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Questions tagged [vco]

VCO (Voltage-Controlled Oscillator) is an electronic oscillator whose oscillation frequency is controlled by a voltage input.

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1answer
57 views

Generating fixed count pulse train from single pulse

EE novice here. I have an analog synth oscillator core which produces a sync pulse each time the waveform resets. I'd like to generate a short series of pulses triggered from each sync pulse, ideally ...
2
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1answer
105 views

Two details about phase noise have been confusing me for a long time. Hope to be resolved

Just like FLOYD M. GARDNER said in the PhaseLock Techniques, 3rd Edition: "In light of that success in spectrum analyzers, a practitioner’s answer to the question above is: The spectrum of phase noise ...
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2answers
440 views

Grounding Vcc and Vee?

I recently started electronics as my hobby. I'm working on this v/oct modular synth and in the schematic that I was working on, it did not make sence to me when all the Vcc and Vee are connected to ...
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2answers
77 views

Can Zener or Schottky diodes be used as a substitute for varicap diodes in tuning a VCO?

In particular, this would be a fairly low frequency VCO with a frequency range of 10 Hz to 20 kHz. I'm thinking of the configuration with the T-junction that has 2 opposite facing, reversed biased ...
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0answers
24 views

BLE VCO Function Divide by 2

Can someone explain or point to some documentation that explains how the RF front-end works for BLE chips? Specifically, I am confused about why the VCO runs at 4.8Ghz and is then divided by 2. I have ...
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1answer
83 views

Link between phase noise and linewidth for a oscillator?

I was googling for a formula to transform the dbc/Hz value given in data sheets for VNA, spectrum analyzers and VCO is often given in dBc/Hz with offset. Now looking up research papers about future ...
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1answer
38 views

Is it possible to power down all the PLLs and VCO of a MAX 10 Device?

We are developing a board in which we would like not to use the analog features, like PLL, VCO and ADCs of a MAX10. UG-M10CLKPLL par. 2.3.6 states : "The only time that the VCO is completely disabled ...
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0answers
600 views

Using ICL8038 as a VCO

I wanted to use this function generator IC as a voltage controlled frequency output especially to obtain low frequency sine waves. But unlike many implementations, I wanted to control the frequency ...
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1answer
113 views

Horn antenna for radar sensor

I have InnoSenT SMR-314 and SMR-334 radar sensors that have quite wide horizontal radiation pattern of over 100 degrees (see datasheet on page 3). I would like to make the sensors far more directional ...
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0answers
97 views

Finding the Analog Bandwidth of a Voltage Controlled Oscillator

We've built a current starved voltage controlled oscillator And tuned it so it works only in the linear region, which means it oscillations between 720-840 mV, and outputs 3.6-4.4 GHz. In order to ...
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0answers
33 views

Designing a VCO ADC - How to go from frequency to digital/binary?

For a final project we're building an ADC based on an article that uses a current starved ring oscillator connected to frequency to digital blocks followed by a counter. We understand how to go from ...
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5answers
159 views

Is there such a thing as a resistance oscillator?

I think I understand how a Oscillator works (VCO). One uses an Oscillator when one wants for example a square wave oscillating between sy, \$0\$ volts and \$5\$ volts. My question is: Is there such a ...
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3answers
482 views

Kickstarting an opamp for oscillating?

I have been building many different variations of op-amp oscillators but have come across a recurring issue that has manifested itself again in this VCO schematic: I find that when turning on my ...
0
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1answer
46 views

What is and how to measure the tuning port capacitance of a VCO

I was asked to check all the specifications of this Voltage Controlled Oscillator. I might have an idea of how to measure all the parameters except for one, the Tunning Port Capacitance. I think my ...
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2answers
202 views

VCO from a rectangular and triangular signal generator

I need to create the simplest rectangular and triangular signal VCO I can using op amps. The output frequency should be changeable between 1k and 15k. I should also be able to change the amplitude of ...
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1answer
82 views

Compact thermostat for VCO temperature stability

So I have a voltage controlled oscillator with an exponential input made using the THAT2181 VCA IC. The schematic is shown below - the THAT2181 IC is used to change the C4 capacitor charging current ...
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0answers
791 views

PWM and PPM using 555 timer

I get what PWM is and how it can be done using a 555 astable circuit. However I feel I don't completely get what PPM is how its circuit works. I understand the VCO circuit, but I don't see how it can ...
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1answer
82 views

Please explain the purpose of following circuit

This is the excerpt from the 2VCO synthesizer unit. Someone, please, can explain me what is this strange arrangement with VCO2 Out jack through the switch inside of it? I understand that when the Jack ...
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3answers
88 views

What is the purpose of the capacitors in this circuit that are in series with this VCO? [closed]

I am learning about how VCO modules operate and I am rekindling an old interest in electronics in general. For one particular VCO, the manufacturer has provided a circuit diagram. Does anybody know ...
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3answers
167 views

Relation between VCO's (Voltage Controled Oscillator's) Frequency and Voltage

I have a question that what is the relationship between the VCO generated frequency and applied volatage. Is there any formula which we can use to find the applied voltage and get the frequency ...
2
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0answers
312 views

Simulating varicap diode in LTSpice

I have been looking into making a voltage controlled oscillator using varicap diodes, however I have had hard time simulating the diodes in spice. Would anyone here have an idea how this would be ...
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1answer
140 views

Looking for an ultra wide modulation bandwidth, ultra linear VCO

I'm searching for a VCO in the 200-500 MHz area with 60 MHz modulation bandwidth which maintains 2% linearity (ideally better) in its tuning range. Would also prefer it to also hold 2% or better ...
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1answer
646 views

Mosfet Switched capacitor in LC tank

I need to coarse control the frequency of oscillation on a parallel resonant tank. The frequency band is in the 500kHz-1Mhz range, so the small capacitance of varactors doesn't suit the task. ...
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0answers
209 views

Principle for converting dual power supply to single

I was recently attempting to build a voltage controlled oscillator from this website: http://www.schmitzbits.de/vco4069.html. I struggled with it, for various reasons, and eventually found this ...
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0answers
225 views

Output waveform of VCO

This is a differential VCO which produces a sine waveform at the output taken across the drains of the MOSFETs. How should I interpret the drain current waveform at that point? Will it be a proper ...
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4answers
1k views

How does VCO in PLL in computer processor work?

In todays personal computers and notebooks, what is usually used as a Voltage-Controlled Oscillator for generating clock signal for processor? Is that a crystal rather than RC circuit? Is it tuned by ...
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1answer
115 views

Voltage gain of a vco

What should be the typical gain of an nmos only LC VCO? Should it be more than 100MHz/V or 200MHz/V or lesser than this? Which is more useful - keeping the gain high or low?
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2answers
264 views

PLL Design - Lock condition

I am designing a PLL. Can anyone explain to me what happens exactly in a lock condition? Should both the reference and input frequency be same in that state? My input freq is 25MHz and my VCO is ...
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2answers
171 views

Self resonant frequency of inductor in VCO

I am designing nmos only LC VCO in cadence TSMC180. I have chosen the self-resonant frequency of the inductor to be twice the working frequency of the LC tank. Is it a proper design for LC tank? Or do ...
2
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3answers
2k views

Can I make a VCO full audio range with only one capacitor?

I'm trying to make a VCO with a low voltage setup (3.3V), and i 'm using a mcp6002 op-amp. I'm controlling the frequency with an MCP4822 (dac). The problem is that i get a limited range of frequencies....
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3answers
185 views

Need help understanding this op amp/BJT configuration to troubleshoot why I'm reading different voltages than expected

I am building this VCO in an attempt to study it and I'm having trouble understanding the references section seen bellow. I have used a KIA431 that I 'stole' from a broken switching power supply on ...
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1answer
154 views

Help needed trying to build an audio sawtooth oscillator

I'm a total beginner hobbyist trying to understand the concept of an audio synthesizer, with a view to building one. Rather than just build a kit I'm keen to understand the concepts. Goal: build a ...
4
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2answers
864 views

Can I use a DAC to tune a VCO?

I found some FM transmitter circuits with the MAX2606 VCO. Example: Can I replace R1 with the DAC output from an AVR microcontroller? Or can I connect the DAC directly to Pin 3 of the MAX2606?
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1answer
178 views

BJT schmitt trigger has linear behavior on negative swings

I am currently building a VCO for an analog synthesizer. The circuit produces a triangle wave by taking a Schmitt trigger output and feeding it into an integrator. The constant output of the Schmitt ...
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2answers
325 views

(PLL) Why is it essential for VCO to continue oscillating when input is zero?

I have designed a simple PLL with current-starved ring VCO. The minimum frequency of oscillation for this VCO is zero since there is no current fed to ring of inverters when control voltage is zero. ...
9
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2answers
6k views

How to design a cheap sine-wave generator up to 200 MHz?

I want to make a cheap wideband oscillator for an antenna analyzer I'm designing. I want a simple sine wave over a wide frequency range. I don't want to use a DDS IC like the AD9851 because it's ...
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3answers
170 views

Is a 555/6 suitable for generating a 1-3000Hz square wave from 0-5V control voltage

The goal is to use a control voltage from 0-5V to generate a square wave signal from 1 (ideally, but around 10 would be acceptable) to 3000 Hz (linearly, although I could work around it not being ...
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3answers
2k views

555 TIMER SQUARE TO SINE CONVERTER

HOW CAN I CONVERT MY(VSC) SQUARE WAVE OUTPUT TO A SINE WAVE OUTPUT
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1answer
438 views

Replacement for MC12149 (Voltage Controlled Oscillator)

I need to build up a VCO from 250-350 MHz. I have found an interesting IC called MC12149 from Motorola. However, it seems to be archived and no longer manufactured. Looking at the datasheet, it looks ...
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2answers
196 views

Why isn't this VCO responding to my sawtooth waveform?

I'm learning how VCOs work, and I'm feeding it a sawtooth waveform to see the impact on my WiFi. This VCO outputs in a 2.4ghz spectrum, and to understand how it sweeps, I'm passing in a sawtooth ...
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1answer
99 views

Control an inductive load with VCO

I am trying to tune this circuit, dimensioning the values of resistors Ra,Rb and the capacitor C... The circuit work in this way: a voltage Vin regulates the current flowing in the inductor, via the ...
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0answers
1k views

voltage controlled oscillator

Given below is a VCO circuit. Can anyone explain how the components work (especially the resistors and capacitors) and why the resistor and capacitor values are selected so. and what are the values to ...
4
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2answers
2k views

Minimoog VCO analysis

The diagram shows part of the schematic for the late-model Minimoog VCO. In the circuit, Q7 and Q8 form a current sink, drawing a current through the collector of Q7 that is exponentially related to ...
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2answers
789 views

Sawtooth VCO and current source for modular synthesizer

I have been working on a current source and sawtooth core VCO based on the Electronotes/Aaron Lanterman/Ian Fritz designs/ideas. I have breadboarded out the attached VCO schematic; the transistors ...
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1answer
558 views

555 VCO Circuit - Speaker to VCC?

Hello! I have a simple question concerning this circuit I have built: It is a 555 Voltage Controlled Oscillator I have built as a foundation for my signal generator circuit. The circuit works great, ...
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1answer
1k views

How do I generate a high frequency sine wave using a PLL? 900 to 950 MHz

I know of a few ways to generate a sine wave; Op-amps, 555, LC, crystals, or microcontrollers. But none of those would really work for a frequency as high as 900 MHz. I have heard of phase lock loops, ...
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1answer
122 views

VCO doesn't work

I've tried to design a voltage controlled oscillator by adding a varactor to a Colpitts oscillator. However simulation shows no change in the oscillation frequency as V3 changes (0.04v to 10v). I ...
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1answer
739 views

Help understanding frequency calculation for VCO Schematic in LM13700 Datasheet

I am trying to work through the math of the following schematic pulled from the LM13700 datasheet: I can certainly hook this up and mess with the values to change the frequency range to my liking (...
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1answer
3k views

How do I make a VCO with a LM 358?

Hi! I am an absolute newbie at electronics (though an Industrial engineer by qualification). I discovered this diagram for a VCO from the datasheet for an LM 358. I assumed when they say 1/2 LM 358 ...
2
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2answers
447 views

How to send analog data using FM/FM Telemetry

I am measuring the strain a bicyclist is placing on a bicycle crank arm throughout riding, using strain gages. I would like to send this data (after amplification) off of the bicycle crank arm and to ...