[Q] : Tektronix 2240 - 300Mhz - Digitals or Analog ? - Page 1
Forum section: electronics / testgear

author: chihaxinh
author_rank: Regular Contributor
timestamp: February 18, 2016, 01:16:18 am
content: Hi everybodyI 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.htmlI concert about digital storage feature of Tektronix, and slowly display on than Analog OSC.Many thank so much !Best regardsNam Nguyen Hai

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: February 18, 2016, 07:38:48 am
content: Quote from: chihaxinh on February 18, 2016, 01:16:18 amThe Tek 2240 is an old analog scope.QuoteWhy 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?

author: oldway
author_rank: Super Contributor
timestamp: February 18, 2016, 09:17:28 am
content: Tek 2240 is a digital scope but Tek 2245A, 2246A and 2247A are 100 Mhz analog scopes.

author: chihaxinh
author_rank: Regular Contributor
timestamp: February 18, 2016, 09:33:46 am
content: Quote from: Wuerstchenhund on February 18, 2016, 07:38:48 amI using old analog convert to make tube, transistor, power mosfet cuver tracert . Digital OSC have low refresh rate

author: ebastler
author_rank: Super Contributor
timestamp: February 18, 2016, 10:14:46 am
content: 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 brochurehttp://www.millivolt.se/bilder/2246/2246%20broschure.pdfthere 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

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: February 18, 2016, 10:36:44 am
content: Quote from: oldway on February 18, 2016, 09:17:28 amAre 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.Quote from: chihaxinh on February 18, 2016, 09:33:46 amNo, 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.

author: chihaxinh
author_rank: Regular Contributor
timestamp: February 18, 2016, 01:58:59 pm
content: Hi AllI mistake when typing, my osc mode it's 2440 - 300Mhz .QuoteOh , 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 )

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: February 18, 2016, 03:05:30 pm
content: Quote from: chihaxinh on February 18, 2016, 01:58:59 pmI 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.

author: oldway
author_rank: Super Contributor
timestamp: February 18, 2016, 04:16:28 pm
content: Quote from: Wuerstchenhund on February 18, 2016, 10:36:44 amYou are right, I made a mistake, that's tek 2440 and not 2240.I wonder if 2240 has even be produced...

author: oldway
author_rank: Super Contributor
timestamp: February 18, 2016, 04:35:06 pm
content: Quote from: chihaxinh on February 18, 2016, 09:33:46 amYou 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 Philipshttp://bee.mif.pg.gda.pl/ciasteczkowypotwor/Philips/pm3233.pdf

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: February 18, 2016, 04:58:47 pm
content: Quote from: oldway on February 18, 2016, 04:35:06 pmCare to elaborate? Because I'd say the last statement is pretty much nonsense.

author: oldway
author_rank: Super Contributor
timestamp: February 18, 2016, 05:26:57 pm
content: Do you like this kind of display ? I do not.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: February 18, 2016, 08:58:35 pm
content: Quote from: oldway on February 18, 2016, 05:26:57 pmWell, don't buy Tektronix then (although X/Y isn't the only reason to not buy them), buy a proper scope. Problem solvedThere 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).

author: oldway
author_rank: Super Contributor
timestamp: February 18, 2016, 09:56:09 pm
content: 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.

author: guido
author_rank: Regular Contributor
timestamp: February 18, 2016, 10:32:21 pm
content: 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.

author: oldway
author_rank: Super Contributor
timestamp: February 18, 2016, 10:46:29 pm
content: But for sure, he don't know the price of such Iwatsu....he speak about cheap analog oscilloscope of 50$ !!!Quote

author: chihaxinh
author_rank: Regular Contributor
timestamp: February 19, 2016, 01:58:15 am
content: Hi allThank for all support ! I will finding other scope match my situation !

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: February 19, 2016, 03:43:14 pm
content: Quote from: oldway on February 18, 2016, 09:56:09 pmI 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.Quote from: guido on February 18, 2016, 10:32:21 pmIt certainly wasn't when it was new. But that's true for most analog boat anchors.QuoteYes, 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 badanalogscope. 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.

author: oldway
author_rank: Super Contributor
timestamp: February 19, 2016, 08:12:32 pm
content: Something like the Tektronix 566 Curve tracer: one of my projects.

author: chihaxinh
author_rank: Regular Contributor
timestamp: February 22, 2016, 04:17:30 am
content: Quote from: oldway on February 19, 2016, 08:12:32 pmWow, 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 ?