First some background -
The Instek GDS-1062A is in the same price range (or slightly more expensive) as Rigol 1052E. On paper it looks better with 2M long memory that can be used at 1GS/s. Bandwidth is 60Mhz, and of course no 100MHz hack. Otherwise very similar!
It was released only a few months ago, so reviews are still few and far between. The only one I found was this -
http://welecw2000a.sourceforge.net/docs/Hardware/GW_Instek_GDS-1152A.pdffor the 150MHz version. It has some high quality photos of the internals (I don't want to take mine apart yet).
The Instek appears to be of higher build quality compared to Rigol's
http://home.comcast.net/~ajawam1/rigol/RIGOL_DS1102E_GUTS.htmlOne interesting thing to note is that Rigol uses 5xAD9288-40 dual ADCs to get 1GS/s (overclocking from 40MHz to 100MHz), while Instek uses 4xAD9288-100 dual ADCs to get 1GS/s (overclocking from 100MHz to 125MHz).
From Digikey,
AD9288BSTZ-40 = $6.32
AD9288BSTZ-80 = $10.09
AD9288BSTZ-100 = $17.09
The total cost of the 4 ADCs Instek is using (17.09 x 4 = 68.36) is much higher than Rigol's 5 ADCs (6.32 x 5 = 31.6). This is for single quantities, but the ratio should be similar at high quantity. The 100MHz parts cost almost 3 times as much as the 40MHz parts. We don't know what's the impact of this difference.
Now fast forward to yesterday... (most parts are copied and pasted from this thread
https://www.eevblog.com/forum/index.php?topic=1189.15)
Just got my GDS-1062A. Have only been playing with it, and probing some few hundred kHz UART signal.
No major (or minor) complaints so far. I'm pretty happy with it, but then I don't have anything to compare it to (except the Tektronix in school lab).
Scrolling is smooth. Tried different time bases, etc. No noticeable lag any time.
I want to test it out for future potential buyers' benefit, but don't really know how. And I don't have a signal generator (I do have MCUs, passive components, diodes, transistors, common chips, etc). Any suggestions? I don't even have something that can generate short enough rise time to test the bandwidth!
Just a note before I forget - Yes, 1GS/s can be used with 2M long memory mode. 100us is the maximum timebase for 1GS/s (2ms recorded). It switches to 500MS/s at 250us.
For equivalent time sampling -
25ns -> 1GS/s
10ns -> 2.5GS/s
5ns -> 5GS/s
2.5ns -> 10GS/s
1ns (min) -> 25GS/s
So when the manual says the long memory cannot be used at <25ns, it just means it cannot be used with ETS. So yes, it is better than Rigol in this regard (1GS/s with 2M).
At 1x probe, DC coupling, averaging off, 1Gsps, probe shorted to ground clip, 2mV/div, 1ms/div, I am getting
Vavg = -117uV, Vp-p = 400uV
If that means anything (I'm curious. Anyone want to do the same on Rigol and see what you get?). PS. tried aluminum foil grounding with same result
Interestingly, if I switch to ground coupling, Vavg becomes 89.1uV, and Vp-p = 0.
From joelby:
The DS1102E registers Vavg 360uV, Vpp 2.00mV, which does seem a bit noisier than yours.
A comment from mojo-chan
I have an Instek with 2M memory and it is excellent.
One thing to watch with long memory scopes is how they display the waveform when zoomed out. The Rigol ones, and apparently even some older Tektronix models, only show one sample per pixel. In other words they show every nth sample of the waveform. The better ones, such as the Instek or newer Tektronix, are a bit cleverer. They show the maximum and minimum samples in the range covered by each pixel.
In practical terms what that means is that is that it is much easier to find interesting events. Say you are looking for a voltage spike or an out-of-band sync signal (such as video sync which is 0.3v lower than the main video part). On a Rigol you have to pan through the waveform while zoomed in looking for it. On an Instek you can see it when zoomed right out and zero in on it very quickly.
I can confirm it on my Instek. If you have different levels in the same pixel's time, it becomes a strip from maximum to minimum.
As for the subjective things -
Build quality is good. Nothing filmsy. User interface is well laid out. Didn't notice any peculiar sequences needed to access any function.
Responsiveness is good when scrolling without math. No noticeable lag any time. With FFT it starts lagging noticeably at high time bases. Gets to about 2 frames per second.
Fan noise I don't know. I am in a room with 5 computers and probably 20 fans =) It sounds like jet engine.
From alm:
Some complaints I've heard about the Rigol are that triggering is not terribly stable (the wave always dances around slightly, even with a stable and noise-free signal) and that the measurements are based on the image on the screen, not the original signal. Things like bad accuracy compared to precision, and measurements that change depending on the vertical position on screen. Since I don't have a Rigol scope, I can't give you specific examples. It would be useful to know if the Instek scope has the same issues.
1. Measurements are done on the actual data. I can still get the 1kHz frequency reading from the compensation output even if I zoom out to 100ms/div (becomes big yellow band).
2. I have no way of measuring accuracy, but vertical offset (tried from -30V to 30V) does not change the readings appreciably (on the compensation output).
3. Used soundcard to generate 8kHz, 2.3Vpp sine wave. Appears to trigger reliably. I put it on continuous trigger mode, and moved the trigger from peak to peak. Waveform display is always very stable, and trace is thin. Tried manual triggering a few times, too. All images look identical.
Conclusion
From my very limited experience with the GDS-1062A, I believe it's well worth the extra $70 or so I paid for it. Main advantages are faster and deeper memory, higher build quality, and better firmware (and maybe analog frontend/triggering).
EDIT:
Another thing I noticed -
The Rigol has 1 set of vertical controls (volts/div and offset) shared between the 2 channels. Instek has 1 set for each channel. Should be easier to use?