外文翻译压控高频LC振荡器的设计Word文档格式.docx

1、 xxx, Jianghan University In recent years,with the rapid development of wireless communication technology, make the market for rf integrated circuit has had a huge demand. In the rf circuit, the voltage control oscillation （VCO） occupied a very important position.With a wide range of applications.In

2、 the early stages of the radio technology development,it is used to produce high-frequency in transmitter carrier voltage,As a specialized superheterodyne receivers in the machine oscillator, be sending and receiving equipment basic components.Now the use of oscillator is more and more widely.For ex

3、ample: in radio communication, radio, and television equipment used to produce the need of the carrier and the machine oscillation signal;In the electronic measuring instruments used to produce all sorts of frequency sine signals, etc.DefinitionOscillator is simply stated a frequency source, usually

4、 in a phase lock loop.Detailed said is that a device dont need the signal to their own motivation, Dc power can be transformed into Ac power .Generally fall into the positive feedback and negative resistance.The so-called oscillating,Its meaning is to allude to exchange,.Oscillator includes a never

5、oscillation to process and function of oscillation.Can completion from dc to ac power transformation,This device can be called oscillator. Oscillator working principle LC circuit consisting of capacitors and inductors, electric field and the conversion of magnetic energy production process free osci

6、llation. To maintain the oscillation also has a positive feedback amplifier circuit, the LC oscillator is divided into a transformer coupled and three-point oscillator, many applications of quartz crystal quartz crystal oscillator, LC oscillator with an integrated operational amplifier. Exactly the

7、same device can not be parameters in the state of the power the moment the two transistor occurs a change, this change due to increasingly strong role in the positive feedback, leading to reach a temporary steady state. During the temporary steady state to another transistor by capacitance gradually

8、 charge conduction or closed state of the flip to another temporary steady state. This cycle of formation of oscillation.The classification of oscillator Oscillator are divided into RC, LC oscillators and crystal oscillator,1. The RC oscillator Use the RC network as frequency selective phase shiftin

9、g network is called RC sinusoidal oscillator Belong to audio oscillator. 2. LC oscillators Use the LC oscillation loop as move and frequency selective network of Positive feedback oscillator is called LC oscillators. LC oscillators classification: （1） transformer coupling Single pipe LC sinusoidal o

10、scillator difference to the LC sinusoidal oscillator （2） Three point pattern Condenser three point pattern oscillator, three point type oscillator （3）The improvement of three type Clapp oscillator, Seiler oscillator （4）The difference of tube oscillator 3.Crystal oscillator The oscillation frequency

11、of the oscillator by quartz crystal controlled oscillator.The temperature coefficient oscillator Temperature coefficient oscillator refers to an oscillator, its oscillation frequency and temperature have a specific relationship between the different temperatures corresponding to different oscillatio

12、n frequencies. Conversely, measuring the output frequency of the oscillator, we can measure the temperature. High temperature coefficient oscillator: its oscillation frequency is affected by temperature, a slight change in temperature, the frequency will change a lot, that is temperature sensitive,

13、and more for the temperature sensor. low temperature coefficient oscillator: the oscillation frequency temperature has little effect, even if the temperature varies greatly, its frequency is essentially the same. Quartz crystal oscillator Quartz crystal oscillator and non-temperature compensated cry

14、stal oscillators, temperature compensated crystal oscillator （TCXO）, voltage controlled crystal oscillator （VCXO）, thermostatically controlled crystal oscillator （OCXO） and digital / p compensated crystal oscillator （DCXO / MCXO） and other types. Among them, temperature compensated crystal oscillato

15、r is the simplest one, in the Japanese Industrial Standard （JIS）, called the standard package crystal oscillator （SPXO）. Now SPXO example, a brief overview of the structure and working principle of the quartz crystal oscillator.Quartz crystals, natural and artificial, is an important piezoelectric c

16、rystal materials. The quartz crystal itself is not an oscillator, it is only by means of the active encouragement and passive reactance network before oscillation. SPXO is mainly composed of high crystal resonators （crystal oscillator） and feedback oscillation circuit of quality factor （Q）. The quar

17、tz crystal oscillator is an important component in the oscillator, the frequency of the crystal （fundamental frequency or the n-th harmonic frequency） and its temperature characteristics depend largely on the cutting orientation.Pole on the crystal oscillator board to impose an alternating voltage,

18、it will cause the chip to produce mechanical deformation vibration, this phenomenon is the so-called inverse piezoelectric effect. When the applied voltage frequency is equal to the natural frequency of the crystal resonator, piezoelectric resonator, resulting in mechanical deformation amplitude inc

19、reases suddenly. With the metal plate between the electrostatic capacitance; L, and C is the piezoelectric resonator equivalent parameters; R is the equivalent resistance of the vibration friction loss. Quartz crystal resonators, there is a series resonant frequency fos （1/2）, there is also a parall

20、el resonant frequency fop （1/2）. Due to a very small difference between the Co. C, fop and fos, and the R OL, the R 1/OC resonant circuit quality factor Q is very high （up to several millions）, so that of the quartz crystal resonator the oscillator frequency stability is very high, up to 10-12 / day

21、. Quartz crystal oscillation frequency can approximate in fos Department, can also work around the in fop, a quartz crystal oscillator can be divided into two kinds of the series and shunt. Quartz crystal resonator and its equivalent circuit, replace the components of the LC oscillator constitutes a

22、 resonant circuit inductance （L） and capacitance （C）, it is easy to understand the working principle of the crystal oscillator.SPXO the total accuracy （including initial accuracy and temperature, voltage, and load changes） can be up to 25ppm. SPXO neither temperature compensated temperature control

23、measures, and its frequency-temperature characteristics almost entirely determined by the frequency-temperature characteristics of quartz crystal oscillator. Within the range of 0 70 SPXO frequency stability is typically 20 1000ppm, SPXO can be used as a clock frequency oscillator.Temperature compen

24、sated crystal oscillator （TCXO）TCXO is generated by the ambient temperature change of a quartz crystal oscillator oscillation frequency change reduction through additional temperature compensation circuitry.1.TCXO temperature compensationIn TCXO quartz crystal oscillator frequency temperature drift

25、compensation method of direct compensation and indirect compensation are two types:directly compensatedDirect compensation TCXO by the thermistor and the temperature compensation circuit composed of resistive and capacitive components in the oscillator in series with the quartz crystal oscillator. C

26、hanges in temperature, the thermistor resistance and crystal equivalent series corresponding changes in the value of the capacitor, in order to offset or reduce the temperature drift of the oscillation frequency. The compensation circuit is simple, lower cost, saving the printed circuit board （PCB）

27、size and space for small and low-voltage current occasion. However, when the crystal oscillator accuracy of less than 1pmm, direct compensation is not appropriate.Indirect Compensation Indirect compensation type is divided into analog and digital two types. Analog Indirect temperature compensation t

28、hermistor temperature sensing element composed of the temperature - voltage conversion circuit and the voltage applied to the crystal oscillator series on a crystal oscillator connected in series varactor capacitance changes nonlinear crystal oscillator frequency drift compensation. The method of co

29、mpensation to achieve high accuracy of 0.5ppm, but restricted in the case of low voltage below 3V. Indirect temperature compensation of the digital plus a temperature in the analog compensation circuit - voltage conversion circuit analog / digital （A / D） converter, analog convert digital. The Act e

30、nables the automatic temperature compensation crystal oscillator frequency stability is very high, but the specific compensation circuit is more complex and higher cost applies only to the precision of base stations and radio stations requirements.2.TCXO development statusTCXO by leaps and bounds in

31、 the last decade, which in the research and development and production of precision TCXO, Japans leading and dominant position. Mainstream products in the late 1970s car phone TCXO volume of more than 20 reduced to 0.4 , TCXO devices of ultra-small volume of only 0.27 . In 30 years, the TCXO volume

32、reduced by more than 50 times or even 100 times. Beijing ceramics company in Japan using the reflow soldering method of production of surface mount TCXO thickness from 4mm to 2mm, rated 90% of the oscillation amplitude in 4ms after the start of the oscillation can be achieved. Stone （KSS） Group TCXO frequency range of 2 80MHz stability when the temperature changes from -10 C to 60 C 1ppm or 2ppm; digital TCXO frequency coverage of 0.2 90MHz frequency stability