Phase frequency detector vhdl tutorial pdf

Resolving the rf amplitude and phase information into their inphase and quadrature iq components during demodulation is advantageous because of the symmetry of the iq signals and the lesscomplicated nature of. The building blocks used for the architecture are explained in detail as well as the software and technologies used for the project. I had received a number of useful replies thanks to all who provided feedback and links to some application notes that have helped me to better understand the design of a pll. Pdf on oct 1, 2010, martin kumm and others published an fpgabased linear alldigital phaselocked loop find, read and cite all the. Phase locked loops pll are ubiquitous circuits used in. Function generators are lowfrequency oscillators which feature multiple waveforms, usually sine, square, and triangle waves. Phase locked loop tutorial file exchange matlab central. Development and implementation of digital phase locked loop. Fpgabased, 4channel, highspeed phasemeter for heterodyne. This impulse train will be synchronized by the pll to a reference impulse train of a given precise frequency, generated inside the fpga from a quartz crystal oscillator. Assume the input data is periodic with a frequency of 1tb hz. Development and implementation of digital phase locked. A pll is a feedback control system that automatically adjusts the phase of a locally generated signal to match the phase of an input signal. If a number of transitions are absent, the output of the multiplier is zero and the.

Phase locked loop pll based frequency synthesizer is presented which is used. Through elaboration it ends at a model of an all digital and fixedpoint phase locked loop. The phase difference between the two impulse trains is. The fact that no real oscillators are perfectly matched to the advertized frequency is why rs232 resyncs to the clock to avoid cumulative phase error frequently and why higher speed transfers use source synchronous clocking or clockanddatarecovery plls. Hi, a small note of caution when using peters xapp028 in virtex ii. A phaselocked 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. This pfd produces up and down signals depending on the phase difference between reference clock and feedback clock figure.

Best does describe one circuit that uses a zero crossing phase detector pd that uses the reference clock to adc sample the input. Modeling the phasefrequency detector with standard gates models in verilogvhdl as well as for the loop divider modeling the charge pump with only 2 current sources and 2 switches. The digital phase frequency detector, digital loop filter and pwm generator are implemented using behavior and structural model with vhdl in fpga. There have been many fine examples of projects that try to solve th. Create simulation scripts that do not require manual updates for. The phase detector output defined in equation 3 is proportional to the difference between the. Detector charge pump1 charge pump2 vco n loop filter data ref clk freq.

This internal high frequency is generated using the available dcm digital clock multiplier ipcore of fpga with the external input frequency of 10 mhz generated from the crystal oscillator. Pulse generator in vhdl with any frequency stack overflow. Lplls are often used for frequency translation and are therefore found in frequency synthesizers, radios, and phase noise instrumentation. Figure 2 shows a popular implementation of a phase frequency detector pfd, basically consisting of. Through elaboration it ends at a model of an all digital and fixedpoint phaselocked loop. A power inverter can be entirely electronic or may be a combination of mechanical effects such as a rotary apparatus and electronic circuitry. Phase locked loop is a closedloop feedback control system that maintains a generated signal in a fixed phase relationship to a reference signal. Behavioral modeling and vhdl simulation of an alldigital phase locked loop vikas gaur1 mrs. I failed to understand why figure 2 a and figure 2b seems. Xor detectors dont, however, deal gracefully with large frequency mismatch.

The frequency of the mostsignificant bits in the accumulator is determined by the value accumulated at each clock cycle. This requires the design to estab lish a certain relationship between the actual gate time and the measured signal 3. We see that the gain of the pdf flattens for small. Xilinx xapp868 clock data recovery design techniques for. Digital techniques for integrated frequency synthesizers. Phase frequency detector has large frequency range while time to digital converter has very fine resolution. If no reference clock is available, a frequency detector has to be used which requires i and q clocks and for typical implementations, the vco frequency cannot be off more that about 25% of the data rate. The phase measurement algorithm was implemented in an fpga board with high processing speed. If the frequency of input a is less than that at input b, the. Phase locked loop pll is a fundamental part of radio, wireless and telecommunication technology. Both of the techniques the phase detection methods can be combined to get the high frequency range of. I am having problems to implement a edge controlled phase detector using a simple srlatch.

The figures, text etc included in slides are borrowed from various books, websites, authors pages, and other sources for academic purpose only. The core idea of equal precision measurement is how to ensure the actual gate time is an integer multiple of the measured signal cycle. Hi, i am new programmer in vhdl and i have to realize a dll in an actel proasic board. If the frequency of input a is less than that at input b, the pfd produces positive pulses at qa, while qb remains at zero. Accurate frequency detection is important for many projects such as guitarpiano tuners, vibration analyzers, heartrate monitors, mems sensor analysis and laboratory instruments. This phase detector counts the number of high frequency clock periods. As well as constraining the logic to the clbs shown in the app note, make sure you specify a maxskew attribute on the reference signal and feedback signal to the circuit. The edge detector doubles the frequency causing the pll to lock to 2tb hz. Behavioral modeling and vhdl simulation of an alldigital. Phase locked loops are used in many radio frequency of rf systems. Block diagram of demodulator incoming 4 qpsk signal is quadrature demodulated using two oscillator signals that have the same frequency as the unmodulated carrier at the transmitter, but not necessarily the same phase. Fpga implementation of phase locked loop pll with synchronous reset 2 input may cause frequency modulation fm or phase modulation pm.

Traditionally, a phase detector is created by taking a product of the input cosine wave with a. Jan 30, 2004 2 clear input a signal that is opposite to d that represent the frequency that come from the dcoto simulate a phase detector in the case when i am in lock state perhaps you can post your code in the appropriate forum. The final model can serve a starting point for code generation both ansi c or synthesizable hdl. To correct this, the sign of in is added to ip the phase detector output about the i axis in the lefthalf of the iq plane, and then the equation can be given as. Fpga based phase detection technique for electron density. The phasedetection circuitry implemented using xilinxs spartan 3e xc3s500e from xilinx platform running at a frequency of 100 mhz. Design of equal precision frequency meter based on fpga. The view of data as flowing through a design, from input to output. Fundamentals of phase locked loops plls fundamental phase locked loop architecture. 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 in the graduate college of the university of illinois at urbanachampaign, 2011 urbana, illinois advisers. Realized as digital gates that create pulsed signals. All data in this application note is based on this phase detector unless otherwise stated. The phase difference between the two impulse trains is measured by a phase detector.

Hardware description languageanalog mixed signal vhdl. The detector output signal value is composed of a dc component and harmonics, which will be eliminated by the loopfilter so that the transfer function of the phase. The conventional rf frequency synthesizer architecture, based on the voltagecontrolled oscillator and the phase frequency detector and chargepump combination, has been replaced with a digitally. Can anyone suggest a solution to this problem which is plaguing me at the. The report is based on the digital implementation of phase locked loop on fpga, the report covers the steps taken for implementing the proposed phase locked loop architecture on the fpga. Sequence detector using mealy and moore state machine vhdl codes. Design of all digital phase locked loop in vhdl ijera. Most of the phase detectors have advantage that their low frequency response. We are targeting our design to a standard cell technology. A phaselocked loop is a feedback system combining a voltage controlled oscillator vco and a phase. Department of electrical and computer engineering university. Lecture 080 all digital phase lock loops adpll reference 2 outline.

Xilinx xapp854 digital phaselocked loop dpll reference. Digital implementation of phase locked loop on fpga. This phase detector counts the number of highfrequency clock periods. The most common pll in use today is the classic digital pll, socalled due to its use of a digital phase detector. The problem of this phase detector is that it has negative slope in the lefthalf of the iq plane. Phase detector pd a wellknown sequentiallogic pfd shown in figure. Components include a vco, a frequency divider, a phase detector pd. Ug012 vhdl code for phase frequency detector vhdl code for multiplexer 64 to 1 using 8 to 1 vhdl code for dcm vhdl code for digital dll.

In the context of the digital distributed clock generator, the following parameters of individual adpll have an impact on the overal network performance. Function generators are low frequency oscillators which feature multiple waveforms, usually sine, square, and triangle waves. This type of detector indicates not only the phase difference but also the difference of the frequencies 3. Phase locked loop design fundamentals application note, rev. When equilibriumstate is reached, the motor speed is precisely synchronized to a multiple of the reference frequency. This is a nonlinear device whose output contains the phase difference between the two oscillating input signals. Provides general information about all intel fpga ip cores, including. The reference design contains two phase detector variants. Modeling and simulation of high speed pll based frequency. Im currently involved in a design requiring clock recovery. This tutorial starts with a simple conceptual model of an analog phaselocked loop pll. Abstract the report is based on the digital implementation of phase locked loop on fpga, the report covers the steps taken for implementing the proposed phase locked loop architecture on the fpga. The first is the accumulating bangbang phase detector. The block diagram of a phasefrequency detector pfd is shown in fig.

Nov 03, 2016 phase locked loops are used in many radio frequency of rf systems. Phase locked loops pll and frequency synthesis rf and. 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. This phase detector includes a filter function defined by the impulse function of the averaging circuitry. This allows the fll to lock successfully at the exact frequency and phase from random dco frequency at the startup. A dataflow model specifies the functionality of the entity without explicitly specifying its structure. The goal of the phase detector is to create a signal that is proportional to how far the pll needs to be made faster or slowed down. Structure of vhdl program data flow modeling behavioral modeling data types structural modeling.

Implementations of equal precision frequency meter. This voltage upon filtering is used as the control signal for the vcovcm vcm. The phase frequency detector will be examined along with the digital filter. The phasefrequency detector is a digital one that implemented on fpga, which compares the width of reference pulse of trains with feedback pulse of trains width from encoder. Henry young, alex tong, ahmed allam implementation of phasefrequency detector. This tutorial starts with a simple conceptual model of an analog phase locked loop pll.