Talk:Voltage-controlled oscillator/Archive 1

Schematic Accuracy

I would like to recommend that the schematic presented here be reviewed or explained by the creator. This schematic does not represent a VCO; in fact, I'm not even convinced that the circuit portrayed herein will even oscillate. My recommendation is that this schematic be deleted or replaced with something that can be proven to work. Further, there is no mention as to what the source of the schematic is. If anyone is interested, I'll gladly explain what the shortage is in the design.--Cam Finnigan (talk) 03:06, 27 November 2007 (UTC)

Please explain. It kind-of looks like Colpitts schematics I have in various references. --Wtshymanski (talk) 01:07, 28 November 2007 (UTC)

It looks like a silly circuit where the choke L4 (with illegible text) short-circuits the varicap control voltage. Cuddlyable3 23:43, 1 December 2007 (UTC)

Yep. Take it out till we can find a good schematic. --Wtshymanski 17:55, 2 December 2007 (UTC)

The biggest problem with this portrayal is the fact that the tuning voltage is shorted directly to ground, as already pointed out. Breaking the connection between D2 and C2 would solve that, and then it should both be an oscillator and a VCO. As for other more conventional designs, I could point out several really good references, one of which is http://www.cel.com/pdf/appnotes/an1034.pdf. This is very similar to VCOs that I implement, but at higher frequencies than the one that was shown on Wikipedia. Another excellent reference is at http://www.ansoft.com/empower/Advanced_VCO_Design_using_Ansoft_Designer.pdf. There is also a good article on Skyworks, but I cannot locate it presently. All of these are in the range of 1 to 2 GHz and make use of bipolars. We still don't know the source of the original image, so it may not be fair to simply hack that up. I could make an image, but not in the next short while. Cam Finnigan (talk) 15:37, 15 December 2007 (UTC)

I should mention that I located a link from the Phase Locked Loop article to a page on U of Guelph that shows a VCO very similar to the one previously presented here. However, it too is broken. In fact, it has no DC return path for the oscillator. Can anyone tell me if there are any standards for schematics on Wikipedia? Cam Finnigan (talk) 04:25, 29 December 2007 (UTC)

Schematic again

If the current schematic is supposed to be this waveform generator it has several mistakes in it. The image should also be credited to the source. SpinningSpark 10:56, 18 June 2009 (UTC)

List of chips

The list of IC chips doesn't belong here. It doesn't add to the understanding of a what a VCO is, and many of the chips are archaic. Glrx (talk) 19:39, 12 October 2011 (UTC)

I agree and have removed the list. The remaining prose is not too much about chips. We need to either change the section title or rework the paragraph or both. --Kvng (talk) 19:43, 15 October 2011 (UTC)

History

Why isn't there a "history" section ?

VCOs were invented by someone (or some people) at a given time in given places. — Preceding unsigned comment added by 88.5.231.79 (talk • contribs) 22:28, 6 August 2016 (UTC)

Comments in Phase-domain equations section

There are two HTML comments in Voltage-controlled oscillator § Phase-domain equations. "this is still messed up" at the beginning of the section and "missing impulse; scaling wrong; need to move constant" on the Laplace versions of the equations. I don't understand these comments and have not yet tried to track down who added them and when. Things don't look particularly messed up in this section at this time. ~Kvng (talk) 18:45, 19 December 2018 (UTC)

Phase domain view is usually focused on frequency stability and the linear harmonic oscillator. Multivibrators (with their triangle and square waveshapes) have poor phase characteristics. The voltage noise at the input of a multivibrator's comparator produces discontinuous phase jumps. Connect a function generator to oven-stabilized counter, and the poor frequency stability is obvious. Multivibrators are not used as local oscillators in radios. Glrx (talk) 20:47, 19 December 2018 (UTC)

This response does not tell us whether or not there is still a problem in the section, what the problem is or how to fix it. ~Kvng (talk) 15:10, 22 December 2018 (UTC)