CN1304214A

CN1304214A - High-frequency signal receiving-transmitting method

Info

Publication number: CN1304214A
Application number: CN 00101536
Authority: CN
Inventors: 旋永南
Original assignee: Individual
Current assignee: Individual
Priority date: 2000-01-10
Filing date: 2000-01-10
Publication date: 2001-07-18

Abstract

A method for sending and receiving high-frequency signal includes the following steps: in a sending machine, modulating the signal to be sent onto two or more than two high-frequency carrier frequencies simultaneously, and sending them out, in a receiving machine, the two carrier frequencies of the received modulated signal are mixed, and frequencies down-converted, the obtained IF signal is passed through filter and taken out, can be directly demodulated or passed through frequency down-conversion and demodulated. Said receiving machine has no need of local oscillator source or has no need of high-frequency local oscillator source. The difference frequency of two carrier frequencies and frequency of IF local oscillator can be changed with pseudo-random code to form bandspreading and despreading processes. Said invention can simplity circuit improve performance and reduce cost.

Description

A kind of high-frequency signal receiving-transmitting method

The present invention relates to a kind of high-frequency signal receiving-transmitting method, belong to the communications field.

In the communications field, people often need utilize high frequency that signal is sent.In the prior art [1,2], Si to be signaled (t) is modulated onto in transmitter on the high frequency carrier frequency and sends.At receiving terminal, after this CF signal is received, with the local oscillation signal of receiver through one or multistage down-conversion, by demodulation original signal Si (t) is taken out again.Use prior art, receiver needs at first order frequency mixer place one high-frequency local oscillation source be arranged at least, and it need have stablely, accurately reaches premium properties such as low noise, makes circuit complexity and cost all increase.In addition, on broad frequency band or different frequency range, receiver usually need be used the local vibration source more than as if system works, and this moment, circuit was more complicated.The high-frequency signal that sends when transmitter is when transmission course changes owing to a variety of causes, and the local vibration source of receiver is difficult to follow the tracks of usually, causes poor system performance.When the high frequency of transmitter changed, the frequency of the local vibration source of receiver also must correspondingly change, and vice versa, thereby increased system design, particularly did in the running to upgrade and improved difficulty.The local frequency of transmission frequency and receiver all needs very accurate, has increased the difficulty of the cost and the option of components and parts.

Task of the present invention, be to reform prior art, make that high-frequency signal is all provided by transmitter in a transmitting/receiving system, and in receiver, under the situation of one-level frequency conversion, without any need for local vibration source, under the situation of multistage frequency conversion, the difficulty that does not then need to be used for the prime mixing is done the high-frequency local oscillation source higher with cost, thereby make the circuit reduction of receiver, even and same circuit can be operated on the wideer different frequency range.With regard to whole receive-transmit system, the difficulty of above-mentioned prior art and shortcoming will be overcome, and make the cost of communication system reduce, and performance improvement and flexibility are improved.

Use method of the present invention, referring to Fig. 1, at transmitting terminal 1, Si to be signaled (t) will be modulated onto on two carrier frequency simultaneously to send.If the frequency of two carrier frequency is respectively FL and FU, and both differences are FIF, i.e. FIF=FU-FL.At receiving terminal 2, after receiver is received the signal that is modulated to FU and FL, make it obtain the difference frequency FIF of FU with FL by multiply by certainly, can realize that the high frequency down-conversion of prime is so that restore the original signal demodulation.For this reason, institute collected mail number is input to nonlinear circuit 7, and its output contains difference frequency FIF and other frequency content of FU and FL.Is the composition taking-up of FIF with intermediate-frequency filter 8 with frequency, has promptly finished the process of down-conversion.Note this process unlike the prior art, participate in the FU of difference frequency and FL, do not need to have in the receiver (normally cost higher also difficult do) high-frequency local oscillation source therebetween all from transmitter.Frequency is the intermediate-freuqncy signal of FIF or can be directly delivered to demodulator 12 demodulation, and original signal Si (t) is taken out, and maybe can be sent to

intermediate frequency mixer

9 and 10 mixing of intermediate frequency local oscillator source.The gained signal is delivered to demodulator 12 demodulation again to take out original signal Si (t) after low-frequency filter 11 leaches, finish the receipts process of sending out of signal.Shown in Figure 1, be that the back is a kind of, i.e. the situation of multistage frequency conversion.

Fig. 1 provides the basic circuit structure that can realize the inventive method.At transmitting terminal 1, basic circuit is by modulator 3, power combiner 4, and high frequency filter 5 is formed.Si to be signaled (t) is from the input A of modulator 3 input, and two output B of modulator 3 and C are connected respectively to two the input D and the E of power combiner 4, and it is synthetic that the modulated signal that frequency is respectively FL and FU is delivered to power combiner 4.The output F of power combiner 4 is connected to the input G of high frequency filter 5, and high frequency filter 5 is selected the frequency range that contains modulated signal So (t), via its output H output, sends to make wired or wireless signal.At receiving terminal 2, the signal So (t) that receives is from the input I input of high frequency filter 6, and the output J of high frequency filter 6 is connected to the input K of nonlinear circuit 7, and the output L of nonlinear circuit 7 is connected to the input M of intermediate-frequency filter 8.The output N of intermediate-frequency filter is connected to the input signal end O of intermediate frequency mixer 9.The output Q in intermediate frequency local oscillator source 10 is connected to the local oscillator end R of intermediate frequency mixer 9.The output P of intermediate frequency mixer 9 is connected to the input T of low-frequency filter 11, and the output U of low-frequency filter 11 is connected to the input V of demodulator 12.Signal Si (t) takes out from the output W reduction of demodulator 12.

The difference frequency FIF of carrier frequency frequency FU and FL can be designed to a constant, also can be a time-varying number, particularly the number that changes with a pseudo noise code (PN sign indicating number).In the situation that FIF changes with the PN sign indicating number, method of the present invention is received the spread spectrum process that a uniqueness is provided for sending out of signal.This moment, the frequency in intermediate frequency local oscillator source 10 also should correspondingly change with same PN sign indicating number in receiver, to realize despreading process.

Use method of the present invention, the number of the carrier frequency that the process of Si to be signaled (t) modulation is used also can be more than two.Situation during with two carrier frequency is similar, at receiving terminal, utilizes nonlinear circuit and filter circuit, can produce and select by the formed intermediate-freuqncy signal of the difference frequency of each carrier frequency, then carry out direct demodulation, perhaps further down-conversion process such as demodulation is again reduced Si former to be signaled (t).

The present invention compared with prior art has following advantage:

A. receiver does not need local vibration source (situation of one-level frequency conversion), perhaps do not need cost higher also difficulty do high-frequency local oscillation source (situation of multistage frequency conversion), make circuit reduction, cost reduces.This is particularly important for the communication system that many receivers are arranged;

B. owing to the high-frequency local oscillation source need not arranged, receiver can be done to such an extent that bandwidth is big or be operated on the multiband, even can work in the different communication systems, and economic benefit is great;

C. participate in the high-frequency signal composition (FU and FL) of receiver prime frequency conversion, all from the frequency reference of transmitter, the influence that they are subjected in transmission course is roughly the same, even make in situations such as multipath fading and Doppler frequency shifts, its correlation is still fabulous, helps the improvement of receiver system performance index;

D. since the high-frequency signal of whole transmitting/receiving system determine by the frequency reference of transmitter, can reduce the requirement of its precision, cost is reduced, and has increased the flexibility of element selection;

E. in addition, because the high-frequency signal of whole transmitting/receiving system determines by the frequency reference of transmitter and the bandwidth of receiver is bigger, within the specific limits, when the frequency of needs change transmitting/receiving system, only need transmitter is changed, and receiver does not need correspondingly to change.This make the signal transmitting/receiving system design simplification and help renewal and improvement in the particularly running of system widely.

F. the situation that changes with the PN sign indicating number at FIF, method of the present invention provide one can with the simultaneously applied further spread spectrum process of traditional band spectrum modulation, improved antijamming capability and confidentiality that signal is sent out receipts widely.

Generally speaking, the prior art that method of the present invention compares has circuit simple, and is functional, and cost reduces, and is easy to main advantages such as renewal.Consider using very widely of communication system, enforcement of the present invention will inevitably produce very huge economic and social benefit.

Fig. 1 in this Figure of description is for implementing the basic circuit structure block diagram of method of the present invention.Fig. 2 is the circuit diagram that contains crucial component of embodiment given below.

Provide one embodiment of the present of invention below.See Fig. 2, at transtation mission circuit 13, modulator 14 is by field effect transistor 31 (model Infineon BSS159), resistance R 1, and R2, R3, R4, R5 and two voltage controlled oscillators 15 and 16 (model MiniCirsuits ROS-1000PV) form.Si to be signaled (t) is by the grid G ATE input of field effect transistor 31.The drain D RAIN of field effect transistor 31 receives an A1 by resistance R 2, receives power supply Vdc through resistance R 1 again.The source S OURCE of field effect transistor 31 receives an A2 by resistance R 4, again through resistance R 5 ground connection.Also be connected to resistance R 3 between the drain D RAIN of field effect transistor 31 and the source S OURCE.The tie point A2 of the tie point A1 of resistance R 1 and resistance R 2 and resistance R 4 and resistance R 5 receives the control end A3 and the A4 of two voltage controlled

oscillators

15 and 16 respectively.Voltage controlled

oscillator

15 and 16 is by power supply Vdc power supply, and their output terminals A 5 and A6 receive two the input A7 and the A8 of power combiner 17 (model MiniCircuitsMSC-2-11) respectively.The output terminals A 9 of power combiner 17 is connected to the input A10 of high frequency filter 18 (model SawTek 855794).Present embodiment utilizes wireless mode to transmit signal, and the output terminals A 11 of high frequency filter 18 is connected to transmitting antenna 19.At receiving circuit 20, power supply Vdc provides circuit at different levels required voltage.Reception antenna 21 is connected to the input B1 of high-frequency amplifier 22 (model MiniCircuits ERA-3), the output B2 of high-frequency amplifier 22 is connected to the input B3 of high frequency filter 23 (model SawTek 855794), the output B4 of high frequency filter 23 is connected to the LO signal input part B5 and the RF signal input part B6 of high-frequency mixer 24 (model LRMS-5L), and the IF signal output part B7 of high-frequency mixer 24 is connected to the input B8 of intermediate-frequency filter 25 (model TOKO SK107MA-AE-10).The output B9 of intermediate-frequency filter is connected to the signal input end of intermediate frequency B10 of intermediate frequency mixer (model MiniCircuits ADE-3L) 26.Intermediate frequency local oscillator source 27 is by oscillator OSC, and inductance L 1 and capacitor C 1 are formed.Its output B11 is connected to the local oscillation signal input B12 of intermediate frequency mixer.The output B13 of intermediate frequency mixer 26 is connected to the input B14 of low-frequency filter 28 (model PTI 6960C), and the output B15 of low-frequency filter 28 is connected to the input B16 of demodulator 29 by coupling capacitance C2.Demodulator 29 is by demodulator IC 30 (model MOTOROLAMC13055), resistance R 6, and R7, R8, R9 and capacitor C 2, C3, C4, C5, C6, C7 and inductance L 2 are formed.Signal Si (t) is reduced taking-up from the output B17 of demodulator 29.

The operation principle of present embodiment is as follows: at transtation mission circuit 13, when Si to be signaled (t) is 0 (low level), field effect transistor 31 is ended, suitably select Vdc and each resistance R 1, R2, R3, the value of R4 and R5, can make tie point A1 and tie point A2 be in suitable current potential respectively, make that the output frequency of voltage controlled

oscillator

15 and 16 is respectively FU=952.7MHz and FL=942MHz.When Si to be signaled (t) is 1 (high level), field effect transistor 31 conductings, the current potential of tie point A1 descends and the current potential rising of tie point A2, makes the output frequency of voltage controlled

oscillator

15 and 16 descend respectively and rise.This frequency keying (FSK) modulated process has been modulated to Si to be signaled (t) on two carrier frequency on the FU and FL, and information then is contained in their difference frequency.Two the input A7 and the A8 of power combiner 17 delivered in modulated voltage controlled

oscillator

15 and 16 output respectively, in power combiner 17 synthetic after,, deliver to antenna 19 again and send the outer composition elimination of band through high frequency filter 18.At receiving circuit 20, after reception antenna 21 is received signal, signal is amplified through high-frequency amplifier 22, again by high frequency filter 23 the outer clutter elimination of band.Signal is delivered to the LO signal input part B5 and the RF signal input part B6 of high-frequency mixer 24 simultaneously then.The composition that the signal intermediate frequency rate is respectively FU and FL will be taken advantage of mutually and produce mixing, make that containing frequency in the output of high-frequency mixer 24 is FU-FL=FIF, FU+FL, and other composition.The task of intermediate-frequency filter 26 is that to select its medium frequency be the composition of FIF and other composition is filtered.Frequency is the output signal mixing of the signal of FIF in intermediate frequency mixer 26 and intermediate frequency local oscillator source 27, its result is in the output B13 of intermediate frequency mixer 26 output, after low-frequency filter 28 filtering, deliver to demodulator 29 demodulation again, thereby original signal Si (t) is taken out and finishes whole signal and send out the receipts process.

List of references [1] Theadore S Rappaport, " Wireless Communications-Priciples﹠amp; Practice ", Pretice-Hall, 1996[2] Peter Vizmuller, " RF Design Guide:Systems, Circuits and Equations ", Artech House, 1995

Claims

1. a high-frequency signal receiving-transmitting method is characterized in that at transmitting terminal 1, and Si to be signaled (t) is modulated onto on two carrier frequency FU and the FL and sends.At receiving terminal 2, after receiver is received the signal that is modulated to FU and FL, make its by nonlinear circuit 7 and intermediate-frequency filter circuit 8 to obtain the difference frequency FIF signal of FU and FL, realize the preceding stage high frequency downconversion process.Frequency is the intermediate-freuqncy signal of FIF or can be directly delivered to demodulator 12 demodulation, original signal Si (t) is taken out, or can with intermediate frequency local oscillator source 10 signal mixings in the receiver, the gained signal send demodulator 12 demodulation through low-frequency filter 11, take out original signal Si (t) again, finish the receipts process of sending out of whole signal.

2. by the difference frequency FIF of described carrier frequency FU of claim 1 and carrier frequency FL, it is characterized in that it can be constant, also can be time-varying number, particularly the number that changes with pseudo noise code (PN sign indicating number).In the situation that FIF changes with the PN sign indicating number, the frequency of intermediate frequency local oscillator source 10 signals also correspondingly changes with same PN sign indicating number, to realize despreading process.

3. by the modulated process of the described Si to be signaled of claim 1 (t), it is characterized in that the number of carrier frequency also can be more than two.