Transfer function

About: Transfer function is a research topic. Over the lifetime, 14362 publications have been published within this topic receiving 214983 citations. The topic is also known as: system function & network function.

Dynamic measurement of room impulse responses using a moving microphone.

Abstract: A technique for the recording of large sets of room impulse responses or head-related transfer functions is presented. The technique uses a microphone moving with constant speed. Given a setup (e.g., length of the room impulse response), a careful choice of the recording parameters (excitation signal, speed of movement) leads to the reconstruction of all impulse responses along the trajectory. In the case of a moving microphone along a circle, the maximal angular speed is given as a function of the length of the impulse response, its maximal temporal frequency, the speed of sound propagation, and the radius of the circle. As a result of the presented algorithm, head-related transfer functions sampled at 44.1kHz can be measured at all angular positions along the horizontal plane in less than 1s. The presented theory is compared with a real system implementation using a precision moving microphone holder. The practical setup is discussed together with its limitations.

Multi-channel echo cancel method, multi-channel sound transfer method, stereo echo canceller, stereo sound transfer apparatus and transfer function calculation apparatus

Abstract: Stereo sound signals are reproduced directly from loudspeakers (SP(L), SP(R)). By using a sum signal and a difference signal of the stereo sound signals as a reference signal, and according to a cross spectrum calculation of the reference signal with a microphone-collected sound signal, calculation is performed to obtain transfer functions of four sound transfer systems between the loudspeakers (SP(L), SP(R)) and microphones (MC(L), MC(R)). The transfer functions obtained are subjected to inverse Fourier transform to obtain impulse responses, which are set in filter means (40-1 to 40-4) to create echo cancel signals and perform echo canceling. This solves the problem of an indefinite coefficient in the echo cancel technique of a multi-channel sound signal.

A delayless subband active noise control system for wideband noise control

Abstract: In this paper, we present an efficient noise control algorithm based on the delayless subband adaptive filter. The algorithm reduces the computational complexity of the delayless subband filter by decomposing the secondary path response into a set of subband functions. In this new algorithm, the filtered reference signal is generated for each subband by using a short impulse response filter that models the secondary path transfer function in a subband-decomposed form. Computational efficiency of the presented method originates from the fact that the filtering process occurs only in one subband for each reference input sample. Furthermore, computational efficiency is enhanced when the presented algorithm is combined with an online identification of the secondary path transfer function. We also propose a frequency-domain implementation of the presented algorithm. In this implementation, it is shown that the computational complexity is further reduced by employing the block-processing approach.

Distributed system simulation using infinite product expansions

Abstract: Linear distributed dynamic system simulation using infinite product expansions for transcendental terms in transfer functions

Properties of Zero-Free Transfer Function Matrices

Abstract: Transfer functions of linear, time-invariant finite-dimensional systems with more outputs than inputs, as arise in factor analysis (for example in econometrics), have, for state-variable descriptio...