Magnova oscilloscope

[MASCH]

It is not so easy to get them both side by side on my test bench, but I did my best

On a testbench like mine, the side facing BNC connectors of the Magnova are clearly a disadvantage since they will block the space I like to reserve for other test equipment.....
Especially with an already very wide instrument, why did they decide to put the BNCs on the side???
And it will get worse if they ever make active probes.....

[jusaca]

Yeah I'm not sure about the side connectors either...
When I have the scope directly on my desk during work to test stuff there, I actually like the way they did it. More room in front of the scope.
But on the bench table it is annoying, because you have to waste so much space on the side ;/

[john74]

maybe this is a solution to the BNC issue, he added also a picture:

Probe Cable Management. I want to share my solution for the side-facing BNC connectors. Using right-angle adapters turned out to be a great fix. It freed up desk space, and the probe routing is much more convenient compared to a traditional front-panel layout.

[john74]

Another QoL improvement for mouse users:

at the moment when the zoom mode is activated and the mouse cursor is located into the zoom window,
the mouse wheel can be used to zoom further in/out of the signal,
but the horizontal center point of the zoom is fix.

I think it would be more convenient to zoom "into" the actual position of the mouse cursor.
(without zoom, this is at least the default behavior)

see attached screenshot...when I place the cursor at a 'special' point in the waveform
the zoom (in x-axis) should center around this location.

[john74]

Non-critical bug noticed.
Saved profile: Roll mode; Time Scale 1s; HiRes=ON
Right after powering up, the trace/picture is moving unevenly (like a push every 250ms). When the first screen is filled (after 12 seconds), the bug disappears.

that same "bug" appears, when you change the y-scaling of one of the analog channels during roll-mode (at 1sec/div)
and the channel offset is <> 0V (strange connection  )

[rf-messkopf]

In order to compare something, you have to create the same conditions, which was not the case here.

True, but I think the difference you and MASCH are seeing between the various probes still needs some investigation. It looks like that what you are seeing is due the pulse generating circuit, which seems to budge under the loading by the probe tip. Are you using the Batronix test board as well? Could you try with a different source?

Attached is the measurement of an approx. 1.5 ns edge with a 50 Ohm source impedance, once with the supplied TESTEC TT-HF 612RA probe, and once directly into 50 Ohms. There is almost no difference. The ringing is there for real, and is not due to bad probing or grounding. This is  the fastest edge I have available at the moment without cobbling together some circuitry.

[MASCH]

Another thing I found is that the testec probe is extremely sensitive even if you touch just the probe cable.
There will be short disturbances coupling into the scope.

I have shorted the probe tip to and and just repeatedly touched the cable:



With my Yokogawa probe I am not able to get this kind of disturbance.

[rf-messkopf]

Another thing I found is that the testec probe is extremely sensitive even if you touch just the probe cable.

Piezoelectric effect, can be seen in many coax cables (e.g. with Teflon insulation). Attached ins the result of hitting a RG58 cable with a wrench. Although the probe seems to be really sensitive.

Or is this an electrical disturbance coupling into the probe?

[KungFuJosh]

If bench space is an issue for you with the right-side connectors, using the VESA mount is awesome. When my Magnova is not in use, it sits recessed in a custom rack. When in use, space is not an issue as I can adjust it however I like.

[kmoonwalker]

With my Yokogawa probe I am not able to get this kind of disturbance.

we always loved Yokogawa for that during my university times

[rf-messkopf]

I just stumbled across an excessively high generator amplitude in my Magnova. Test setup: Generator output connected directly to a channel input. Input set to 50 ohms, generator set to 2 Vpp sine into 50 ohms.

Results (see the attachments):

• At 1 Mhz: 2.0334 Vpp: OK
• At 20 MHz: 2.6887 Vpp: NOK
• At 50 MHz: 7.8483 Vpp: NOK

I verified that the generator output is indeed high by using another scope (R&S RTM2054), where I see 8.11 Vpp at 50 MHz (the slight difference may be due to cabling), screenshot also attached.

Does anybody else see this behavior, or is that an issue with my generator module?

[Martin72]

Hi,

No problems here....

[rf-messkopf]

One more experiment: Set up a linear sweep from 1 kHz to 50 MHz with 5 s sweep time, amplitude again 2 Vpp into 50 ohms. Generator connected to ch 1, and triggered off the generator. Now the amplitude is correct across the sweep. Again, the slight amplitude droop that is visible will be due to cabling.

This looks like a software issue.

[rf-messkopf]

No problems here....

Thanks Martin for checking. It is odd that I don't see this problem in sweep mode. I also tried to restore the factory settings and re-booted the scope, but the issue remains.

[Martin72]

There should be another firmware update coming soon; try it again then, and if the issue persists, contact Batronix.

[KungFuJosh]

I would also suggest restoring the factory/default settings first, then try again and see if the issue persists.

[Andre77]

I just stumbled across an excessively high generator amplitude in my Magnova.

Thanks a lot for the report!

What you’re seeing is an issue that is already known internally at Batronix - although it definitely shouldn’t have made it into shipped units. We believed we had caught all affected generators before delivery, but since you’re seeing this behavior, it’s clear that some from that batch slipped through. The root cause is a calibration issue - more on that below.

- We can send you a replacement generator module that you can swap yourself
- You can send in the complete Magnova (or just the generator module), and we’ll fix it here
- In principle, you could also recalibrate your unit yourself, but that would require us to prepare a firmware update with that capability. In practice, it may be faster to simply replace the module. We can provide a free DHL shipping label to cover the return costs.

We’ll take another close look at this issue to better understand whether additional units might be affected. If so, we’ll make sure to inform all affected customers. If more units are affected, we will provide a solution, potentially via a firmware update, to make it easier for customers to resolve the issue.

Background: After improving our internal generator calibration software a few weeks ago, we introduced a bug in the calibration process. Under certain conditions, this could cause a calibration value to be set completely incorrectly during the final fine-tuning step - after all earlier tests had passed.

We believed we had identified and fixed this in time before any affected units were shipped. Since you’ve now encountered this behavior, it appears that at least one (and possibly more) generator modules from that calibration batch did make it into the field. That shouldn’t have happened - we sincerely apologize for that.

Why it behaves differently during a sweep: The parameter in question is an amplitude correction factor used to compensate for the natural low-pass behavior of the output stage. During a frequency sweep, this correction is not applied, because the amplitude adjustment cannot be changed dynamically while the signal is being generated. As a result, the sweep amplitude appears normal.

Under normal conditions, this correction is relatively small. Due to the bug, however, it was set far too high, which explains the strong amplitude increase at higher frequencies.

If anyone wants to check their Magnova generator, here’s a simple test:
1. Connect the generator output to (for example) analog channel 1 using a 50 Ω BNC cable
2. Enable 50 Ω termination on the input
3. Generate a 100 mVpp sine wave at 1 MHz and measure the amplitude
4. Increase the frequency to 50 MHz and measure again

The amplitude should not increase.

If anyone else is seeing this behavior, please reach out to us directly.

Again, apologies for the trouble - this should not have made it out into the field. We’ll get this sorted as quickly as possible.

[rf-messkopf]

Again, apologies for the trouble - this should not have made it out into the field. We’ll get this sorted as quickly as possible.

No worries. These things happen to the best of us.

I'll shoot you an email.

[kaspich]

An additional bug was identified while testing my generator (my unit works fine).
Generator = ON. F = 50Mhz. Amplitude: 1Vpp
HiRes = OFF
Changing horizontal resolution:
20us and less = everything is fine
20us = amplitude of the signal is jittering
50us = only the DC offset (jittering) is on the screen
100us = jittering amplitude, etc.
In Roll mode:
50ms = jittering DC offset only
100ms = ok
200ms = only DC offset.

[Martin72]

Hi,
First, your trigger is out of range. Then, when you apply a 50 MHz signal, what you “see” in the lower us/ms range could be anything, but it’s no longer the correct waveform.

[rf-messkopf]

I think what you see is aliasing. E.g, you sample a 50 MHz signal at 50 MSa/s. So this signal gets folded to DC. Every digital scope behaves like this.

[hotze]

I think what you see is aliasing. E.g, you sample a 50 MHz signal at 50 MSa/s. So this signal gets folded to DC. Every digital scope behaves like this.

…especially when generator and scope are time-correlated.

[tautech]

Hi,
First, your trigger is out of range. Then, when you apply a 50 MHz signal, what you “see” in the lower us/ms range could be anything, but it’s no longer the correct waveform.

Yup, some don't understand the trigger is all powerful !

[kaspich]

Hi,
First, your trigger is out of range. Then, when you apply a 50 MHz signal, what you “see” in the lower us/ms range could be anything, but it’s no longer the correct waveform.

Yup, some don't understand the trigger is all powerful !

Guys, I understand why it's happening. At the same time, I marked this as a bug because (again, my own subjective point of view) for such a segment (I am talking about price range) scope, there should be more advanced algorithms than ''let's reduce samplerate if/when timebase is increased''.

[kaspich]

Hi,
First, your trigger is out of range. Then, when you apply a 50 MHz signal, what you “see” in the lower us/ms range could be anything, but it’s no longer the correct waveform.

Sure. I am talking about a different aspect. If/when a slow timebase is selected (as the result - low samplerate, etc., in addition/moreover - when the trigger is not set/active/activated), there is a lot of ''spare'' time for creation of ''signal preview''. If/when I am inspecting an unknown signal/shape, in such a case (for example), I have no clue that there is some high-frequency signal, too. Signals that cannot be displayed ''correctly'' (due to their too high frequency) should more or less appear as a "filled'' screen (from min to max amplitude).