Shared Filter Bank Harmonic Transposition for Audio HFR

The patent implements a single analysis filter bank and a single synthesis filter bank that serve multiple transposition orders simultaneously. The analysis filter bank decomposes the input signal into subbands, and the synthesis filter bank reconstructs the signal from these subbands after nonlinear phase modification. This universal filter bank pair replaces what would traditionally require multiple separate filter bank pairs, thereby reducing computational complexity while maintaining the ability to perform accurate harmonic transposition at different orders.

The patent employs a universal analysis filter bank and synthesis filter bank pair that can be reused across multiple transposition orders. Instead of having separate filter banks for each transposition order (which would increase the quantity of components), the same filter banks are applied repeatedly with different nonlinear phase modifications. This reduces the number of filter bank components from multiple to just one pair, while still achieving high-quality synthesized signals through the nonlinear processing stage.

The patent merges the upsampling function with the existing synthesis filter bank structure. The synthesis filter bank, which already operates at the output sampling rate, performs both the signal reconstruction and the implicit upsampling in a single operation. By combining these functions, the system achieves sampling rate compatibility without adding a separate upsampling stage that would increase computational complexity. The filter bank inherently handles the sampling rate conversion as part of its reconstruction process.