Abstract this report focuses on secondorder digital phase locked loops dplls with uniformly sampled input, an amplitudeinsensitive phase extractor and a conventional loop filter. Unfortunately plls are up to now mixedmode circuitries that must combine analog parts as loop filter and vco with digital parts as the frequency divider. This control strategy allows microgrids to seamlessly transition between gridconnected and autonomous operation, and vice versa. A conventional digital phase locked loop dpll is designed using baker et al. This is the frequency range around the free running frequency that the loop can track. A multiband phaselocked loop frequency synthesizer. Phase locked loops an overview sciencedirect topics. The cd4046b design employs digital type phase comparators see figure 3. A software phaselocked loop from theory to practice. A 45nm cmos, low jitter, all digital delay locked loop with a circuit to dynamically vary phase to achieve fast lock a thesis presented by soumya shivakumar begur to the department of electrical and computer engineering in partial ful llment of the requirements for the degree of master of science in electrical and computer engineering. In this way the same theory can be applied to a phase locked loop as is applied to servo loops. Performance evaluation of digital phaselocked loops for. Within this study, the xor phase comparator pc together with a variable gain of the loop filter lf and a high capacitance rcfilter is found as the best solution.
Architectures and applications digital phase lock loops are critical components of many communication, signal. Phase locked loop pll is a feedback system that is configured as frequency multipliers, tracking generators, demodulators and clock. Tim wilmshurst, in designing embedded systems with pic microcontrollers second edition, 2010. The analog and digital signals are used in the phase locked loop. Designs of all digital phase locked loop ieee xplore. Phase locked loop pll is a closed loop feedback system that is capable to track the fixed phase relationship between phase of output and the reference clock. Phase detector 1 is used in applications that require zero frequency and phase difference at lock. A phase locked loop, pll, is basically of form of servo loop. The lock range usually increases with an increase in input voltage but falls with an increase in supply voltage. Index termsalldigital phaselocked loop adpll, clock gen erator, frequency synthesizer, hdl, low jitter. A versatile building block for micropower digital and analog applications 5 3. This phase locked loop tutorial gives all the basics required for an.
A conventional digital phaselocked loop dpll is designed using baker et al. Spectral purity of the pll output is specified by the phase noise and the level of the referencerelated spurs. Phase locked loop pll its operation, characteristics. In this video, i have explained phase lock loop by following outlines. Plls and dlls cmos vlsi designcmos vlsi design 4th ed. The heavy digital activity of the sigmadelta modulator, which provides the. A phaselocked loop is a feedback system combining a voltage controlled oscillator. Phase locked loops, block diagram,working,operation,design. This paper describes a frequency control method as an alternative to the traditional phase lock loop pll. The output voltage of the phase detector is a measure of the phase.
The four quadrant arctan based phase detector, which requires the inphase and the quadrature inputs of the signal, is easily implemented in software 8,9 and has got several advantages over the. A digital phase locked loop uses a digital phase detector. Cd74act297 digital phaselocked loop schs297d august 1998 revised june 2002 6 post office box 655303 dallas, texas 75265 detailed description continued thus, the simple firstorder phaselocked loop with an adjustable k counter is the equivalent of an analog. Type order phaselocked loop design fundamentals application note, rev. Performance is important phase noise can limit wireless transceiver performancejitter can be a problem for digital processors the standard analog pll implementation is problematic in many applicationsanalog building blocks on a mostly digital chip pose design and verification challenges. Perrott 2 why are digital phaselocked loops interesting. Precise digital phase detection and deterministic feedforward correction replace analog. The multiband pll frequency synthesizer uses a switched tuning voltage. A 45nm cmos, low jitter, alldigital delayed locked loop with. Pdf designs of all digital phase locked loop researchgate. The capture range of pll is given as fc flock2 103c212. The phase locked loop detector compares the input frequency and the output frequency of the vco to produces a dc voltage which is directly proportional to the phase distinction of the two frequencies. Performance evaluation of digital phase locked loops for advanced deep space transponders t.
The phase detector compares the phase of the input signal with the phase of the reference signal. It consists of 2 digital phase detector, a charge pump and an amplifier. The phase locked loop or pll is a particularly useful circuit block that is widely used in radio frequency or wireless applications. Abstract this report focuses on secondorder digital phaselocked loops dplls with uniformly sampled input, an amplitudeinsensitive phase extractor and a conventional loop filter. A phase locked loop is a feedback system combining a voltage controlled oscillator vco and a phase comparator so connected that the oscillator maintains a constant phase angle relative to a reference signal. L lock range where kv ko kd, the product of the phase detector and vco gains. Sometimes a frequency detector is added to the phase detector to assist in initial acquisition of lock. Interaction amongst the various components are also discussed. The phase lock loop employed is a narrowband secondorder loop designed to track large dopplerfrequency excursions. Over the years, digital phase locked loops dplls have been designed in a variety of forms for example, see references 1 through 3, utilizing various phase extractors, loop filters, and numbercontrolled oscillators ncos. Phase locked loop pll is a feedback system that is configured as frequency multipliers, tracking generators, demodulators and clock recovery circuits. Phase locked loop phase comparator 2 is an edgecontrolled digital memory network. Phase comparator 2 pc2 pc2 is a positive edgetriggered phase and frequency detector. You will see later that the loop filter bandwidth has an effect on the capture range.
So at least the analog circuitry must be adapted to every new cmos process technology. Phase locked loop design fundamentals application note, rev. Block diagram of an adpll digital phase detector digital loop filter digital vco v1 v2 vd vf square waves advantages. Precise digital phasedetection and deterministic feedforward correction replace analog. Phase locked loop pll working let us consider the free running frequency to be fr. This exciting new book covers various types of digital phase lock loops. A phase locked loop is used for tracking phase and frequency of the input signal. Fpgabased digital phase locked loop analysis and implementation by dan hu thesis submitted in partial fulfillment of the requirements for the degree of master of science in electrical and computer engineering. It presents a comprehensive coverage of a new class of digital phase lock loops called the time delay tanlock loop tdtl. In view of its usefulness, the phase locked loop or pll is found in many wireless, radio, and general electronic items from mobile phones to broadcast radios, televisions to wifi routers, walkie talkie radios to professional communications systems and vey much more. As shown in the schematic of the pfd dpll in figure 10 and mentioned in the earlier section, this dpll has four parts and they are as follows. A dll can be used to change the phase of a clock signal a signal with a periodic waveform, usually to enhance the clock rise.
Fpgabased digital phaselocked loop analysis and implementation by dan hu thesis submitted in partial fulfillment of the requirements for the degree of master of science in electrical and computer engineering. Short course on phaselocked loops and their applications. Topics include vcos, loop filters, phase detectors, timeto digital converters, vcobased analogto digital converters. Figure 1, digital phase locked loop model an alternative approach to design the phase detector is to use the four quadrant arctan function. Kundert, ken august 2006, predicting the phase noise and jitter of pllbased frequency synthesizers pdf 4g ed. Fundamentals of phase locked loops plls fundamental phase locked loop architecture. Phaselocked loops can be used, for example, to generate stable output high. We will discuss the details of phase detectors and loop filters as we proceed. A digital voltagecontrolled oscillator for phase lock loops. Phase locked loop operating principle and applications. Phase noise can limit wireless transceiver performance. Phase detector 2, if quadrature lock is desired, when detector 1 is used in the main loop, detector can.
The cd74act297 provides a simple, costeffective solution to highaccuracy, digital, phaselockedloop applications. A frequency and phase locked loop is built of connecting the output of the frequency locked loop outt with the input of the phase locked loop to output a frequency and phase locked signal outt. The root locus for a typical loop transfer function is found as follows. Lecture 070 digital phase lock loops dpll reference 2 digital phase locked loops dpll outline building blocks of the dpll dynamic performance of the dpll noise performance of the dpll dpll design procedure dpll system simulation lecture 070 dplls i 51503 page 0702. This article explains some of the building blocks of pll. Phase locked loop control of inverters in a microgrid. It is mainly influenced by the phase comparator and the loop filter. While this digital control box could therefore be used to phase lock other systems, the discussion below assumes the user is operating a frequency comb. Phase lock loops and frequency synthesis wiley online books. Perrott on analog and digital phase locked loops and their applications.
Digital phase lock loops are critical components of many communication, signal processing and control systems. A phase locked loop is a clever piece of analog and digital circuitry that can be used, among other things, to multiply by an integer number the frequency of a signal. The signal are digital binary and may be a single digital signal or a combination of parallel digital signals. Figure 1block diagram of digital vco phase lock loop. The phase locked loop or pll is an electronic circuit with a voltage controlled oscillator, whose output frequency is continuously adjusted according to the input signals frequency. Nov 11, 2014 a phase locked loop is built of phase detect, logic 2, phase control, divider a, divider b, and divider c. An alldigital phaselocked loop for highspeed clock generation. Although a pll performs its actions on a radio frequency signal, all the basic criteria for loop stability and other parameters are the same. A phaselocked loop or phase lock loop pll is a control system that generates an output. The loop bandwidth determines the frequency and phase lock time. More generally, together with the hardware, it provides a digital control box that can support a dualchannel phase locked loop including the frontend iq detection of the input rf signals. At this point the phase lock loop is said to be in lock and the frequency of the reference and vco are exactly the same. Kyriacou spacecraft telecommunicationsequipment section the performances of the digital phase locked loops dplls for the advanced.
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