| Products > Test Equipment |
| New toy(?) scope, DSO154pro, 1ch, claimed 40MS/s |
| << < (16/19) > >> |
| Fungus:
--- Quote from: Dave_g8 on March 26, 2024, 01:53:24 pm --- --- Quote from: BillyO on March 26, 2024, 02:12:42 am ---In this video @ 15:40 the bandwidth of the 154Pro is tested and does just fine @ 18MHz. No where near -3dB. --- End quote --- Yes, the analogue bandwidth of the front end is greater than 18MHz. --- End quote --- Yep. I've got one, if I put in a 22Mhz sine wave I see a perfect 18MHz sine wave on screen (as predicted). You need to go up to maybe 28Mhz before you see much attenuation. Those things are nice little gadgets but aliasing is a big problem even at "Arduino" frequencies. |
| Dave_g8:
Hi Bill, If you inject a 1MHz square wave with a faster edge, you will see more of a difference. The top trace is a Rigol sampling at 1GSa/s and there is no ripple. The DSO154Pro is fine, but you may not be seeing a true representation of the signal. |
| BillyO:
--- Quote from: Dave_g8 on March 26, 2024, 05:14:27 pm ---Hi Bill, If you inject a 1MHz square wave with a faster edge, you will see more of a difference. The top trace is a Rigol sampling at 1GSa/s and there is no ripple. The DSO154Pro is fine, but you may not be seeing a true representation of the signal. (Attachment Link) --- End quote --- You are seeing exactly what you should be seeing for a scope with 18MHz bandwidth. Harmonics above 18MHz will begin to be attenuated. Your image is showing good contributions from the first 16 or so harmonics. That is 100% expected for an 18MHz scope. I am willing to bet the other image comes from a scope with far greater bandwidth. In this case it has nothing to do with sample rate. Just bandwidth. |
| Dave_g8:
Hi Bill. If you put a 1MHz square wave into a 20MHz analogue oscilloscope, you will not see the ripple as seen on the DSO154Pro. |
| BillyO:
--- Quote from: Dave_g8 on March 26, 2024, 05:27:12 pm ---Hi Bill. If you put a 1MHz square wave into a 20MHz analogue oscilloscope, you will not see the ripple as seen on the DSO154Pro. --- End quote --- Well, you will but it will be harder to see because of the response of an analog scope. Here is an image of a square wave composed of the first 16 harmonics. Does it look familliar? |
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