Remote sensing (RS) image change detection methods based on deep learning such as convolutional neural networks (CNN) and transformers are still spatial domain-based image processing methods by nature, and their detection accuracy is strongly affected by chromatic aberration due to imaging time, shadows caused by lighting conditions, and object confusion and other disturbances. In this study, we revisit change detection (CD) from a signal processing perspective, framing it as the task of consistency detection of the distributional features of two 2D signals. We aim to extract the primary components of the two signals while suppressing interfering noises. To address this, we propose a novel CD method called DFNet, which leverages a dual-frequency learnable encoder. First, we construct a dualfrequency feature encoder Siamese framework to capture local high-frequency signals and global low-frequency signals using CNN and attention mechanisms after dividing the input RS image signals into two channels. Second, we introduce the frequency explicit visual center (FEVC) module as part of the multifrequency domain dense interaction (MFDDI) module at the decoder stage, allowing long-distance dependency to be established between high-low frequency components in the same layer as well as signal aggregation in regions of small edge variations. In addition, the MFDDI module adopts a layer-bylayer interactive fusion approach to synthesize discriminative information in a wide frequency domain range, enhancing the characterization capability of frequency domain signals. We