On Fri, 29 Jan 2016 15:00:37 -0800 (PST), Lasse Langwadt Christensen <langwadt@fonz.dk> wrote:>Den fredag den 29. januar 2016 kl. 23.45.45 UTC+1 skrev John Larkin: >> On 29 Jan 2016 22:23:17 GMT, Jasen Betts <jasen@xnet.co.nz> wrote: >> >> >On 2016-01-29, John Larkin <jjlarkin@highlandtechnology.com> wrote: >> >> >> >> >> >> I'd like a sine wave generator to come up at a randon, different phase >> >> every time I do a transient run. >> >> >> >> Or a pulse generator that has a random startup delay. >> >> >> >> Any good way to do this? My tries aren't working. >> > >> >So you want a simulation that gives non-repeatable results? >> >That seems counter-productive. >> >> I have a system that has an input that's not synchronized to the >> system clock. Making that reliable is not counter-productive. >> >> LT Spice doesn't seem to have a mechanism for randomizing a voltage or >> a time between runs. So voltage {rand(x)} seems to be exactly the >> same every run, regardless of x. I need x to be time-of-day or >> something that changes. >> >> That's not too much to ask for. >> >> A parameter that's persistant between runs could be made to work, >> maybe, if I could increment it. Call it runnum or something. >> > >can't just keep running it with an input that doesn't have simple >relation to the clock so that you sweep through the danger zone? > >but then, how many cases to you really hit? > >you really need to make stuff like synchronizers safe by design, >there's really no way to simulate if it works > > >-LasseI'm not trying to prove that a synchronizer is safe. I'm trying to visualize and get a feel for a number of possible numerical options. Part of the design involves selecting some integer-ratio frequencies (like 2+13/16 : 1) out of a lot of possibilities of various degrees of messy. -- John Larkin Highland Technology, Inc lunatic fringe electronics
LT Spice random phase
Started by ●January 29, 2016
Reply by ●January 29, 20162016-01-29
