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本帖最后由 fm007 于 2012-7-28 17:24 编辑
这篇文章是老外写的:
关于带宽、噪声以及和Tek的波形比较等,个人觉得不错
http://owon.freeforums.org/some- ... ersion-2-6-t10.html
关于ADC:
About ADC
SDS7102 have max samplerate 1Gs/s realtime (one channel) and 2 x 500Ms/s simultaneous for two channel.
ADC construction principle is most good what I have seen in this price class oscilloscope. Better than Hantek solution.
Owon use single chip ADC what is directly made for this speed!
(hantek use several 100MHz ADC's interleaved)
Owon ADC Chip is MXT2002 (RuiFeng China)
MXT2002 is National ADC08D500 clone. (exept case. ADC:128pin, MXT:144pin))
Some specs are slightly reduced but in my opinion not markable in this scope aplication and frequency range.
Non DES
ENOB 100MHz National typical 7.5 and clone 7.4
SNR 100MHz typical 47dB and clone 46dB
If go higher frequencies as example >200MHz then littlebit more differencies so than original win.
My opinion is: in this application differencies are not meaningfull.
National original chip is markable more expensive. (you can buy many clone chips with one original chip price - but in critical aplications these small differencies may be just enough)
Here is RuiFeng datasheet (not much text becouse can use national datasheet)
Note, you need support for chinese language, if want look all)
This ADC support directly 1Gs/s or 2x500Ms/s capturing.
Just simple change chip mode selection.
In this mode these two ADC's are internally interlieved with same clock.
This is very reliable and better way to do oscilloscope ADC than what example Rigol, Hantek, Atten, Siglent, GW etc. have used. But Hantek/Tekway and others basic design is old. They use same principle as Rigol (etc). Several low speed ADC interleaved. Problem is timing and leveling these separate ADC's so it need lot of care that there do not rise any bad efects with timing jitter and level unbalance and other unformity between ADC's.
This OWON solution is nearly free from these problems.
And also, this smart ADC have its own inside build low level calibration routine (it is not same as scope self calibration).
ADC is clocked with 500MHz clock and it need only one Clock source.
This clock generator is:
Analog Devices ADF4360-7 Integrated Synthesizer and VCO (350-1800MHz)
Clock reference is 10MHz.
不知道这个人为什么知道这么多,ADC MXT2002居然是仿的国半的ADC08D500 ,指标好像还可以哦!
希望使用SDS7102的人共同关注一下,视窗扩展如果能够设计的一点就好了,改成那种扫描形式的
现在的视窗拓展给我感觉就是实时快速分辨率切换了,没有别的功能,在视窗扩展中STOP后,是回不到主存储中间去的,回到主存储中也只有那么一截信号,对于观测小概率信号异常不利!
![](http://i181.photobucket.com/albums/x2/aghp55/tstNoise.jpg)
Owon set here 10k memory and Tek 5k memory and "fit to window"
With this they are more comparable becouse then Owon have 10k 20div Tektronix 5k 10div.
![](http://i181.photobucket.com/albums/x2/aghp55/Owon26_5mVdivTri.png)
Owon 100MHz full BW just as it is (-3dB far over 150MHz)
![](http://i181.photobucket.com/albums/x2/aghp55/TDS520A_5mVdivTri100BW.png)
Tektronix with 100MHz rejected BW
![](http://i181.photobucket.com/albums/x2/aghp55/TDS520A_5mVdivTriFullBW.png)
Tektronix with full BW
Noise without signal.
Oscilloscope 1M input with 50ohm terminator.
![](http://i181.photobucket.com/albums/x2/aghp55/Owon26_5mVdiv.png)
(cursors show Owon OLD version noise peak level.)
NOTE: Owon have used 10M memory. Tektronix have only tiny sampling memory so also trace looks different.
(if drop Owon memory it looks same but, these tests was done different time and I did not use Owon small memory becouse with it, noise looks "too good" visually in display (of course it do not reduce real noise p-p).
![](http://i181.photobucket.com/albums/x2/aghp55/TDS520A_5mV100BW.png)
![](http://i181.photobucket.com/albums/x2/aghp55/TDS520A_5mVFullBW.png)
Need realize that Tektronix is old but totally different price class oscilloscope.
Owon result is very good.
In this price class I do not know any other what is as good as owon if look noise.
Still Owon have noise, of course, and it also affect to triggering stability. But also so do this Tektronix.
Due to lack of time this was only small test.
(specially becouse need add floppy disk driver to this old Tek for images and it need some improvisation becouse not original parts.)
后面还有不少,懒得贴了,如果厂家看到能够把视窗扩展改进一下那真是Happy啦!
贴一个以前用TEKMSO4054的图,同样是10M的存储,TEK就能在低速下观察不良信号:
不求完全一样,但是这种低速下长时间观察波形的能力应该是高存储所必须具备的啊,厂家可能更看重高速下的信号细节,可是很多人都要关注低速下的信号细节。
如果没有好的视窗扩展,对低速信号的观察能力肯定是一个缺失。
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