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# Vco And Control And Voltage

100 Threads found on edaboard.com: Vco And Control And Voltage

## LC-VCO control voltage

Hello, does anybody know that why a resistance is made in series with the control coltage of LC oscillator and in which range should be this resistance? Thanks

## Control voltage range of VCO

If you're set up for SPICE analysis then I'd just step through the practical range (0 - VDD) and observe waveshape and frequency; you can pick off the freq value by an expression and plot vs the vcoNT value (either in a decent waveform viewer, or exported to Excel). (...)

## Minimum possible voltage on the loop filter in a charge pump PLL

It surely is specified in the datasheets Notice that this is an IC design question, there's no datasheet, instead the IC designer (the OP) has to answer the question himself. I agree that the useful control voltage will be restricted by the linear PFD and vco linear range.

## What the input impedance of VCO should be? And how delay influences PLL?

Hi everybody, I met a problem in PLL design. Actually design has finished, the problem found in verification. TI PLL chip 4816B is used, and follow is the external 2nd order LPF. 122208 For VCXO, we have several vendor to select. All of the VCXOs works well except one. The phenomena is the PLL will unlock with onl

## VCO Control Voltage variation in PLL

I have created an integer and fractional PLL. The integer PLL is locking fine. The fractional PLL has a delta-sigma modulator which varies the feedback frequency divider modulus. Maybe that's why the control voltage on the vco is varying periodically? Is there a way to mitigate the periodic variation of (...)

## PLL loop bandwidth and Phase margin

My PLL output frequency is 8GHz.and I have a problem,my control voltage of vco variation is high? how can eleminate this issue? I have R=9k ohm and C1=80p and C2=2p ????

## Voltage to frequency converter NOISE

Actually a VFC is a vco, just with a broader frequency range, and without the feedBack control mechanism via PFD. So the noise calculation should be similar.

## I have this Dual voltage-controlled oscillator SN74S124N - make it send 45Mhz

Only 45MHz ? Is that nominal , min or max? Being a linear vco with wide variations of stray and PN junction capacitance , nominal f is not precise. But figure 2 shows Cx=10 pF (1e-11) for Vf=Vrng=2V Both voltages can span from 1-5V but are more linear from 1.5 to 4.5V. Vrng is lowest range at 1V I.e. 10%, while f increase (...)

## Variable frequency ring oscillator design

Did you ever inspect the ring oscillator waveforms to understand how the current control works? There might be an unwanted voltage swing at the inner supply nodes. A standard vco technology uses differential stages, and if I remember right, (...)

## how to plot frequency vs voltage control for vco in tanner spice

You can sweep the control voltage of vco in transient simulation, collect the vco frequency data and handle them in excel to plot the frequency vs control voltage.

## hspicerf simulation problem for measure vco frequency under different control votage

Hi guys, The following is my measure commands: .HBOSC TONE=2500e6 NHARMS=12 PROBENODE=vin,vip,1 + SWEEP v_control LIN 10 0.1 1.6 .measure hbosc fh find 'hertz' at=0.1 .measure hbosc fl find 'hertz' at=1.6 v_control is the control voltage for my vco. I wanna to (...)

## how to simulate VCO phase noise sensitive to power supply

Do a pxf analysis and plot the outputs from the control voltage source (Signal) and the power supply (Noise). Look for the "-1" ref sideband to observe the frequencies that matter. Note their relative levels and model it as (...)

## Loop Filter Poles and Zeros

This is a loop filter used in the PLL loop. The input is current and the output is the control voltage of the vco Yes - that`s what I have expected. As said - derive the transfer function Vout/Iin and determine poles and zeros. This (...)

## Voltage-controlled oscillator explanation

Hello from Greece !!! This is a voltage-controlled oscillator (vco). Αn oscillator that its frequency is controlled using a voltage signal. The vco described here provide both triangular and square wave output. The control (...)

## Measure potentiometer value using a constante current source

Some original joysticks used the Pot to control a vco and thus frequency was the output, however DMM use constant current ( 0.0001mA to 1mA) to drive the probes and thus Resistance is the voltage on the probes.

## need help with the gain of LC VCO

Hi， I am new to vco, I am trying to design a vco at 2.5GHZ. but I found that the gain of my vco appear positive or negitive with the control voltage seems totally different from what I find in the textbook. I want to know why the gain of vco performance like that? (...)

I'm doing simulations on a vco using Cadence at the moment (relative n00b to Cadence). I've got my circuit functioning and have a plot of the transient performance of the circuit for a set control voltage. What I'd like to do is sweep my control voltage (...)

## Transient response of the vco control voltage of a PLL

Hi, 1. I have attached transient response of the control voltage of my PLL in Cadence. This is NOT behavioral reponse. 2. From t=0 to 100us it is the startup time. No frequency step provided 3. At t=170us a frequency step of 40MHz (max size for the pll) is provided and resulting transient response is shown. The (...)

## VCO Frequency tune range

Hi all ! I have a vco IC with code MQK001-896-T7- 896MHZ. I find datasheet with link below : But i unknow frequency range output and control voltage range. Anyone that done,can help me ?Thank all!

## vco control voltage in pll behavioral simulation in simulink

Hi, i simulated my pll using simulink n time domain and ended up with peculiar control voltage even with 60 deg/75deg PM. Fig 1 shows the output of loop filter. Fig. 2 shows output after VDD saturation. I want my vco control voltage to slightly rise from 0 at t=0 (...)

I am designing LC vco using PMOS varactor in ADS. In typical LC vco, L and C values are selected according to the formula f=1/√LC. How to find the PMOS varactor width values?. Also oscillation frequency versus control voltage is plotted for this vco. very small (...)

## VCO design and sizing

77867 The image shown is a delay cell, where Vctrl is the control voltage. Where MC: a current source work in triode region MX: a negative resistance MK: adjustable resistor M+, M-: input pair Connecting the delay cells in a loop will form a vco. Next, given Kvco, how can i size the MOS in this (...)

## How to use CADENCE IC to measure PLL lock time

Set the vco control voltage to zero and measure the locking time with a transient simulation.

## PLL control voltage variation

Hello, Assuming that supply voltage and reference oscillator is spectrally clean, the phase comparator's output voltage is determined by the phase noise of the vco and the df/dVvco ratio. You should ignore the out of (...)

## Discontinuities in "Tuning Sensitivity" curve for LC VCO

Hi, I am designing an LC vco , and when I plot the tuning sensitivity plot, i.e. frequency - voltage curve (varactor control) , with a larger number of steps, I get discontinuities in the curve, and errors at some values ... in other words, at couple of (...)

## Folding Varactor Terminals in Cadence spectre

Hi , I am designing an LC vco ... So I need a varactor ... when I connect the varactors RIGHT, I mean the positive terminals to oscillating nets and the -ve terminal to ground, the oscillating frequency does not vary with varying control voltage ... So, I folded the varactors, it worked ! ... But with -ve (...)

## Problem while locking PLL for 6GHz

Is your control loop stable? Did you take the loading from the vco side in to account while you designed the loop filter?

## Question on Control Voltage of Current starved VCO !!

Hi, I have designed a 5 stage current starved vco in gpdk 90nm Cadence. I have seen in all papers and tutorials that the control voltage is swept from 0V to Vdd for plotting the tuning curve. But in my work control voltage is a sinusoidal voltage from (...)

## Generating BFSK, what is the best way?

Hi! I 've designed a 23 ghz fsk transmitter and i used a vco like you. I injected the modulating signal into the vco control voltage. We didn't see if the signal was continuous or what (because it didn't care to us), because the input signal already has a pulse shaping filter that smooth (...)

## VCO Varactor Bank Control Logic Noise

vco tuning voltage is usually low-pass filtered to make vco generate a stable frequency. In your case I would try to use a series R and parallel C for such low-pass filter.

## how to design the size of buffer stage in PLL VCO?

I guess you are referring to phase noise here. I cannot give you a step by step procedure but you will have to focus on matching both w/i each stage and among stages. Having the control voltage modulating the current load does not seem as good as modulating the tail current (since the first method relies on matching of separate

## Loop filter placement in PLL design

Hi, Loop filter is to proved dc voltage to vco and hence vco provides frequency based upon input control voltage. There are calculations from loop filter for stable operation of PLL like Bandwidth, damping factor, natural frequrency, (...)

## Measure Hittite VCO Vtune vs Frequency automatically

You should use automation test program such as HPVEE or LabView. You shoud write a routine to control your Power Supply and Spectrum Analyzer via GPIB interface and you can change the Tuning voltage and the Center frequency of SA by using "peak search" (...)

## KVCO of maneatis delay cell

Hello all, I have a question. I believe everybody knows about Maneatis's symetrical load based delay cell. My question is this. Let's assume you are building a vco based on the delay cell to be used in a PLL. The control voltage is comming from the charge pump. The frequency of vco is proportional to the (...)

## VCO centre frequency- Ring Oscillator

The centre frequency is the mean frequency of the upper frequency (when chargepump voltage is the highest) and the lowest frequency (when chargepump voltage is the lowest) of vco.

## VCO Control voltage range

Hi, I am designing a PLL (output freq. 400MHz-500MHz,Supply=3.3V) and I am at the preliminary stage. I have done a behavioral model of the PLL using Verilog-A. I observe that the control voltage of vco goes beyond 3.3V initially before it locks to 500MHz at 3.3V. My vco gain is such that (...)

## measuring tunning range of VCO

hi, please,can anyone tell me how to measure tunning range of vco in hspice?is it possible in hspice?if i sweep control voltage how it is possible to measure frequency exactly?if it is possible in cadence than how?what will be the settings? please help me,please You can sweep the control voltage (...)

## PLL control voltage issue

you didnt make any comments at all about your power supply poor regulation and filtering on the PSU is one of the biggest causes of vco (or any osc. for that matter) instability cheers Dave

## Help me improve VCO performance

Hi Guys, I am simulating a vco with the following design: Process: 0.18 um Tool: Cadence Spectre Topology:Three stage Differential amplifier (with symmetric load) Supply: 3.3V Frequency: 2.4GHz I measured the phase noise and it was -100 dbc/Hz at 10 MHz. Is this a good performance? I am using a DC control (...)

## Varactors of TSMC0.13 - which one to use?

Hi all , i am building a vco using tsmc0.13 - if anyone used it - there are several mos varactors in the kit , with 3 terminals (is the middle one for control voltage ?) i need to know what is the difference between them ? and which one to use? Thanks in advance.

## How to eliminate ripples in VCO control voltages

Hi guys, When the PLL locks I zoom in the signal that controls the vco. The signals has periodic ripples that occurs at the speed of the PFD/CP. The controle voltage range is between 0 and VDD. The ripple represent 3.6% of VDD. Is that big or normal ? Are these ripples the responsible (...)

## how to get the measure waveform from AFC transient response?

If you expect, that the vco control voltage represents the present oscillator frequency, it's simply it's waveform. There are however signal analyzers, that can measure frequency versus time directly. THank you, FvM. Have you used the signal analyzers? What's its name?

## How to use calculator to plot the VCO gain,

How to use calculator to plot the vco gain, freqency vs control voltage. Thanks

## Loop bandwidth and effect of power supply noise on PLL?

Considering power supply noise, if we want to decrease its effect on PLL, should we increase loop bandwidth or decrease bandwidth? If the vco is composed of transconductor (PMOS)+ICO+power match, I think the power supply noise has the some effect as the noise of loop filter on control (...)

## wide range VCO control circuitary

I have different vcos and most of them have a different operating and tuning voltage, I want to control the combined region of the vcos i.e eg if I have 3 vcos from 50-100, 100-250, 250-500 I want a control circuitary by (...)

## Question about ring VCO start up

Thank you for ravirajdv and FvM. I have read a paper there is a start-up circuit in the vco. I have some quesiton about it. The fig is the schematic. When Vc(control voltage) is 0 . M5 is closed . and M11 and M4 is opened because start up (...)

## How the gain of vco influence the jitter of pll?

In a type 2 PLL, it does not affect the static phase offset a bit., and it reduces the output jitter. The static phase offset is created only because of path mismatches in PFD and current and switching mismatches in CP. The control voltage will experience (...)

## Characterization of a Varactor

Hi; I am trying to use the capacitance of MOSCAP as a varactor in a vco deisgn. For a DC sweep, the MOSCAP capacitance changes and can be simulated. I have gone through some paper but i cant understand as how to characterize a MOSCAP capacitance for the case where there is a control (...)

## Why we use Triangle wave in mobile jammer?

Assume you mean the control voltage for a vco?? The shape and rate of this voltage will define the output spectrum of your oscillator. Often the goal is equal spaced spectral energy and this will be acheived by using saw tooth shaped sweep, with shortest (...)

## VCO design -- NEGATIVE Kvco

Whatever negative or positive, the only important thing is that the kvco vs control voltage is monotonic.