EEVblog Electronics Community Forum
Products => Test Equipment => Topic started by: sharktank1 on June 06, 2020, 01:05:14 am
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I just did this update and it did fix a few things (Auto setup used to brick the scope). But now I've lost my impedance settings per channel and the frequency filtering per channel. Where did they go?
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Surely you didn't do a hardware update...
I've also noticed that the impedance setting is gone in this firmware, but I guess it's because you couldn't really change the impedance anyway. It's fixed at 1 M for this scope, so having a menu item for it makes no sense. What do you mean by frequency filtering? The channel bandwidth limit (to 20 MHz) is where it used to be.
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Don't you think that impedance could be also 50 ohm if you use a terminator?
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OP do you mean you can no longer set 1x, 2x, 5x 1Meg, etc probe imp?
And you can't choose 20MHz or full BW ?
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SDS1104X-E never had 50ohm input impedance option, only 1M
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OP do you mean you can no longer set 1x, 2x, 5x 1Meg, etc probe imp?
And you can't choose 20MHz or full BW ?
No, very early SDS1*04X-E SW had a 50 ohm input selection yet the X-E models have never had the HW installed to accommodate such.
AFAIK this was a SW carryover from the earlier SDS1*02X models that share the same UI.
As it was confusing and 50 ohm inputs are not supported the option was removed from the X-E channel menu.
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But, in BodePlot menu and in FFT meny there need be impedance selection and afaik there is and if user do not change default value is 50ohm. And this impedance setting mean EXTERNAL impedance (load) in scope input terminal. Impedance setting must be there and it is there. Other case it is impossible to select power scale for vertical (usually dBm). So, all places where need be 50ohm selection there is. (there is more, user can select also of course some other values just arbitrary or mostly used standard values like 75, 120, 300, 600 ohm etc)
In SDS1x04X-E models have never been internal 50ohm (but as @tautech told in scope input menu it have been in very old FW but without any effect as residue from other model).
And when user set these values in FFT or BP settings user is responsible about impedance matching in scope end of test setup, so if your transmission line is 50ohm need add external feed tthru terminator to scope input and select 50ohm in scope settings. In SDS1104X-E there is not this setting in normal xt scope setup menu. But there is also not power scale. This setting is with operating modes where user can also select power scale instead of voltage (or current). In this scope BP and FFT.