Intelligent modulation recognition for multi-band signals based on a broadband Rydberg-atom receiver.

The broadband characteristic of Rydberg atoms renders them suitable for spectrum monitoring in high-frequency and multi-band joint wireless communication systems. We demonstrate a cross-band spectrum monitoring system, integrating atomic sensing with intelligent recognition. The cross-band signals resonate with different Rydberg transitions, and are coherently mapped to a unified intermediate-frequency channel via atomic superheterodyne detection. This scheme enables simultaneous multi-band reception with no observable inter-band crosstalk. The system achieves real-time modulation recognition directly from atomically-sensed streams, using a lightweight automatic modulation recognition model on an embedded platform. We demonstrate that the system enables low error-vector-magnitude reception of high-order modulated signals. Moreover, the system maintains a recognition accuracy above 80% with low latency over a signal-to-noise ratio range from -15 dB to 20 dB. This unified framework provides a viable route toward scalable, quantum-enhanced intelligent sensing in complex electromagnetic environments.