what an oscilloscope recommended for a woman passionate about electronics?

[borjam]

Yesterday i discovered another bug in our Rigol: I had setup the screen with infinite persistence to discover rare signal errors (missing pulse) and by chance some serial decoding was active (without on-screen result). Bug: No persistence at all in that configuration. I kept the scope running all night waiting for error records, to no avail. As soon as i turned off that decoder, i had the first exception record after 40 seconds. Then i used the missing pulse trigger to get a nice and clean image. That worked well..

I know that almost all oscilloscopes have bugs, from what you read ... oh well they are not too frequent 

Complex software always has bugs. And modern digital oscilloscopes do a lot of stuff. Even the very best brands must release firmware updates to address errors. Nothing new

[CharlotteSwiss]

Complex software always has bugs. And modern digital oscilloscopes do a lot of stuff. Even the very best brands must release firmware updates to address errors. Nothing new

of course; I see that the latest firmware dates back to 2019, I hope they can solve this key bug, half the time touches disconnect the instrument from the network to reset ..

------------------

meanwhile, I solved the failure of my friend's sound card, in this case using only a multimeter, moreover with the oscilloscope I am too new .. but now that the card sounds and is on the bare bench, I can experience the input and out signals of the 4 channels of the sta540 amplifier; it will be like going to school 

[dietert1]

When we got our DS2202E (new), there immediately was a software update to be installed. Apparently they shipped half ready scopes to gain time for development work.
2 or 3 months after we got the DS2202E i tried to get technical support from Rigol. Nothing. It's not included. That's why they are cheaper. No other software update appeared for several years, so that's it.

Some months later i bought a pre-owned Lecroy and i remember some phone calls. So there was somebody to talk to. Rigol has more expensive models, too. I won't try whether they support those better. I think they deserve this rant.

Regards, Dieter

[rstofer]

There are at least 3 kinds of failures:

• Design error or omission - the device was never designed to have a particular capability or the final design is deficient
• Bug - the device was intended to have some particular capability but it is deficient
• User error - the device does do what it was intended to do, just not the way the user tried to do it

Bugs can be fixed with firmware upgrades, design errors seldom can.  There is no hope for user errors, they will continue indefinitely.

The Rigol DS1054Z has had several iterations of firmware upgrades but they were fairly quick to push them out.  Within a couple of years of its introduction, all the legitimate bugs were removed.  The driving force was the fact that, at the time, Rigol OWNED the entry level scope market and they were selling thousands of units per week (I watched the inventory levels at TEquipment at the time) and if they wanted to retain that position, they had to respond.  And they did...

There have been comments over in the Test Equipment forum about Siglent being slow to respond with firmware upgrades and just due to the fact that the SDS1202X-E is newer on the market, it can be expected to still have some issues.  We'll just have to wait and see how they respond.

Some of the 'bugs' are at the edges of operation where I never go.  If it doesn't affect me, I don't care when they fix it.

I wouldn't necessarily want to be the test case for firmware upgrades.  If I didn't have a problem, I wouldn't install an upgrade to fix it.

[rstofer]

Signal generation...  Won't this guy ever dial it back...

Earlier I linked to some cheap waveform generators and they will do fine.  Even earlier I recommended the Arduino for the same task and, when it comes to things like PWM or serial streams, most waveform generators can't do it anyway.

But let's talk about one of the nicest features of these DSOs and that is 'protocol decoding'.  True, this is only important if you are working with computers and microcontrollers but that's a pretty big arena.  There are 3 primary protocols that an Arduino or Raspberry Pi can easily generate:  UART serial, SPI and I2C.  CAN is an important protocol but it usually takes a much more capable processor.

So, if you think in terms of Arduino for signal generation, you can practice decoding for free.  With PWM, you can measure Frequency, Period, Duty Cycle, Rise Time, Fall Time and a host of other parameters.

The Arduino UNO (fake) is about $13 on Amazon.  The Starter Kits from ELEGOO are excellent and the tutorials are WELL documented.  I have several kits because I wanted to play with GPIO on a Pi 4.  Real Arduino UNOs are about $23.  I go for the real ones just to support the cause.

https://www.amazon.com/s?k=arduino+uno+r3

It's early times with the scope but, sooner or later, you're going to need real signals and there are a lot of ways to get them.  I do digital so I would head toward the Arduino approach.

Just wait until you see how many Measurements these scopes can make.  User Manual page 139, PDF page 154 kicks it off.  These scopes are amazing!

It is going to be hard to find a more versatile signal source than the Arduino for less than $13.  The 555 timer is a good place to start but it runs out of capability pretty quick.  For certain, it won't generate a serial stream.  It is, however, a flexible source of square waves.

[tautech]

The 555 timer is a good place to start but it runs out of capability pretty quick.  For certain, it won't generate a serial stream.  It is, however, a flexible source of square waves.

Very true however for the newbie a 555 timer is almost a right of passage. A lot can be learnt from just probing around it.
tggzzz IIRC suggested it earlier.

[Neomys Sapiens]

Why should you dabble with an arduino? Match your oscilloscope with a decent function generator. Which I would advise you to aquire in a different way. (I saw your thread only when the result was already done).
If you are really intending to improvise, you could convince me to offer you a XR2206 or ICL8038. But of a perfboard they won't shine - to build a decent function generator out of them you should look for a design with a PCB available.

[Gyro]

Why should you dabble with an arduino? Match your oscilloscope with a decent function generator. Which I would advise you to aquire in a different way. (I saw your thread only when the result was already done).

At what point would you advise the OP to actually start build something? Or should she just buy bits of test gear to look at with other bits of test gear?

[rstofer]

The 555 'right of passage' went out the window back in the '80s but it might be worth a few minutes to watch the RC charge and discharge curves.  There are niche' applications where the 555 shines.

For some reason, I like watching the square wave change duty cycle when I put some PWM code (which I don't have to write) into an Arduino.  I like being able to use a pot to change the duty cycle of the PWM.

I have a terrific Siglent SDG2082X Arbitrary Waveform Generator but it won't let me play with protocol decoding.  The only reason I bought the DS1054Z was 4 channels and protocol decoding of SPI.  Of course I'm going to want to play with decoding from time to time.

I don't have any use for pure sine waves although the Siglent produces a very nice output.  Anything that came out of the Arduino and was passed through a low pass filter would be good enough.  I don't do audio so THD is kind of meaningless, to me.  The Internet is full of Arduino signal generator projects, some quite involved, others quite simple.  In fact, the Arduino output even without the low pass filter would be interesting.  Actually, more interesting.  To me...

But buying a high end AWG, equivalent iin quality to the scope, is something that can be put off for a very long time.

The OP's interest at the moment is troubleshooting and that's fine.  It might be helpful to play with known signals first.

[Neomys Sapiens]

Why should you dabble with an arduino? Match your oscilloscope with a decent function generator. Which I would advise you to aquire in a different way. (I saw your thread only when the result was already done).

At what point would you advise the OP to actually start build something? Or should she just buy bits of test gear to look at with other bits of test gear?

That is why I mentioned those chips. So the question is unneccessary.

[rstofer]

Here's an old thread on AWGs:

https://www.eevblog.com/forum/chat/a-valentine_s-day-activity-for-your-scope-and-function-generator/msg1136847/#msg1136847

The requirement is for 2 channels with a fundamental frequency plus the 2d, 4th, 6th and 8th harmonics added in at various voltages and phases.  The result is a Valentine's Day heart shape on a scope using X-Y mode.

Now that's an AWG!  Check Tautech's Reply #4 for a screen shot.  Or watch the linked video.

Some of the AWGs are quite sophisticated.  They can wait for a later date.

[tautech]

I have a terrific Siglent SDG2082X Arbitrary Waveform Generator but it won't let me play with protocol decoding. 

Do you mean protocol generation ?

Some stuff in this thread that might get you there:
https://www.eevblog.com/forum/testgear/siglent-sdg1025-matlab-programming-arb-waveform/

I guess the protocol scripts can be entered into EasyWaveX then uploaded into your SDG via a direct connection or USB stick.

[CharlotteSwiss]

When we got our DS2202E (new), there immediately was a software update to be installed. Apparently they shipped half ready scopes to gain time for development work.
2 or 3 months after we got the DS2202E i tried to get technical support from Rigol. Nothing. It's not included. That's why they are cheaper. No other software update appeared for several years, so that's it.

Some months later i bought a pre-owned Lecroy and i remember some phone calls. So there was somebody to talk to. Rigol has more expensive models, too. I won't try whether they support those better. I think they deserve this rant.

Regards, Dieter

you did well to tell this thing, customers must be a fundamental part of a company, and be treated with merit!
 

There have been comments over in the Test Equipment forum about Siglent being slow to respond with firmware upgrades and just due to the fact that the SDS1202X-E is newer on the market, it can be expected to still have some issues.  We'll just have to wait and see how they respond.

Some of the 'bugs' are at the edges of operation where I never go.  If it doesn't affect me, I don't care when they fix it.

I wouldn't necessarily want to be the test case for firmware upgrades.  If I didn't have a problem, I wouldn't install an upgrade to fix it.

I must point out that I have experienced it a little for now, but the problem with the key came immediately, quite frequently. Then maybe with a certain brand and size of usb stick it wouldn't happen. I have 3 of keys, it happened with all .. Then for heaven's sake I won't use this tool every day, so it won't be a problem for me.

But let's talk about one of the nicest features of these DSOs and that is 'protocol decoding'.  True, this is only important if you are working with computers and microcontrollers but that's a pretty big arena.  There are 3 primary protocols that an Arduino or Raspberry Pi can easily generate:  UART serial, SPI and I2C.  CAN is an important protocol but it usually takes a much more capable processor.
So, if you think in terms of Arduino for signal generation, you can practice decoding for free.  With PWM, you can measure Frequency, Period, Duty Cycle, Rise Time, Fall Time and a host of other parameters.
The Arduino UNO (fake) is about $13 on Amazon.  The Starter Kits from ELEGOO are excellent and the tutorials are WELL documented.  I have several kits because I wanted to play with GPIO on a Pi 4.  Real Arduino UNOs are about $23.  I go for the real ones just to support the cause.
https://www.amazon.com/s?k=arduino+uno+r3
It's early times with the scope but, sooner or later, you're going to need real signals and there are a lot of ways to get them.  I do digital so I would head toward the Arduino approach.
Just wait until you see how many Measurements these scopes can make.  User Manual page 139, PDF page 154 kicks it off.  These scopes are amazing!
It is going to be hard to find a more versatile signal source than the Arduino for less than $13.  The 555 timer is a good place to start but it runs out of capability pretty quick.  For certain, it won't generate a serial stream.  It is, however, a flexible source of square waves.

I leafed through the manual on the fly and actually does a lot of things a dso. I will get there calmly, some are complex for me. Meanwhile, I am going to order. In my recent successful repair (it happens 1 time out of 100  ), I was still bitter with an oscilloscope, it was there on the table together with the multimeters and bench power supply .. but I bypassed it: I am convinced that it would have given me a lot of useful information for example on the dual / quad power amplifier, which a multimeter cannot give. However, I used it to see the DC power supply voltage of the board (classic low cost 12vdc switching power supply), or set a vertical div of 100mv and I could see that it was quite stable, some light waves but never more than 50mv. I liked to observe this thing, even if at the beginning I didn't find the signal on the display, obviously the left marker was at -12v .. and I was lost in space
If I had a sinusoidal signal generator I would have used it already, to see the quality of the satellite L and R output signal and to the subwoofer (I will try with the signal generated online for this time)
I believe that to learn all the qualities of these DSOs, they can be exceptional companions.

I admit that Arduino interests me, it also costs very little; as soon as I free my head from the bases of the siglent, I start to look better at this product, to understand if it could be a good companion for me .. (not only to generate signals ..)
thanks rstofer 

Why should you dabble with an arduino? Match your oscilloscope with a decent function generator. Which I would advise you to aquire in a different way. (I saw your thread only when the result was already done).

also the arduino generates signals doesn't it? 
basic signals will suffice for me, I don't do anything complex, for the signal generator I would have no idea of spending too much for now
thanks for the contribution 

 

[StillTrying]

I have 3 of keys, it happened with all ..

Before you give up have you tried copying all the important data off one of the memory sticks and freshly reformatting it.

[CharlotteSwiss]

Before you give up have you tried copying all the important data off one of the memory sticks and freshly reformatting it.

I honestly didn't format the sticks. I don't keep data on the stick. I also do this test, format fat32 ..
thank you for your suggestion
 

[CharlotteSwiss]

I made the first measurements on external signals (not the internal oscilloscope) so out of curiosity on a sound card that I repaired and now it sounds again (stall audio system, low cost ..)
I report only the left channel
Signal generated online - 1khz - sinusoid
Measurements detected in auto set (I only had to set HFr, otherwise as previously written it reported a bogus frequency from the signal generated online by the pc)

Card input signal (basically the quality of the signal generated by the PC ..)


Sta540 amplifier input signal


Output signal from the sta540 amplifier


Beginner considerations:
a) I also note that I am poor    that the PC's audio signal is then considerably improved as noise from the circuit board
b) you can clearly notice the gain of the signal between the amplifier input and output.
c) I left the probe on the measuring point about 1 minute, the wave has always been stable on the display, so I imagine that the audio  channel works well
d) I did not understand one thing: in the input signal of the board the car set generated the wave with the exact zero volt marker in the center.
While in the two amplifier input and output signals, it is seen that the left zero volt marker is always lower than the wave (in one case 616mv and in the other 5.48v)
is the car set wrong? the zero volt of a sinusoidal voltage should be in the center of the wave.
Where's the mistake? in my head maybe?
thanks,
bye

[StillTrying]

While in the two amplifier input and output signals, it is seen that the left zero volt marker is always lower than the wave (in one case 616mv and in the other 5.48v) is the car set wrong? the zero volt of a sinusoidal voltage should be in the center of the wave.

If its supply is 0V and +12V the mid level of +5.48V DC directly on the outputs is probably correct.

Study the STA540 data sheet,   to see where the DC has to be blocked by caps.

You don't need 200 MHz of BW to see see audio frequencies, switching CH1's 20 MHz BW Limit on would give slightly cleaner waveforms.

[CharlotteSwiss]

If its supply is 0V and +12V the mid level of +5.48V DC directly on the outputs is probably correct.
Study the STA540 data sheet,   to see where the DC has to be blocked by caps.

the power supply of the sta540 on pins 3 and 13 is 12.2vdc. I looked at the sta540 pdf many times to solve the problem that the card did not sound (stby signal problem), it sounds good (for what you can expect from a system that costs like a pizza and beer), my curiosity, saw the purchase of the oscilloscope was to try to see some new signal 
There are 4 outputs in this system (2 towards satellites, and two towards the subwoofer).
But isn't the audio output signal AC? why are you talking about DC? aren't they on different paths?
I have to think about it, I also expected the waves of IN and out sta540 with the classic 0v in the center sine wave ..

it is clear that my room in the forum will be this for a long time, the outside is full of rooms only for expert people (nerds). A minimum nerd I also feel, not for the competence though ..

thank you for your suggestion
 

[StillTrying]

"There are 4 outputs in this system (2 towards satellites, and two towards the subwoofer)."

There should be 2 caps on the satellite's outputs then, like the last pic I posted and maybe none on the subwoofer outputs, it's a mix of the 2nd and 3rd diagram.

If you probe the IC side of the 2200uF caps you should see approx. 6V +/- 2v, if you probe the speaker side of the 2200uF you should see the expected 0V +/- 2V.
www.electricaltechnology.org/2019/10/why-capacitor-block-dc-pass-ac.html

[CharlotteSwiss]

"There are 4 outputs in this system (2 towards satellites, and two towards the subwoofer)."

There should be 2 caps on the satellite's outputs then, like the last pic I posted and maybe none on the subwoofer outputs, it's a mix of the 2nd and 3rd diagram.

If you probe the IC side of the 2200uF caps you should see approx. 6V +/- 2v, if you probe the speaker side of the 2200uF you should see the expected 0V +/- 2V.
www.electricaltechnology.org/2019/10/why-capacitor-block-dc-pass-ac.html

thanks for link, now I understood what capacitors are used here on the amplifier outputs
considering only the outputs 1 and 2 out to the two satellites R and L, it is true that there are two capacitors, however they are 470.
I don't understand why they have mssi from 470uf, in fig.4 ok they have that capacity, but if you use only one capacitor for both channels.
If I remember correctly, however, I put the probe after the condenser, at the channel output there is a special Tp (I guess test point?) And not on the output pin of the sta 540.
So the signal should already be cleaned by the capacitor.
Unfortunately I made the audio device to my friend and I can't do any other checks, too bad it was a nice way to learn with the oscilloscope.

An image:
red pin out1 sta540 - green 470uf capacitor - yellow wire to satellite - white point where I put the probe


The repair went well, but my interest is precisely to understand that signal that I captured with the probe coming out towards the satellite
 

[CharlotteSwiss]

before mounting the card in the device, I had tried out of curiosity to measure with two probes the two outputs to the satellites
Nice story 



This measurement of the R channel together with the L channel, I measured it on the pins of the sta540 (therefore before the capacitors) as I would not then have had my free hand to press print
So this double signal is first, while the one above the L channel should (I think) be with the tip of the probe on tp12, then after the capacitor. I have to compare them ...

I see that the two channels have the signal exactly in the opposite phase

[StillTrying]

I see that the two channels have the signal exactly in the opposite phase

If you look at the internal block diagram every other channel is inverting, so that you can use it in a 2 channel no-capacitor bridged speaker mode.
The data sheet does mention that if you're using amp1 and amp2 as 2 stereo channels or 2 satellites you have to reverse the connections to one of the speakers to undo the signal inversion.

[CharlotteSwiss]

If you look at the internal block diagram every other channel is inverting, so that you can use it in a 2 channel no-capacitor bridged speaker mode.
The data sheet does mention that if you're using amp1 and amp2 as 2 stereo channels or 2 satellites you have to reverse the connections to one of the speakers to undo the signal inversion.

thanks still,
now I have seen: signal 1 goes to the amplifier +, while signal 2 goes to the amplifier - (this is inverse).
My yellow probe was on reverse channel 2.

I see that both waves of the two output channels (1 and 2) are sinusoidal and range from about + 2v to about + 9v (vpp about 7v)
I thought the sine waves were half positive and half negative, instead both waves are completely positive here.
 

[rstofer]

Without a negative power supply, how could the output go negative?  It is said that the capacitors block DC and that's true.  But in the case of audio, they also allow the signal from an amplifier with no negative supply produce a negative output and that's because the capacitor voltage will 'settle in' at the average DC value, subtracting the DC value from the signal.  On the output side, the signal will be positive when the amplifier output is higher than average and negative when the amplifier output is lower than average.  For this to work, there must be a load.

Take your audio signal and run it into a 100 ufd capacitor (or any other large capacitor).  Put the channel 1 probe where the signal enters the capacitor.  Put the channel 2 probe where the signal exits the capacitor.  Now connect a load resistor between the channel 2 connection and one of the scope ground leads.  I'm using a real signal generator so there is a common connection between the ground side of the generator and the ground side of the scope through the power cords.  If you're using something that doesn't have one side connected to earth ground (battery operated, for example), you need to connect that resistor ground, the probe ground(s) and the signal ground together.

I added a DC offset at the signal generator and that's why there is DC in the output (yellow trace).  If you don't have any DC value present (the generator has internal capacitors, for example), you can add DC by running the signal generator output through a battery before making the connections above (I think!).  Exercise:  Prove I'm right by adding a DC value to a symmetric AC waveform.  You could get that symmetric waveform by removing any existing DC (with a coupling capacitor) before adding in the battery voltage.

In any event, the yellow trace is the AC signal sitting on a DC offset and the blue trace is the AC component only.  You can see the effect of the coupling capacitor.  Look where the 0V reference is for Ch 1 -- it's near the bottom of the screen.  Then look at the 0V reference for Ch 2 -- it's right in the middle of the trace.

You will find coupling capacitors all over the place in audio; they will be on the inputs and outputs of amplifiers.  DC is harmful to speakers.

When you have bridged outputs, like the schematics above indicate, you must still connect the scope ground clip to circuit ground.  You can NOT put the clip on one output and the probe on the other because you will very probably short out one side because circuit ground on audio systems is very likely connected to earth ground and back to the BNC connector on the scope.  In effect, you have to put two traces on the screen and that's not what is always desired.  As you observed above...

For this reason, they have A-B mode (in the Math menu on the Rigol) where two channels are used to display a single trace by subtracting one from another.  One probe goes to one output, the other probe goes to the other output and, MOST IMPORTANT, the ground clips go in the drawer.  You can read about A-B mode in the manual.  This is what is known as a differential measurement and using 2 probes without the ground clips is a lot like having a differential probe except that differential probes may also be rated for higher voltages.  They may also be more accurate at differential measurements but I haven't proven that.

That ground clip causes an amazing amount of difficulty.

ETA:  I used a 220 uF capacitor and a 150 Ohm resistor.  The generator output is 1Vp-p riding on a constant offset of 1VDC.  I added a little schematic using LTspice.  I really don't like creating schematics this way but I don't have anything any better.

We're having fun now!

[rstofer]

With just a little extra thinking, it is apparent that the scope coupling setting (DC vs AC Coupling) does exactly the same thing.  In my example above, the channels are DC coupled so that I could show the DC offset.  If I switched to AC coupling, both traces would be centered over their 0V line.
 
With Channel 1 set to AC coupling, all that offset voltage would disappear.

That's why it is important to know how the channels are coupled.