Questions tagged [pll]
PLL is short for "Phase Locked Loop". A PLL is a circuit that is able to keep a local (voltage controlled) oscillator synchronized with an independent given signal frequency.
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How to generate a sine wave that is in phase with a generated square wave at 1MHz for lock-in amplifier?
I am building a lock in amplifier (LIA) for fluorescence lifetime measurement using off the shelf components, after going through literature, I have decided to use square wave for excitation of the ...
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STM32F407 PLL config not producing 1ms SysTick
I've a bare metal PLL setup for my STM32F407 which should generate a 168MHz system clock.
However for some reason the 1ms SysTick interrupt is orders of magnitude off the grid.
The math works out on ...
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What Exactly Is Meant by a 2nd Order Phase Locked Loop?
I'm teaching myself about polyphase clock sync for demodulation of OQPSK. An article from gnuradio.org entitled "Polyphase Clock Sync" makes references to a 2nd order loop. The context seems ...
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finding PID coefficient for my PLL system
I have a feedback loop as shown below,We are fixing the noisy YIG with a cavity resonator and feedback.(shown in the attached paper and diagram below).
the phase difference between the signal is ...
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Are two FPLLs in sync?
Two FPLLs are being driven by a common clock and the output of each FPLL is used to drive a counter after achieving a lock. When we turn on the circuit both FPLLs miraculously lock EXACTLY at the same ...
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Debugging PLL STW81200TR not locking
I need a bit of debugging help with SWT81200 PLL that I am using on my custom designed PCB. I am able to configure registers through SPI communication, but the problem is that I am not able to achieve ...
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Type 2 comparator locking on ringing
I have successfully designed a 4046 IC with a phase 2 comparator locking to an external 10 MHz VCOCXO. The circuit is simple
vcoxco---->
divide by 10-->
Schmitt Trigger -->
divide by 10 -->...
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What is the maximum PLL output frequency in the STM32H7A3?
I'm setting up a hyperram, and I want to run it at 200MHz, with the DHQC setting enabled. The peripheral manual on page 874 says:
DHQC must not be set when the prescaler value is 0, as this action ...
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Designing loop filter for frequency-modulated PLL
I'm designing a PLL circuit to stabilize a ~200MHz VCO against temperature-induced frequency drift. However, I need to be able to occasionally (~few times/sec) send a short pulse (~few μs) to modulate ...
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How to synthetize a 10 kHz signal from 1 Hz analogically
I would like to synthesize a 1 Hz signal to a 10 kHz one without using MCU or related DPLLs.
Anyone has a schematic example? I found this reference schematic on Art of Electronics.
Would that suit (...
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How to find the direction of phase difference of sine signals using multiplier phase detector?
I am using a multiplier phase detector like here 1to find the phase difference between two phase shifted sine signals, and I got the value of magnitude but how to find if the signal 2 is leading/...
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Using MMCM/PLL source clock pin elsewhere in design breaks timing
TL;DR: New to Vivado Clocking Wizard, using the clock pin from the FPGA for anything other than the input to MMCM/PLL IP fails timing.
I'm working with Vivado ML 2022 in VHDL targeting an Artix-7 FPGA ...
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Best way to close GPSDO PLL digital loop?
I am trying to build a GPSDO with a holdover capability of 500us/24hs (maximum drift accumulated).
The system uses a 10MHz OCXO and it is my intention to use a microcontroller (ATMega, STM or ...
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Creating a large number of crystal-stabilized pulse waves at precise frequencies
I intend to generate 22 separate 50% duty cycle pulse or square waves. The frequencies range from about 5 Hz to 350000 Hz and are all irrational numbers, so I would like as much precision as possible.
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Calculating AC-Coupled input current
I'm using an SDR which uses and ADF4002-based PLL with its REFIN input AC-coupled via a 0.1 uF capacitor to an external input. I'd like to connect an external reference clock to it, but I'm unsure how ...
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N-counter issue ADF4001
I designed and tested a PCB with a PLL circuit. The goal is to lock on the reference signal which is a square wave. The problem I am having is that the signal of the N-counter shows no response, just ...
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Problems Comparator II of this CD4046 for LTspice
I downloaded a CD4046B model from user ale_t, which can be found here:
https://www.electro-tech-online.com/threads/new-spice-model-for-cd4046b-phase-locked-loop-ic.149093/
However, the Phase ...
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About PLL input frequency
I am working on a PLL design. I am at the research stage now. I am confused about the PLL input frequency range.
This frequency has to remain constant. If this input frequency stays constant, how can ...
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Clock crystal oscillator and PLL accuracy
If I use an 8 MHz oscillator with accuracy of 25 ppm and the PLL multiplies it to 32 MHz, then the accuracy is also multiplied (x4 = 100 ppm) or is it not? Thanx.
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Frequency multiplication with PLL circuit
I am currently working on frequency multiplication with a PLL circuit.
I want to give it an input frequency of 10 kHz to 100 kHz and I want to get 160 kHz to 1.6 MHz from the VCO output. That's a ...
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Thermal shutdown in HMC510, HMC507 and ADF4159
We have following chip combination cards:-
ADF4159CCPZ-RL7 and HMC507LP5ETR
ADF4159CCPZ-RL7 and HMC510LP5E
We have both PLL and VCO are on a single board. We are using same board for above combination....
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How to get freq stability with constant offset for PLL synthesizer?
I used ADF5356 PLL synthesizer. And i use reference oscillator freq is 10MHz with initially offset 0.1ppm and stability is 10 ppb. I need to output freq is 3750 MHz.
Expected output result:
10MHz × 0....
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How to generate correct frequency in DDS using stm32?
I had asked a question a week ago regarding DDS on STM32 and I got some good answers. Based on that I tried to write a code to implement DDS on stm32.
In my project I need to generate a 10 KHz sine ...
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Implementing direct digital synthesis in STM32 microcontroller
I am working on a project that requires phase locking (digitally) of an output signal from a sensor to the reference signal which needs to be done on STM32 microcontroller. I am new to this area, and ...
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Meaning of "three-stating" a PLL charge pump
I am designing a phase lock circuit using an Analog Devices ADF4107 PLL Frequency synthesizer (https://www.analog.com/en/products/adf4107.html).
The PLL is programmed manually and one of the settings ...
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PLL design in amplifier
We have designed a PLL for an operating range of 11-14 GHz. The output of the VCO goes directly to the amplifier, and then to a divider, see the picture.
Is there anything that affects PLL locking ...
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Reliability issue of HMC833 PLL
We are using an HMC833LP6GE PLL in our design for generating 122.88 MHz from a reference of 100 MHz.
We are feeding a reference signal of >5 dBm. What we are observing is that out of 10 times, if ...
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Can't find transistor-based PLL circuit example
I am learning electronics as a hobby. My current interest is phase locked loops (PLL.) I was able to find a lot of block diagrams with explanations of how PLLs work and also CD4046 based PLL ...
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PLL minimum frequency: how much tolerance?
Many FPGAs have phase-locked loops which can multiply the frequency of a clock. The signal path of a PLL is rather simple:
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Selecting optimal phase locked loop (PLL) frequency for microcontroller peripherals
Typically microcontrollers use an input clock source with a certain frequency. This clock source is then divided and multiplied to a PLL frequency which is much higher. Finally, the PLL frequency is ...
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How did he calculate the error in this example?
He found an error of about 18%.
What is the error formula used in this example?
From section 1.5.1 of the book Design of PLLs by Behzad Razav.
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Designing circuit of clock recovery from data line [duplicate]
I am currently struggling with the following challenge.
In the system I am currently designing, the transmitting device is equipped with an image sensor with MIPI output (1 data line, 12 Mbit data ...
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Oscillator with low frequency drift
I need a ~70MHz oscillator with low frequency drift (less than 1%) over a wide temperature range (10°C to 50°C).
I dont have any experience with oscillators, so I have no idea which type of oscillator ...
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ATTiny861A fast PWM mode not working
For a couple of hours, I struggle to find the source of my PWM output to not generate a PWM signal. I changed register values to explicitly show their contents - I hope it will make the diagnostics ...
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LMX2820 readback operation [duplicate]
How can a readback operation be done on LMX2820?
I've looked through over it's datasheet, register map and AN documents and there is no information about that. In LMX2594 read and write operations are ...
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I2C Protocol. Receiving a byte from slave device. How does the slave pull down the SDA line between two edges of SCL?
As we know, the waveforms of the I2C signals (SDA and SCL) are very similar to the following:
The main requirement is that during the transmission of a byte, the SDA does not transition while SCL is ...
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Phase detection accuracy with USRP N210 and CBX-40
I have designed a simple TX/RX system in GRC with a single USRP N210 and CBX-40.
I am transmitting sinusoidal signals at various frequencies within the 2-6GHz range and detecting the amplitude and ...
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STM32 PLL settings make my program crash
I am following a course on USB programming on STM32 platform. My board is a STM32F746G-DISCO with a STM32F746NG microcontroller.
In the course, the teacher sets his board to these frequencies:
SYSCLK ...
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Dead zone in phase frequency detector (PFD)
I am working on a design of a PFD for a PLL. I came across an issue of dead zone which requires a minimum time for the switches to be on so the charge pump works the way we want (image 1.)
The ...
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Can I use a resistor to transfer voltage to current rather using transconductance amplifier?
The situation is I intend to transfer voltage to current to control a laser.
The voltage comes from an optical phase-locked loop (OPLL). It is changing over time, so the current transferred from this ...
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Do any FPGAs that set undefined values in registers after power up exist?
There is some discussions how to set default values or start an initial sequence in FPGAs design after programming/power-up.
The most reliable method is using a supervisor IC which guaranteed send ...
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Getting ADC value of potentiometer at a 100 ms sample rate. For the sample, would using a timer for a delay suffice?
I am using the ADC on my HCS12 to get the value of a potentiometer. I am already using a PLL and a prescaler to change the frequency of the clock.
Due to the requirements on my board, this value must ...
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Help me select an option to generate 25 kHz PWM
I'm running Arduino Mega with Marlin Firmware (as my 3d printer controller) which to my understanding has its PWM set to 1 kHz.
I want to control a 4-wire fan (Pfc0612de) with PWM from 30% to 100% and ...
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PLL phase error plot confusion
I am working on the implementation of different PLL for grid-connected converters. I have confusion in a particular plot for my research which is the phase error.
First of all, I generated the ...
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How does this phase advance loop filter work?
I am reading this paper titled A Versatile Digital GHz Phase Lock for
External Cavity Diode Lasers. This is part of the circuit.
I am confused about the functionality of the part labeled "Phase ...
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PLL phase frequency detector
If there is a constant phase difference between the VCO signal and reference signal, the phase frequency detector will always givr an error signal. How can the PLL lock in this condition?
I mean the ...
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Why is the MCU clock out waveform sinusoidal and not square pulse
I got a new oscilloscope :) (proud amateur moment)
I am trying to visualize the internal clock of a STM32G431RBT6 MCU. So I built an example program given by the vendor which provides the MCU clock ...
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Problems increasing VCO frequency above datasheet recommendations
Firstly, yes I contacted ST for answers. Until now, no answer.
I'm using STM32F429 MCU and embedded USB FS PHY. To keep the 48 MHz USB PHY clock the maximum PLL clock that I can achieve is 168 MHz, ...
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Costas Loop QPSK/4QAM
I can use a Costas Loop, modified for QPSK/4QAM and recover the frequency and phase successfully when using a pattern of all 1s or all 0s or a pattern that is repetitive for each I and Q data rail (in ...
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How to determine phase sequence of the unbalanced three phase grid?
Let's say I have three phase voltage grid which is unbalanced (three phase utility grid). The phase voltages are sampled by the adc (suppose that the analog channel is properly designed from the hw ...
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