This work demonstrates correlation of microwave signals encoded with 16-bit codes using the parametric interaction of spin waves. Signal processing correlators are devices that compare two signals, such as a reference code and a received code, where the output indicates the similarity between the signals. Correlators are used in communication systems such as wireless mobile networks, wireless local area networks, and the global positioning system in order to increase signal-to-noise ratio and in some cases to selectively communicate with individual devices. Modern correlators have digital components, which require complex circuitry. In contrast, state-of-the-art analog correlators offer simpler topologies, but lack code reprogrammability, which is common in digital correlators. This work implements a novel analog correlator that operates at microwave frequencies, has a simple topology, and offers code reprogrammability. The correlator in this work uses a microwave magnetic field to parametrically pump spin waves in a yttrium iron garnet thin film. The performance of the correlator was verified by computing the cross-correlation of 16-bit orthogonal Walsh-Hadamard codes and by exhaustively computing the cross-correlation of all combinations of 4-bit, 5-bit, 6-bit, and 7-bit codes. The maximum processing gain achieved by the correlator in this work was 8.05 dB for 7-bit codes, which is .40 dB less than the theoretical maximum.