A good digital oscilloscope?
in [Design]
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From: Tim Williams on 13 Dec 2009 14:20 "John Larkin" <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in message news:0lcai5hpf04sealni6moe3orn09jbdk7eq(a)4ax.com... > Older triggered-sweep scopes, like the Tek 545, had a "stability" > knob. It usually set the threshold of the Schmitt trigger that > followed the trigger discriminator. At high trigger frequencies, one > would tweak it for a stable display. Turning the stability knob one > way would free-run the timebase (before "auto" was invented), the > other way would kill it. > > http://www.barrytech.com/tektronix/vintage/tek545bfront.jpg Yup, I played with one of those in lab once (school lab, for doing real school lab work). The Rigols they hand out suck at X-Y plotting, so I rolled that behemoth on over, plugged it in and away I went. The first thing I noticed is the knobs are all in terrible positions. I guess they didn't have the luxury of putting things in nice places, since everything is stacked up inside, tubes and terminal strips and all. Not like the 475, where there still isn't a lot of free space, but it's all on PCBs, positioned where it needs to be. The second thing I noticed is, the "delayed/B sweep" -- which sounds to me like the delayed sweep on the 465 -- I couldn't get to work, at least as I thought it should. Lastly, the manual (which was convieniently sitting on the cart) includes complete schematics. What madness drove them to hybrid tube/SS circuits, who knows! ;-) Tim -- Deep Friar: a very philosophical monk. Website: http://webpages.charter.net/dawill/tmoranwms
From: John Larkin on 13 Dec 2009 14:42 On Sun, 13 Dec 2009 13:20:43 -0600, "Tim Williams" <tmoranwms(a)charter.net> wrote: >"John Larkin" <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in message >news:0lcai5hpf04sealni6moe3orn09jbdk7eq(a)4ax.com... >> Older triggered-sweep scopes, like the Tek 545, had a "stability" >> knob. It usually set the threshold of the Schmitt trigger that >> followed the trigger discriminator. At high trigger frequencies, one >> would tweak it for a stable display. Turning the stability knob one >> way would free-run the timebase (before "auto" was invented), the >> other way would kill it. >> >> http://www.barrytech.com/tektronix/vintage/tek545bfront.jpg > >Yup, I played with one of those in lab once (school lab, for doing real >school lab work). The Rigols they hand out suck at X-Y plotting, so I >rolled that behemoth on over, plugged it in and away I went. > >The first thing I noticed is the knobs are all in terrible positions. I >guess they didn't have the luxury of putting things in nice places, since >everything is stacked up inside, tubes and terminal strips and all. The 545-547 scope front panels were wonderful. You could grab a fist full of knob, with serious detents, and wail away. They were a pleasure to drive. Kids these days. John
From: Jan Panteltje on 13 Dec 2009 14:41 On a sunny day (Sun, 13 Dec 2009 13:12:54 -0600) it happened "Tim Williams" <tmoranwms(a)charter.net> wrote in <hg3ebq$rn3$1(a)news.eternal-september.org>: >"Jan Panteltje" <pNaonStpealmtje(a)yahoo.com> wrote in message >news:hg399d$2na$1(a)news.albasani.net... >> Consider this circuit: > >Ewwww! An UJT! > >It's a bad scope, okay, but not THAT bad! ;-) > >> The Venier speed ('stability?') is set by R1, and set a bit lower in >> frequency (or fraction of that) then the signal observed. > >No, that's a bad way to control stability, you'd want to control dead time >or discharge time (the latter isn't possible with an UJT). As shown, you're >changing dV/dt, which needs to be in calibrated ranges. > >Tim 'Vernier' is the time base speed, or in this case frequency. Actually that circuit needs a comparator so it can only trigger when the sweep is past the most right point. UJTs are cool. Unlike tubes, that get hot. Only synced scopes I have seen were old and had tubes...
From: Tim Williams on 13 Dec 2009 16:07 "John Larkin" <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in message news:4ogai51nv3vosmev14ug9mljcp10059368(a)4ax.com... > The 545-547 scope front panels were wonderful. You could grab a fist > full of knob, with serious detents, and wail away. They were a > pleasure to drive. > > Kids these days. You've got a point about "fistful of knob" and "drive". Tim -- Deep Friar: a very philosophical monk. Website: http://webpages.charter.net/dawill/tmoranwms
From: Ralph Barone on 13 Dec 2009 17:00
In article <7oic52F3oj5r3U1(a)mid.individual.net>, Joerg <invalid(a)invalid.invalid> wrote: > > The amazing thing is that my wife still fits into her dress. I, on the > other hand ... So, you're saying that you no longer fit into your wife's wedding dress... Perhaps it's all for the best :-) |