High frequency small signal tuned amplifier
Department: Department of Electrical and Information Engineering
Student name: Chen Ying.
Instructor: lecturer Jia Yaqiong.
Major: Electronic Information Engineering
Class level: Electronic 0903
Completion time: 201165438+February 6th.
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With the rapid development of electronic technology, social development has entered the information age. With the requirement of high-quality talents and informatization in the information age and the development trend of higher education, people's living standards have improved, and the requirements for spiritual and civilized life have also improved, which puts higher demands on the electronic field.
Communication electronic circuit is a widely used and rapidly developing science and technology. In order to learn this technology well, we must first systematically study the basic theory, and then carry out technical training to cultivate our ability to integrate theory with practice, design circuits, operate in practice, correctly handle data, analyze comprehensive experimental results, and check and troubleshoot. At the same time, it has deepened our understanding of electronic products.
In wireless communication, the transmitted and received signals should be suitable for space transmission. Therefore, the signals processed and transmitted by communication equipment are modulated high-frequency signals with narrow-band characteristics. Moreover, through long-distance communication transmission, the signal will be attenuated and interfered, and the signal reaching the receiving equipment is a very weak high-frequency narrow-band signal, which can only be further processed after amplification and interference. This needs to be done through a high frequency small signal amplifier. This small signal amplifier is a resonant amplifier.
High-frequency small signal amplifiers are widely used in broadcasting, television, communication, measuring instruments and other equipment. High-frequency small signal amplifiers can be divided into two categories: one is a resonant amplifier with a resonant circuit as the load; The other is a centralized frequency selective amplifier with filter as load. Their main function is to select useful signals from many received electrical signals and amplify them, while suppressing useless signals, interference signals and noise signals, so as to improve the quality of received signals and anti-interference ability.
High-frequency small signal amplifier is a common functional circuit in communication equipment, and its amplified signal frequency ranges from several hundred thousand hertz to several hundred megahertz. The function of high frequency small signal amplifier is to amplify weak high frequency signal without distortion. From the spectrum of the signal, the spectrum of the input signal is the same as that of the amplified output signal.
Task book
I. Design Theme: High Frequency Small Signal Tuned Amplifier
II. Application category: electronic 090 1 ~ 0903
Third, the instructor: Jia Yaqiong
Four. Design purpose and task:
Students solve corresponding practical problems through theoretical design and physical production, consolidate and apply the theoretical knowledge and experimental skills of communication electronic circuits they have learned, master the general design methods of communication electronic systems, improve their design ability and practical ability, and lay a good foundation for future electronic circuit design and electronic product research and development.
Verb (abbreviation of verb) design requirements
Design a high frequency small signal tuning amplifier. It is required that the center frequency is 20MHz, the voltage gain is 4MHz, the load resistance is 100, and the power supply voltage is+12V.
Almost orderly
High-frequency small signal amplifier is a common functional circuit in communication equipment, and its amplified signal frequency ranges from several hundred thousand hertz to several hundred megahertz. The function of high frequency small signal amplifier is to amplify weak high frequency signal without distortion. From the spectrum of the signal, the spectrum of the input signal is the same as that of the amplified output signal.
Classification of high frequency small signal amplifiers;
Divided into transistor amplifier, field effect transistor amplifier and integrated circuit amplifier according to components; According to the frequency band, it is divided into: narrowband amplifier and broadband amplifier; According to the circuit form, it is divided into single-stage amplifier and multistage amplifier; According to the load nature, it is divided into resonant amplifier and non-resonant amplifier; Characteristics of high frequency small signal amplifier;
The center frequency with higher frequency is generally from several hundred KHz to several hundred MHz, and the bandwidth is from several kHz to several tens of MHz. Therefore, it is necessary to use the frequency selection network to work in the linear range (class A amplifier) because the small signal is small, that is, it works in the linear amplification state.
When the resonant circuit is used as a load, the signal gain near the resonant frequency is large, and the signal gain far away from the resonant frequency drops rapidly, that is, it has the function of frequency selective amplification.
Among them, high-frequency small-signal tuned amplifiers are widely used in communication systems and other radio systems, especially at the receiving end of transmitters. The signal induced by the antenna is very weak, so it needs to be amplified by an amplifier. The principle of high frequency signal amplifier is simple, but it is difficult to make it in practice. The most common problem is self-excited oscillation, and frequency selection and impedance matching between stages are also difficult to achieve. On the basis of theoretical analysis and practical production, this paper eliminates the self-excited oscillation of high-frequency amplifier and realizes accurate frequency selection with the help of LC oscillation circuit. In addition, other circuits are added to realize impedance matching between the amplifier and the front and rear stages.
The first chapter introduces the main performance indexes of high frequency small signal amplifier.
The main performance indexes of high frequency small signal amplifier include voltage gain and power gain, bandwidth, rectangular coefficient and working stability.
1. Voltage gain and power gain
The voltage gain is equal to the ratio of the output voltage to the input voltage of the amplifier; And the power gain is equal to the ratio of the output power to the input power of the amplifier.
2. Bandwidth
Because of the frequency selection function of the resonant circuit, when the working frequency deviates from the resonant frequency, the voltage amplification of the amplifier decreases. Conventionally, the frequency range corresponding to the reduction of the voltage amplification factor Av to 0.707 times of the resonance voltage amplification factor Avo is called the passband BW of the amplifier, and its expression is:
BW = 2δ = formula 1- 1- 1.
Where is the on-load quality factor of the resonant circuit. It is known that the relationship between the resonance voltage amplification factor Av and the passband BW of the amplifier is as follows: formula 1- 1-2.
The above formula shows that when the transistor is selected and the total capacitance of the loop is fixed, the product of the resonant amplification coefficient Avo and the passband BW is constant. This is the same as the concept that the gain of low-frequency amplifier is constant. The frequency characteristic curve of the amplifier is shown in figure 1- 1- 1 because the voltage amplification factor decreases after the resonance circuit is detuned. From the formula 1- 1- 1:
Formula 1- 1-3
The wider the passband, the smaller the voltage amplification factor of the amplifier. In order to obtain a passband with a certain width and improve the voltage gain of the amplifier, it can be seen from the formula 1- 1-2 that besides selecting a larger transistor, the total capacitance of the tuning loop should be reduced as much as possible. If the amplifier is only used to amplify the weak signal with fixed frequency from the receiving antenna, the passband BW can be reduced and the gain of the amplifier can be improved as much as possible.
The frequency characteristic curve is shown in figure (1- 1):
Fig. (1- 1- 1) frequency characteristic curve
3. Rectangular coefficient
Rectangular coefficient is a parameter to characterize the selectivity of amplifier. Indicate by ... The rectangular coefficient is the ratio of the corresponding frequency range when the voltage amplification coefficient drops to 0. 1Avo and the corresponding frequency offset when the voltage amplification coefficient drops to 0.707Avo, that is
= formula 1- 1-4
In the formula 1- 1-4, it is the passband and corresponding bandwidth of the amplifier when the voltage gain of the amplifier drops to 0. 1 times of the maximum value. The closer the rectangular coefficient is to 1, the better the adjacent channel selectivity and the stronger the interference filtering ability. Generally, the selectivity of single-stage resonant amplifier is poor because its rectangular coefficient is much larger than 1. In order to improve the selectivity of amplifier, multistage resonant amplifier is usually used.
4. Work stability
Refers to the stability of the main performance of the amplifier when the DC bias, transistor parameters and circuit component parameters of the amplifier may change. The performance of the amplifier is not affected by external factors such as temperature and power supply voltage as much as possible, and the internal noise is small, especially there is no self-excitation. Adding negative feedback can improve the performance of the amplifier. The comparison curve of its stability with or without feedback is shown in the following figure (1-2):
Fig. (1-2) Influence of feedback on resonance curve of amplifier
Chapter II Circuit Design Principles
2. 1 single tuned resonant amplifier
Small-signal resonant amplifier is the front-end circuit of communication receiver, which is mainly used for linear amplification of high-frequency small signals or weak signals. The circuit of the experimental unit is shown in figure 1- 1. The circuit consists of transistor Q 1 and frequency selection loop T 1. It can not only amplify high-frequency small signals, but also has a certain frequency selection function. In this experiment, the frequency of the input signal is fs = 10.7 MHz. Base bias resistors W3, R22, R4 and emitter resistor R5 determine the static operating point of the transistor. Adjusting the variable resistor W3 and changing the base bias resistance will change the static operating point of the transistor, so the gain of the amplifier can be changed.
The main performance indexes of high frequency small signal tuned amplifier include resonance frequency f0, resonance voltage amplification factor Av0, passband BW and amplifier selectivity (usually expressed by rectangular coefficient Kr0. 1).
Figure 2- 1- 1 Single Tuned Amplifier
2. 1. 1 resonance frequency
The frequency f0 corresponding to the resonance of the amplifier tuning loop is called the resonance frequency of the amplifier. For the circuit shown in figure 1- 1 (which is also the circuit corresponding to the following indicators), the expression of f0 is
Where l is the inductance of the inductance coil of the tuning circuit;
Is the total capacitance of the tuning loop, and the expression is
Where Coe is the output capacitance of the transistor; Cie is the input capacitance of the transistor; P 1 is the tap coefficient of the primary coil; P2 is the tap coefficient of the secondary winding.
The measurement method of resonance frequency f0 is: using a frequency scanner as a measuring instrument, measuring the amplitude-frequency characteristic curve of the circuit, and adjusting the magnetic core of the transformer T so that the peak of the voltage resonance curve appears at the specified resonance frequency point f0.
2. 1.2 voltage magnification
When the resonant circuit of the amplifier resonates, the corresponding voltage amplification factor AV0 is called the voltage amplification factor of the tuned amplifier. The expression of AV0 is
Where is the total conductance of the resonant circuit at resonance. It should be noted that yfe itself is a complex number, so the phase difference between the output voltage V0 and the input voltage Vi at resonance is not 180? But 180? +φFe .
The measurement method of AV0 is: when the resonant circuit is in the resonant state, use a high-frequency voltmeter to measure the magnitude of the output signal V0 and the input signal Vi in Figure 1- 1, and then calculate the voltage amplification factor AV0 according to the following formula:
AV0 = V0/Vi or AV0 = 20 lg (V0 /Vi) dB.
2. 1.3 passband
Because of the frequency selection function of the resonant circuit, when the working frequency deviates from the resonant frequency, the voltage amplification of the amplifier decreases. Traditionally, the frequency offset corresponding to the voltage amplification factor AV falling to 0.707 times of the resonance voltage amplification factor AV0 is called the passband BW of the amplifier, and its expression is
BW = 2△f0.7 = f0/QL
Where QL is the on-load quality factor of the resonant circuit.
The analysis shows that the relationship between the resonant voltage amplification factor AV0 of the amplifier and the passband bandwidth is as follows.
The above formula shows that the product of resonant voltage amplification factor AV0 and passband BW is constant when the selected transistor, yfe, determines that the total capacitance of the loop is constant. This is the same as the concept that the gain bandwidth product in a low-frequency amplifier is constant.
The measurement method of passband BW is to find the passband by measuring the resonance curve of the amplifier. The measurement method can be sweep frequency method or point-by-point method. The measurement steps of the point-by-point method are as follows: firstly, tune the resonant circuit of the amplifier to make it resonate, and record the resonant frequency f0 and voltage amplification factor AV0 at this time, then change the frequency of the high-frequency signal generator (keep its output voltage VS unchanged) and measure the corresponding voltage amplification factor AV0. Because the voltage amplification coefficient decreases after the loop detuning, the resonance curve of the amplifier is shown in figure 1-2.
Available:
The wider the passband, the smaller the voltage amplification factor of the amplifier. In order to get a certain bandwidth and improve the voltage gain of the amplifier, besides choosing transistors with larger yfe, the total capacitance cσ of the tuning loop should be reduced as much as possible. If the amplifier is only used to amplify the weak signal with fixed frequency from the receiving antenna, the passband can be reduced and the gain of the amplifier can be increased as much as possible.
2. 1.4 selectivity
The selectivity of the tuning amplifier can be expressed by the rectangular coefficient Kv0. 1 of the resonance curve, as shown in figure 1-2. The rectangular coefficient Kv0. 1 is the ratio of the corresponding frequency offset when the voltage amplification factor drops to 0. 1 AV0 to the corresponding frequency offset when the voltage amplification factor drops to 0.707 AV0, that is
kv 0. 1 = 2△f 0. 1/2△f 0.7 = 2△f 0. 1/BW
The above formula shows that the smaller the rectangular coefficient Kv0. 1, the closer the shape of the resonance curve is to the rectangle, and the better the selectivity, and vice versa. Generally, the selectivity of single-stage tuning amplifier is poor (rectangular coefficient Kv0. 1 is much greater than 1). In order to improve the selectivity of amplifier, multistage resonant amplifier with single tuning ring is usually used. The rectangular coefficient Kv0. 1 can be obtained by measuring the resonance curve of the tuning amplifier.
The product of rectangular coefficient and bandwidth of a single tuned amplifier is a constant. In other words, the gain and passband of a single tuned amplifier are a pair of contradictions. In order to increase the gain, the passband must be lowered. Will shrink. But this contradiction does not conflict in the case of low gain or narrow band amplifier. The general solution is to choose as large a transistor as possible and design a smaller total loop capacitance.
Chapter 3 Design of High Frequency Small Signal Tuning Circuit
3. 1 Design of Single-stage Tuning Circuit
3. 1. 1 Selection of circuit structure
According to the requirements of the design task, because the gain of the amplifier is greater than 20dB and can be realized by a single-stage amplifier, the circuit schematic diagram of the high-frequency small-signal resonant amplifier as shown in Figure 3- 1- 1 is drawn.
Figure 3- 1- 1 high frequency small signal single-stage tuned amplifier circuit
In Figure 3- 1- 1, transformer T 1 is a coupling element and transformer T2 is a coupling element; The primary coil and the capacitor c form a frequency selection loop; Transistor t amplification element; Resistors Rb 1 and Rb2 are bias resistors to fix the static potential of the transistor base; The emitter DC negative feedback resistor of the resistor ring stabilizes the static working point; Capacitor C, CT and T2 primary coil constitute the transistor collector resonant load, which plays the role of frequency selection. Capacitance CT resonant circuit resonant frequency adjustment capacitor; The resistance RT resonant circuit can adjust the resistance, adjust the quality factor of the resonant circuit and realize impedance matching. Capacitor Cf power filter capacitor; Base bypass capacitance of capacitor Cb; Capacitor Ce emitter bypass capacitance; Vcc is DC power supply.
Static working process When the input signal ui=0V, the amplifier is in DC working state (static). Ideally, the secondary side of transformer T 1 and the primary side of transformer T2 are regarded as short circuits, and capacitors Cb, Ce and Cf are regarded as open circuits. The DC path of the amplifier is shown in Figure 3- 1-2(a). At this time, the output signal is 0.
Figure 3- 1-2 AC and DC paths of amplifier
Dynamic working process When the input signal ui is not equal to 0V, the amplifier is in AC /DC working state (dynamic). Ideally, the capacitors Cb, Ce and Cf are considered as short circuits, and the AC path of the amplifier is shown in Figure 3- 1-2(b).
3. 1.2 Circuit parameter calculation and component selection
(1) Select the transistor and calculate the y parameter.
According to the equivalent circuit of transistor Y parameter, in order to ensure the stability of atmospheric operation, the transistor with small yre should be selected. In order to work at the top frequency, transistors are required to have good frequency characteristics, and electron tubes are generally selected. When high voltage gain is needed, the transistor with |yfe| should be selected.
Due to the design requirements, and the voltage gain is not very large, the transistor 3DG6C can meet the requirements in performance. After the transistor is selected, the resonant amplifier should work in the linear region according to the high-frequency small signal, and be as small as possible to reduce the static power consumption on the premise of meeting the voltage gain requirements. It is worth noting that the change will cause the change of y parameter. Within the normal range, with the increase of |yfe| becomes larger, and gie and goe increase slightly. Here, use the value equal to 1mA to calculate the y parameter to see if it can meet the needs of gain, otherwise adjust it.
Known parameters of transistor 3DG6C are,,,,. According to this, we can get:
(1) junction resistance of emitter junction 3;
(2) The junction conductance of emitter junction is-3s;
(3) The transconductance of the transistor is-3s;
(4) The emission junction capacitance is-12f = 24.5pf. ..
2. Find the Y parameter from the mixed parameters.
Because, can be calculated according to the following formula:
* * * Input admittance of emitter transistor
(3- 1- 1)
From this we can get:,-12F.
* * * Output admittance of emitter transistor
(3- 1-2)
From this we can get:,-12F.
* * * Forward transmission admittance of emitter transistor
(3- 1-3)
From this, we can get:
* * * emitter transistor reverse transmission admittance
(3- 1-4)
From this, we can get:
Determine the static working point
According to the known transistor mixing parameters, we can know that the transistors are 3DG6C,,,. In order to stabilize the static operating point, the current flowing through the transistor's voltage-dividing bias resistor generally needs to be set to (5~ 10), where the relationship is 10 times. If,, then
When the nominal value is set to 13K, the actual current flowing through the bias resistor can be obtained by the following formula:
In the actual production process, a resistor of 30 and a potentiometer of 50 can be connected in series to adjust the static working point.
Calculating the parameters of the resonant circuit
The Y-parameter equivalent circuit and simplified equivalent circuit of the high-frequency small-signal resonant amplifier are shown in figures 1-3 and 1-4 respectively.
Figure 3- 1-3 Y parameter equivalent circuit
Figure 3- 1-4 Simplified Equivalent Circuit
Calculate the total capacitance of the resonant circuit
As can be seen from the figure, the total capacitance of the resonant circuit is
(3- 1-5)
Where?,,,,.
Select,,,, and the total capacitance of the resonant circuit is
For the convenience of calculation, the variable capacitance CT can be adjusted.
Choose inductance l according to resonance frequency.
According to the formula:
=44.38
According to the center frequency, the loss conductance of the loop can be obtained.
(3- 1-6)
It contains quality factors, so
0.542 ms
From Figure 3- 1-4, we can know the loop loss conductance.
(3- 1-7)
Where is the no-load quality factor, and its expression is
(3- 1-8)
If the no-load quality factor of the road is retrieved, there is.
Substitute,, in the formula (3- 1-7), and you can get it.
Solve.
voltage gain
(3- 1-9)
Chapter 4 EWB simulation analysis
4. Introduction of1EWB software
EWB is a computer simulation software for electronic circuits. It is called electronic design work platform or virtual electronic laboratory, and its English full name is Electronics Workbench. EWB was developed by Canadian Interactive Image Technology Company in 1988. Since its release, it has been used by people in 10 languages in 35 countries. EWB takes SPICE3F5 as the software core, which enhances its simulation function in mixed-signal of digital and analog. SPICE3F5 is the latest version of SPICE, and it has become the standard software for analog integrated circuit design since 1972 was used.
EWB is based on SPICE and has the following outstanding features:
(1) Create a circuit with an intuitive graphical interface: simulate the workbench of a real laboratory on a computer screen, and the components needed for drawing a circuit diagram and the test instruments needed for circuit simulation can be directly selected from the screen;
(2) The appearance and operation mode of the control panel of the software instrument are similar to the real object, and the measurement results can be displayed in real time.
(3)EWB software has a rich library of circuit components, providing a variety of circuit analysis methods.
(4) As a design tool, it can exchange data with other popular circuit analysis, design and board making software. (5)EWB is also an excellent electronic technology training tool. The virtual instrument provided by EWB can conduct circuit experiments, simulate the actual operation of circuits and be familiar with the measurement methods of common electronic instruments in a more flexible way than in the laboratory.
4.2 Use EWB simulation software to simulate high frequency small signal single-tuned amplifier circuit.
4.2. 1 high frequency small signal single-tuned amplifier analog circuit
Figure 4- 1- 1 Analog Circuit of High Frequency Small Signal Single Tuned Amplifier
static test
Select "analyst →" DC operating point "and set the analysis type as DC analysis to get the DC operating point of the amplifier, as shown in Figure 4- 1-2 below.
Figure 4- 1-2 DC operating point of amplifier
dynamic test
Voltage Gain When the signal source Ui is connected, turn on the power switch of the simulator experiment, double-click the oscilloscope, and adjust the appropriate time base and the sensitivity of A and B channels to see the input and output waveforms as shown in the following figure. As shown in figure 4- 1-3.
Figure 4- 1-3 input and output waveforms of high frequency small signal resonant amplifier
Rectangular coefficient, double-click Porter plotter, and properly select the starting and ending values of vertical and horizontal coordinates, and you can see the characteristic curve of high-frequency small-signal resonant amplifier as shown in Figure 4- 1-4 below.
Figure 4- 1-4 Characteristic Curve of High Frequency Small Signal Resonant Amplifier
4.3 EWB simulation software is used to simulate the emitter double-tuned amplifier circuit of high frequency small signal.
4.3. 1 high frequency small signal double tuning * * * emitter amplifier analog circuit
As shown in the following figure 4-2- 1.
Fig. 4-2- 1 high frequency small signal double tuning * * * emitter amplifier simulation circuit
dynamic test
(1) voltage gain
After connecting the signal source Ui, turn on the power switch of the simulator experiment, double-click the oscilloscope, adjust the appropriate time base and the sensitivity of channels A and B, and you can see the input and output waveforms as shown in the following figure. As shown in figure 4-2-3.
Figure 4-2-2 Input and Output Waveforms of High Frequency Small Signal Double Resonance * * * Emitter Amplifier
Rectangular coefficient
Double-click Porter Plotter, and properly select the starting and ending points of vertical and horizontal coordinates, and you can see the characteristic curve of high-frequency small-signal resonant amplifier as shown in Figure 4-2-3 below.
Figure 4-2-3 High Frequency Small Signal Characteristic Curve of Double-tuned * * * Emitter Amplifier
4.3 Influence of resonance parameters on output waveform
When the parameters of the input signal remain unchanged and the parameters of the resonant network change, the waveforms of the input signal and the output signal are shown in Figure 4-3- 1.
Figure 4-3- 1 Influence of resonance parameters on output waveform
When the frequency of the input signal is not within the frequency band of the resonant frequency, serious distortion will occur. Even a straight line. Because small signal resonance amplification is to use the nonlinear characteristics of transistors to convert collector DC into high frequency signals according to certain characteristics.
Design experience
Through the course design, we not only exercised our basic design ability of communication electronic circuits, but more importantly, let us have a deeper understanding of the practical application of communication electronic circuits.
In this design, we also encountered many difficulties and problems, but with the concerted efforts of our colleague Qi Xin, we studied hard and finally overcame these difficulties and solved the problems. Many of the problems encountered are not found in books, so I have to find relevant information by myself and use the library and network. This is a rather difficult and long process. You must separate useful information from countless information, then sort it out, and finally learn to turn it into your own and use it in design. It is also in this process of searching and sorting that we first learned how to find useful resources for ourselves. Because in the modern society with highly developed information, if a person wants to succeed, he must learn to make more use of other people's knowledge besides his own efforts, so that we can master knowledge and ability quickly. Of course, this process is an accumulation process. When you do more, you will accumulate considerable experience, and you will notice those problems in the design process. These methods can make the design complete at one time without repeated rework. Unlike when we didn't know anything at first, we really did it with a little knowledge of our class. Of course, there will be many unreasonable places in the design, which need to be revised and improved in the later work.
Life is like this, sweat indicates the result and witnesses the harvest. Labor is an eternal topic of human existence and life. Through this course design, I really realized the true meaning of the word "hard struggle". I want to say that design is a bit hard, but it is also fun. In today's single theoretical study, there are few opportunities for practice, but we can. Design is also a team task. We can do curriculum design together, help each other and cooperate tacitly. How much human joy has flowed here, and the cooperation in these ten days can't catch up. I feel closer to my classmates. At the same time, it also cultivated our team consciousness. I want to say that we are really tired, but we are inevitably excited when we see what we have done. It also stimulated our interest in the follow-up professional knowledge.
For us, the knowledge gain is of course important, and the spiritual gain is even more gratifying. Frustration is wealth, experience is possession. This course design process will definitely become a very beautiful memory on my life journey!
Through this course design, I understand that it is very important to combine theory with practice. Theoretical knowledge is not enough. Only by combining theoretical knowledge with practice and drawing conclusions from theory can we really serve the society and improve our practical ability and independent thinking ability. At the same time, I sincerely thank the teacher for providing us with such a rare exercise opportunity.
refer to
[1] Hu. Analog electronic technology [M]. Third edition. Beijing: Higher Education Press, 2008.
[2] Electrical and Electronic Laboratory, Department of Electrical and Information Engineering, Hunan Institute of Technology. Guide to Circuit Analysis and Electronic Technology Testing [M].2005.
Thanks. Electronic circuit design. Experiment. Testing. [M]。 Wuhan: Huazhong University of Science and Technology Press, 2000.
[4] Cao Caikai. Circuit analysis. Beijing: Tsinghua University Publishing House, 2008.
[5] Liu Quan, Communication Electronic Circuit-Wuhan: Wuhan University of Technology Press, 2005
Zhang Suwen, High Frequency Electronic Circuits-Beijing: Higher Education Press, 2004.
[7] Liu Cheng, High Frequency Electronic Technology-Beijing: People's Posts and Telecommunications Publishing House, 2006.