Xor phase detector pdf

Design of an efficient phase frequency detector for a digital. The exclusive or, xor phase detector circuit can produce a highly functional simple phase detector for some applications. This is because a digital phase detector has a nearly infinite pullin range in comparison to an xor detector. The ad9901 is a digital phasefrequency discriminator capable of directly. They are physically similar, but each type of product is specified on its data sheets in accordance with its principal application. The output characteristic of the xor phase detector show repetitions and gain changes. The slope of the characteristic in either case is kd.

You will see later that the loop filter bandwidth has an effect on the capture range. What are the differences between xor and edge controlled. Phase detector detects phase difference between feedback clock and reference clock the loop filter will filter the phase detector output, thus to characterize phase detector gain, extract average output voltage the k pd factor can change depending on the specific phase detector circuit 4 when used with a impedance filter. Led to a simple pd model large perturbations knock us out of that confined phase rangepd behavior varies depending on the phase range it happens to be in. The gain of the phase detector is the ratio between vpd and when the phase difference is larger than. A versatile building block for micropower digital and analog applications phase comparator i is an exclusiveor network that operates analogously to an overdriven balanced mixer. Detector phase detector reft divt ref2t div2t t t1 1 et xor based pfd tristate pfd figure 3. Among minicircuits products, what is the difference between a phase detector and a doublebalanced mixer dbm.

I had pick phase detector diagram, and i just make like it. Figure 5 illustrates the schematic of an exclusive or phase detector. Pdf monolithically integrated heterodyne optical phase. In pll applications, the vco is treated as a linear, timeinvariant system. Phaselocked loops plls with the proposed hybrid phase detector possess the intrinsic advantage of the low timing jitter of plls with a two xor phase detector in lock states and the fast locking process of plls with an improved bangbang phase. Modeling of xor phase detector universitas hasanuddin. Frequently asked questions about phase detectors an41001. You should be able to answer this question theoretically and experimentally. Practically, however, mixers often display some very nonideal characteristics e. Depending on the phase detector you are using, you will need to add some o.

When an xor gate phase detector is used in a phase locked loop pll system it generally locks near a 90 phase difference in the middle of the phase detection range. Im trying to design a pllbased frequency synthesizer using a 74hc297. Mixers as phase detectors most systems which require phase information use mixers somewhere in the measurement or comparison of the phase information. It will be assumed in our modeling effort that the charge pump scales the pfd output by the value icp before the signal is fed into the loop filter. Recall phase detector characteristic to simplify modeling, we assumed that we always operated in a confined phase range 0 to. Still in progress to get proper input for arduino, code still the same as last code posted. The only digital block is the phase detector and the remaining blocks are similar to the. One advantage of such a phase detector is that the loop gain is now independent of input signal amplitude. Monolithic phaselocked loops for clocking subsystems.

Pdf monolithically integrated heterodyne optical phaselock. Loop filter averages out phase detector output severe cycle slipping causes phase detector to alternate between regions very quicklyaverage value of xor characteristic can be close to zeropll frequency oscillates according to cycle slipping in severe cases, pll will not relock pll has finite frequency lockin range. Phase detector difference of input and feedback clock phase often built from phase frequency detector pfd 22. To maximize the lock range, the signal and comparatorinput frequencies must have 50% duty cycle. We will first analyze a pll with a simple phase detector pd first. Pdf design, implementation and characterization of xor phase. Monolithically integrated heterodyne optical phase lock loop with rf xor phase detector. At 90 the xor has a 50% duty cycle squarewave output at twice the frequency of the input. The xor detector compares well to the analog mixer in that it locks near a 90 phase difference and has a. An xor gate based phase detector interprets phase differences greater than 180 as actual phase difference minus 180. Monolithically integrated heterodyne optical phase lock loop with rf xor phase detector article pdf available in optics express 1921. Digital phase locked loop devon fernandez and sanjeev manandhar december 8, 2003 1. Doesnt depend on the loop filter does depend on dc loop.

Pdf design, implementation and characterization of xor. Study and implementation of phase frequency detector and. Depending on the type of application the phase detectors are chosen in the digital pll. A trilevel resistor dac is also introduced as complementary to the new quantizer, enabling high dr while creating a dynamic power saving mechanism for the proposed design. Vco for pll frequency synthesizer ammattikorkeakoulut. Average value of pulses is extracted by loop filter. 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.

At initialization, the average value of xor output v pd is close to 0. Osa design of a delayed xor phase detector for an optical. Xor phase detector will try tolock on both rising as well as falling edge while the pfd phase frequency detector will lock on eitherrising edge or falling edge of reference signal and feedback. Unlike an analogue mixer phase detector, the xor version is independent of input amplitude and constant over a. Fractionalinteger n pll basics 7 a phase detector is a digital circuit that generates high levels of transient noise at its frequency of operation, fr.

This means that if there is a frequency difference between the input reference and pll feedback signals the phase detector can jump between regions of different gain. Two sources, at the same frequency and in phase quadrature, are presented to a doublebalanced mixer which, together with a lowpass filter, acts as a phase detector. The nominal lock point with an xor phase detector is also at the 90 static phase shift point. A tutorial approach to analog phase by angsuman roy yg locked. Our devices can significantly improve frequency lock time, and include automatic and configurable lock detect indicators.

For the clock and data recovery, xor gate is used as the phase detector. Digital pll mixer replaced with xor gate or phase frequency detector pfd. What are the differences between xor and edge controlled phase detectors. Monolithically integrated heterodyne optical phaselock loop with rf xor phase detector article pdf available in optics express 1921. Arduino forum using arduino programming questions phase detector by using bitwise. Thus, a series of studies is conducted to address this issue. For instance, a phase difference of 270 will be interpreted as 90. A phase detector or phase comparator is a frequency mixer, analog multiplier or logic circuit. To take care of these disadvantages, we implemented the phase frequency detector, which can detect a difference in phase and frequency between the reference and feedback signals.

Figure 5 exclusive or phase detector, modified from ian poole 2. But, at this point, we will treat the pll as a linear feedback system. Phase frequency detector pfd topologies considered here. A phase frequency detector pfd is an asynchronous circuit originally made of four flipflops i. The exclusive or, xor phase detector circuit can provide a very useful simple phase detector for some applications. This noise is superimposed on the control voltage to the vco and modulates the vco rf output accordingly. Plls and dlls cmos vlsi designcmos vlsi design 4th. Alexander phase detector characteristic with noise total transfer characteristic is the convolution of the ideal pd transfer characteristic and the noise pdf noise linearizes the phase detector over a phase region corresponding to the peaktopeak jitter 14 lee td j k pp pd 2 td is the transition density. If you are using a type 2 pll, create a schematic with your phase detector.

Plls and dlls cmos vlsi designcmos vlsi design 4th ed. When the phase detector output voltage is applied through the loop filter to the vco, out max kv. For a variety of reasons, it may be desirable to have a loop which does not produce a sinusoidal clock but instead a square wave clock. The basic phase detector method is shown in figure 16. Furthermore, an xor phase detectors response can have a larger linear range than a sinusoidal detector mixer. A tutorial approach to analog phase by angsuman roy yg. Exclusive or xor gate based phase detector db6sw kf5obs. Theoretically, any mixer with a dc coupled port could be used as a phase detector. Sep 02, 2012 an xor gate based phase detector interprets phase differences greater than 180 as actual phase difference minus 180. Analog devices phase frequency detectors offer high performance and ultralow phase noise in a low cost, compact package.

We will discuss the details of phase detectors and loop filters as we proceed. The phase detector measures di erences in phase between the input and the divided output. The characteristic of the phase detector is as shown below. The xor phase detector is simply exclusive or gate. This is because an xor gate based phase detector doesnt know which of the two signal was first and which signal is preceding which. The operations of the exclusive or phase detector is illustrated in figure 6 below. Pdf in this paper the implementation of xor phase detector in 45 nm submicron cmos technology and itscmos design layout using microwind 3. I trying to read power factor that compare the signal input from voltage and current by using bitwise xor. First, a delayed exclusive or gate xor phase detector with multilevel loop compound control is proposed. Then, a 50 ps delay line and relative signaltonoise ratio control at 15 db are produced through theoretical derivation and simulation.