Follow along with the video below to see how to install our site as a web app on your home screen.
Note: This feature may not be available in some browsers.
audioguru said:I think pushing and pulling of an oscillator are when the frequency changes when the supply voltage changes and maybe when the load resistance changes.
audioguru said:I think pushing and pulling of an oscillator are when the frequency changes when the supply voltage changes and maybe when the load resistance changes.
eng1 said:I agree with you.
Frequency pushing is the sensitivity of the output frequency to the supply voltage.
Frequency pulling is the sensitivity of the output frequency to the load conditions.
RadioRon said:Yes, this is correct. Here is a reference:
https://www.electro-tech-online.com/custompdfs/2007/10/vco15-15-1.pdf
ericgibbs said:hi Ron,
IIRC this explains the undesirable 'side effects' that one can get from these sources.
Frequency pushing is the sensitivity of the output frequency to the supply voltage.
Frequency pulling is the sensitivity of the output frequency to the load conditions.
But some applications, musical instruments etc, the VCO is designed so that it can be pulled in a controlled way to produce a desired effect.
audioguru said:I think pushing and pulling of an oscillator are when the frequency changes when the supply voltage changes and maybe when the load resistance changes.
That's what I thought until I did a little research. That's why I edited my previous post.Sceadwian said:I thought pushing and pulling in concerns to a VCO were the intentional effects. I'm guessing it means it has a wide range of frequency responce in the given voltage range. Something that has bad push-pull performance might require more drive voltage for a given frequency shift. That's the way I read it at least in concerns to a VCO.
Furthermore, for efficiency reasons, it is also desirable to have a wide span of FM control of the oscillator. A common measure of the span of control is often called "pullability" of the oscillator, and refers to an extent that an oscillator can be modulated.
Frequency stability (which should include VCC stability) and pullability are listed as seperate paramaters. But the first link mentions that they're linked, meaning something that is highly pulable is always going to be less stable to circuit conditions. While it obviously refers to both in the context of a VCO I'm certain it refers to the span of frequency variation with a given input signal.Oscillator parameters such as frequency pullability, startability, stability, temperature, and crystal drive are easily optimized and can be set by mutually independent selection of individual circuit element values. In particular, the crystal drive level is well controlled due to the well-defined limiting character of the negative resistance circuit.
I see it refered to a lot with using different value capacitors to slightly trim the frequency of a crystal oscillator as well.High Pullability Voltage Controlled Oscillator
A voltage controlled crystal oscillator was developed which has extended tuning range while main- taining good Cl and temperature stability. With the circuit values indicated in the attached figure, * f .045% tuning was achieved over a 2.12V steering line change.
Apparently it depends on your search parameters. As I said, my original thoughts were what you verified here. But try searching for "VCO pushing pulling" and you get mostly the opposite result.Sceadwian said:**broken link removed**
http://www.freepatentsonline.com/4518930.html
**broken link removed**
In brief
Frequency stability (which should include VCC stability) and pullability are listed as seperate paramaters. But the first link mentions that they're linked, meaning something that is highly pulable is always going to be less stable to circuit conditions. While it obviously refers to both in the context of a VCO I'm certain it refers to the span of frequency variation with a given input signal.
I see it refered to a lot with using different value capacitors to slightly trim the frequency of a crystal oscillator as well.
That's what I found doing a Google search in about 3 minutes. How is the opposite conclusion being reached by other people?
Sceadwian said:RadioRon, that link is a 404.
This one isn't
https://www.electro-tech-online.com/custompdfs/2007/10/vco15-15-4.pdf
Bad parenthesis'