit, gain 15dB in the output of intermediate frequency sound table.Finish up-conversion to revert back frequency be F for enter frequency mixer and another road local oscillation signal mixing through filtering and amplified IF signal
CRadiofrequency signal.Radiofrequency signal after the up-conversion enters radio frequency sound table, the band connection frequency of radio frequency sound table is equal to the operating frequency with the repeater, filtering local oscillation signal and other useless mixed frequency signals, enter radio-frequency (RF) power amplification pipe 2SC2351 again and carry out gain compensation, mate laggardly to go into radio frequency power tube 05 and carry out final stage and amplify by Л type network, finally by radio frequency sound table from radio frequency delivery outlet RF
OUT, output.Has only the F of satisfying
CL<F
C<F
CHSignal could normal filter network by forming by high and low end selections device, put the centre frequency F of high and low end selections device by the software adjustment
C1And F
C2Thereby change is passed through the high low side of signal by frequency, finishes variable Frequency Band Selection.