1. The problem is to understand the MATLAB code snippet involving signal processing operations. 2. The code defines a vector $b$ as a product of several components: a scaled sinc function, a complex exponential, and a Blackman window. 3. The sinc function $\text{sinc}(x)$ is defined as $\frac{\sin(\pi x)}{\pi x}$ and is used here as $0.3 \times \text{sinc}(0.219 \times (-x:x))$, which creates a band-limited filter shape centered around zero. 4. The complex exponential term $\exp\left(-i 2 \pi \frac{0:N}{\text{numFFT}} \left((1-\frac{1}{2}) \times \text{subbandSize} + 0.5 + \frac{\text{numFFT}}{2}\right)\right)$ shifts the frequency of the sinc function to the desired sub-band. 5. Multiplying by the Blackman window $\text{blackman}(65)'$ tapers the edges of the filter to reduce spectral leakage, improving frequency selectivity. 6. In summary, this code constructs a band-pass filter $b$ by windowing a frequency-shifted sinc function with a Blackman window. Final answer: The code creates a frequency-shifted, windowed sinc filter for sub-band filtering in signal processing.