Optimized Volume Control Architecture for Cascaded Audio System

Cascaded audio systems (CASs) widely exist in consumer electronics, within which volume control is one of the most basic functions. However, the current volume adjustment schemes cannot automatically achieve optimal control, leading to performance degradation of CASs. Meanwhile, there is a lack of mathematical models and quantitative analysis between CASs performance and volume control position. In this study, an optimal volume control architecture named local processing and amplification (LPA) is proposed to minimize the volume control's adverse impact on CASs' performance automatically. First, a general CAS model is established through effective analysis and reasonable equivalence of diverse complicated CASs. Second, the quantitative relationship between the volume control and the CAS performance is theoretically analyzed using the noise figure theory, hence, the LPA architecture is proposed. Finally, the proposed LPA's performance improvement effect is analyzed and compared with the other volume controls in a wide volume range. Simulations and experiments using multiple indexes show that the signal-to-noise ratio (SNR) and the total harmonic distortion plus noise (THD+N) improvement of the proposed architecture are up to 5.2 dB and 4.8 dB, respectively, under a typical -9 dB volume.