| Products > Test Equipment |
| Oscilloscope input noise comparison |
| << < (15/27) > >> |
| Andreas:
--- Quote from: maxwell3e10 on November 03, 2018, 01:03:11 pm --- Does anyone have any other high-end Keysight scopes to compare? --- End quote --- Unfortunately not; only a Tek 4104 MSO (from work). The device has 1 GHz bandwidth and 5 GS/s maximum sample rate. so this gives 20us/div * 10 div = 200 us for 1 MS on the x-axis. the most sensitive range is 1mV/Div * 10 Div so +/-5mV. @ 8 Bit giving 40uV/LSB. First set of measurements is done with internal 50 Ohms input. with full 1 GHz BW and 250 MHz /20 MHz limited band width. Interestingly the noise is much smaller with the 50 Ohms input (int) than with a external 50 Ohms terminator (ext). (see next post). So it seems that there are different signal paths for the 1 Meg and the 50 Ohms input resistance. with best regards Andreas |
| Andreas:
And now the measurements with external 50 Ohms terminator. (End cap). with best regards Andreas by the way: the RMS-value on the scope measurement seems to be including DC-Offset If I calculate standard deviation the values are much lesser. internal 50 Ohms: 1 GHz bandwidth SD = 90 uV 250 MHz bandwidth SD = 68 uV 20 MHz bandwidth SD = 29 uV external 50 Ohms: (1Meg input). 1 GHz bandwidth SD = 136 uV 250 MHz bandwidth SD = 108 uV 20 MHz bandwidth SD = 46 uV |
| maxwell3e10:
Here is a comparison of the 1 GHz+ scopes that I have so far. For full bandwidth I used 50 Ohm input, for 20 MHz bandwidth - 1 Mohm input. So far Rohde&Schwarz still looks the best. |
| _Wim_:
Hi, could it be that in the above graph for the RTM3004 the 20Mhz curve is for 1M input, and the 1Ghz one is for 50 ohm? If not, why is the low frequency noise higher with the 20Mhz limit enabled? I should read also, and not only look at the picture... :) |
| JPortici:
is it me or is the 20 MHz trace for the keysight showing a digital filter? |
| Navigation |
| Message Index |
| Next page |
| Previous page |