All-in-one test instrument or seperate instruments

[Wilson__]

The Rxxxx Digital Oscilloscope can have option of Logic Analyzer and Arbitary Waveform generator.

Will an all-in-one instrument better?  Will it be easier to see digital signal (logic analyzer, says, SPI bus) in SYNC with analogue waveform?   Says, MCU send SPI command to a DAC chip and then the chip output analogue signal after some delay (n clock cycle to do the DAC action).

Can the arbitary waveform generator generate digital signal, says, UART TX data (since it is one line, cannot do SPI nor I2C, right?)

Many thanks

[inse]

Lorem ipsum…

[shabaz]

Will an all-in-one instrument better?

It's definitely useful. Even if you later want a separate AWG or LA. AWG+LA go very well with oscilloscopes, it's quite a natural thing to have them built-in, so yes, if you can purchase that, you will find you will make very good use of those features.

Can the arbitary waveform generator generate digital signal

Assuming you're not talking about running a suite of tests and applying deliberately broken messages etc., then ordinarily you could use any Arduino or Pi or Pi Pico board or Bus Pirate board to generate UART transmit data, or SPI, or I2C. Would be far simpler than using AWG, since the AWG is not natively protocol-aware. MicroPython + Pi Pico is quite useful, but there are lots of ways to do it.

[jbb]

Combining the oscilloscope and logic analyser is nice because makes it easy to see relationships between analog and digital waveforms. One problem is that you end up with a lot of traces on the screen; it gets hard to see.

Combining an AWG with an oscilloscope... I don't think you get a particular functional benefit.  However, it could be cheaper than buying a separate instrument and take up less space on the bench. That's not nothing.

If I had a big lab upgrade budget, I'd get a combo oscilloscope + logic analyser and a separate dual channel AWG.

[RoGeorge]

I was for standalone instruments since a few days ago, when the summer days went so hot that I can't turn on the standalone oscilloscope, and power supply, and generator without making the room too hot to bare.

Got back to a wall adapter and a 3v3 LDO instead of a lab power supply, soundcard instead of generator, and a small 1MHz handheld oscilloscope (no more than a microcontroller with ADC and an LCD) instead of the oscilloscope.  Most of the time is spent developing software anyway, so don't need 3 lab instruments humming all day long doing mostly nothing but heat.

I'm thinking of making a more permanent DIY setup to replace the lab instruments:
- a few adjustable LDOs as a power supply
- a small analog functions/signal generator
- maybe another MCU as a logic analyzer
- a few LEDs to probe logic states
things like that, nothing fancy, and anchored all together on the same platform so to be easy to probe without the harness of extra probes and wires going to all the lab instruments.  All low power and with quiet/passive cooling, no fans.

An Analog Discovery looks tempting, though at that price I'd rather cobble something from whatever parts and devboards I might already have at hand.


As for your question about the oscilloscope, read the user manual to see if it can generate UART signals (probably not) or other kind of arbitrary waveform that can be used to emulate an UART Tx.

It would be much easier to use yet another Arduino (or whatever other board/MCU you prefer) to generate UART/I2C/SPI or other digital patterns, or maybe a logic analyzer that can also generate digital patterns (IIRC "bus pirate" was able to do that, but I don't have one https://en.wikipedia.org/wiki/Bus_Pirate ).

When I've bought my oscilloscope, the LA option was 3-4 times more expensive than a standalone LA, so I've bought a standalone logic analyzer and never felt the need for exact correlation between analog and digital timing, so I don't think LA+Analog traces on the same screen would be a big advantage.

Of course, it all depends on one's needs, so buy what appeals you most, but don't break your budget for whatever shiny feature.  No instrument will cover all the possible needs anyway.

[Kleinstein]

All in one is problematic, as it gets really large und the choices are limited (e.g. no good AWG with cheap scope). It can make sense if the work together and can use more than a common power cable, but there can be interferences. With individual instruments one has naturally more grades to choose from.

It still makes sense to have some additional functions (e.g. scope plus logic analyser) in one unit. This is especially the case if the functions work together, like use the same screen and trigger. Another thing is a counter function with a DSO - not really much extra HW needed to make a good counter from a DSO.

The power consumption is a different thing and can go both ways: all in one may cause extra power when needing only part of the functions, but can also save on power by sharing parts (e.g. the screen or transformer).

[pdenisowski]

Will an all-in-one instrument better?  Will it be easier to see digital signal (logic analyzer, says, SPI bus) in SYNC with analogue waveform?   Says, MCU send SPI command to a DAC chip and then the chip output analogue signal after some delay (n clock cycle to do the DAC action).

Yes, it will be much easier.  Frankly, it would be kind of painful to (try to) do what you are describing with two separate instruments.  And you will need some kind of logic analyzer capability if you have more conductors than scope channels (e.g. in GPIB or other parallel buses)

Can the arbitary waveform generator generate digital signal, says, UART TX data (since it is one line, cannot do SPI nor I2C, right?)

Depends on the generator.  The R&S RTB2000 has a 4 bit pattern generator built-in and can natively generate signals like SPI, I2C, etc.  But the function generators integrated with scopes are often not the best tool for creating patterns.

When I need to create serial protocol data for testing / demonstration, I typically use a RaspberryPi or Arduino.  I also have a "pattern generator" that I can use to define arbitrary bit sequences on multiple conductors, but this is overkill (and more difficult to configure) for most of my needs.

Incidentally, I just did a webinar on UART, SPI, and I2C last week: 

https://event.on24.com/wcc/r/4620077/10F692D61834C32BEFF0DFA697686F5E

[Doctorandus_P]

There is no "better".

In general I like separate instruments so each has it's own set of knobs to twiddle and a display.
Even for the scope / logic analyzer I have separate instruments (Siglent SDS1104X-E and Kingst LA2016) Sometimes it is very useful to have both analog and digital synchronized with each other, but with a 4-channel scope, you can usually use one of the channels to see that synchronization. And the scope can also do I2C, Serial, and some other signal decoding on it's own. (Especially with I2C signal integrity can be an issue, and this should always be verified separately).

I thought about buying the LA extension for my scope, but I did not. First, I very much like my big PC monitor mouse & keyboard for the logic analyzer (labeling channels, saving data 4k, 107cm screen). Second, the LA extension for the scope is much more expensive. The Kingst was around EUR100 and works nicely on Linux with it's own software. Recently apparently also works with Sigrok (which I actually prefer)

Integrating all the stuff in a single instrument is less ergonomic, but (apart from the synchronization) it also uses much less desk space, and it's much easier to haul around if you're traveling a lot. But those factors are not very important for me either.

[CosteC]

All-in-one is always a limited instrument when it comes to "added instruments"
Lowest limitations apply to Logic Analysers - those usually are very good. Mixed Signal Oscilloscopes are on market for decades. If you need it-get it.

Arbitrary Waveform Generators are usually limited with amplitude (2.5-5V often, see datasheet) and haven't seen more than 25 MHz bandwidth. Modulation options may vary also a lot. Usability greatly depends what you do. Audio - probably great, RF - probably not at all.

Multimeter, which I seen here and there may be sensible or use oscilloscope channel. In latest case it is pointless with 3% accuracy.

Personally I love build-in Bode Plot option - it is very convenient. It also takes less space, but I often hit limitations of bandwidth or amplitude or rise times.
I am sure lot of people use Logic Analyser with great success.
Personally, I do not care about "build-in" multimeter.

Financially - you need to decide by yourself.

[Thomas]

...
Arbitrary Waveform Generators are usually limited with amplitude (2.5-5V often, see datasheet) and haven't seen more than 25 MHz bandwidth. Modulation options may vary also a lot. Usability greatly depends what you do. Audio - probably great, RF - probably not at all.
...

Agreed.
Scope AWGs should be considered with caution.
Some (Siglent, I am looking at you) have amplitude limited to ±1.5V into 50Ω, ±3V into hi-Z.
I wouldn't want that as my only generator.