Zoom In and Recapture for More Detail December 20, 2016BasicScope, HowToroderick A full 10 seconds of data are captured at 1 S/div. This appears as a big smear on the screen. We will move the time slider at the top 9 clicks to the left to zoom in. At 2 mS/div, we start to see some structure in the waveform. It appears that there are narrow pulses every millisecond. We will zoom in on the second pulse from the left, to see how wide it is. Position the mouse cursor over that pulse, and push the mouse wheel forward 5 clicks to zoom in 5 times. At this zoom level, the pulse appears to be 30 μS wide. But remember that this is just a digital magnification of the trace that was originally captured at 100 kSps. We will click on the “run oneshot” button to recapture this trace at a sample rate appropriate for 50 μS/div. On the recaptured trace, the pulse width is more like 20 or 25 μS wide. Note at the lower left that the sample rate of this recaptured trace is 1 Msps. There also appears to be a suggestion of some ringing on the edges. We will use the mouse wheel again to zoom in 3 more clicks to 5 μS/div. The pulse width is clearly 20 μS now. But we’re still looking at a trace captured at 1 Msps. We click the “run oneshot” button again to get more detail. The recapture at 5 μS/div provided us with 16 Msps. Now the ringing is defined – we could even take a frequency measurement on it if we wanted to. Let’s zoom and recapture one more time at the maximum sample rate of 48 Msps. Oops. Because the sampling buffer is very short at high sample rates, we cannot capture data this far away from the trigger – about 1 mS (1000 μS) in this case. Fortunately, this is a repetitive waveform, and we can drag or scroll the trace to a similar point closer to the trigger. This part of the trace looks exactly like the previous display, except that we are now 5.19 μS from the trigger. We try clicking on the “run oneshot” button again. This trace was taken at the limit of the hardware’s performance. Due to noise, 48 Msps does not look much better than 16 Msps, and moreover, the sample buffer is tiny – a mere 1016 samples. This is why some have said that, in practical terms, the 6022BE is really a 16 Msps scope. Hantek does provide sin(x)/x filtering to make the waveform look better, but this is turned off in BasicScope, to gain a tiny bit of performance, and because it doesn’t add any real information. Note that although the “run oneshot” button was used in this example, we could have used “run norm” for most things. Basicscope is able to scroll and zoom a trace while it is running.