125-14 4CH, high frequency clipping of LV input
Posted: Tue Oct 01, 2024 2:31 pm
I plan to use Red Pitaya 125-14 4-channel to measure a signal between -5 V and +1 V.
I am only interested in the part of the signal between -1 V and +1 V, so my plan is to measure in LV input range and just let the signal clip whenever it is below -1 V.
The specification page says: absolute maximum input voltage 30 V.
But then it also says:
I would like to understand the reason for the 1 kHz limitation. My signal contains frequencies up to 1 MHz. How will this affect the overload protection in the Red Pitaya?
The schematic implies that the input filter can handle up to 30 mA. It seems to me that even at 1 MHz and 10 pF input capacitance, the input current will stay far below that limit.
So what is the specific risk in overloading the input with a high frequency signal?
Switching to HV input range will impact the noise of our measurement, so I would very much like to avoid that.
I am only interested in the part of the signal between -1 V and +1 V, so my plan is to measure in LV input range and just let the signal clip whenever it is below -1 V.
The specification page says: absolute maximum input voltage 30 V.
But then it also says:
https://redpitaya.readthedocs.io/en/lat ... astIO.htmlThe overload protection is valid for low-frequency signals. For input signals that contain frequency components beyond 1 kHz, the full-scale value defines the maximum admissible input voltage.
I would like to understand the reason for the 1 kHz limitation. My signal contains frequencies up to 1 MHz. How will this affect the overload protection in the Red Pitaya?
The schematic implies that the input filter can handle up to 30 mA. It seems to me that even at 1 MHz and 10 pF input capacitance, the input current will stay far below that limit.
So what is the specific risk in overloading the input with a high frequency signal?
Switching to HV input range will impact the noise of our measurement, so I would very much like to avoid that.