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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