Why must the ADC sampling rate in an EW receiver be high enough?

• A. To reduce power consumption
• B. To simplify digital downconversion
• C. To preserve information by capturing the signal bandwidth for processing
• D. To eliminate quantization error entirely

Answer: (C)

The most important idea is that the ADC must be fast enough to capture the entire signal bandwidth so the digital processor can reconstruct and analyze the waveform without losing information. According to Nyquist principles, sampling at or above twice the bandwidth prevents aliasing, meaning all spectral content within the band can be represented in the digital domain for processing such as detection, demodulation, and feature extraction. If the rate is too low, high-frequency components fold into lower ones, corrupting the information you rely on in EW processing.

Higher sampling rates do not magically eliminate quantization error, and they don’t inherently make digital downconversion simpler; they mainly preserve the information in the signal for later processing.