What is an Anti-Aliasing Filter & How to Use It

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An anti-aliasing filter is a low-pass filter used before analog-to-digital converters (ADCs) to prevent aliasing, which occurs when high-frequency signals are misrepresented as lower frequencies. It attenuates frequency components that exceed the Nyquist frequency, which is half the sampling rate. This filtering is crucial for ensuring accurate digital representation of analog signals. Without an anti-aliasing filter, high-frequency signals can interfere with the integrity of the sampled data. Proper use of an anti-aliasing filter is essential for high-quality signal processing.
meldave00
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Hi,

Can anyone tell me what an anti-aliasing filter is and how it is used?

regards,

meldave
 
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Aliasing is an undesired effect in the use of analog-to-digital converters. Frequency components above the the Nyquist band (above half the sampling frequency) get "mirrored" into lower frequencies inside the Nyquist band. Once a high frequency has been aliased, there is no way to distinguish it from a real low-frequency signal.

An anti-aliasing filter is a low-pass filter, put before the ADC, that attenuates frequency components above the Nyquist band.

- Warren
 
Thanks. I appreciate it.
 

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