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278 Threads found on Digital Pll
Hello everyone, does anybody have experience in designing a digital pll in simulink. I am new to this stuff and need some resources to study about the method. Thanks
Hi, I am using altera IP core pll with the setup shown in the image. 136648 When I check the waveform in the scope, I have got a sine wave of 2 vpp with a DC component of 1.5 v. The issue here is that am using that clock to sync with the Audio codec WM8731 for I2S communication but it seems that the codec is not un
In most ICs I encounter, plls are present. But I don't know actually what's the use of it. Some registers are associated with it which you need to program. May I know what's the use of this pll and why are the registers need to be configured? I know how pll works. It takes 2 input frequencies, one is from a crystal oscillator which is (...)
If you have implemented an all digital pll, you have the angle information available.
Hi, We are getting the current from Charge pump and then we converted it into voltage and the again into current. What is the use of this procedure. Are there any advantages. Normally a digital pll has a phase comparator and an integrator with lead/lag compensation RC network to drive the VCO. Using a charge pump
Hi, I am trying to find examples of TDC used in CDRs for use between the phase detectors and digital loop filter. Thus far I could only find TDC for use in frequency acquisition in plls, and nothing really for CDRs. A large number of TDC circuits I found for pll use the lower-speed reference clock as a sampler, but that option is not (...)
Research about "all digital pll". Circuit is simple, connect input signal to ADC input. Other option to convert sine to square wave and process with digital input.
What is meant by acquisition range of pll? How does it depend on loop bandwidth? When we work on discrete pll domain, how does it affect the acquisition range? I am currently working on timing recovery design of digital receiver. One of the specification is given as Acquisition range should be 10% of Symbol rate. From this information, (...)
A standard solution uses an all-digital pll with the grid voltage as reference, comprised of ADC, multiplier phase detector, PI loop filter, NCO with sine table. To generate the sine pwm, the NCO signal has to be multiplied with a factor to adjust the output to the actual grid voltage, usually driven by a current/power control loop. Fitting the
A long time ago, Texas Instruments developed the 74LS297 digital pll chip. The application notes for this chip may be of some
I'm looking for ideas on where to start designing a circuit to send serial data between a set of uC's (Arduino & Raspberry Pi). I need to encode data, transmit it on top of a 24VAC/60hz wire, and decode it at the other end. The data is digital -- speeds around 19,200 baud or better would be ideal. I was considering: Using a single pll on a ch
since the phase detector is running on some very low frequency, and the divider chain makes the oscillator track any tiny phase jump at the detector but making it N times bigger at the VCO output, yes the phase noise floor of the digital detector gets multiplied by 20 Log N
I am designing an ADpll but am not getting which phase detector to use. EXOR gate phase detector JK Flip-flop phase detector digital phase frequency detector DETDFF moreover there remains a TDC along with it , but some papers tell that TDC alone is sufficient. please help me understand what should be the preferred choice.
Hi, I have some experience with digital pll. However, I am completely new all digital pll. I am looking for a practical design book on all digital pll. Any recommendation?
pll's have many purposes for scaling up or down , fractions, digital clocks, RF clocks, time of day clocks. Crystals are chosen when the design has a need for tight specifications but lowest cost. Otherwise TCXO's are very accurate (<2 ppm) and easy to use. Voltage, stability and temperature requirements are mandatory when making any choice. Vol
There are numerous text books on the topic but I assume you need/want hands-on :) Why not d/l the free software from Analog Devices Simpll. You can play with all sorts of settings and get a feeling for what happens when you alter loop filter vs. switching time and spur supression. If you really want to read some basic stuff, digital pll (...)
In an all digital pll with a NCO how exactly can you expect the generated sine wave track the input sine wave? I've been working on one using atan Q / I computed every millisec. It will track frequency if it starts out close enough but there are clear cycle slips on the oscilliscope. I've also tried another pfd thst tracks risig edges to determine
hi Anyone worked on digital pll ? I want to make a design on it but without using any kind of analog circuit. I though about this and may be I need to design clock multiplier and divider to generate a desired clock frequency by reference clock. If anyone have any document or link .. please let me know. Thanks Rahul J
That device is a digital output (CMOS), not a sine-wave. How are you measuring your output? If you need your "output to be 12.8MHz", why do you need a VCO? If you really need a VCO, what's your frequency range? Accuracy?
i want to make a software pll using DSP controller...i have googled a lot and found many links but mostly are in paper form i.e. they describe the conversion from analog to digital and the transfer functions of that... i am more of a controller guy so dont know how to implement them on controller...... if anyone has experience in designing softwa
The purpose of Gain in pll is to analyze Loop gain stability under different conditions. a Phase detector has a transfer function of k/s, like an integrator, since the integral of frequency is phase and the output , k will be in terms of volts per cycle of phase error. Thus k is usually the mixer voltage with a scale factor of 1/2 or 1 depending
... and what on Earth has a MC1496 got to do with MIMO digital transceivers??? Brian. should add - the MC1496 was in production before digital was invented :wink:
Hello Please check these expressions. Which is true? An analog pll is a pll that is implemented by analog blocks (PFD, Loop filter, VCO). This pll produces analog signal. A digital pll is a pll that is implemented by digital PFD, but uses loop filter and analog VCO. An (...)
hi i am new in this field. can anyone help me regarding the single phase dq pll hardware implementation(not in digital domain) for grid synchronization. is it available in the form of ic or any set up which is commercially available?
Hi, I implemented a integer-N pll based frequency synthesizer but it takes 2m second to lock at desired frequency. But my adviser didn't accept it. Now I want to use DDFS but my project's details are as below: 1- output frequency between 880 MHz and 912 MHz 2- reference frequency 880 MHz or 900 MHz 3- step size 125 KHz And the question i
Generally speaking, it's not possible without a dedicated pll block which includes an analog VCO. There are nevertheless ways to implement a kind of pll in pure digital logic, I guess it win't fit xc9572
how to extract the Lock Time information from DDS datasheet. i am using ad9915..if i program it using its parallel much time it takes to transit from one frequency to another frequency(that is called its lock time)?? minimum write time for ad9915 is 10.5 nsec according to datasheet..and i need to write two times to update FTW (FTW=32 bits
Well, if you had a choice of using an extremely low noise crystal or saw oscillator at 100 MHz, or a crappy integrated VCO with a pll trying to clean it up inside of the DDS, which one would u choose? The phase noise will be AT LEAST 20 Log (Neffective) worse. But there are additional terms...quantization noise, small discrete spurs, digital jitt
how to measure the Locking Time for DDS practically?..i want to measure the Lock Time of AD9912
Hello, I am designing a 10-bit SAR ADC and it's output chain. My SAR ADC input is 20MHz(mCLK), internally with pll multiply to 260MHz(sCLK), with 3 sCLK to finish T/H, and 10 sCLK for conversion. Is it possible for me to use a 200MHz clock to serial output the 10-bit digital data. I think the syncronization is a big problem for me. Or Iӌ
Hi All, I am working on digital pll which include VCO, frequency divider, TDC, digital filter. I want to simulate the digital pll in cadence. I have the transistor level implementation of all blocks including digital filter. If i include digital filter in the simulation (...)
Yes, that is the standard way of generatin and distributing many clocks from a single clock input in an FPGA. Open coregen and search for DCM (digital Clock Manager). There will be a link to the datasheet. r.b.
I have a few doubts related to implementation of DDS ( Direct digital Synthesis) in place of conventional Fractional -N pll in LO section of FM receiver. since phase noise is much better than pll can we use DDS instead of pll ?? Is the spurious of DDS is more than pll ?? What is the effect of spurious of LO (...)
a better way would be make 2.495 MHz pll, and use digital phase sifter as a frequency translator to shift it to 30.010 kHz.
Hi fenngou, Kdco although known, is not constant and varies quite a bit with process, voltage and temperature. By normalizing it, we make sure the variations do not impact the pll operation as long as we estimate its value correctly. Gain estimation is also straight forward because, unlike analog pll, OTW is digital and can be easily (...)
Any circuit dealing with intermediate voltages other than high and low. Combination of above with few digital logic can also be termed as mixed signal. SerDes, pll etc.
Iam programming the pll through PIC micro controller. i need help in deciding the required phase detector frequency for 10MHz reference frequency.
More easily, the frequency doubling can be achieved with a single XOR gate and a delay element. The latter is the problem, of course. You might use logic cell delay, involving the usual PVT (process, voltage, temperature) induced delay variations. Ultimately, a pll is the way to generate multiplied frequencies with precise dut
Apart from detail questions of signal waveform (I assume a digital square wave for simplicity), a pll can do it for rational frequency ratios. 13:2 would be sufficiently accurate (+ 0.3 %) I think. It can be achieved with a CD4046 pll and additional logic. A modern solution would use a small microprocessor and do everything in so
A big hi to all!! :-) I am looking forward to design a full custom level design of an analog pll at transistor level for digital video broadcasting applications... all relevant information regarding above will be highly appreciable. thanks.. :-)
Hi, I have a simulink model design of three cascade interpolator FIR filtering with samples times respectively 128 kHz, 512 kHz and 8.192 MHz generated by a digital pll that clocked the filtering process. Please can any one help me how can i connect the filtering process with digital pll in simulink environnement??? (...)
Can anyone help me with this fm projects it's in Italian and source code is so complicated and i cant converted to hex file .... please help
pll blocks of recent FPGAs (e.g. from Altera and Xilinx) can easily do what you want, because they expose an input, feedback and output scaler. Review the user manuals and you'll see how. I presume you want a clean 78 MHz output clock, not 78 MHz generated by skipping part of the 100 MHz clock pulses as a digital clock generator (DCO) would do.
can anyone send me the all digital pll output with simulation result
what are the inputs should give for a digital pll in model using 3 -10 ghz frequency
Ok!As the title sugest it i want to learn how to use the FPGA DCM!As far i have understood this DCM is used to adjust the default clock of the fpga to match your application needs.Correct me if i am wrong. In my case i want to adjust the 50Mhz default frequency to 40 MHz.Can someone guide me in doing that?
Hi Could some one give me a pointer? I have built a Analog CMOS pll in Cadence Simulation but would like now to build a digital pll. I viewed the code for the dpll.m in Mathlab but I don't know then how or what that means? ie transfer functions and so on? How do you build from Mathlab code to a CMOS circuit? 1) what (...)
i'm doing behavioral model (MATLAB) for digital pll the most significant difference between Dpll and analog pll is the filter where digital loop filter of Dpll is consists of a proportional path and integral path (2nd-order system) my problem is, for propotional path and integral path (...)
For an analog pll, the loop filter is to filter out high frequency jitter from the output of CP. But for a digital pll, why we still need to use digital loop filter? I mean, for a typical digital pll, its architecture is: in_ref, in2--> TDC --> DLF --> DCO --> in2 The output of TDC is (...)
I have never heard of a phase cleaner. Almost anything can cause phase noise. One experiment you could try is to replace the pll derived control DC with DC from a PSU to see what rubbish is coming from the pll. Is the Q of the oscillator tuned circuits OK. One problem I had about 40 years ago was feedback from the "digital" circuits back (...)