Check frequency
in [Basics]
|
From: Michael A. Terrell on 17 Dec 2009 16:43 John Fields wrote: > > Phil Allison wrote: > > > Idiot. > > A dog smells his own farts first, yes? Then they run in circles chasing it. :) -- Offworld checks no longer accepted!
From: Phil Allison on 17 Dec 2009 17:41 "John Fields" "Phil Allison" >> >>> For this application an oscilloscope will be useless and you should use >>> a frequency counter. >> >> >>** Shame how even the cheapest DSOs have built in frequency measurement >>to >>5 decimal places. >> > > --- > Shame how analog scopes, which is (since he didn't say "DSO") ** Pedantic bollocks. The OP is a novice and has no scope at present. A low price ( ie $300) DSO is just what he should get. ..... Phil
From: Phil Allison on 17 Dec 2009 17:44 "John Fields" "Phil Allison" >> >>** To get the frequency exact, you need resolution better than 1 Hz > > --- > I don't think so. ** You don't think straight at all. Never have. > If you've got a 32768 Hz crystal in an oscillator and you want to > measure the output frequency to an accuracy of, say, +/- one part in > 32768, then if you use a 1 second timebase to accumulate cycles it has > to have a resolution of +/- 30.51757... �s ** Meaningless drivel. ...... Phil
From: John Fields on 17 Dec 2009 20:10 On Fri, 18 Dec 2009 09:41:28 +1100, "Phil Allison" <phil_a(a)tpg.com.au> wrote: > >"John Fields" > "Phil Allison" > >>> >>>> For this application an oscilloscope will be useless and you should use >>>> a frequency counter. >>> >>> >>>** Shame how even the cheapest DSOs have built in frequency measurement >>>to >>>5 decimal places. >>> >> >> --- >> Shame how analog scopes, which is (since he didn't say "DSO") > > > ** Pedantic bollocks. > > The OP is a novice and has no scope at present. > > A low price ( ie $300) DSO is just what he should get. --- Got any suggestions as to which one? JF
From: John Fields on 17 Dec 2009 20:18
On Fri, 18 Dec 2009 09:44:14 +1100, "Phil Allison" <phil_a(a)tpg.com.au> wrote: > >"John Fields" > "Phil Allison" > >>> >>>** To get the frequency exact, you need resolution better than 1 Hz >> >> --- >> I don't think so. > > ** You don't think straight at all. > > Never have. --- Just because you don't recognize it as straight thinking doesn't mean it isn't. For example, if you think that the '8' in 32768 Hz represents 1 Hz, as you seem to indicate, I suggest you consider that it represents 1 part in 32768 Hz, which is ~ 30.5�s, not 1s/1Hz. --- >> If you've got a 32768 Hz crystal in an oscillator and you want to >> measure the output frequency to an accuracy of, say, +/- one part in >> 32768, then if you use a 1 second timebase to accumulate cycles it has >> to have a resolution of +/- 30.51757... �s > > ** Meaningless drivel. --- How would you state it then? JF |