With the rapid advancement of Earth observation technologies and the growing demand for intelligent remote sensing applications, high-resolution remote sensing imagery provides critical data support for a range of downstream applications, including land monitoring and disaster assessment. In this context, multi-label remote sensing image classification has become an important research task, because a single image may contain multiple ground-object categories with complex spatial distributions and semantic co-occurrence relationships. However, challenges such as the coexistence of multiscale objects, complex semantic dependencies, and long-tail category distributions impose significant limitations on existing methods in terms of feature representation capacity and class-balanced modeling. To address these challenges, a Multiscale Dynamic Reasoning Network (MSDR-Net) is proposed. Different from methods that focus on localized optimization for a single challenge, MSDR-Net establishes a task-driven modeling framework that jointly integrates multiscale feature extraction, label-aware semantic reasoning, and long-tail category optimization within an end-to-end architecture. The proposed network consists of three core modules. The Multiscale Feature Enhancement (MSFE) module incorporates a Feature Pyramid Network-based fusion mechanism, integrating deep semantic information with shallow, detailed features to effectively enhance the representation of multiscale objects. The Dynamic Semantic Reasoning (DSR) module introduces a Transformer-based global attention mechanism that models long-range dependencies among image features, enabling the capture of complex global semantic relationships. In the loss optimization stage, a Difficulty-Weighted Loss (DW-Loss) is introduced, which jointly incorporates category frequency weights and prior difficulty coefficients to dynamically regulate the contributions of rare classes and hard samples during training, thereby mitigating bias induced by class imbalance. Experiments conducted on the large-scale Detection in Optical Remote Sensing Images dataset demonstrate that the proposed method achieves superior performance. Ablation studies validate the effectiveness of each component, while comparative experiments indicate that MSDR-Net achieves a mean Average Precision of 95.88%, outperforming existing state-of-the-art methods. An improvement of approximately 1.74% is observed over the strongest baseline, MSCA, with consistent advantages demonstrated across Overall F1 and Class-wise F1 metrics. By unifying multiscale feature extraction, global semantic reasoning, and balanced loss optimization within a single framework, MSDR-Net provides a robust and efficient solution for multi-label classification in complex remote sensing scenarios.

To address limitations in the modulation-quality analysis of high-order Quadrature Amplitude Modulation (QAM) signals, including insufficient timing synchronization accuracy, challenges in carrier recovery, and coupling between synchronization errors and parameter estimation, a cascaded digital baseband processing framework tailored for measurement scenarios is proposed. The proposed framework is designed to integrate synchronization recovery and parameter measurement. In the timing synchronization stage, a feedforward open-loop structure based on the Oerder–Meyr (OM) algorithm is employed to estimate the optimal sampling instants rapidly. In the carrier synchronization stage, a two-stage recovery structure is constructed, comprising coarse frequency offset estimation based on polarity decision and fine synchronization using an improved frequency–phase detector (FPD), thereby achieving both robust acquisition of large frequency offsets and high-precision compensation of residual errors. On this basis, a unified modulation quality evaluation model is established, enabling the joint estimation of the Error Vector Magnitude (EVM) and the Modulation Error Ratio (MER), as well as amplitude, phase, and frequency errors, within a consistent analytical framework. System-level validation of 256 QAM and 1024 QAM signals is conducted using a MATLAB R2021b-based simulation platform. The results demonstrate that stable synchronization recovery can be achieved under timing, frequency, and phase perturbations, yielding well-defined constellation diagrams. In terms of parameter estimation, the relative errors of all evaluated metrics are maintained within 2%, which is significantly below the conventional 5% measurement criterion. Further analysis indicates that the proposed method maintains strong robustness across varying signal-to-noise ratios (SNRs) and sampling rates. The results confirm that the proposed cascaded processing framework effectively unifies synchronization recovery and modulation quality analysis, significantly improving parameter estimation accuracy while maintaining high synchronization precision. This approach provides a practical and efficient solution for high-order QAM signal testing and measurement systems.