Most of the current speech transmission systems are only able to deliver speech signals in a narrow frequency band. This narrowband speech is characterized by a thin and muffled sound. In this paper, we propose a data hiding scheme to artificially extend the speech bandwidth so that the speech quality can be improved. The hardware perspectives of implementing the proposed scheme are also discussed. A Xilinx MicroBlaze soft processor is used in this study. To balance the trade off between logic resource consumption and processing speed, the data hiding scheme are mainly implemented in application software while fast Fourier transform (FFT) is designed into a hardware acceleration model. Experimental results demonstrate the effectiveness of the proposed data hiding scheme.