Author Topic: Rogol 1054Z actual bandwidth  (Read 1502 times)

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Offline rad400

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Rogol 1054Z actual bandwidth
« on: October 31, 2017, 12:01:23 PM »
When a Rigol DS1054Z 50Mhz scope is updated to a 100Mhz, do you really get an improvement in the bandwidth?.   At 100MHZ are you down only 3db or considerably more?
 

Offline MarkF

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Re: Rogol 1054Z actual bandwidth
« Reply #1 on: October 31, 2017, 12:29:32 PM »
The 3dB bandwidth for the DS1104Z 100MHz scope is approx 160Mhz.
The 3dB bandwidth for the DS1074Z 75MHz scope is approx 90Mhz.
 

Offline rstofer

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Re: Rogol 1054Z actual bandwidth
« Reply #2 on: October 31, 2017, 12:41:12 PM »
When a Rigol DS1054Z 50Mhz scope is updated to a 100Mhz, do you really get an improvement in the bandwidth?.   At 100MHZ are you down only 3db or considerably more?

You need to watch Dave's video on the subject.  There are two filters on the front end of each channel.  One for 50 MHz bandwidth and one for 100 MHz bandwidth.  The choice is made by the firmware.  If it thinks it is a 50 MHz scope, it chooses the 50 MHz filter.  If it thinks is is a 100 MHz scope it chooses the 100 MHz filter.  That's why tweaking the scope settings make a difference.

Set to 100 MHz, the scope has been tested and found to have rather more than 100 MHz of bandwidth to -3 dB.  I don't recall the number but it's up around 150 MHz.
 

Offline ebclr

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Re: Rogol 1054Z actual bandwidth
« Reply #3 on: October 31, 2017, 03:26:28 PM »
1054Z hacked go far away from 100 Mhz, at least 130 Mhz without attenuation, and +- 200 Mhz with attenuation
 

Online Fungus

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Re: Rogol 1054Z actual bandwidth
« Reply #4 on: November 02, 2017, 05:43:01 AM »
When a Rigol DS1054Z 50Mhz scope is updated to a 100Mhz, do you really get an improvement in the bandwidth?.

Yes.

At 100MHZ are you down only 3db or considerably more?

The 3dB point is usually around 130MHz (as measured by several people here).
 

Online Fungus

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Re: Rogol 1054Z actual bandwidth
« Reply #5 on: November 02, 2017, 05:45:16 AM »
1054Z hacked go far away from 100 Mhz, at least 130 Mhz without attenuation, and +- 200 Mhz with attenuation

You can still see 300MHz+ signals on one, although very attenuated, obviously.
 

Offline rhb

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Re: Rogol 1054Z actual bandwidth
« Reply #6 on: December 20, 2017, 11:49:27 AM »
How about a screen shot of a sweep generator feeding a "hacked" scope? Has anyone posted that?
FeelTech FY-6600 2 Channel Function Generator: a buggy piece of test gear sold by a disreputable company which refuses to correct known software problems for buyers who bought the defective units.  Those foolish enough to buy one will have a very nice paper weight for the desktop.
 

Offline xrunner

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Re: Rogol 1054Z actual bandwidth
« Reply #7 on: December 20, 2017, 12:20:56 PM »
How about a screen shot of a sweep generator feeding a "hacked" scope? Has anyone posted that?

Fstart ?
Fstop ?
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Offline rstofer

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Re: Rogol 1054Z actual bandwidth
« Reply #8 on: December 20, 2017, 12:52:58 PM »
How about a screen shot of a sweep generator feeding a "hacked" scope? Has anyone posted that?

Fstart ?

I suppose something less than 50 MHz for those who don't think the original bandwidth has changed.  Say 10 MHz?

Quote
Fstop ?

No point in going beyond 200 MHz because it is pretty well establised that the -3dB point is around 130 MHz.

I have no idea if those values are realistic...
 

Offline xrunner

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Re: Rogol 1054Z actual bandwidth
« Reply #9 on: December 20, 2017, 02:10:28 PM »
I suppose something less than 50 MHz for those who don't think the original bandwidth has changed.  Say 10 MHz?

...

No point in going beyond 200 MHz because it is pretty well establised that the -3dB point is around 130 MHz.

I have no idea if those values are realistic...

I don't strictly have an RF sweep generator, but I might be able to cobble together something, if another member doesn't beat me to it.  :)
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Offline kahe40

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Re: Rogol 1054Z actual bandwidth
« Reply #10 on: December 21, 2017, 01:40:49 AM »
here a  sweep 50M to 500M with 10M step, you see those spikes every 10M.
Rigol is not fast enough, but Micsig and Siglent show them clearly.
Center of Grid is around 225M, so you get an idea of BW and Freq.
Micsig goes down very fast, Siglent is the best of all
and Rigol has a linear degree, like a triangle.
Rigols 5ms are too short for the entire sweep (or user error?),
but I tried to make it comparable.
Sweep was done with RF-Explorer-SigGen,
yes, maybe it is a toy but better than nothing...

Micsig TO1104   https://ibb.co/hTupS6

Rigol 1074Z hack  https://ibb.co/mf2b76

Siglent 1202XE   https://ibb.co/cMZCfR


edit: have not found out, how to post pictures with iPad, sorry
« Last Edit: December 21, 2017, 01:45:58 AM by kahe40 »
 

Offline bingo600

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Re: Rogol 1054Z actual bandwidth
« Reply #11 on: December 21, 2017, 04:18:33 AM »
I measured mine to around 134Mhz , for the 3dB mark
DS1054Z (100Mhz Hacked)

/Bingo
 

Offline xrunner

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Re: Rogol 1054Z actual bandwidth
« Reply #12 on: December 21, 2017, 06:03:46 AM »

I suppose something less than 50 MHz for those who don't think the original bandwidth has changed.  Say 10 MHz?

No point in going beyond 200 MHz because it is pretty well establised that the -3dB point is around 130 MHz.


Here's my data. First up is from 10 MHz to 150 MHz. The -3dB point is where the cursors on the right intersect, about 130 MHz.

Second is from 10 MHz to 500 MHz, again where the cursors intersect is -3dB @ 130 MHz. But certainly the scope can easily display signals in excess of 500 MHz.

Note: Using TG output of a Rigol DS815 triggered externally, some amplitude anomalies are expected. The TG output was set to 0 dBm into 50 ohms at the scope.
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Offline rhb

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Re: Rogol 1054Z actual bandwidth
« Reply #13 on: December 21, 2017, 12:31:02 PM »
The Rigol has  a very strange response.  It looks like a filter  skirt with the corner frequency below 50 MHz.
FeelTech FY-6600 2 Channel Function Generator: a buggy piece of test gear sold by a disreputable company which refuses to correct known software problems for buyers who bought the defective units.  Those foolish enough to buy one will have a very nice paper weight for the desktop.
 

Online Fungus

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Re: Rogol 1054Z actual bandwidth
« Reply #14 on: December 21, 2017, 04:38:06 PM »
here a  sweep 50M to 500M with 10M step, you see those spikes every 10M.
Rigol is not fast enough, Rigol has a linear degree, like a triangle.

What sort of settings are these?


Rigol has 1GSa/s and 24M pts.

The Rigol has  a very strange response.  It looks like a filter  skirt with the corner frequency below 50 MHz.

Just a display artifact from the settings, nothing to do with frequency response.
« Last Edit: December 21, 2017, 04:41:04 PM by Fungus »
 

Offline Mechatrommer

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Re: Rogol 1054Z actual bandwidth
« Reply #15 on: December 21, 2017, 06:23:05 PM »
How about a screen shot of a sweep generator feeding a "hacked" scope? Has anyone posted that?


But certainly the scope can easily display signals in excess of 500 MHz.
no, beyond 500MHz, you will see aliased signal...
if something can select, how cant it be intelligent? if something is intelligent, how cant it exist?
 

Offline xrunner

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Re: Rogol 1054Z actual bandwidth
« Reply #16 on: December 22, 2017, 12:38:34 AM »
no, beyond 500MHz, you will see aliased signal...

Yes, if you don't care about amplitude or frequency accuracy. 900 MHz signal shown below, is displayed quite nicely. The amplitude and frequency you would measure with the scope will be wrong, but that's not the point.
« Last Edit: December 22, 2017, 12:44:27 AM by xrunner »
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Offline scopeman

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Re: Rogol 1054Z actual bandwidth
« Reply #17 on: December 22, 2017, 02:34:10 AM »
Hello,

You should re-run this test with a known good 50 ohm feed through termination and start with a 50KHz signal with six divisions of
signal and increase the frequency to the point where you have 4.2 divisions of signal and repeat this for each attenuation setting to get a better idea of what the bandwidth of the scope itself is.

Sam
"scopeman"
 

Offline Mechatrommer

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Re: Rogol 1054Z actual bandwidth
« Reply #18 on: December 22, 2017, 02:48:07 AM »
no, beyond 500MHz, you will see aliased signal...
900 MHz signal shown below, is displayed quite nicely.
thats called 100MHz garbage

The amplitude and frequency you would measure with the scope will be wrong, but that's not the point.
if the point is try to make out something from garbage, then yes i get your point.
if something can select, how cant it be intelligent? if something is intelligent, how cant it exist?
 

Offline xrunner

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Re: Rogol 1054Z actual bandwidth
« Reply #19 on: December 22, 2017, 03:05:02 AM »
if the point is try to make out something from garbage, then yes i get your point.

You aren't understanding the point I'm making. It's not garbage - it's a signal, it's useful information. If you want to trace a signal on a board to see if it exists then it's just fine for that above ~130 MHz. The signal is very easy to view on the DS1054Z hundreds of MHz higher than it's bandwidth limit (which is simply the -3dB point - not where it completely stops working).  :-//
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Offline rhb

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Re: Rogol 1054Z actual bandwidth
« Reply #20 on: December 22, 2017, 05:46:56 AM »
To paraphrase Harry Calahan, "A man's got to know his scope's limitations."  Unfortunately, many people are held  by economic considerations in a state of ignorance.  The linear loss of amplitude on the Rigol, *is* a serious issue if you're trying to measure the rise time of a pulse.

Thank you to those who have provided screenshots.  I'd like to suggest, though, that you document the signal generator used.  There are two terms in the equation.

It would be very interesting to see a head to head of a hacked DS1054Z vs a DS1104Z using a top tier signal generator.
FeelTech FY-6600 2 Channel Function Generator: a buggy piece of test gear sold by a disreputable company which refuses to correct known software problems for buyers who bought the defective units.  Those foolish enough to buy one will have a very nice paper weight for the desktop.
 


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