DSO noise floor - seems high?
![Post Post](./styles/prosilver/imageset/icon_post_target.gif)
Hello
I was taking some measurements of harmonic levels from a 7MHz sine wave carrier and was struggling to spot the harmonics amongst the general noise levels, so I thought I would investigate some more.
My setup is a Windows 10 laptop (latest software - build 1903), plus a Virtins DSO-2820E running MI v3.8.5.2. The laptop was running on battery. WiFi was switched off. No other equipment was running in the same room.
With only the 'A' channel enabled and the probe connected but short-circuited, the attached spectrum was seen using a 200MHz sample rate. The 'Y' scale was set to 'dbR'. Some smoothing was enabled (20 frames linear average) in order to achieve a stable display.
This noise floor seems very high and if correct is only allowing a very poor dynamic range. Would you regard this as any way normal? Is there something wrong with my setup. Is this noise being generated within the DSO?
I have tried using ferrite magnet cable clamps on the USB connecting cable - this made no difference.
I would appreciate your thoughts please.
regards
Bob
I was taking some measurements of harmonic levels from a 7MHz sine wave carrier and was struggling to spot the harmonics amongst the general noise levels, so I thought I would investigate some more.
My setup is a Windows 10 laptop (latest software - build 1903), plus a Virtins DSO-2820E running MI v3.8.5.2. The laptop was running on battery. WiFi was switched off. No other equipment was running in the same room.
With only the 'A' channel enabled and the probe connected but short-circuited, the attached spectrum was seen using a 200MHz sample rate. The 'Y' scale was set to 'dbR'. Some smoothing was enabled (20 frames linear average) in order to achieve a stable display.
This noise floor seems very high and if correct is only allowing a very poor dynamic range. Would you regard this as any way normal? Is there something wrong with my setup. Is this noise being generated within the DSO?
I have tried using ferrite magnet cable clamps on the USB connecting cable - this made no difference.
I would appreciate your thoughts please.
regards
Bob