I was surfing the Web yesterday, and I came across a YouTube video of a presentation on scope basics that was held in my home state of New Jersey for some ham radio enthusiasts (hosted by The New Jersey Antique Radio Club).
Admittedly, I watched only the first 30 minutes of this two-hour juggernaut, but I was taken by the scope history section. You should know that I am a bit of a history buff, so when the presenter covered the origins of the oscilloscope (especially the oscillograph), I was all ears.
The Duddell Moving Coil Oscillograph for frequencies up to 300Hz. The section marked A contains the oil bath, and the electromagnet is housed in section B.
Here is a picture of the interior of the cinematograph camera as used on the Duddell moving coil oscillograph. One of the reels that carried the film is lying in the front.
A little Web searching told me that the earliest methods of recording waveforms used a galvanometer and hand-drawn "oscillograms" on graph paper. These were replaced by automatic paper-drawn oscillographs and then photographic oscillographs in the late 19th century. The invention of the CRT in changed things for the better, and Karl Ferdinand Braun is credited with inventing the first CRT oscilloscope in 1897. This early scope only applied vertical deflection to the internal plates, so the horizontal time base was revealed using a rotating mirror! Two years later, Jonathan Zenneck tried using beam-forming plates and a magnetic field for sweeping the trace. Innovation continued in the late 1930s with the invention of dual-beam scopes, which were used during World War II to develop and service radar.
The stage was set for someone to pull the trigger...
What's the oldest scope you've ever seen? Anything we can learn from the old scopes?
I have owned several cros. The 1st one was an old american made Dumont, all valve (around 30 odd i remember), and it came complete with an enormous 240v to 110 v transformer. Of course, all the calibrations on the front panel were for american 60 hz, not our 50 hz, but that didnt matter to a 15 year old hobbyst.
I owned that cro for over 30 years and it didnt miss a beat, in fact when I donated it to a museum it still worked, althugh the timebase switches were getting a bit rough electrically, and the front stainless steel panel was showing signs of scuffing and wear around the controls. I remenber being amazed (at 15 years old) at being able to produce lissujus figures on the 5 inch scren.
I then bough a smaller audio only cro made by techtronics in the 1950's. It worked well until the power transformer lost all its smoke.
I also owned a small (3 inch) philips service scope, once again all valve. It had a transformer fault, but a small filamanet transformer fixed that.
My current scope is a 1960's design (radio tv and Hobbies), home made valve type, with a fq response to 10 mhz,and calibrated timebases. Still woks as good as the day it was made.
We have a Rigol pc type scope here at work, but it doesnt have the hands on feel of my old one. In fact it seems cold and dead, not withstanding it has markedly better specs.
>>We cannot connect a wire to optical IC in case of traditional 'Scopes.
Tektronix TDS/CSA8200 scopes have optical plugins as an option (have been available for years). Feed in the optical signal (with an optical fiber), of course internally it gets converted into an electrical signal. I'm sure Agilent and Lecroy have similar options for their high-end sampling scopes.
That would give you the capability of an analog scope with the CRT replaced by laser beams. I doubt you'd get very high sweep rates (projectors are for video displays, so MHz range, not GHz). Would make for a cool demo though!
What do you think about creating the Laser Scope? We can take pluses of old technologies combining with new's ones. For instance we can plot channels inputs with green and red beams and the grid with blue one.
There're laser picoprojectors on the market now, MEMs and solid-state devices for beam control, etc.
We can avoid expensive high-speed ADCs, signal discretization due the fact that lines will be continuous and smooth.
If think further we can add optical computing achievements.
I think still most of us have a nostalgic feels with our old scopes, especially to the first one we had used in colleges or labs. For the last 20 years with in the scope lots of changes had happened in terms of functionality and features, but the outer appearance is almost same.