CRO unit - definately one for the old timers

[JERD]

This one is definately for the old timers.

Maybe 20-40 years ago I recall one of the tech magazines describing a unit
that could be used on a single trace CRO to produce two traces. Used some
kind of electronic switch to produce the two traces.

Of course it was limited to the lower frequencies, below the switch rate.

Does this ring any bells with anyone and/or reference to a similar unit
available these days.

JERD

 

[David L. Jones]

This one is definately for the old timers.

Maybe 20-40 years ago I recall one of the tech magazines describing a
unit that could be used on a single trace CRO to produce two traces.
Used some kind of electronic switch to produce the two traces.

Of course it was limited to the lower frequencies, below the switch
rate.
Does this ring any bells with anyone and/or reference to a similar
unit available these days.

JERD

That rings a bell, in EA I thought, possibly also in one of the old
compilation "Test Gear Vol.X" mags too.

Quick search here show no mention of it:
http://www.electronicsaustralia.com.au/files/ea_proj.txt

The ETI index shows a "Dual beam Adaptor" in Jul 74.
http://www.electronicsaustralia.com.au/files/eti_proj.txt

I have not seen another design since those days.

Dave.

 

[Trevor Wilson]

This one is definately for the old timers.

Maybe 20-40 years ago I recall one of the tech magazines describing a
unit that could be used on a single trace CRO to produce two traces.
Used some kind of electronic switch to produce the two traces.

Of course it was limited to the lower frequencies, below the switch
rate.
Does this ring any bells with anyone and/or reference to a similar
unit available these days.

**This was the standard to most analogue CROs built since the late 1960s
(maybe even earlier). There were, of course, many dual BEAM CROs produced.
These were made with two sets of vertical deflection plates and two guns.
The traces were completely separately accessible. The downside was the
limited deflection area for the traces. Dual TRACE CROs neatly circumvented
this limitation. There are (or were) two methods used:

1) Chopped. This is where the waveforms are modulated with a square wave and
displayed on the tube very quickly. Normally, this type of display is used
for low(ish) frequencies (<300Hz).
2) Alternate. This is where the waveforms are displayed alternately on the
tube at high speed. Due to the persistence of vision and the persistence of
the phosphors used, the traces appear to be contiguous ones. Normally, this
type of display is used for frequencies in excess of about 300Hz.

Most (all?) dual trace analogue CROs have a switch that allows either
chopped or alternate to be used.

 

[JERD]

That rings a bell, in EA I thought, possibly also in one of the old
compilation "Test Gear Vol.X" mags too.

Quick search here show no mention of it:
http://www.electronicsaustralia.com.au/files/ea_proj.txt

The ETI index shows a "Dual beam Adaptor" in Jul 74.
http://www.electronicsaustralia.com.au/files/eti_proj.txt

I have not seen another design since those days.

Dave.

Thank you! A good start.

I remember building one of these units but after some 36 years it is long
time lost. I have a really old CRO that I would like to use for a particular
task. Also have a more modern Rigol unit - thanks to your reviews!

Now all I have to do is find the particular mag.

JERD

 

[Phil Allison]

"JERD"

Now all I have to do is find the particular mag.

** All you have to do is contact Bob Barnes at RCS Radio - as they have the
PCB for ETI project 114 advertised under bin no. 904 for $13.50.

http://users.tpg.com.au/rcspcb/index0.htm

Normally, Bob will include a copy of the original article if you simply ask.



..... Phil

 

[JERD]

"JERD"



** All you have to do is contact Bob Barnes at RCS Radio - as they have
the PCB for ETI project 114 advertised under bin no. 904 for $13.50.

http://users.tpg.com.au/rcspcb/index0.htm

Normally, Bob will include a copy of the original article if you simply
ask.



.... Phil

Thanks Phil.

JERD

 

[keithr]

**This was the standard to most analogue CROs built since the late 1960s
(maybe even earlier). There were, of course, many dual BEAM CROs produced.
These were made with two sets of vertical deflection plates and two guns.
The traces were completely separately accessible. The downside was the
limited deflection area for the traces. Dual TRACE CROs neatly circumvented
this limitation. There are (or were) two methods used:

1) Chopped. This is where the waveforms are modulated with a square wave and
displayed on the tube very quickly. Normally, this type of display is used
for low(ish) frequencies (<300Hz).
2) Alternate. This is where the waveforms are displayed alternately on the
tube at high speed. Due to the persistence of vision and the persistence of
the phosphors used, the traces appear to be contiguous ones. Normally, this
type of display is used for frequencies in excess of about 300Hz.

Most (all?) dual trace analogue CROs have a switch that allows either
chopped or alternate to be used.

Thats just the way that my old Tek 475A works, you use chopped at low
timebase rates, and alternate at the faster ones, and it manages 250MHz.
The 475 is definitely the king of the analog scopes, accurate,
versatile, and you couldn't break it with an axe. Mine is probably 30
years old and still running fine, I bought it 10 years ago for less than
half the price of a Rigol.

 

[JW]

Thats just the way that my old Tek 475A works, you use chopped at low
timebase rates, and alternate at the faster ones, and it manages 250MHz.
The 475 is definitely the king of the analog scopes,

I would say that the 2465B has that throne, but YMMV.

 

[keithr]

I would say that the 2465B has that throne, but YMMV.

I'm just old skool, in 30 years I have never seen a 475 break, but the
2465 has some nice features.