Recommendation Request - NEW Rigol DS1054Z or USED Tektronix 2467BHD

[vk6zgo]

Either the Waverunner is "making heavy weather"  resolving the burst & horizontal sync pulse,or the originator of this video picked a particularly poor example of a video signal.

I think the idea was to present looking at a poor video signal, but yes the video isn't great.

There's another one:



At the end of the day the idea of WaveStream was to provide a mode that looks and feels "analog" like. Nothing more. I can't say I've ever felt the need to use it, though.

Yes,I guess they were in a "no win" situation.
If they used a "copybook" waveform out of a TV Studio,people would blame the LeCroy when the signal out of their 30 year old VCR didn't look the same!
After years in TV Broadcasting,I'm just hypercritical!

The "jitter" test looks good,though I agree with you that the "Wavestream" feature doesn't really add much functionality.

[xrunner]

Can you still hack the DS1054 to 100 MHz? I wasn't sure if they had blocked that or not. The DS1074 is only about $66 more, but if the 1054 can still be hacked I'll buy that one. Thanks. 

[c4757p]

Yeah, I just did my brand new one a couple days ago. Nothing blocked.

[vk6zgo]

Next try, this time I did even pay attention to the timebase settings 

Again, source is a R&S CRTU-RU at 100MHz modulated at 1kHz AM 50%. The scope is a provisionally assembled LeCroy WaveRunner 64Xi, and since the CRTU-RU has no Mod out it's triggered from the input signal.

These screenshots show the signal in Persistence (intensity graded) mode at 500MS/s and 1GS/s:



https://www.eevblog.com/forum/testgear/recommendation-request-new-rigol-ds1054z-or-used-tektronix-2467bhd/?action=dlattach;attach=180776;image


And this is what it looks like in Normal mode:

At 2GSa/s:




And at 500MSa/s:




Anyways, as it was said above that's a pretty synthetic test for a digital scope which is unlikely to matter in a practical sense.

Yes,you are very unlikely to come across an Amplitude Modulated 100MHz signal "in the wild",except in the Aeronautical service,which is a pretty specialised & highly regulated area,where "just looking at the envelope" would only be a rough check.

I have looked at TV modulation envelopes at VHF,but it is again,hardly a definitive test.

In any case,the only thing you are likely to be interested in is the envelope amplitude  & to a lesser extent, shape,to determine modulation percentage,& fairly roughly,distortion.

How the RF is "drawn in" doesn't really matter for these applications--a little featheriness of the envelope "line" can be worked around.

For AM MF Broadcasting,around 1MHz or so,where this test is more likely to be used,the DSO display would show no such artifacts.

 On HF,"plain old AM" pretty much tops out around 30MHz--SSB is far more common for other than Short Wave Broadcasting,even in the lower range.

[Wuerstchenhund]

Yes,I guess they were in a "no win" situation.
If they used a "copybook" waveform out of a TV Studio,people would blame the LeCroy when the signal out of their 30 year old VCR didn't look the same!

Actually, I wouldn't be surprised if someone at LeCroy just said "hey, on the way to work I found that old VCR at the curb. Lets do some a video". They didn't really seem to have any strategy for doing these videos at that time.

After years in TV Broadcasting,I'm just hypercritical!

Well, I can imagine that spec compliance is a big think in public broadcasting. Also nothing wrong with being a bit hypercritical (better than a "good enough" attitude).

The "jitter" test looks good,though I agree with you that the "Wavestream" feature doesn't really add much functionality.

Yes, I see it mostly as a nod to the "analog forever" crowd. When I did the tests at 1ms/div WaveStream didn't even produce anything useful.

It also seems to be gone from their current scopes so I guess it didn't really catch on.

[Rupunzell]

Signals with close in side bands such as AM does matter for more than a few analog folks. It is one of the reasons why some old analog geezers stick with a crt based time domain instrument over any DSO. This most basic example also points to how different some analog folks use a time domain instrument compared to digital-data centric folks do.

Common test signal types such as sine. triangle, square, pulse and such are not always the case for analog stuff. If the instrument display is full of test signal related artifacts, more often than not, it would render the data displayed mostly useless due to questions of what is real and what is not.

Absolute precision of measured data might not matter nearly as much as that digital stuff (timing measurement accuracy, instant rise-fall time, frequency, amplitude and...) as what cam matter more in analog systems or circuit behavior over a broad range of test parameters since one is dealing with a lot more states than on or off.

As for that LeCroy real time "Jitter" test, there are better ways to achieve this. Active real time information display such as this can reveal rate information relative to a fixed wave form transition edge giving clues as to what could be the cause of the displayed jitter.  This could be the reason why the LeCroy folks offered it as a feature, except the majority of users had not idea of how to get useful information from this feature.


Bernice

Anyways, as it was said above that's a pretty synthetic test for a digital scope which is unlikely to matter in a practical sense.

Yes,you are very unlikely to come across an Amplitude Modulated 100MHz signal "in the wild",except in the Aeronautical service,which is a pretty specialised & highly regulated area,where "just looking at the envelope" would only be a rough check.

I have looked at TV modulation envelopes at VHF,but it is again,hardly a definitive test.

In any case,the only thing you are likely to be interested in is the envelope amplitude  & to a lesser extent, shape,to determine modulation percentage,& fairly roughly,distortion.

How the RF is "drawn in" doesn't really matter for these applications--a little featheriness of the envelope "line" can be worked around.

For AM MF Broadcasting,around 1MHz or so,where this test is more likely to be used,the DSO display would show no such artifacts.

 On HF,"plain old AM" pretty much tops out around 30MHz--SSB is far more common for other than Short Wave Broadcasting,even in the lower range.
[/quote]

[Howardlong]

Yes,you are very unlikely to come across an Amplitude Modulated 100MHz signal "in the wild",except in the Aeronautical service,which is a pretty specialised & highly regulated area,where "just looking at the envelope" would only be a rough check.

When ever I've looked at civilian NAV/COM equipment (from 108MHz to 137MHz) it has never occurred to me to even attempt to look at the RF with a scope, I use a comms test set and spectrum analyser, plus a VOR/ILS baseband generator with an RF signal generator. I'm not sure what the point is of looking at the RF on a scope would be, but I'm happy to be educated! At AF/baseband and IF a scope is certainly of value.

[vk6zgo]

Yes,you are very unlikely to come across an Amplitude Modulated 100MHz signal "in the wild",except in the Aeronautical service,which is a pretty specialised & highly regulated area,where "just looking at the envelope" would only be a rough check.

When ever I've looked at civilian NAV/COM equipment (from 108MHz to 137MHz) it has never occurred to me to even attempt to look at the RF with a scope, I use a comms test set and spectrum analyser, plus a VOR/ILS baseband generator with an RF signal generator. I'm not sure what the point is of looking at the RF on a scope would be, but I'm happy to be educated! At AF/baseband and IF a scope is certainly of value.

Sometimes,you have to "just run what you brung".
We had a strange problem with an NEC FM broadcast Transmitter.

This Tx had a FET PA driving a big tetrode in common cathode configuration.
There was an output meter on the FET PA,to show the drive to the tetrode control grid tuned circuit.

Using the time honoured "peak the grid & dip the anode" tuning method,we found a seemingly ridiculous situation where more grid drive on the meter caused lower output power.

The FET PA had an adjacent monitor point,so,as it was to hand,I grabbed the 200MHz Iwatsu 'scope & looked at that point.
The problem was immediately obvious----a horrible,peaky waveform,with a high second harmonic component.
The FET PA output meter was a "peak & hold " type----higher peaks from the distorted waveform looked like more grid drive.

All that second harmonic power was suppressed in the anode tuned circuit--hence less transmitter output power!
From then on,we tuned "for maximum smoke"instead!

We had a 7L12 in a Tek 7000 mainframe,so  could have used that,but it was hard to get to the monitor point,& I wasn't quite as familiar with the 7L12 as I later became.

In any case,the time domain display gave an immediate insight into the problem.

Apart from that,I had very little occasion to look at VHF RF signals in the time domain.

If your 'scope will do it,it is a very quick way of checking modulation percentage of AM transmitters,but this is mostly done in the MF & HF case.

I feel it is a very savage test of a DSO,asking it to display frequency components with a ratio of 100,000:1.

Looking back,though,we condemned early DSOs because they aliased their hearts out when trying to display
2 fields of PAL video ---that was a ratio of 200,000:1!

[AF6LJ]

The Tek is a much nicer instrument. It is like buying an older Mercedes va. a new Hyundai...

No, it's nothing like that.
There is a huge fundamental difference between analog and digital scopes. One allows you to single shot capture waveforms, the other does not. One of them literally lets you work easily on any type of signal in any scenario, the other does not.
It's like comparing a car that only goes in a straight line and can't stop, to one that has steering and brakes.

So tell me;
What do you do when the Rigol fails and needs fixed.
Do they provide service information?
Do they provide a way for it to be calibrated without sending it back to China?
Do they sell replacement parts to people who (like myself) have the skill to repair it?

Now for the final question; why would I buy a scope I couldn't fix myself or send it out locally for calibration??

[Rupunzell]

Sine wave modulated AM does not reveal all that could be happening.

Gigatronics 1018 synthesizer at 1Ghz, hp 3326A synthesizer at 9Khz square wave driving the Gigatronics 1018 AM mod input.

Tek 7104, 7A26, 7B15, 7B10.

Square wave driving the AM modulator reveals the step response of this synthesizer:



Switching over to pulse modulation (1Ghz carrier), Tek 2102 Pulse generator driving the Gigatronics Pulse mod input also reveals the step response of the pulse modulator. The cable reflections can be seen on the monitoring trace on top.


Frequency domain of the same, 75Mhz span:


At 17.5 Mhz span:


At 4.26 Mhz span:


Step response of the pulse modulator not so easy to interpret from frequency domain.
Precise shape of the modulation envelop shape provides good information of modulator step response. If there are artifacts due to the data conversion process (DSO) what would the results be, how much resolution and can the presented information be trusted?


Bernice









 

[AF6LJ]

Sine wave modulated AM does not reveal all that could be happening.

Gigatronics 1018 synthesizer at 1Ghz, hp 3326A synthesizer at 9Khz square wave driving the Gigatronics 1018 AM mod input.

Tek 7104, 7A26, 7B15, 7B10.

Square wave driving the AM modulator reveals the step response of this synthesizer:



Switching over to pulse modulation (1Ghz carrier), Tek 2102 Pulse generator driving the Gigatronics Pulse mod input also reveals the step response of the pulse modulator. The cable reflections can be seen on the monitoring trace on top.


Frequency domain of the same, 75Mhz span:


At 17.5 Mhz span:


At 4.26 Mhz span:


Step response of the pulse modulator not so easy to interpret from frequency domain.
Precise shape of the modulation envelop shape provides good information of modulator step response. If there are artifacts due to the data conversion process (DSO) what would the results be, how much resolution and can the presented information be trusted?


Bernice

Well done; I am not convinced that the lower end DSOs are the be-all and End-all.
Perhaps it is just me, but I think not. One RF lab I visit on a regular basis has a number of analogue Tek 400 and 7000 series scopes and a couple of Tek DSOs collecting dust except for the times when they are used for digital troubleshooting tasks.

[xrunner]

Yeah, I just did my brand new one a couple days ago. Nothing blocked.

Well I got it ordered and should be here this Friday. This will be a real treat for me 'cause I've had a Hitachi V-212 since 1985. I plan to spend the weekend in Nirvana. 

[vk6zgo]

Sine wave modulated AM does not reveal all that could be happening.

Gigatronics 1018 synthesizer at 1Ghz, hp 3326A synthesizer at 9Khz square wave driving the Gigatronics 1018 AM mod input.

Tek 7104, 7A26, 7B15, 7B10.

Square wave driving the AM modulator reveals the step response of this synthesizer:



Switching over to pulse modulation (1Ghz carrier), Tek 2102 Pulse generator driving the Gigatronics Pulse mod input also reveals the step response of the pulse modulator. The cable reflections can be seen on the monitoring trace on top.


Frequency domain of the same, 75Mhz span:


At 17.5 Mhz span:


At 4.26 Mhz span:


Step response of the pulse modulator not so easy to interpret from frequency domain.
Precise shape of the modulation envelop shape provides good information of modulator step response. If there are artifacts due to the data conversion process (DSO) what would the results be, how much resolution and can the presented information be trusted?


Bernice

I agree,Bernice.

The time domain display is more immediately intuitive than the frequency domain.
(This was definitely the case with  the FM Tx problem I referred to in reply #82)

Having seen the former,you have a reasonable idea what is happening in the latter,& can select the correct settings on the SA.

Most of us don't have 'scopes with the capabilities of yours,so if we want to get an idea of the modulator step response have to use a "Precision detector" of some kind to look at the baseband demodulated signal,(introducing another device into the test,with it's own possible errors).

In analog TV,we formerly used a DSB detector,or more recently,a precision receiver to look at such things,but obviously not quite as high in frequency.

For higher frequencies we are usually pretty much stuck with the frequency domain.

[smbaker]

What do you do when the Rigol fails and needs fixed.

It's a sub-$400 piece of equipment. In the unlikely event that mine fails before it becomes obsolete and I'm unable to repair it, then it would get recycled and replaced. In that respect it's no different than my dvd player or my computer monitor.

As a practical matter, if I can't fix my Rigol myself and it's out of warranty, I'd probably ship it to Dave. It'd be worth the shipping cost to see what he does with it.

[AF6LJ]

What do you do when the Rigol fails and needs fixed.

It's a sub-$400 piece of equipment. In the unlikely event that mine fails before it becomes obsolete and I'm unable to repair it, then it would get recycled and replaced. In that respect it's no different than my dvd player or my computer monitor.

As a practical matter, if I can't fix my Rigol myself and it's out of warranty, I'd probably ship it to Dave. It'd be worth the shipping cost to see what he does with it.

Seems wasteful to me to build something that a company has no intention of providing a means to repair it.
But...
That is just me. 

[Rupunzell]

Point of all this is to illustrate digitizing artifacts can and do happen and might be of significance to measurements required. Knowing what can happen due to instrumentation is very relevant to the measurement required.

Back in a time when video was analog, some video systems did push slightly past the Nyquist limit to achieve a recovered BW slight more than the Nyquist limit using double pulse type discriminators and fancy dancy filters. There was a price to pay for doing this, but the overall results remained acceptable.

The more common way and technique to measure microwave pulse modulator rise-fall time and shape is to use a biased detector. These can produce accurate pulse response time of less than 10nS. The common RF detector has a baked in filter network and detector diode response that is impedance dependent far more than a biased detector.

While the Tek 7104 performed admirably in these examples, It would be a total and utter failure at measurements involving many modern data systems as it is simply not design for that requirement.

There are DSOs today that perform well into the 30Ghz range allowing more possibilities of using time domain instruments well into the microwave region of the EM spectrum. Yet, for the vast majority of RF and microwave work, a frequency domain instrument is often more useful in many ways.

This is all very much an issue of knowing what to use, when to use and how to get the very most from instrumentation.

There are so many excellent choices for instrumentation on the used market today. Many absolutely state of the art items of instrumentation from the past can be had for a tiny fraction of their original cost-value. Current market value for many of these classic instrumentation creations is driven by market demand and the needs of current-modern technology. Items like NTSC-PAL-SECAM signal generators, monitors, vectorscopes and such are now a low demand item. Items such as precision power supplies appear to have an on-going demand due to the basic nature of how power supplies are used.



Bernice

I agree,Bernice.

The time domain display is more immediately intuitive than the frequency domain.
(This was definitely the case with  the FM Tx problem I referred to in reply #82)

Having seen the former,you have a reasonable idea what is happening in the latter,& can select the correct settings on the SA.

Most of us don't have 'scopes with the capabilities of yours,so if we want to get an idea of the modulator step response have to use a "Precision detector" of some kind to look at the baseband demodulated signal,(introducing another device into the test,with it's own possible errors).

In analog TV,we formerly used a DSB detector,or more recently,a precision receiver to look at such things,but obviously not quite as high in frequency.

For higher frequencies we are usually pretty much stuck with the frequency domain.

[smbaker]

Seems wasteful to me to build something that a company has no intention of providing a means to repair it.

That's true of consumer electronics in general though. They're often intended to be thrown away rather than repaired. It's a shame, but I've come to expect it, especially with lower price equipment.

Unless I abuse my DS1054Z, I don't really expect anything to go wrong with it during the time period where it's not obsolete.

[nfmax]

Seems wasteful to me to build something that a company has no intention of providing a means to repair it.

Unless I abuse my DS1054Z, I don't really expect anything to go wrong with it during the time period where it's not obsolete.

I didn't expect anything to go wrong with my Agilent DSO1014A during the time period when it wasn't obsolete, either. That didn't stop the PSU failing less than one year out of warranty, which is 'beyond economic repair'. I'm working on it when I get time https://www.eevblog.com/forum/repair/only-just-out-of-warranty-agilent-dso1014a/ - there is no service information whatsoever available.
I guess you might be lucky, you might not. Is it possible to insure against failure (at a reasonable cost)? Do Rigol offer extended warranties?

[smbaker]

Do Rigol offer extended warranties?

Maybe this is just me, but I'm not the type of person who buys extended warranties. Whenever the guy at the Best Buy tells me I need an extended warranty for my new TV, I figure he's just trying to make extra money insuring against a very unlikely occurrence. Is it a gamble? Yes.

[Rupunzell]

This is what the world of tech has become after the profit driven CEO's, MBA's, share holders and more have done after their take-over of the T&M industry. Turned it into a universe of disposable, non serviceable, feature driven consumable.

This is not the way it once was, but today has become a requirement due to the easy availability of low cost manufacturing in China-Asia and else where. Add to this, the marketing of older is never desirable or worthy to keep permeates the majority of user ideology.

Instrumentation once were designed, built and intended to be completely serviceable, have long life times, designed to the very limits of technology and be well supported by it's manufacture and produce a reasonable profit for the organization company that produced them.

This business model and user mind-set is mostly gone today. This is the same way MBAs, CEO's share holders and all treat their employees, equally disposable once aged beyond their best by date.

It is curious to note some vintage technology items have become collectable which has driven their market value up significantly.



Bernice

Do Rigol offer extended warranties?

Maybe this is just me, but I'm not the type of person who buys extended warranties. Whenever the guy at the Best Buy tells me I need an extended warranty for my new TV, I figure he's just trying to make extra money insuring against a very unlikely occurrence. Is it a gamble? Yes.

[AF6LJ]

Seems wasteful to me to build something that a company has no intention of providing a means to repair it.

That's true of consumer electronics in general though. They're often intended to be thrown away rather than repaired. It's a shame, but I've come to expect it, especially with lower price equipment.

Unless I abuse my DS1054Z, I don't really expect anything to go wrong with it during the time period where it's not obsolete.

I have had a lot of experience with electronics of all types and things fail, it doesn't matter if it is a Sony Walkman or a 1,000,000 ion implanter. Someone must fix it or throw it out. I've seen brand new HP spectrum analyzers fail within a month after their warranty period expired. Modern test equipment is built not to be repaired, toss it out and buy another one... This is a waste of resources as much as waging war over stupid political ideas is.

[smbaker]

Instrumentation once were designed, built and intended to be completely serviceable, have long life times, designed to the very limits of technology and be well supported by it's manufacture and produce a reasonable profit for the organization company that produced them.

Ultimately, I think it comes down to what consumers want. If our goals are Serviceable, Featureful, and Cheap, we can get at most two of those.

It is curious to note some vintage technology items have become collectable which has driven their market value up significantly.

I love vintage equipment. It's fun. It's nostalgic. It's usually well built. Just turning the knobs you can feel the quality.

When it comes down to it though, the measurement capability of a modern DSO is just too advantageous to me not to prefer that equipment. I have an analog scope, but it hasn't been taken out of the box since I bought my first DSO (an 1052E).

If I could justify a more expensive more quality scope than the 1054Z (preferably something where the damn selector knob doesn't skip), then I would. I made a practical decision to optimize for the most bang for the buck, and assume the risk that it may not be practical to repair it if there's a failure.

This is a waste of resources as much as waging war over stupid political ideas is.

Sure it's a waste of resources, but who do we blame? Consumers are buying DS1054Z scopes, myself included. We've made the decision to optimize for price and features, rather than optimize for serviceability.

[AF6LJ]

Sure it's a waste of resources, but who do we blame? Consumers are buying DS1054Z scopes, myself included. We've made the decision to optimize for price and features, rather than optimize for serviceability.

Do what you have to do; I am not here to change your mind simply to shed light on the problem. I suppose if you use all the features that is good.

[Wuerstchenhund]

I have had a lot of experience with electronics of all types and things fail, it doesn't matter if it is a Sony Walkman or a 1,000,000 ion implanter. Someone must fix it or throw it out. I've seen brand new HP spectrum analyzers fail within a month after their warranty period expired.

This. I've also seen my fair share of very expensive instruments dying shortly after or even when still in warranty. Every complex product can fail. The questions is what happens then.

Modern test equipment is built not to be repaired

That is probably true for cheap Chinese B-brand kit like the gear from Rigol and Siglent but most big brand gear (aside from the cheap bottom-of-the-barrel stuff) definitely is designed for repair. What has changed however is how the repair is performed. In the old days, components were replaced in the field, but due to the much higher integration these days it's mostly module/board swaps where at the customer site the defective module/board is replaced, and the defective board goes back to the manufacturer for repair and thorough testing, and afterwards ends up in storage waiting to be used as a spare in another customer's instrument. Alternatively, in many cases the defective board can be sent in for repair, which might be cheaper but takes longer than the onsite replacement (often a defective instrument can be brought up again in less than an hour).

[AF6LJ]

Agreed.