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1000 Threads found on Pll Lock Measurement
Hi All, I have a question on clking scheme in a SoC. Say there is a pll in SoC. So clk supplied to all the modules from pll. Now pll needs to be locked before it gives accurate clk freq and expected duty cycle. This means that we should not suppy the unstable clk(i.e. clk before pll lock is (...)
I also need a pll lock detector, could anyone provider some papers or some schematic diagrams? Many thanks in advance! To rania_hassan, Up and Down signals could not be exactly same in practice. If using XOR gate, it might generate wrong message. How to avoid it? To rfsystem What's mean the fraction of digital supply? Do you mean that the
lock time is inverse proportional to pll filter bandwidth. You should 2 things simultaneously -locking time -Bandwidth Also, you have to find a optimum way between trade-off
Hi What does it really mean when someone says that the pll lock range is 47 Hz - 63 Hz? I was thinking that this should be related to the reference freq. which is usually in KHz-MHz range. But as this is in Hz so I am very confused. Does it mean that the reference freq. will be between 47 Hz - 63 Hz and my pll should lock (...)
The capture range is determined by the difference between the free-running frequency of the VCO, the input frequency and the bandwith of the loop filter. Simply said this difference has to become small enough so that it can fall within the BW of the low-pass loop filter. That is, you sweep the input frequency from let's say 0Hz toward the free run
Hello, I am testing a 2.4G pll. This pll couldn't lock if just after power-on, and vco free-run at 2480MHz, vtune=0v. When I increse both vco current and vco's tuning cap, the pll can now lock in 2400M-2490MHz. After this, I decrese both vco current and vco's tuning cap to original value, then the (...)
I'm reading up on Type II ( charge pump ) plls using PFDs similar to Alexander's PFD for clcok recovery systems. I would like to know what determines the lock range of such a pll, or for that matter any bang bang pll. Furthermore, can this be calculated given circuit topology and parameters. kartik
I am a bit confused over these pll terminologies. This is what I get. lock range: Maximum initial frequency offset which pll acquire lock without cycle slips (in a single beat between reference signal and feedback signal) Pull in range: Maximum initial frequency offset which pll eventually acquire (...)
Does anyone know how to compute for the lock range and capture range of the pll used in the following link: thanks.
hi guys........plz can any one help me how to find lock range and capture range of a pll using simulink.............plzzzzzzzzzz help me........thanks in advance
Hi I have 2 board with same configration except first uses SPI1 of STM32F103 and second uses SPI2 and I also use USART3, I connect first board to a pll circut (ADM4106) and it configures it and pll is locked and so well. But with second one Nothing happen what so ever except when I touch clock pin of SPI by prob it clear (...)
I'm using Virtuoso 6.1.4. I have a working pll, and i would like to determine how long it takes the pll to acquire lock after the reference frequency is altered from the minimum to maximum (or from any reference frequency to another for that matter). I'm not too conversant with cadence and would like some help on how to go about simulating (...)
Hi ! A Phase locked Loop circuit is used to synthesize frequencies from the following blocks: a reference generator, a phase comparator, a low pass filter, a voltage controlled oscillator and the feedback loop (with or without ferquency divider). In a very simple explanation, pll works by changing the voltage applied to the VCO, which (...)
In the lab, my pll locks to different frequency with different board. For one board, pll locks to the right frequency=Fref*divider ration N, say 1.5GHz. But for another board the pll locks to a slightly different frequency such as 1.5GHz+100kHz(always 100kHz offset). This is a fractional (...)
It is possible that there is a big variation in the VCO frequency. Try to change the pll output frequency (change the comparison frequency for example) and see if the pll lock at lower frequency. By
yeah , u can use a beavioral models for the divider to speed up the simulation , i have seen the ADMS simulator of mentor , reduce the time of the pll simulation very mch by using verilog model of the divider khouly
Hello everyone In simulation, I can see the VCO control voltage to find when pll lock. But in real silicon, how can i know when pll is locked? Is there any circuit can detect it ? thank
Generally, parameters in the time domain help determine the lock time. For example, in GSM/EDGE, the system is TDMA, so the handset switched back and forth between transmit and receive. The timing on that determines the pll lock time. In a CDMA system, the handset is full duplex, so the lock time is determined by base (...)
One one would be running transient simulation, measuring time jitter and transferring it into phase noise. You may also try to run PSS with tstab longer than pll lock time and run PNOISE.
There may be many reasons of this problem.If you supply reference signal and oscillator signal properly, check the programmation and pll lock filter. Feedback may be not properly provided by oscillator or programmation can be wrong..etc. If chrage pump is closed to Vdd, input frequency may be very low than expected or programmation is not loaded
pll lock Time = [400 / Loop_Bandwidth * [1-10*LOG(Freq_tolerance / Freq_jump
Hi, I met a problem when simulate the whole loop of pll. locking spent about 30us, but after about 80us, Vcrl(the input of VCO) exhibits a ripple about 40mV.and it seems like it will appear again after an amount of time. my question is: what caused this spur or ripple? Is it possible that it is caused by the simulation tools (Hsim)? Th
Hi everyone, I have met a problem on pll lock time. I found that the pll with 10MHz PFD freq has a great smaller lock time than a pll with 30MHzPFD,although they have the same loop band width and phase margine. this is an experiment measurement resault. I once use (...)
hi all I am working on a pll. The maximum phase error that I can afford between my input and output is 2 degrees. The pll lock range is 47Hz to 63Hz with a reference of 60Hz grid 3v peak to peak. VCO center frequency is 55Hz ...I am having too much phase lag...what is needed to reduce it....I am using a 2nd order LPF (...)
In Xilinx Spartan6 FPGA, instantial two plls, use output clock as pll feed back in clock , one for clock multiple(25MHz in, 75MHz Out), another for clock division(125MHz in, 62.5MHz). The test result shows the two pll can pll lock, the (...)
Hi, I my design pll is taking a amount of 20Kns to get locked. Due to this i am getting errors during ATPG simulations. Is there any way to say the tool to wait untill this period. Can some one help me regarding this.
I'm not aware of any oscilloscope, that has built-in a similar analysis function. You should consider, that it would be only reasonable for those signals, that have a clear, dominant frequency. Many signals presented to an oscilloscope don't have it. It's however possible to generate a similar frequency plot by signal processing of aquired data.
I am trying to design a BASIC pll IC using cadence in an analogue envrionment. However i am having trouble finding a good circuit i can easily integrate. I would like some help in where i can find one. I am going to make some modifications later, but for now i simply need the most basic pll circuit that works. Parameters like frequency range and ot
Seems the answer may relate to how much jitter you can tolerate when creating the 4MHz clock. The problem is that you would be providing a relatively infrequent "correction" into the pll, and the pll's oscillator can drift in between these events, due to e.g. external P/S noise or other internal pll effects. And if you are (...)
1. Usually the data signal is coded to insure transitions and avoid long sequences of 0s or 1s. Also a scrambler at TX, descrambler at RX is used to randomize the transmitted data. The transmission is continous if the data link is synchronous - even if no data is to be transmitted a dopping seq is transmitted. If the transmission is asynchron
Hi Before trying to write to LCD - check that LCD controller work as expected. Try writing and reading from a scrap register(GPIO register) Also test whether the pll lock to programed frequency try writing a single pixel and look for it on the LCD Whether you pass all this test - your LCD is ready to accept data for display A
I am looking to partner up with an experienced all round RF engineer that can help me complete a design for a 12v DC powered pll tuned low power AM transmitter for the 160m (1.8-2.0MHz) amateur band. I already have a fairly well developed crystal controlled transmitter design and there are a whole bunch of fairly simple pll's out there including
I have been having trouble getting a Maxim MAX2769B chip to work on a protoboard. I'm hoping someone here has worked with one of these before. Basically I have tried mounting several to proto-advantage boards. The latest one I took extra care to mount all mount all of the decoupling, AC coupling, DC blocking capacitors and the pll CRC filter onto t
A fundamental pll theory for you to start...
Hi All, Can anyone help me find papers, techniques used to measure precise amount of Jitter occuring in pll. Any help in this regards is appreciated. Cheers, Gold_kiss
After I have replaced new plls (LMX2326), some Frequency synthesizers is ok! but others is still bad. the output voltage of charge pump of pll is 0V or +5V If I understand you correctly, you have made several of these pll, some work and other does not. I.e. you are dead sure your IC is programmed correctly :?: Loo
I have a pll and want to add the lock_Detector block. How to design the block? If I use the D flip-flop, with the Fref to clk and Fout to D, I could watch the output of it after a definited time. But there is a question, because of the jitter, we have a character named period jitter and that will make the result (...)
pll's divider ratio changes frequently. Is there any reliable solution? thx!
Free pll ebook (more than 300 pages) from National Semiconductor There are useful mathcad formulae for lock time
VCOs are very sensitive to control voltage. So you need to filter it as much as you can. Supply voltage has to be filterd also, and a shield for the board can be necessary. A good way to measure it is lock with a pll with a very small loop bandwidth. For freqs larger then the loop bandwidth you'll see the VCO phase noise. A more expensive solutio
Hi, I am designing a frequency multiplier (five times) with the LM565 pll. My input range is from 500Hz to 2000Hz, which means my output range is 2500Hz to 10000Hz. From what I know the free running frequency should be in the center of the range. Now should that center be between 500Hz to 2000Hz (fo = 1250Hz), should the center be between 2500Hz
The suggested method is ok, but suffer from inaccuracies; let me explain better. Suppose that your KVCO is 100 MHz/V and you want to know when the pll has settled his freq whithin a range of 10 KHz. The voltage accuracy has to be 1^4/1^8<1 mV!! One more accurate method is, with a spectrum analyzer that is able to demodulate the signal, use freq
the settling time , depend on my paramters , the step or the jump in frequency , the gain of the pll and the BW of the pll so u need to optimize it within all these paramters , so ur pll give u the disred performance khouly
Dear All : DOes any work on H-lock pll ,the video applcaition ? Now I have some problems about that , The reference is 10k ~60KHz. we see some product is no loop flter , how do they do that ?? Thanks
hello is there any way for calculating lock time of a pll in the design process?
Hi! How does a pll without a charge pump attains lock? After all No integrator is inherent in it!
DLL or pll in two frequency input. How I use lock & Unlock to DLL or pll ? plz help me.
At which VCO frequency did you get 43° phase margin? The phase margin may vary with VCO frequency as Kvco may vary. I calculated the loop filter values using Analog Device pllsim3.0 loop bandwidth is 800Hz, phase margin is 43 degree. Perhaps the phase margin simulation is not same as measurement. When lock at 1
First possibility is to use a dedicated instrument such as Agileng signal source analizer. It has a specific test mode to measure freq vs time. Another good option is to use a spectrum analizer with FM demod option. Setting the spectrum freq at final pll value, just trigger properly at the correct event, you'll see when the signal enter the rece
For your typical modern frequency synthesizer, one that contains some sort of integrating function in the loop filter, they are probably the same. I can think of some scenarios where they might be different, though. Lets say I was using a pll as a receiver, say for a satellite system. On first turn on, the pll might simply sit there (...)