HP 204C

[Zenith]

From fiddling with mine, I came to the conclusion that it's a feature with window functions which produces a trace that looks a bit like an FFT display. There's not much to control it, and working out what the horizontal and vertical axes represent would be hard work or guesswork. It doesn't have the option of log scales. I had a go with it once or twice, but it never seemed to be something that would help solve any problems. Otherwise those scopes are value for money, and most of the features work well or are good enough. For instance the frequency counter feature is nowhere near as good as a dedicated frequency counter, but for a lot of things it's close enough, it's convenient, and it saves firing up a proper frequency counter.

It strikes me that it may have been something that marketing insisted should be put in, because Rigol had one, or something like that. But either the scope didn't have the resources to support it, or R&D didn't have the time to develop it properly, and it was something of a token.

[tggzzz]

No scales?! Seriously? April 1st is long gone.

That's prehistoric, or at least early 1960s. Even my 1970s and 1980s analogue spectrum analysers (Tek492, DP8562) have comprehensive readout of all the settings!

Oh well, back to using a neon bulb as a voltage reference in a DVM, and having a front panel trimpot to adjust the reading to 1.0186V, and using a crystal controlled impulse generator to calibrate the display.

I wonder how the Siglent playbook manages to spin that into an advantage over an analogue S.A.

[MED6753]

So it's basically just eye candy?

My crusty old eyeballs are better TE.

[tggzzz]

So it's basically just eye candy?

My crusty old eyeballs are better TE.

Only in the sense that, say, the HP180 with S.A. plugins is eye candy

Extra deeper understanding is needed before it can be understood.

[Zenith]

No scales?! Seriously? April 1st is long gone.

That's prehistoric, or at least early 1960s. Even my 1970s and 1980s analogue spectrum analysers (Tek492, DP8562) have comprehensive readout of all the settings!

It reminds me of those little scopes that came out in the 50s, where there wasn't much of a graticule, and if there was it didn't mean much. They weren't measuring instruments. Any kind of oscilloscope back then was a very exotic piece of test gear. They would show a signal up to a couple of MHz. They were used to tweak a waveform to more or less the right shape in a TV set and that sort of thing. I can't see the FFT feature on my SDS1102CML+ is even that useful.

Oh well, back to using a neon bulb as a voltage reference in a DVM, and having a front panel trimpot to adjust the reading to 1.0186V, and using a crystal controlled impulse generator to calibrate the display.

I wonder how the Siglent playbook manages to spin that into an advantage over an analogue S.A.

No scales I could find, no markers, no tables, very little control over what it does and not much indication of what it presents. I don't think the cursors apply to FFT.

Siglent didn't spin it very much at all. It was just there as a feature. I bought the SDS1102CML+ as a basic DSO and in that I've been pleased with it. I didn't buy it because of its FFT capabilities. I didn't take much notice of it. I wasn't gagging to use the FFT feature and was devastated when I found it was of dubious use. I've only tried to use it a few times. Siglent and Rigol make well thought of low end DSOs, they do bother to fix bugs and update their software. Their products are capable of "enhancement", which adds to the attraction.

They also both make pretty good low end to mid market digital spectrum analysers.

[Zenith]

So it's basically just eye candy?

My crusty old eyeballs are better TE.

Something they felt they could bung in, and would add to the attraction, and they could mention on the data sheets. Certainly not a well-developed feature. I don't think many reviewers caned the scopes for not having an FFT display that was up tight and outa sight. It was probably about par for the course for scopes in that price range.

[tautech]

I suppose this is much more meaningful?

To a point.... move the trigger level well within the waveform amplitude, pressing the level encoder will autoset it to 50%.

Then you could go to a FFT exclusive display and examine the menu for axis scaling and markers to place on peaks although I'm not sure if the DL models provided them.

[tggzzz]

Then you could go to a FFT exclusive display and examine the menu for axis scaling and markers to place on peaks although I'm not sure if the DL models provided them.

So modern Siglent equipment is like 1960s SAs and significantly more primitive than 1970s SAs?

Disappointing.

[MED6753]

So it appears that the only real solution is the purchase a proper hp branded spectrum analyzer. I'll put it on my "wish" list.

[tggzzz]

So it appears that the only real solution is the purchase a proper hp branded spectrum analyzer. I'll put it on my "wish" list.

I've got useful results with my Digilent Analog Discovery, which also comes with a scope, dual AWG, digital pattern generator, simple LA, plus other tools created by scripting that lot together.

Is 14-bit so decent linearity and noise floor, but is only 10MHz (conservative spec for once!)

Examples of using it: https://entertaininghacks.wordpress.com ... rrelevant/ and https://www.eevblog.com/forum/beginners ... msg5165424

[AVGresponding]

So it appears that the only real solution is the purchase a proper hp branded spectrum analyzer. I'll put it on my "wish" list.

If you let me know what your approximate budget is, I'll keep an eye out and post any appropriate ones I see in the US, in Private Marketplace

[mansaxel]

So it appears that the only real solution is the purchase a proper hp branded spectrum analyzer. I'll put it on my "wish" list.

You need at least two -- one for LF and one for RF. I've got a 8592L for the RF part, which sadly is a bit deaf. It's on one of the kitchen tables in somewhat disassembled state. I need to muster up courage to dive in to the plumbing and dig out the components for testing. 26,5 GHz bandwidth does not come simply...

I believe the hp 3582 would be a suitable model for LF work. And I'd love to have one.

Happy to help, et c.

[Zenith]

Then you could go to a FFT exclusive display and examine the menu for axis scaling and markers to place on peaks although I'm not sure if the DL models provided them.

So modern Siglent equipment is like 1960s SAs and significantly more primitive than 1970s SAs?

Disappointing.

Not at all. These fairly old Siglent introductory scopes offered an FFT facility which really wasn't up to much. I'd guess the latest cheapies they do are significantly better, the SDS800X 12 bit HD ones. The dearer ones offer a much better FFT display, but who buys a DSO for the FFT display anyway?

Their spectrum analysers are proper spectrum analysers.

I confess to being a Siglent fanboy.

[tggzzz]

Then you could go to a FFT exclusive display and examine the menu for axis scaling and markers to place on peaks although I'm not sure if the DL models provided them.

So modern Siglent equipment is like 1960s SAs and significantly more primitive than 1970s SAs?

Disappointing.

Not at all. These fairly old Siglent introductory scopes offered an FFT facility which really wasn't up to much. I'd guess the latest cheapies they do are significantly better, the SDS800X 12 bit HD ones. The dearer ones offer a much better FFT display, but who buys a DSO for the FFT display anyway?

Their spectrum analysers are proper spectrum analysers.

I confess to being a Siglent fanboy.

I prefer devices/shops/people to do one thing well rather that two things poorly. Half-arsed things just wastage everybody''s time and money. Hence I dislike toasters with a built-in swiss army knife, and food shops with a sideline in computer accessories.

The Digilent Analog Discovery is an example of how to do digitise+postprocess well; all the tools were excellent fro the start, and have been improved.

[Zenith]

There are all sorts of features it's easy to add to a DSO, such as voltage readings of various sorts. They are useful because you are often interested in voltage levels on a scope and they save you squinting at the display and fiddling about to refer to the scales. They are not as accurate as a cheap DMM, but that's not what they are there for.

The FFT function on cheap Siglent scopes seems particularly ropy. It's so bad I wonder why they bothered. It looks to be a lot better on low end Rigol scopes such as the very popular Rigol DS1054Z - four channels, 50MHz.

Thrown in features which are slightly useful apply to a lot of things, such as the frequency, capacitance and temperature ranges on DMMs. I've rarely ever used them. I'm sure some people think they are great.

[tggzzz]

There are all sorts of features it's easy to add to a DSO, such as voltage readings of various sorts. They are useful because you are often interested in voltage levels on a scope and they save you squinting at the display and fiddling about to refer to the scales. They are not as accurate as a cheap DMM, but that's not what they are there for.

The FFT function on cheap Siglent scopes seems particularly ropy. It's so bad I wonder why they bothered. It looks to be a lot better on low end Rigol scopes such as the very popular Rigol DS1054Z - four channels, 50MHz.

That's the point about that scope's FFT: it is not sufficient to be useful.

Thrown in features which are slightly useful apply to a lot of things, such as the frequency, capacitance and temperature ranges on DMMs. I've rarely ever used them. I'm sure some people think they are great.

Provided those functions meet the spec, are usable, and don't get in the way of "normal" operation, I agree.

If the capacitance meter etc didn't indicate the range, it would be useless.

[tautech]

That's the point about that scope's FFT: it is not sufficient to be useful.

That may have once been the case and for the old SDS1052DL Mike has I would agree due to its very limited feature set.

1 MHz 0dBm via a 50 Ohm feedthrough into SDS814X HD
Notice how many cycles provide far better FFT's.

ScreenImg (72).png

ScreenImg (73).png

ScreenImg (74).png

[Zenith]

The SDS1000 DL, CML and CML+, must have been introduced a long time ago. 15 years back or so. They were introductory models. You can certainly argue that it was poor judgement to include an FFT feature that was basically useless.

The recently introduced SDS800X HD series look like the oscilloscope bargain of the age. I'm not surprised they have a much better worked out and useful FFT capability.

[tggzzz]

That's the point about that scope's FFT: it is not sufficient to be useful.

That may have once been the case and for the old SDS1052DL Mike has I would agree due to its very limited feature set.

The SDS1000 DL, CML and CML+, must have been introduced a long time ago. 15 years back or so. They were introductory models. You can certainly argue that it was poor judgement to include an FFT feature that was basically useless.

The recently introduced SDS800X HD series look like the oscilloscope bargain of the age. I'm not surprised they have a much better worked out and useful FFT capability.

It is rare[1] that newer equipment is worse than existing equipment, of course.

It was poor judgement to say the least. Such highly visible poor judgement can colour marketplace perceptions for a long time ("bad then, why should I expect it to be good now" or "I'm not going to risk my job by being a guinea pig")

[1] but not unknown, e.g. digitising scopes of the 80s and 90s vs contemporary analogue scopes, except when looking at one-off events. Since the 90s the improved capabilities of ADCs and DACs has been nothing less than stunning.

[Zenith]

It is rare[1] that newer equipment is worse than existing equipment, of course.

It was poor judgement to say the least. Such highly visible poor judgement can colour marketplace perceptions for a long time ("bad then, why should I expect it to be good now" or "I'm not going to risk my job by being a guinea pig")

[1] but not unknown, e.g. digitising scopes of the 80s and 90s vs contemporary analogue scopes, except when looking at one-off events. Since the 90s the improved capabilities of ADCs and DACs has been nothing less than stunning.

Analogue storage scopes were a nightmare and best avoided unless you absolutely had to capture one off events. A lot of people didn't like digital scopes and found them alien and confusing.

I don't think this was a highly visible deal breaker. I'd looked at the FFT feature in the course of exploring what the scope could do, and found it wasn't much good, but that's not why I bought the scope, and when I was buying it, I never considered FFT, much less comparing the FFT facilities of similar priced scopes. Med doesn't seem to have used it on his scope in the years he's had it. I've never heard much discussion of the FFT capabilities of that class of scope.

There are a lot of curious decisions taken with some pieces of test equipment. For instance the popular Feeltech function generators included a rubbish frequency counter which I never saw as much use. They have a sweep function, but it doesn't have a trigger output, so there's no straightforward way to sync the sweep. There are BNC connectors on the back for various other functions I've never seen much point to.

[tggzzz]

It is rare[1] that newer equipment is worse than existing equipment, of course.

It was poor judgement to say the least. Such highly visible poor judgement can colour marketplace perceptions for a long time ("bad then, why should I expect it to be good now" or "I'm not going to risk my job by being a guinea pig")

[1] but not unknown, e.g. digitising scopes of the 80s and 90s vs contemporary analogue scopes, except when looking at one-off events. Since the 90s the improved capabilities of ADCs and DACs has been nothing less than stunning.

Analogue storage scopes were a nightmare and best avoided unless you absolutely had to capture one off events. A lot of people didn't like digital scopes and found them alien and confusing.

I've never liked ASOs, but having said that the Telequipment DM63 is quite nice, but slow. The Tek DM464 ASO was a pain, but fast.

The 468 DSO was a 465B plus 10MHz DSO based on a "proper" ADC so slow. However that did something the later Tek's DSO based on CCDs couldn't do: display the envelope of an AM waveform and hence - I guess - a TV signal.

Now ADCs have caught up, the issue is moot.

I don't think this was a highly visible deal breaker. I'd looked at the FFT feature in the course of exploring what the scope could do, and found it wasn't much good, but that's not why I bought the scope, and when I was buying it, I never considered FFT, much less comparing the FFT facilities of similar priced scopes. Med doesn't seem to have used it on his scope in the years he's had it. I've never heard much discussion of the FFT capabilities of that class of scope.

There are a lot of curious decisions taken with some pieces of test equipment. For instance the popular Feeltech function generators included a rubbish frequency counter which I never saw as much use. They have a sweep function, but it doesn't have a trigger output, so there's no straightforward way to sync the sweep. There are BNC connectors on the back for various other functions I've never seen much point to.

There's probably a reason nobody discussed that FFT Personally I'd be suspicious of any 8-bit DSO, especially since the low end ones are probably only 6 ENOB.

[tautech]

Med doesn't seem to have used it on his scope in the years he's had it.

IMO it's been his sanity check when fixing stuff although he prefers to use a CRO.
There's no doubt he got it for its advanced features of which it has few other than being a capture tool....it's a 15yr old design comparable with the TDS200 series.

In my game understanding what a tool is to be purchased for is key for the customer not to be disappointed.
These days with the great additional capability available we can point buyers to model ranges with complete confidence it will serve a wide range of needs.

It's not until you get out and about seeing what some backyard dudes are doing with our gear that you really get a feeling why they settled on a brand, any brand for their development projects.
Can't say much more due to the NDA's signed recently.....

[tggzzz]

Fitness for purpose is key. That requires an understanding of the purpose.

Nonetheless, even if a user knows their purpose, matching the two requires someone who knows the equipment.

• with cheap equipment, it can be discarded if no good
• with expensive equipment, a salesman can spend time with a customer
• and then there is the uncanny valley in between: neither throwaway nor sufficient profit

For a non-professional or for a small company, a lot of equipment falls into the last category, and can result in significant disappointment. Being able to point to successes in some circumstances does not balance disappointments in others.

Much better if X does what it does well, and doesn't entice people with false delusion of adequacy in others.

[MED6753]

When I got back into the hobby 15 or so years ago DSO's were completely foreign to me. I had never seen nor used one. So once I got myself acclimated and current with the latest tech I decided to dip my feet in the shallow end of the pool and buy a low end model. I've learned to use it and I see the advantages of a DSO vs analog but typically I still grab for the analog because that's what I know best. Do I see myself upgrading to the latest gee whiz DSO? Not in the immediate future. But I do try to stay current with the latest releases and features.

[Zenith]

I bought the SDS1102CML+ pre-Covid, maybe 2018. It's small and neat and it's the one I've reached for. There a few things it doesn't do, such as serial decoding, and the channel 2 trace is a dark blue, which made it hard to see, so I've just bought a better one. I never had to use the FFT facility for anything serious. I experimented with it and thought it was crude.

That scope was money well spent, and I've had a lot of use out of it.