Decimation and interpolation change the sampling rate.
Decimation reduces the sample rate by M after low-pass filtering to avoid aliasing; interpolation raises the rate by L by inserting zeros and filtering. Polyphase structures and CIC filters make rate conversion efficient. Used in sample-rate converters and sigma-delta ADCs.
Converting 44.1 kHz audio to 48 kHz uses L/M=160/147.
Multirate processing changes the sampling rate in a system, which saves computation and allows different parts to run at suitable rates.
Decimation and interpolation change the sampling rate.
Multirate processing changes the sampling rate in a system, which saves computation and allows different parts to run at suitable rates.
Reducing the sampling rate by keeping every Mth sample, after low-pass filtering to prevent aliasing.
Increasing the sampling rate by inserting zeros and filtering, which fills in the new samples with smooth values.
Typical applications include reducing a high-rate audio stream before storage with decimation, upsampling a sensor record to match a DAC rate and converting between audio rates such as 44.1 kHz and 48 kHz.
Study "Butterworth, Chebyshev and elliptic filters" first (topic 34 of 101 in Signals, Control & Comms). It covers the groundwork this topic builds on.
Fractional rate change L/M. Polyphase. Efficient filter banks.
Converting 44.1 kHz audio to 48 kHz uses L/M=160/147.
The next topic is "Adaptive filters", which builds directly on this one.
It is classed as Beginner in Signals, Control & Comms (topic 35 of 101). It is an entry-level topic. It relies only on basic school mathematics and the ideas introduced earlier in this discipline.
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