Help with Oscilloscope

[Ultimate Dev'r]

Okay, I have an (ancient) Tectronix 2335 100 MHz Oscilloscope. I'm trying to make it display something similar to this with two signals: **broken link removed**

 

[zevon8]

I'm not sure I really understand your question, but I think all the settings you need for your older Tek scope are shown on the menus at the right side of the picture.

Trigger: falling ( negative slope )
Source: External, ( channel A )
Auto triggering
DC Coupling
5 volts per division
25uS time base.

With a bit of trigger adjustment ( take the scope off of Auto trigger ) you should see the same thing, except the waveforms will likely start at the first falling edge of the upper waveform.

By the way, the scope I use most often is older than your 2335, it's a 2235, militarized version. Digital is great, but does have its limitations sometimes too.

 

[Ultimate Dev'r]

Yes, thank you for your help. I also looked around elsewhere on this forum, and found out some good information. I guess the only question I have now is how to make the lines stop zipping across the screen. I've been able to slow them down, but I'd like to know if there's a setting to freeze frame or something like that.

 

[Nigel Goodwin]

Yes, thank you for your help. I also looked around elsewhere on this forum, and found out some good information. I guess the only question I have now is how to make the lines stop zipping across the screen. I've been able to slow them down, but I'd like to know if there's a setting to freeze frame or something like that.

Only if it's a storage scope, a conventional analogue scope can't do that.

 

[atferrari]

If both signals are repetitive...

...and sinchronized - the chanel 1 pulse sinchronic with the channel 2 pulse above, given a frequency that the oscilloscope can handle, the image should be stable, I think.

Just in case, trigger should be through chanel 1 signal.

Am I right?

Agustín Tomás

 

[Ultimate Dev'r]

About how much does a storage scope run for?

 

[jrz126]

broken ones (some faults, but they still function) can run for upwards of 400.

 

[Ultimate Dev'r]

:shock: :shock: :shock: What about the cheap end of storage scopes?

 

[jrz126]

There is no cheap end...I was lucky enough to find my storage scope in a junk room at work. they charged me a whopping $0.25 / lb. I paid $6.75 for it
and they also have a really sweet 4 channel LCD type scope sitting there. goes for about $3,000 on ebay. but they are keeping it for parts

 

[Nigel Goodwin]

:shock: :shock: :shock: What about the cheap end of storage scopes?

They don't have a 'cheap' end.

There are basically two types:

1) Analogue storage scopes - old scopes, these use a special tube, able to store the image on the screen - VERY expensive!.

2) Digital storage scopes - anything remotely modern, these digitise the signal and store it in digital memory, it's then played back on some kind of display - usually either CRT or LCD.

You can get 'cheap' PC scopes, which use a PC as the display device, but they still aren't very cheap!, and performance isn't great.

What exactly are you trying to read?, you can download free scope software for PC's that uses the sound card as the input device, giving a 'free' low spec storage scope.

 

[Ultimate Dev'r]

I'm using it for timing on SNES controllers and PIC I/O lines.

 

[Nigel Goodwin]

I'm using it for timing on SNES controllers and PIC I/O lines.

Assuming it's only low audio frequencies?, the sound card scopes would probably be good enough!.

 

[Ultimate Dev'r]

But will it be able to freeze frames? I havn't seen that setting on any of them yet.

 

[CoTang]

Depending on how fast you want as a sampling rate. Go with a USB oscilloscope for around $150US ish. Check out HVWTECH.com or HWVTECH.com.....hmmm one of them anyways.

 

[Nigel Goodwin]

But will it be able to freeze frames? I havn't seen that setting on any of them yet.

I've never played with one, but I would expect them all to?, it's a very trivial facility with the way they work.

 

[Ultimate Dev'r]

Well, I got my Dad to help me, and he showed me how to get it to stop on my oscilloscope. Apparently there was a hidden setting I didn't know about, and he learned years ago. One of those old tips you learn from old folks

 

[evandude]

Nigel, unless you are using some additional hardware and fancy software... PC sound-card based scopes can't handle DC voltages, since the input to the soundcard is ac-coupled...

 

[Nigel Goodwin]

Nigel, unless you are using some additional hardware and fancy software... PC sound-card based scopes can't handle DC voltages, since the input to the soundcard is ac-coupled...

Quite true, but I never suggested they could!.

As for Ultimate Dev'r, what is this "old tip you learn from old folks ", I'm an "old folk" (at least oldish) - I can only assume you have a storage scope, and he showed you how to operate it?.

 

[Ultimate Dev'r]

No; I have a really, really old oscilloscope, and he just told me to set the source to ext. and to set the VAR knob precisly in order to get the signal to stop moving.

 

[Nigel Goodwin]

No; I have a really, really old oscilloscope, and he just told me to set the source to ext. and to set the VAR knob precisly in order to get the signal to stop moving.

Right, so the signal is repetative?, so you can simply lock the scope to it, and see the screen refreshed by the identical images.

From your description, and the screen shot, I presumed it was a 'one off' signal, like many remote controls put out.