多谐振荡器 毕业论文外文翻译.doc

一、英文原文multivibratorabstract:frequently used in digital systems, circuit multivibrator. multivibrator is a self-excited oscillator, after the power is turned on, the need for external trigger signal can be generated on a rectangular wave of a certain frequency and a certain width, this output waveform for the circuit of the clock signal source. the square wave rich in high harmonics, it used to turn rectangular wave oscillator called a multivibrator. in accordance with the principle of the circuit, the multivibrator isbroadly divided into astable multivibrator and monostable multivibrator.key words: harmonic oscillator trigger signal duty-cycle oscillation period1 astable multivibrator1.1 ttl gate circuit composed of symmetrical astable multivibratortypical symmetrical multivibrator circuit shown in figure 1, it is by two inverters gl, g2 by the coupling capacitors c1, c2, connect the positive feedback oscillation circuit. circuit g1 and g2 using sn74ls04n inverter rfl = rf2 = rf, c1 = c2 = c and the oscillation period t 1.3rfc, the duty cycle of the output waveform is about 50%. rf1, rf2 resistance for lsttl 470 , 3.9k standard ttl between 0.5 1.9k.figure 1 symmetrical multivibrator type sensor1.2 the use of non-symmetrical astable multivibrator circuit of the cmos gatefurther simplify the symmetrical multivibrator circuit, remove c1 and r2 in the feedback loop to keep the capacitor c2, the circuit is still not steady state, only in two temporary steady state reciprocating oscillation circuit shown in figure 2 below.figure 2 non symmetrical multivibrator type sensor1.3with 555 timer astable multivibratorschmitt trigger 555 circuits can be formed using the hysteresis characteristics of the schmitt trigger, charge and discharge the capacitor c and the access between the two input and ground of the circuit feedback resistor between the output and input access rf on the formation of a direct feedback multivibrator, as shown in figure 3(a) below. power circuit after each flip charge-discharge process is the temporary steady state time and two temporary steady state, respectively capacitor charge time tl and discharge time t2. t1 = o. 69rfc, t2 = 0.69rfc, the oscillation period t = t1 + t2, the oscillation frequency f = 1 / t.figure3change the r and c values can change the charge and discharge time, ie to change the oscillation frequency f of the circuit. direct feedback from the shortcomings of multi-harmonic oscillator is: due to charge the output capacitor c, as well as affected by load factors will cause the instability of the oscillation frequency. indirect feedback to the multi-harmonic oscillator as shown in figure 3(b) below, the circuit works the same, but its performance is greatly improved. charging through r1 and r2 are two of the circuit resistance, the discharge resistor r2 a two temporary steady state time is not equal t1 = 0.69 (r1 + r2) c, t2 = 0.69r2c oscillation period t = t1 + t2 = 0.69 (rl +2 r2) c and oscillation frequency f = 1 / t. if the circuit to improve the access diode d1 and d2, the circuit shown in figure 4 (c) shows, the capacitor charge and discharge currents flowing through the different paths, the charging current only flows through r1, the discharge current only flows through r2, charge and discharge time of capacitor c, respectively, for t1 = 0.69r1c t2 = 0.69r2c, the oscillation period t = t1 + t2 = 0.69 (r1 + r2) c, the oscillation frequency f = 1 / t. if we take r1 = r2 50% duty cycle. the 555 timer is a versatile digital-analog mixed integrated circuits, the use of flexible, convenient, and the 555 timer waveform generation and transformation, measurement and control, home appliances, electronic toys, and many other fields have been applied.1.4 quartz crystal multivibrator in some circuits require a higher stability of the digital pulse, the pulse generated by several multi-vibrator is difficult to meet the requirements. this is because the oscillation frequency of the oscillation circuit is increased by the gate input voltage to the conversion level needs time to decide. affected by the supply voltage, temperature, and some confounding factors, the conversion time of the gate can not very precise and stable. the quartz crystal multivibrator that produces a pulse of high stability oscillators, quartz crystal resonator in the feedback loop to the original multivibrator constitute. the frequency stability of quartz crystal has a very high frequency stability (up to 10-10 10-11), and the quality factor is high, so it has excellent frequency selection characteristics. when the applied voltage frequency is equal to the natural frequency of the quartz crystal f0, its minimum impedance, frequency f0 voltage signal is most easily passed, multivibrator oscillation frequency of the quartz crystal depends only on the quartz crystals natural frequency f0, regardless of the external r, c components.monostable multivibrator2.1 monostable multivibrator circuitusing the ttl gate circuit monostable multivibrator circuit shown in figure 4. rl and r2 in the g1 input clamp, to improve the trigger sensitivity. figure 42.2 integrated monostable multivibratorvery common view of the monostable multivibrator, ttl circuits and 3cmos circuit, the products are produced monolithically integrated monostable multivibrator devices. when using these devices only need a few external components and connections, and very convenient to use the device internal circuits are generally attached to the rising edge and falling edge trigger control and zero.2.2.1 monostable ring oscillator circuit structurethe output pulse of the monostable at all levels in order as a trigger to the trigger input signal, and then the final output signal is fed back to the first level, as the first level trigger input signal, can constitute a the new type of ring oscillator that is a single ring oscillator.monostable delay effect, the the monostable ring oscillator waveform, as shown in the cycle of the oscillator output signal is: t = t1 + t2 + l + tn, where t1 (i = l, 2, ., n) for all levels of single-shot transient stability time. the same levels temporary stabilization time, the circuit is a typical sequential pulse generator, the waveform and the identical to the d flip-flop consisting of ring counter. difference is that the ring counter must be performed by the same clock pulse drive circuit output pulse width and the cycle of the clock signal must be changed by changing the frequency of the clock signal to the output pulse width. the monostable ring oscillator can be automatically generated pulse signal, pulse width can be adjusted by changing the timing monostable element rc parameters, so easy to adjust.二、英文翻译：多谐振荡器摘要： 在数字电路系统中，经常使用多谐振荡器。多谐振荡器是一种自激振荡器，接通电源后，不需要外加触发信号便能自行产生一定频率和一定宽度的矩形波，这一输出波形用于电路中的时钟信号源。由于矩形波中含有丰富的高次谐波分量，所以多谐振荡器也把矩形波振荡器叫做多谐振荡器。根据电路设计原理，多谐振荡器大致分为无稳态多谐振荡器和单稳态多谐振荡器。关键词：多谐振荡器 触发信号 占空比 振荡周期1无稳态多谐振荡器1.1晶体管门电路组成的对称无稳态多谐振荡器典型的对称多谐振荡器电路如图1所示，它是由两个反相器gl、g2经耦合电容c1、c2连接起来的正反馈振荡电路。电路中g1和g2采用sn74ls04n反相器，rfl=rf2=rf，c1=c2=c，振荡周期t13rfc，输出波形的占空比约为50。rf1、rf2的阻值对于lsttl为470 39k，对于标准ttl为0519k之间。图1 对称式多谐传感器1.2使用门电路组成的非对称无稳态多谐振荡器图2 非对称式多谐传感器进一步简化对称多谐振荡器电路，删除c 1和r2的反馈回路保持电容c2，该电路处于不稳定状态，只有在临时稳态之间往复振荡。电路如图2所示。1.3由555个定时器组成的无稳态多谐振荡器施密特触发电路是由555定时器组成，充电和放电的电容器并在输出与输入端之间接入反馈电阻rf，如图3所示（a）下。接通电源电路后，每个翻转充放电过程是暂时稳定状态的时间，分别电容器充电时间和放电时间。t = o69rfc，t 2 =0.69rfc，振荡周期= t1+2，振荡频率=1/t，改变阻值可以改变的充电和放电时间，即改变电路的振荡频率。直接反馈的缺点是：由于电荷的多谐振荡器输出电容器，以及负荷影响的因素会导致不稳定的振荡频率。间接反馈的多谐振荡器，如图3所示（b）中，电路工作原理相同，但其性能大大提高。充电通过电路的电阻r 1和r 2，放电电阻器不平等临时稳态时间的t =0.69（r 1+2），t 2 =0.69r2c振荡周期 t=t1+t2和振荡频率=1 /t，如果电路改变rc，在图4所示电路（c）中，该电容的充电和放电电流通过不同的路径，充电电流仅流经r 1，r 2，放电电流只流过电容器，充电和放电时间，分别为t 1= 0.69r1c,t2= 0.69r2c，振荡周期= t 1+t2=0.69（r 1+r2），振荡频率=1 /t，此时我们视占空比为50