CN101488768B

CN101488768B - FSK transmitter for sharing one antenna circuit by two transmission chips and manufacturing method

Info

Publication number: CN101488768B
Application number: CN 200910071485
Authority: CN
Inventors: 付永庆; 陶宝泉; 刘占亚; 张�林
Original assignee: Harbin Engineering University
Current assignee: Harbin Engineering University
Priority date: 2009-03-04
Filing date: 2009-03-04
Publication date: 2013-01-16
Anticipated expiration: 2029-03-04
Also published as: CN101488768A

Abstract

The invention provides an FSK transmitter with two transmitting chips sharing an antenna circuit and a preparation method thereof. Two ASK transmitting chips of the same type with the drain electrode open circuit output mode is provided; PA output ends of the two ASK transmitting chips are connected together and jointly connected into the input end of a matching network; input control ends of the two ASK transmitting chips are connected into two I/O wires of a microprocessor. The invention provides a special method in engineering which augments the FSK lauching power. Compared with other methods, the method uses less peripheral circuit elements, is simple and convenient and easy to be realized, provides an efficient solving technical proposal for using the ASK transmitting chips to form an FSK transmitting circuit with greater power.

Description

Two transmission chips is shared FSK transmitter and the method for making of same antenna circuit

(1) technical field

The present invention relates to a kind of FSK transmitter.The invention still further relates to a kind of preparation method of FSK transmitter.A kind of FSK transmitter that biplate ASK transmitting chip shares same antenna circuit and preparation method thereof that uses specifically.

(2) background technology

FSK/ASK superhet transceiving chip is existing at aspects such as long-distance wireless meter-reading system, automobile tyre pressure check system (TPMS), wireless sensers to be used widely.

Be subjected to the restriction of international standard, the integrated RF transmitting chip of the FSK modulating mode that can use at the 433MHz frequency at present is operated in-40～125 ℃ of transmitting powers under the temperature and there is no product above 10dBm.For the requirement of the application scenario of satisfying the larger transmitting power of some demand, common solution is to adopt two ASK transmitting chips design FSK transmitters that exceed the 10dBm transmitting power.

" the theoretical and design of VHF wave band power combiner " (China passes the coal college journal, 2006,13 (2): 44-46) with " design of power amplification circuit in the wireless transmitting system " (Northcentral University, 2007, proposed 5:25-63) by with power synthetic technique with add the method that the power amplifier element increases transmitting power, but this need to provide respectively antenna circuit or use power synthesis circuit to reach the purpose that shares same antenna circuit.The method has not only increased the complexity of circuit, has reduced the reliability of transmitter but also has increased static dissipation power, especially is not suitable for having in long-life application system with powered battery and requirement.

(3) summary of the invention

The object of the present invention is to provide a kind ofly can effectively solve the synthetic problem of small-power FSK transmitter power, can design more high transmit power FSK transmitter, the two transmission chips that can avoid chip to damage is shared the FSK transmitter of same antenna circuit.The present invention also aims to provide a kind of two transmission chips to share the preparation method of the FSK transmitter of same antenna circuit.

The object of the present invention is achieved like this:

The composition that two transmission chips of the present invention is shared the FSK transmitter of same antenna circuit comprises: two same models have the ASK transmitting chip of the open-drain way of output, the PA output of two ASK transmitting chips links together, jointly receive the input of matching network, the input control end of two ASK transmitting chips is connected on two I/O lines of microprocessor.

Preparation method's step that two transmission chips of the present invention is shared the FSK transmitter of same antenna circuit is:

1, select two ASK transmitting chips that same model has the open-drain way of output, its monolithic power output must be satisfied the transmitting power requirement of FSK transmitter;

2, according to selected chip technology handbook, determine chip power, output matching network, crystal oscillating circuit;

3, two by the FSK transmitter launch frequency f _RF1, f _RF2The passive crystal oscillator X that selection is complementary with it ₁And X ₂Frequency;

4, the PA output with two ASK transmitting chips links together, and jointly receives the input of output matching network;

5, respectively the input control end of two ASK transmitting chips is connected on two I/O lines of microprocessor.The working method of microprocessor is: make in the transmitting data information ' 0 ' and ' 1 ' respectively corresponding two different ASK chip input control ends.

Key feature of the present invention is to utilize the alternation of two ASK chips to realize the function of FSK transmitter, and has used same antenna circuit.For common FSK transmitter, its transmitting power is identical with the transmitting power of monolithic ASK transmitting chip.Therefore can reach by the ASK transmitting chip of selecting to surpass monolithic FSK transmitting chip transmitting power and design the more purpose of high transmit power FSK transmitter.

Essence of the present invention is: utilizing the ASK transmitting chip is the open-drain output characteristic, and the output of two ASK transmitting chips is connected together, and externally output is high impedance when chip is not worked, and can not affect the output of other chips., make and under any circumstance all only have a slice ASK transmitting chip in work by two ASK transmitting chips of microprocessor control at data input pin, so just can guarantee that same peripheral radiating circuit all is the optimum Match state to any one transmitting chip.Can close by the input of control ASK transmitting chip simultaneously the work of ASK transmitting chip, to reach the purpose of avoiding chip to damage.

Specific works process of the present invention with principle is: the mode according to Fig. 1 connects together each hardware module.Wherein microprocessor U1 judges that current transmitting data information bit is ' 0 ' or ' 1 ', if data bit is ' 0 ', then the I/O mouth I/O_1 by microprocessor is f with tranmitting frequency _RF1The data input control end D1 of ASK transmitting chip U2 set high, enabling ASK transmitting chip U2, to produce frequency be f _RF1Radiofrequency signal; If data bit is ' 1 ', then the I/O mouth I/O_2 by microprocessor is f with tranmitting frequency _RF2The data input control end D2 of ASK transmitting chip U3 set high, enabling ASK transmitting chip U3, to produce frequency be f _RF2Radiofrequency signal.Along with the continuous renewal of transmitting data, the alternation of two ASK transmitting chips, thus the FSK that finishes base band data modulates, and it is f that last PA output by two ASK transmitting chips replaces output frequency _RF1, f _RF2Radiofrequency signal is gone out by same antenna resonance matching network and antenna transmission.

Intentionally effect of the present invention is:

1. provided a kind of specific process of the FSK of increase transmitting power in engineering, it is than additive method use peripheral circuit element still less, and easy being easy to of method realized.

2. provide a kind of effective solution for using the ASK transmitting chip to consist of more powerful FSK radiating circuit.

(4) description of drawings

Fig. 1 is structured flowchart of the present invention;

Fig. 2 is the electrical block diagram of the specific embodiment of the present invention.

(5) embodiment

For example the present invention is described in more detail below in conjunction with accompanying drawing:

In conjunction with Fig. 1, the performing step that two transmission chips of the present invention is shared the FSK transmitter of same antenna circuit is:

1, select two ASK transmitting chips that same model has the open-drain way of output, its monolithic power output must be satisfied the transmitting power requirement of FSK transmitter.

2, according to selected chip technology handbook, determine chip power, output matching network, crystal oscillating circuit.

3, two by the FSK transmitter launch frequency f _RF1, f _RF2The passive crystal oscillator X that selection is complementary with it ₁And X ₂Frequency.

4, the PA output with two ASK transmitting chips links together, and jointly receives the input of matching network.

In conjunction with Fig. 2, it is the embodiment that the present invention is used for Vehicular tyre pressure monitoring system (TPMS).Detected and main control chip U1, ASK transmitting chip U2 and U3, crystal oscillator X1 and X2, output matching filter circuit and antenna, JTAG download mouthful and power circuit forms jointly by tire temperature tire pressure.

The temperature that U1 is built-in, the transducers such as pressure are responsible for gathering the tire real time data, send into ASK transmitting chip U2 and U3 by data-in port D1 and D2 after processing by analysis.Chip U2 is the f that realizes in the FSK emission _RF1, chip U3 is the f that realizes in the FSK emission _RF2X1 provides reference frequency for the U2 chip, and X2 provides reference frequency for chip U2.The power amplifier output PAOUT of U1, U2 is connected to common simple PCB loop antenna or the other forms of 50 Ω antennas of driving of same coupling resonant circuit.The antenna match resonant circuit is comprised of inductance L 1, L2 and capacitor C 7, C8, C11 and variable capacitance C9, C10 etc.

The design parameter that present embodiment adopts is:

1, main control chip uses SP30, and this built-in chip type temperature, pressure sensor use the JTAG mouth to download;

2, the ASK transmitting chip uses MAX7044;

3, the reference frequency f of crystal oscillator _XATL1=13.546312MHz, f _XATL2=13.556687MHz;

4, two frequencies of FSK modulation are respectively f _RF1=433.79MHz and f _RF2=434.15MHz;

5, transmitting power P _OUT=+13dBm;

More than be described as a kind of embodiment of the present invention, can carry out respective change according to technical scheme of the present invention.

Claims

1. a two transmission chips is shared the FSK transmitter of same antenna circuit, it is characterized in that: two same models have the ASK transmitting chip of the open-drain way of output, the power amplifier output of two ASK transmitting chips links together, jointly receive the input of antenna match filter circuit, the input control end of two ASK transmitting chips is connected on two I/O lines of the detection of tire temperature tire pressure and main control chip; Specifically jointly formed by the detection of tire temperature tire pressure and main control chip (U1), an ASK transmitting chip (U2), the 2nd ASK transmitting chip (U3), first crystal oscillator (X1), the second crystal oscillator (X2), antenna match filter circuit, antenna, JTAG download mouth and power circuit;

Tire temperature tire pressure detects and built-in temperature, the pressure sensor of main control chip (U1) is responsible for gathering the tire real time data, sends into respectively an ASK transmitting chip (U2) and the 2nd ASK transmitting chip (U3) by the first data-in port (D1) and the second data-in port (D2) after processing by analysis; The one ASK transmitting chip (U2) is the first tranmitting frequency f that realizes in the FSK emission _RF1, the 2nd ASK transmitting chip (U3) is the second tranmitting frequency f that realizes in the FSK emission _RF2First crystal oscillator (X1) is that an ASK transmitting chip (U2) provides reference frequency, and the second crystal oscillator (X2) is that the 2nd ASK transmitting chip (U3) provides reference frequency; The power amplifier output of the one ASK transmitting chip (U2), the 2nd ASK transmitting chip (U3) is connected to common simple PCB loop antenna or the other forms of 50 Ω antennas of driving of same described antenna match filter circuit; The antenna match filter circuit is connected to form by the first inductance (L1), the second inductance (L2), the first electric capacity (C7), the second electric capacity (C8), the 3rd electric capacity (C11) and the first variable capacitance (C9), the second variable capacitance (C10).

2. a two transmission chips is shared the preparation method of the FSK transmitter of same antenna circuit, it is characterized in that:

(1) select two ASK transmitting chips that same model has the open-drain way of output, its monolithic power output must be satisfied the transmitting power requirement of FSK transmitter;

(2) according to selected chip technology handbook, determine chip power, output matching network, crystal oscillating circuit;

(3) two by the FSK transmitter launch frequency f _RF1, f _RF2The passive crystal oscillator X that selection is complementary with it ₁And X ₂Frequency;

(4) the power amplifier output with two ASK transmitting chips links together, and jointly receives the input of matching network;

(5) respectively the input control end of two ASK transmitting chips is connected on two I/O lines of microprocessor.