ZT-703S Bandwidth Issue Revisited, Firmware Upgrade
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- Опубликовано: 29 июн 2024
- In this video, I clarified the 30 MHz bandwidth issue observed in my review video of the Zotek ZT-703S. I also updated the firmware on both my ZT-703S and ZT-702S.
• Zotek ZT-703S Handheld...
00:00 Bandwidth issue clarified
04:17 Current consumption in high performance mode
05:38 Rel mode, charging indicator
06:40 703S firmware update
08:26 702S firmware update
09:23 Did the firmware update fixed the issues? 
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Seems that for some strange reason Zotek either don't watch your videos, or just ignore your suggestions.
The inability to auto range at 46MHz is inexcusable.
And I agree that the normal and fast range switching is a bit silly and could be a tad frustrating.
I appreciated your followup and details. I've been very satisfied with the Owon 200MHz scope I got after your review.
I wonder if the auto range offset is due to it being a 2 channel unit, I bet channel 2 gets placed above it with a positive offset, I should try my one to see if that is the case.
According to the sampling theorem (Shannon, 1949), to reconstruct a one-dimensional signal from a set of samples, the sampling rate must be equal to or greater than twice the highest frequency in the signal.
So with a 50Mhz sampling rate don't expect to measure more than 25Mhz signal frequency accurately.
from the manual:
Normal Mode: Maximum sampling rate 200MSa/s, Maximum measurement bandwidth 30MHz
Lower power consumption, more power efficient.
High Speed Mode: Maximum sampling rate 280MSa/s Maximum measurement bandwidth 50MHz
Higher power consumption.
Good stuff, Kerry. FYI - I could not update my 702S until I had Windows repair the FIRMWARE file in the 702S. I think my 702S was 1.03.41 originally. My 702 also came with a bad battery. Still, I like it except for the recessed BNC makes it hard to attach a probe to.👍
I wonder if the signal generator can be turned off on the 703S. Setting it to off doesn't seem to work.
I think that Kerry Wong once found out, that Owon HDS was overclocking a 200 Ms/sec converter to 250 MS/sec. Perhaps Sotek is doing the same thing, but only then it is really needed?
Ordered my 703 yesterday.
Thank you for the update. I use a scope to find signal interference. Do you have any examples showing waveforms that are not perfect?
02:29 10:19 Kerry, thankyou so much for bringing up the Auto Ranging issue!!! So annoying :( So it's still not fixed? I am on V1.3.2 . I really hope they are able to solve it.
Witam Panie Kerry, świetna robota. Proszę dodać język polski do translatora. Pozdrawiam z Polski👋
I have the ZT-703S, the Aneng version of the 702S (the Aneng can run the Zotek firmware) and two of the Owon HDS series scope meters. I’ve had the Owon units for over a year and the 700 series for about four months.
I really like the compact and somewhat sleeker styling of the 700 series units. The 703 is a bit of a disappointment because it fails to fully deliver on the advertised bandwidth. The other wart is if you leave the meter probe in the wrong socket when taking current measurements, you get crazy values displayed. True, there is a reminder flashed on the screen, but it is only there for about one second. I would have programmed the firmware to leave the reminder on the screen until some current flow is sensed; that way you’re sure the user read the reminder. The last complaint is that not enough of the BNC socket is poking through the plastic far enough to firmly seat a standard Amphenol plug on its detent. The probe included with the meter does firmly seat on its detent.
The Owon HDS series meters outperform their promised specifications. The 200 MHz rated HDS-2102S will easily lock on a 300 MHz signal, and you can get a reasonable lock on 400 MHz, though sensitivity is about 6 dB down by that point. I am inclined to believe the Owon meters meet their CAT safety ratings. Even the BNC connector outer shells are insulated. The signal generator in the HDS S meters is pretty good. The output scaling can be set to 50, 75 or other Ohm load. Frequency, offset, duty cycle and amplitude are continuously variable. A variety of arbitrary waveforms are available.
Unless you’re seriously restrained by budget, I would go with one of the Owon HDS series meters. My recommendation for the hobbyist just getting started would be to go with the Owon HDS-2101S - it is rated at 100 MHz (one channel operating) or 50 MHz (two channels active) and includes a 25 MHz signal generator. The price difference is only about 20 to 30 Dollars depending on the seller. It is definitely worth it to get the improved capability.
I have the opposite experience. The 703s has been much more reliable and precise than the owon I had before
Cheaper too
@@shaolin95 Thanks for the sharing your experience, adding another data point. My guess is that one or both manufacturers have variable quality control and there are good and not so good units sold. I particularly like the ergonomics of the 703S, the shape makes it easy to hold and the adjustments of gain/timebase and trace position are more logical than Owon’s. The 703S signal generator could use improvement. The applet menu is intriguing as they’ve left some blank spots in the grid where additional functions could be added. It is good to see that the 703S firmware is being actively updated. I haven’t yet found what’s different between 1.3.5 and 1.3.8 firmware, but 1.3.5 was a large improvement over what shipped on the meter. I give Zotek high marks on making the update process easy.
太贵了，100-200就合适