[Q] : Tektronix 2240 - 300Mhz - Digitals or Analog ?

[chihaxinh]

Hi everybody

I have 1 question , tektronix 2240 - 300Mhz BW it's Digitals or Analog OSC ? I really need OSC analog like Iwattsu SS-7800P series.

https://www.iti.iwatsu.co.jp/en/products/ss/ss7811ap_e.html

I concert about digital storage feature of Tektronix, and slowly display on than Analog OSC.

Many thank so much !

Best regards
Nam Nguyen Hai

[Wuerstchenhund]

I have 1 question , tektronix 2240 - 300Mhz BW it's Digitals or Analog OSC ?

The Tek 2240 is an old analog scope.

I really need OSC analog like Iwattsu SS-7800P series.

https://www.iti.iwatsu.co.jp/en/products/ss/ss7811ap_e.html

Why the hell would you want an analog boat anchor like the old SS-7800P in this day and age?

Analog scopes have pretty much been dead for many years, and that is for a reason.

What exactly do you want to achieve?

[oldway]

Tek 2240 is a digital scope but Tek 2245A, 2246A and 2247A are 100 Mhz analog scopes.

[chihaxinh]

I have 1 question , tektronix 2240 - 300Mhz BW it's Digitals or Analog OSC ?

The Tek 2240 is an old analog scope.

I really need OSC analog like Iwattsu SS-7800P series.

https://www.iti.iwatsu.co.jp/en/products/ss/ss7811ap_e.html

Why the hell would you want an analog boat anchor like the old SS-7800P in this day and age?

Analog scopes have pretty much been dead for many years, and that is for a reason.

What exactly do you want to achieve?

I using old analog convert to make tube, transistor, power mosfet cuver tracert   . Digital OSC have low  refresh rate

[ebastler]

I won't join the discussion on the pro's and con's of analog vs. digital scopes for your use case... But maybe can help sort out the contradictions about the "Tek 2240" scope in the posts above:

There is a "2240 series" of Tek scopes, although not including a model number 2240 to my knowledge. These are analog scopes. But according to this brochure http://www.millivolt.se/bilder/2246/2246%20broschure.pdf there is no 300 MHz model; all models have 100 MHz bandwidth.

Tek also had a model 2440, which is a digital scope with 300 MHz bandwidth. Maybe you got the model number wrong in your initial post? http://www.usedmeter.com/en/pro/2440.html

[Wuerstchenhund]

Tek 2240 is a digital scope but Tek 2245A, 2246A and 2247A are 100 Mhz analog scopes.

Are you sure? The Tek 2440 was a 300Mhz digital scope, pretty much an old sampling scope with a very low sample rate of 500MSa/s which is not enough to capture a 300MHz signal in realtime.

Why the hell would you want an analog boat anchor like the old SS-7800P in this day and age?

Analog scopes have pretty much been dead for many years, and that is for a reason.

What exactly do you want to achieve?

I using old analog convert to make tube, transistor, power mosfet cuver tracert   . Digital OSC have low  refresh rate

No, they haven't. It's just your particular scope that has a low update rate.

These old Tek digital scopes are some 30yrs old, they are early generation digital scopes and of course they are slow like hell. That doesn't mean that all digital scopes are or that technology has not changed in the last three decades.

Why don't you use something that hasn't obsolete for decades? It might well make your job easier.

[chihaxinh]

Hi All

I mistake when typing, my osc mode it's 2440 - 300Mhz .

No, they haven't. It's just your particular scope that has a low update rate.

These old Tek digital scopes are some 30yrs old, they are early generation digital scopes and of course they are slow like hell. That doesn't mean that all digital scopes are or that technology has not changed in the last three decades.

Why don't you use something that hasn't obsolete for decades? It might well make your job easier.

Oh , in my country finding old Analog analog easy than Digital OSC and very cheap , around 50$ for like new . So i thing Tek 2440 not good choice in situation . So sad (very very slow )

[Wuerstchenhund]

Oh , in my country finding old Analog analog easy than Digital OSC and very cheap , around 50$ for like new . So i thing Tek 2440 not good choice in situation . So sad (very very slow )

I don't know what your country is (you can set your country in your profile which helps people to give you more appropriate advice) and what your budget is but you can get a decent digital scope (i.e. Rigol DS1054z) for less than $400, and something like the Siglent SDS1072CML/CNL can often be had around $300.

$50 for an analog scope sounds cheap but it's still some 30yrs old and very limited in what it can do. It's generally more sensible to not spend the $50 or so for an antique and rather save for something better instead.

[oldway]

Tek 2240 is a digital scope but Tek 2245A, 2246A and 2247A are 100 Mhz analog scopes.

Are you sure? The Tek 2440 was a 300Mhz digital scope, pretty much an old sampling scope with a very low sample rate of 500MSa/s which is not enough to capture a 300MHz signal in realtime.

You are right, I made a mistake, that's tek 2440 and not 2240.
I wonder if 2240 has even be produced...

[oldway]

What exactly do you want to achieve?

I using old analog convert to make tube, transistor, power mosfet cuver tracert   . Digital OSC have low  refresh rate

You will have to use your scope in XY function, DSO are not that good for this use.
My choice for this purpose is a low bandwith analog scope with long decay phosphor crt (P7).

NB: with a 2 beams crt, you can display curves of 2 devices (transist, diodes, vacuum tubes, ...) at the same time.
For exemple, PM3233 Philips
http://bee.mif.pg.gda.pl/ciasteczkowypotwor/Philips/pm3233.pdf

[Wuerstchenhund]

You will have to use your scope in XY function, DSO are not that good for this use.

Care to elaborate? Because I'd say the last statement is pretty much nonsense.

[oldway]

Do you like this kind of display ? I do not. 

[Wuerstchenhund]

Do you like this kind of display ? I do not. 

Well, don't buy Tektronix then (although X/Y isn't the only reason to not buy them), buy a proper scope. Problem solved 

There are many scopes which do X/Y better than a Tek DSO. And some scopes like the R&S RTM even do X/Y/Z (yes, brightness modulation).

[oldway]

chihaxinh only want a cheap scope to make a curve tracer like a tektronix 576 or 577.
No need of an expansive R§S DSO to do this.

[guido]

The mentioned iwatsu ain't cheap. It is no old boatanchor either. Very nice scopes and relatively modern. Production only ceased a few years ago.

[oldway]

But for sure, he don't know the price of such Iwatsu....he speak about cheap analog oscilloscope of 50$ !!!

Oh , in my country finding old Analog analog easy than Digital OSC and very cheap , around 50$ for like new .

[chihaxinh]

Hi all

Thank for all support ! I will finding other scope match my situation ! 

[Wuerstchenhund]

chihaxinh only want a cheap scope to make a curve tracer like a tektronix 576 or 577.
No need of an expansive R§S DSO to do this.

I didn't say he needs an expensive DSO for that. I'm sure even an el-cheapo Rigol delivers decent enough X/Y for a curve tracer. In fact, even one of the old HP 54600 DSOs with MegaZoom ASIC from the mid-'90s will probably do a better job at X/Y, and these scopes often go for little money.

My simple point was just because the Tek sux at X/Y doesn't mean all DSOs do, contrary to your statement.

The mentioned iwatsu ain't cheap.

It certainly wasn't when it was new. But that's true for most analog boat anchors.

It is no old boatanchor either. Very nice scopes and relatively modern. Production only ceased a few years ago.

Yes, it's a newer analog scope with microprocessor controls which came out in the mid-'90s and which Iwatsu kept in their portfolio in various stages of refresh (A, AP) until 2011 or so, and I'm not saying it's a bad analog scope. But at the end of the day it's still an analog scope, and suffers from pretty much all of the shortcomings an analog scope has over a decent DSO. Iwatsu pretty much only had them for certain (japanese) customers that required a programmable analog scope for some of their ATEs.

Apparently there are still companies that make analog scopes (GW Instek, Atten). That doesn't mean buying an analog scope in this day and age is a good investment.

[oldway]

Something like the Tektronix 566 Curve tracer: one of my projects.

[chihaxinh]

Something like the Tektronix 566 Curve tracer: one of my projects.

Wow, can you share complate project ! I see in your transformer using 2x18 or 2x20V 1A , so if in low current , how to check power mosfet like irfp240 ?