Aliasing Frequenz Rechner
Berechnen Sie den aliased frequency when sampling above the Nyquist limit. Understand und prevent signal aliasing.
Aliased Frequency
14,100 Hz
Aliased Frequency vs Sampling Rate
Formel
How Aliasing Works
When a signal exceeds the Nyquist frequency (half the sampling rate), it "folds" back into the representable range, appearing as a lower frequency.
Formula
The aliased frequency is found by folding the signal into the first Nyquist zone:
f_alias = f_signal - round(f_signal / f_sample) x f_sample
If this result is above Nyquist, subtract from the sampling rate.
Example
A 30 kHz tone sampled at 44.1 kHz aliases to 14.1 kHz (44.1 - 30 = 14.1 kHz).Lösungsbeispiel
A 30 kHz signal sampled at 44.1 kHz.
- 01Nyquist: 44,100 / 2 = 22,050 Hz
- 0230,000 > 22,050, so aliasing occurs
- 03Alias: |30,000 - 1 x 44,100| = 14,100 Hz
- 04The 30 kHz signal appears as 14,100 Hz
Häufig Gestellte Fragen
Can I remove aliasing after sampling?
No. Once aliased, the false frequency is indistinguishable from a real signal at that frequency. Prevention (anti-aliasing filters) is the only solution.
Is aliasing always harmful?
Usually yes, but some systems exploit it intentionally (e.g., undersampling/bandpass sampling in RF receivers).
What is an anti-aliasing filter?
A low-pass filter placed before the ADC that removes frequencies above the Nyquist frequency to prevent aliasing.
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