On the flipside to all the "worrying about digital scopes" remember we're talking an Keysight (gonna hit specs) 50 MHz scope (even oscillations aren't going to be challenging the bandwidth!). Derating by 5x still gives you a lot to work with. We're not talking <1 MHz jobs from the 80's anymore, nor the beginner hobby level tools. This is a nice instrument that will handle whatever he can build for analog (and i2s protocol, DAC sidebands) audio electronics. It's not high speed communication, nor can you buy a new analog scope.
The other recommendations are good stuff.
Make sure your probes are good enough to handle the bandwidth, too. Hopefully it came with the system.
The other recommendations are good stuff.
Make sure your probes are good enough to handle the bandwidth, too. Hopefully it came with the system.
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That's an awesome CRO Bix and a really good investment - there's nothing better than being able to just see what you're doing straight up.
While this can be said for some of the earlier digital CROs, the newer units with faster sampling and better triggering really isn't any different to using an analogue CRO. I guess I'm biased, as I've spent pretty much my entire career using a range of digital CROs, and only rarely have used an analogue one.
Many years ago the organisation I worked for bought a really high zoot-factor (at the time) HP 54100A 1GHz bandwidth CRO. We mounted it in a rack in the laser room to use for aligning the cavity, as it was the only instrument that we had that was fast enough to see the ps pulses coming out of the laser.
It was the first HP CRO I'd ever used, and I got to really, seriously hate it. We called it the "one knob wonder", because basically everything was done by selecting menus from buttons on the side of the screen and then spinning the one knob. To add insult to injury the screen phosphor was a pretty good match for our laser safety goggles, so we could barely see the screen. You'd hear howls of rage come from the laser room if anyone fiddled with the settings, 'cos we all hated driving it.
Fast forward ten years from there and I'm shopping for CROs for work - from memory I was after something that could do 2-3 GHz with a decent sample rate and gobs of memory - around $100K of kit once you include the probes, so we did the work in choosing the best instrument we could get for the dough. We ended up buying a LeCroy (I really like LeCroy CROs), but we gave all the sales droids a hard time - insisting that the instrument needs "a knob that makes each input bigger and littler, one that moves it up and down on the screen, another knob that makes things wider and narrower, and one that moves things left and right". They were a bit taken aback, because they were primed to sell based on bandwidth and math and advanced triggering stuff. We wanted something that was fast enough to display the signals we needed to see, and useable enough so we wouldn't waste time trying to use the bloody thing.
I guess we weren't the only ones making such demands, as most all decent CROs these days have just that - they've come to the realisation that people don't just buy instruments based on speed, but on useability as well.
While this can be said for some of the earlier digital CROs, the newer units with faster sampling and better triggering really isn't any different to using an analogue CRO. I guess I'm biased, as I've spent pretty much my entire career using a range of digital CROs, and only rarely have used an analogue one.
Many years ago the organisation I worked for bought a really high zoot-factor (at the time) HP 54100A 1GHz bandwidth CRO. We mounted it in a rack in the laser room to use for aligning the cavity, as it was the only instrument that we had that was fast enough to see the ps pulses coming out of the laser.
It was the first HP CRO I'd ever used, and I got to really, seriously hate it. We called it the "one knob wonder", because basically everything was done by selecting menus from buttons on the side of the screen and then spinning the one knob. To add insult to injury the screen phosphor was a pretty good match for our laser safety goggles, so we could barely see the screen. You'd hear howls of rage come from the laser room if anyone fiddled with the settings, 'cos we all hated driving it.
Fast forward ten years from there and I'm shopping for CROs for work - from memory I was after something that could do 2-3 GHz with a decent sample rate and gobs of memory - around $100K of kit once you include the probes, so we did the work in choosing the best instrument we could get for the dough. We ended up buying a LeCroy (I really like LeCroy CROs), but we gave all the sales droids a hard time - insisting that the instrument needs "a knob that makes each input bigger and littler, one that moves it up and down on the screen, another knob that makes things wider and narrower, and one that moves things left and right". They were a bit taken aback, because they were primed to sell based on bandwidth and math and advanced triggering stuff. We wanted something that was fast enough to display the signals we needed to see, and useable enough so we wouldn't waste time trying to use the bloody thing.
I guess we weren't the only ones making such demands, as most all decent CROs these days have just that - they've come to the realisation that people don't just buy instruments based on speed, but on useability as well.
Hi Suzy,
I've been going to various equipment demos and workshops put on by the various companies for years. I can see why you would have hated that particular scope.
However, for the past while the Agilent / Keysight 'scopes have been the easiest to use from my perspective. Right now I'm using an Agilent 54642D 500 MHz MSO. I use it for almost everything - except for eye patterns. Here an old analog scope still does a better job. Looking at the newer products in the line, I could use just a digital 'scope. The analog Philips still has a better trace for eye patterns. My Tek 2465B is too fuzzy by comparison. The old HP 1722A is stellar. Not bad for a product from 1974 (275 MHz!).
I'll say that all new products are better to use. My least favorite DSO / MSO would be Tektronix products, Keysight the best and everything else falling in between. I like the LeCroy products too, but the Keysight really does it for me. It's a far cry from the instrument you learned to hate.
Mind you, whoever decided on that scope for your laser application made a wrong choice either in location, eye protection and 'scope type. You were trying to use a lab scope as a monitoring instrument. That's like trying to use a Keysight 3458A meter for a service bench. An application owned by the 34401A and now newer versions. The 3458A has no equal, but it is a lab meter and operates like one. I wouldn't be surprised if that 'scope you used had different phosphor options for the CRT.
Cheers, Chris
I've been going to various equipment demos and workshops put on by the various companies for years. I can see why you would have hated that particular scope.
However, for the past while the Agilent / Keysight 'scopes have been the easiest to use from my perspective. Right now I'm using an Agilent 54642D 500 MHz MSO. I use it for almost everything - except for eye patterns. Here an old analog scope still does a better job. Looking at the newer products in the line, I could use just a digital 'scope. The analog Philips still has a better trace for eye patterns. My Tek 2465B is too fuzzy by comparison. The old HP 1722A is stellar. Not bad for a product from 1974 (275 MHz!).
I'll say that all new products are better to use. My least favorite DSO / MSO would be Tektronix products, Keysight the best and everything else falling in between. I like the LeCroy products too, but the Keysight really does it for me. It's a far cry from the instrument you learned to hate.
Mind you, whoever decided on that scope for your laser application made a wrong choice either in location, eye protection and 'scope type. You were trying to use a lab scope as a monitoring instrument. That's like trying to use a Keysight 3458A meter for a service bench. An application owned by the 34401A and now newer versions. The 3458A has no equal, but it is a lab meter and operates like one. I wouldn't be surprised if that 'scope you used had different phosphor options for the CRT.
Cheers, Chris
Hi Daniel,
Yes, I did say that the analog bandwidth is more than wide enough (as it is on my Agilent). The 5 : 1 ratio suggested is to maintain waveform fidelity assuming that you are not looking at a sine wave. I think it's a valid safety precaution.
I've not fed an overband signal into one of these, so I don't know what it will do with aliasing. Would it reject the above band signal? Would be nice, but it is far better to test it and make absolutely sure. Instruments are great until they start lying to you.
-Chris
Yes, I did say that the analog bandwidth is more than wide enough (as it is on my Agilent). The 5 : 1 ratio suggested is to maintain waveform fidelity assuming that you are not looking at a sine wave. I think it's a valid safety precaution.
I've not fed an overband signal into one of these, so I don't know what it will do with aliasing. Would it reject the above band signal? Would be nice, but it is far better to test it and make absolutely sure. Instruments are great until they start lying to you.
-Chris
Loved that story about the HP54100D, a very long time ago I owned one of its predecessors, the HP54100A.
It was great for looking at digital stuff, but not nearly as good with analog signals repetitive or not. One knob to rule everything turned out to be inconvenient, but the scope was not well suited to my needs in general.
Quantization noise was rather visible on sine waves and triangle test signals which I used extensively at the time, it was very good for displaying pulses and square waves, establishing timing relationships, etc. (Good for looking at synchronous data buses). Not the sort of uses to which I put it for the most part.
I ended up regretting the purchase immensely, but the story has a happy ending as I managed to sell it on eBay for somewhat more than I paid for it. (Covered all my original purchasing and shipping costs)
My Tek TBS1052 is much better for analog than that old scope, but I still keep a 2245A around for the odd job.
It was great for looking at digital stuff, but not nearly as good with analog signals repetitive or not. One knob to rule everything turned out to be inconvenient, but the scope was not well suited to my needs in general.
Quantization noise was rather visible on sine waves and triangle test signals which I used extensively at the time, it was very good for displaying pulses and square waves, establishing timing relationships, etc. (Good for looking at synchronous data buses). Not the sort of uses to which I put it for the most part.
I ended up regretting the purchase immensely, but the story has a happy ending as I managed to sell it on eBay for somewhat more than I paid for it. (Covered all my original purchasing and shipping costs)
My Tek TBS1052 is much better for analog than that old scope, but I still keep a 2245A around for the odd job.
Yeah, my current work CRO is a Keysight MSO7104B, which is a real joy to use. Straightforward knobs for everything, easy to set up triggering, easy to capture data etc. I use it as a pseudo logic analyser as much as anything, and it's pretty good at that.
Agreed about the Tek stuff - whereas in my younger years it was pretty-much Tek or go home, now they've slipped pretty badly - IME their newer CROs tend to be underpowered and annoying.
That said though, their old stuff is great - both analog (I've got a couple of 465's that still get dug out at work very occasionally) and digital (my home CRO is a TDS340A, 100MHz of goodness).
Thanks everybody for the wonderful feedback and interesting stories. I have to say I do enjoy turning the knobs and finding the signal, loads of fun. There’s also a convenient “auto scale” button which really helps when I’m totally off track.
Which happens a lot as I’m still wrapping my head around calculating a voltage devider common emitter circuit. I manage to get them going eventually but only after tweaking the Vcc and input signal Vpp. This is where the scope saves the day. It seems I’m always off by around 1 - 2 volts Vcc.
Any suggestions for the beginner friendly method for calculating, would be appreciated. Thanks gang, you’re all great
Which happens a lot as I’m still wrapping my head around calculating a voltage devider common emitter circuit. I manage to get them going eventually but only after tweaking the Vcc and input signal Vpp. This is where the scope saves the day. It seems I’m always off by around 1 - 2 volts Vcc.
Any suggestions for the beginner friendly method for calculating, would be appreciated. Thanks gang, you’re all great
We would have to see the circuit to see what it is you are trying to calculate
Thank you, here is the latest circuit.
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It’s seems that my calculations work but I have to raise the Vcc by 1 - 2 volts.
The circuit I posted works at 9 Vcc but the input range is 300 - 550 mV. I’m trying to work out how to raise the input voltage without it clipping. Simple beginner mistakes, No formal training, just a desire to learn.
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Approx. calculations with assumed Ib ~ 0
I * R2 = 1.825V
I = 1.825V / 15000 = 0.000122A
Also
I = Vcc / (R1 + R2)
R1 + R2 = Vcc / I
R2 = Vcc / I - R1
R2 = 9V / 0.000122A - 15000ohm
R2 = 58770 ohm (the closest standard value is 56k)
Next
(Vcc - Vc) / Rc = Ve / Re
Rc = (Vcc - Vc) * Re / Ve
Rc = (9V - 4.5V) * 1125ohm / 1.125V
Rc = 4.5 * 1000ohm = 4500ohm (closest standard value 4k7)
I guess OK res values for Vcc = 9V would be:
R1 = 56k
R2 = 15k
Re = 1k2
Rc = 3k9
I * R2 = 1.825V
I = 1.825V / 15000 = 0.000122A
Also
I = Vcc / (R1 + R2)
R1 + R2 = Vcc / I
R2 = Vcc / I - R1
R2 = 9V / 0.000122A - 15000ohm
R2 = 58770 ohm (the closest standard value is 56k)
Next
(Vcc - Vc) / Rc = Ve / Re
Rc = (Vcc - Vc) * Re / Ve
Rc = (9V - 4.5V) * 1125ohm / 1.125V
Rc = 4.5 * 1000ohm = 4500ohm (closest standard value 4k7)
I guess OK res values for Vcc = 9V would be:
R1 = 56k
R2 = 15k
Re = 1k2
Rc = 3k9
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@Bix experimenting is much easier on a breadboard (eg PJRC Store). You simply pin-down the parts. Every reasonable hobby electronic store has it. Highly recommended.
Hi Bix,
Ah yes, "the button" can do wonders for getting a setup that is close to what you need. It doesn't generally do well for looking at RF envelopes as it will opt to show you the high frequency sine wave.
That oscilloscope you have will probably last you a lifetime, and it's features are reasonably complete for any scope in that classification. I'll have to check one of those out because it seems they might make keeping an analogue scope handy is less important.
I don't know if you can upgrade that one to an MSO or not. The MSO, or Mixed Signal Oscilloscope has multiple digital inputs, like mine. The one I use has 16 channels of digital input. Yours might have 8 or 16, I can't remember much about that option on the entry level 'scopes. Suffice to say, you have bought yourself a blue chip type instrument. Highly useful and very reliable.
Analogue measurements. Your voltage readings should be pretty close. I think it uses an 8 bit word to determine the voltages. Early analogue scopes were not very accurate, maybe 2% for the best ones, like a Tektronix 2465A or B, or the 465's. Your scope is accurate enough for most measurements. Look up the voltage measuring accuracy in your manual. Please post it as I'd like to know as well as many others here.
Now it's time to enjoy your hobby.
Ah yes, "the button" can do wonders for getting a setup that is close to what you need. It doesn't generally do well for looking at RF envelopes as it will opt to show you the high frequency sine wave.
That oscilloscope you have will probably last you a lifetime, and it's features are reasonably complete for any scope in that classification. I'll have to check one of those out because it seems they might make keeping an analogue scope handy is less important.
I don't know if you can upgrade that one to an MSO or not. The MSO, or Mixed Signal Oscilloscope has multiple digital inputs, like mine. The one I use has 16 channels of digital input. Yours might have 8 or 16, I can't remember much about that option on the entry level 'scopes. Suffice to say, you have bought yourself a blue chip type instrument. Highly useful and very reliable.
Analogue measurements. Your voltage readings should be pretty close. I think it uses an 8 bit word to determine the voltages. Early analogue scopes were not very accurate, maybe 2% for the best ones, like a Tektronix 2465A or B, or the 465's. Your scope is accurate enough for most measurements. Look up the voltage measuring accuracy in your manual. Please post it as I'd like to know as well as many others here.
Now it's time to enjoy your hobby.
Yep I’m a happy Chappy, very lucky to have this scope.
Heres a screenshot from the spec sheet.
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