Question
What is the function of decimation?
Answer Options
- A) Converting data to binary-coded decimal form
- B) Reducing the effective sample rate by removing samples
- C) Attenuating the signal
- D) Removing unnecessary significant digits
Correct Answer: B
Explanation
In digital signal processing, particularly in Software Defined Radios (\text{SDRs}), the initial Analog-to-Digital Converter (\text{ADC}) often samples at an extremely high rate (many mega-samples per second) to capture a wide range of the radio spectrum. However, if the operator is only interested in a small portion of that spectrum (a narrow band), such a high data rate is unnecessary and inefficient.
The function of decimation is reducing the effective sample rate by removing samples (i.e., taking only every N^{th} sample). Decimation lowers the bandwidth required for the subsequent digital processing stages, simplifying the computations needed for filtering and demodulation in the narrow passband of interest.
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