1、 外 文 翻 译 原文 1： Frequency Modulation in Microwave Phase Lock Loop Synthesizers 译文 1： 微波锁相回路合成器的调频 原文 2： The Design of A Low-Power Low-Noise Phase Lock Loop 译文 2： 低功率低 噪声的锁相环的设计 Frequency Modulation in Microwave Phase Lock Loop Synthesizers Abstract This paper shows, that frequency modulation bandwidt
2、h of phase locked controlled oscillator (CO) can be simple expanded using precorrecting circuit (corrector) connected to control port of oscillator. A method is presented of calculation of corrector according to exact PLL and frequency response of modulation channel, with experimental demonstration
3、presented of adequacy of described technique being shown. Index Terms Microwave PLL synthesizer, frequency modulation, maximum deviation, modulation bandwidth. I. INTRODUCTION In many microwave systems the synthesizer must generate frequency modulated signal in addition to monochromatic signal gener
4、ation, its main function. Solution of this problem in case of phase lock loop (PLL) synthesizer becomes complicated due resistance of PLL to the CO modulation, as an automatic control system. The most difficulty is the expansion of modulation band and the modulation index range. The purpose of this
5、paper is contribution in solution of these problems. II. TARGET SETTING It is well known that frequency modulation possibility of phase locked CO is limited by cutoff band. Modulation bandwidth corner is equal to PLL angular frequency 1. In band above cutoff the loop makes no resistance to the CO mo
6、dulation, but below cutoff its resistance increases when modulating frequency decreases. Thus, modulation bandwidth of CO must be widened up to down the PLL angular frequency. It can be made by three issues: By decrease of PLL cutoff frequency； by impact modulating signal into PLL: modulation of the
7、 reference frequency, manipulation of feedback division ratio, addition of the modulating signal to control signal of phase detector； by application of linear precorrection to modulating signal for compensation of high-pass properties of PLL 2,3. Further the last method is considered. It is more eff
8、ective as it makes no worse on dynamic and spectral purity characteristics of PLL synthesizer like first method and has no limitation of modulation bandwidth above like second way. III. MATHEMATICAL DESCRIPTION OF CORRECTOR MODEL To improve the modulation sensitivity of CO an active corrector instea
9、d the passive corrector 2 is proposed in Fig. 1. Fig. 1. Corrector schematic Modulating signal comes to input 1. PLL control signal comes to input 2. Driving signal for CO goes out through output 3. A. Small signal model Corrector transfer function K1(p) from input 1 to output 3 is represented by: w
10、here a, c are gain factors of third stage at low and high frequencies respectively； is high frequency time constant of third stage； k is depth of dip of response curve in PLL corner frequency area； b is gain factor of first stage at high frequencies； 1, 2 are low and high frequency time constants of
11、 dip of response curve respectively. Parameters in (1) can be selected in case of an exact PLL and modulation channel requirements. B. Large signal model Maximum deviation Fmax is limited by several factors, which are bound with nonlinear distortions of modulated signal envelope. These distortions appear in such cases as:
