Zoom on clever scope

In traditional oscilloscopes, increasing the volts per division scale to zoom in on a specific signal can lead to clipping, which may degrade the signal's accuracy. Is this the same phenomenon observed in the cleverscopes ?"

In traditional oscilloscopes, increasing the volts per division scale to zoom in on a specific signal can lead to clipping, which may degrade the signal's accuracy. Is this the same phenomenon observed in the cleverscopes ?"

Hello Biiro,
Our CS548 has only two ranges - +/-0.8V and +/-8V. These get multiplied by the probe ratio - eg a 10x probe is +/-8V and +/-80V.

We have a main capture window called the Scope display. It is a what you see is what you get display. If you were using a 10x probe, a +/-7V signal, and the max or minimum of the graph was less than +/-8V then the whole signal would be captured, even though you were looking at only a small part of it. If you had a signal that went outside +/-8V say +/-30V, then if you zoomed in to less than +/-8V the signal would get clipped.

Our resolution is 14 bits, so you get good resolution even when capturing a big signal, but looking at a small portion of it.

However, there is another way! We also have the Tracking Display, which lets you zoom on any part of the signal without changing the capture settings. Here you capture the big picture with the scope display, and then zoom on any part of it with the Tracking display. We have good zoom tools for that.

In the captures below I plugged a coax with a 1 MHz 1.2V signal into the A channel. I captured the signal on the left. Then I used the tracking graph to display the zoomed values on the right.

You can clearly see the capacitively coupled 1 MHz signal as the coax BNC approaches the A channel. Then you can see momentary bouncing disconnects. In the second set of signals I zoomed into small set of about 4 cycles heading downwards. You can see it is easy to check out any portion of the waveform. The CS548 has a deep buffer in both time and amplitude.

Does this help?
Bart

Hello Biiro, Our CS548 has only two ranges - +/-0.8V and +/-8V. These get multiplied by the probe ratio - eg a 10x probe is +/-8V and +/-80V. We have a main capture window called the Scope display. It is a what you see is what you get display. If you were using a 10x probe, a +/-7V signal, and the max or minimum of the graph was less than +/-8V then the whole signal would be captured, even though you were looking at only a small part of it. If you had a signal that went outside +/-8V say +/-30V, then if you zoomed in to less than +/-8V the signal would get clipped. Our resolution is 14 bits, so you get good resolution even when capturing a big signal, but looking at a small portion of it. However, there is another way! We also have the Tracking Display, which lets you zoom on any part of the signal without changing the capture settings. Here you capture the big picture with the scope display, and then zoom on any part of it with the Tracking display. We have good zoom tools for that. In the captures below I plugged a coax with a 1 MHz 1.2V signal into the A channel. I captured the signal on the left. Then I used the tracking graph to display the zoomed values on the right. You can clearly see the capacitively coupled 1 MHz signal as the coax BNC approaches the A channel. Then you can see momentary bouncing disconnects. In the second set of signals I zoomed into small set of about 4 cycles heading downwards. You can see it is easy to check out any portion of the waveform. The CS548 has a deep buffer in both time and amplitude. Does this help? Bart

The zoomed Tracking Display, with 25mV/div resolution:

The zoomed Tracking Display, with 25mV/div resolution:

And here is the bottom of that tracking display zoomed again, now with 10mV/div vertical resolution:

And here is the bottom of that tracking display zoomed again, now with 10mV/div vertical resolution:

Hi.

How is it for CS328A ? So these are 2 input ranges ? Same values ?

Marcin

Hi. How is it for CS328A ? So these are 2 input ranges ? Same values ? Marcin

Hi.

I found the document "Scaling and Offset in Cleverscope", So CS548 has 2 ranges, CS328A has 21 ranges (+/10V to +/- 21 mV) ? Do I understand correctly ?

Marcin

Hi. I found the document "Scaling and Offset in Cleverscope", So CS548 has 2 ranges, CS328A has 21 ranges (+/10V to +/- 21 mV) ? Do I understand correctly ? Marcin

Hello Marcin,
The CS328a has two hardware ranges which are +/-2.5V and +/-20V. Then we have variable gain amplifiers for sub range, and DAC's for offset. This allows you to choose a subsection of the available range eg 4.5 - 5.5V.

However the VGA and Offset Generator add noise to the signal. The net result is that just using a low noise 14 bit ADC without any scale or offset is better in most circumstances.

So that is why the CS548 only has two ranges.

I hope that helps,
Bart

Hello Marcin, The CS328a has two hardware ranges which are +/-2.5V and +/-20V. Then we have variable gain amplifiers for sub range, and DAC's for offset. This allows you to choose a subsection of the available range eg 4.5 - 5.5V. However the VGA and Offset Generator add noise to the signal. The net result is that just using a low noise 14 bit ADC without any scale or offset is better in most circumstances. So that is why the CS548 only has two ranges. I hope that helps, Bart