Understand PXIe-4302 Alias-Free Bandwidth Specification

Updated Jul 16, 2026

Reported In

Hardware

  • PXIe-4302

Issue Details

I am reviewing the NI PXIe-4302/4303 Device Specifications and observing that the devices list different frequency limits. I have doubts related to which value I can use for the PXIe-4302.
As a result, I am unable to determine the correct value to use when calculating the alias-free bandwidth for the PXIe-4302.
Additionally, I would like to better understand what these frequency specifications represent and how they relate to the alias-free bandwidth.

Solution

 
Aliasing occurs when the sampling rate does not satisfy the Nyquist criterion (fs ≥ 2 × highest input frequency). If a signal is sampled at a sampling rate smaller than twice the Nyquist frequency, false lower-frequency components appear in the sampled data. This phenomenon is referred to as aliasing.  
 
The PXIe‑4302 supports sampling rates from 1 S/s to 5 kS/s. All filtering specifications can consider this range as a reference.
 
The usable input frequency range (alias-free bandwidth) depends on fs as follows:
  • For 1 S/s ≤ fs < 25 S/s:
    Alias-free bandwidth = 0.1 × fs
  • For 25 S/s ≤ fs ≤ 5 kS/s:
    Alias-free bandwidth = 0.45 × fs
Example calculations:
  • If the device is configured to sample at 3 kS/s:
    • Alias-free bandwidth = 0.45 × 3000 S/s = 1350 Hz
    • The passband frequency will be from 0 Hz to 1350 Hz.
  • If the device is configured to sample at 10 S/s:
    • Alias-free bandwidth = 0.1 × 10 S/s = 1 Hz
    • The passband frequency will be from 0 Hz to 1 Hz.
In other words, the filter passes all input signals with frequencies between 0 Hz and the passband's upper cutoff frequency, while attenuating or rejecting signals with frequencies above this cutoff.