Re: [time-nuts] Spice simulation of PSRR and phase noise

Hoi Bert, On Sun, 29 Oct 2017 08:06:37 -0400 Bert Kehren via time-nuts wrote: > Thank you for posting the link to Richard's excellent paper that does not > only apply to Cs. In my opinion it is a must read for any one serious in > doing any work on time and frequency

Re: [time-nuts] Spice simulation of PSRR and phase noise

Attila Thank you for posting the link to Richard's excellent paper that does not only apply to Cs. In my opinion it is a must read for any one serious in doing any work on time and frequency issues. Bert Kehren In a message dated 10/27/2017 3:14:48 P.M. Eastern Daylight Time,

[time-nuts] Spice simulation of PSRR and phase noise

And it's the only way to be sure... never trust a simulation, particularly for such flighty and subtle things like noise. Simulations can be useful for pointing you in the right direction for a design, but where the rubber meets the road there is nothing like real hardware to get to the true

Re: [time-nuts] Spice simulation of PSRR and phase noise

Hi The “fun part” of harmonic balance is making sure you are not off in a corner case where the results are not as good as they might otherwise be. Maybe not as much an issue for a VCO as for some other structures. Bob > On Oct 28, 2017, at 7:36 AM, Rafael Gajanec wrote:

Re: [time-nuts] Spice simulation of PSRR and phase noise

Hi Attila, On 27-Oct-17 8:25 PM, Attila Kinali wrote: Hi Rafael On Sun, 22 Oct 2017 17:20:52 +0200 Rafael Gajanec wrote: you haven't specified what sort of circuits would you like to simulate, Simplified, they are differential amplifiers driven into saturation. A bit

Re: [time-nuts] Spice simulation of PSRR and phase noise

On Tue, 24 Oct 2017 12:12:24 -0700 "Richard (Rick) Karlquist" wrote: > This problem came up in the design of the 5071A. > I elected to avoid narrowband filters by using > some tricks described in my FCS paper of about > 25 years ago. I didn't find it necessary to ovenize

Re: [time-nuts] Spice simulation of PSRR and phase noise

Hoi Bruce, On Mon, 23 Oct 2017 09:58:40 +1300 (NZDT) Bruce Griffiths wrote: > Since close in phase noise can result from up conversion of supply noise > etc via circuit non linearities, using an AC analysis won't work. > > Only transient simulation or perhaps

Re: [time-nuts] Spice simulation of PSRR and phase noise

Hi Rafael On Sun, 22 Oct 2017 17:20:52 +0200 Rafael Gajanec wrote: > you haven't specified what sort of circuits would you like to simulate, Simplified, they are differential amplifiers driven into saturation. A bit more detailed, I am looking at ring oscillator stages

Re: [time-nuts] Spice simulation of PSRR and phase noise

Hoi Dana, On Sun, 22 Oct 2017 09:23:26 -0500 Dana Whitlow wrote: > But I am surprised about the simulation times that you speak of. > Would you be willing to post some information detailing your > methodology and an example "simple" circuit? As Bruce already mentioned,

Re: [time-nuts] Spice simulation of PSRR and phase noise

On 10/24/17 11:54 AM, Bob kb8tq wrote: Hi If you have the money, almost anything can be (and has been) done. It’s rare to find a real world application where this kind of thing is considered cost effective. Fancy radar systems are about the only thing that comes to mind. Radar of this sort

Re: [time-nuts] Spice simulation of PSRR and phase noise

Hi If you have the money, almost anything can be (and has been) done. It’s rare to find a real world application where this kind of thing is considered cost effective. Fancy radar systems are about the only thing that comes to mind. Radar of this sort is always high cost / low volume. Bob

Re: [time-nuts] Spice simulation of PSRR and phase noise

On 10/24/2017 11:10 AM, Hal Murray wrote: aph...@comcast.net said: My applications were broadband. If I remember correctly, aggressive bandwidth limiting can cause phase shift problems due to temperature changes unless one is careful in the design of the filter. Does anybody ovenize

Re: [time-nuts] Spice simulation of PSRR and phase noise

aph...@comcast.net said: > My applications were broadband. If I remember correctly, aggressive > bandwidth limiting can cause phase shift problems due to temperature > changes unless one is careful in the design of the filter. Does anybody ovenize amplifiers and filters to avoid that

Re: [time-nuts] Spice simulation of PSRR and phase noise

I never had much luck with current feedback amplifiers such as the LMH6702. Their input current noise (at the time) was too high for my needs and their output peaks at higher frequencies if the feedback resistors aren't optimal for the part. I had the best results with voltage feedback op

Re: [time-nuts] Spice simulation of PSRR and phase noise

Hi One would guess that they put them in parallel to get more drive. If that’s correct, details of the loading are going to get into the simulation pretty quickly. In a lot of cases, these amplifiers were designed against a specific need. If you have a signal source that is in the -180 dbc /

Re: [time-nuts] Spice simulation of PSRR and phase noise

FWIW I recently took a peek inside a commercial distribution-amplifier and it seems to use two LMH6702 op-amps in parallel. There are two of these dual-LMH6702 stages with a 1:2 splitter after the first, and then a 1:4 splitter after the second stage. 8 outputs in total, with an additional op-amp

Re: [time-nuts] Spice simulation of PSRR and phase noise

Am 22.10.2017 um 22:58 schrieb Bruce Griffiths: Hoi Attila Since close in phase noise can result from up conversion of supply noise etc via circuit non linearities, using an AC analysis won't work. Only transient simulation or perhaps analytical modelling of the various non linearities will

Re: [time-nuts] Spice simulation of PSRR and phase noise

One has to provide noise models that work with the Spice transient simulation for all devices including resistors. Random number generators can be used but they need to be independent and must not repeat during the entire simulation. Bruce > > On 23 October 2017 at 10:25 Bruce Griffiths

Re: [time-nuts] Spice simulation of PSRR and phase noise

If one for example wishes to estimate PN down to an offset of 1Hz then an equivalent filter noise bandwidth of 0.1Hz or perhaps less is desirable (the PN spectrum at low offsets is far from flat). To achive accurate noise estimates a simulation time of at least 100 x the reciprocal of the

Re: [time-nuts] Spice simulation of PSRR and phase noise

Hoi Attila Since close in phase noise can result from up conversion of supply noise etc via circuit non linearities, using an AC analysis won't work. Only transient simulation or perhaps analytical modelling of the various non linearities will provide accurate estimates of upconverted PN. If

Re: [time-nuts] Spice simulation of PSRR and phase noise

Dear Attila, you haven't specified what sort of circuits would you like to simulate, but maybe the answer is Harmonic Balance. Have a look at http://qucs.sourceforge.net/ and http://qucs.sourceforge.net/tech/node36.html HSPICE from Synopsis and ADS from Keysight (which I use) also have the

Re: [time-nuts] Spice simulation of PSRR and phase noise

Hello Attila, It seems to me that an AC simulation could never work since the very generation of phase noise by the mechanisms that matter is a modulation process at heart, automatically forcing one into the realm of transient simulations. But I am surprised about the simulation times that you

[time-nuts] Spice simulation of PSRR and phase noise

Hi, I have been looking into spice simulations of circuits, in particular trying to extract PSRR and phase noise information. Unfortunatelly, the obvious way of putting AC sources at the right places does not work, as the (ideal) input signals are not small and drive the circuit into