A novel design of two-way multimedia loudspeaker
A multimedia loudspeaker usually stands on a desk, so the reflected sound from the desk interferes with the direct sound from the loudspeaker. Reflected sound from the desk must be taken into consideration in the designing process in order to obtain the flattest possible resultant frequency response in the listening position. This paper introduces a novel design of a two-way multimedia loudspeaker, which gives flat frequency response at broad range of distances from the listener.
Loudspeaker fault detection using Artificial Neural Network
Traditionally, loudspeaker's quality control has been done manually and inspection of loudspeaker faults is time consuming and causes error in the quality evaluation. In order to reduce the time consumption and errors in the quality evaluation, in this research work, a simple loudspeaker diagnosing system is developed based on the harmonic distortion. The faulty and normal loudspeakers are tested using the sound emanated from the loudspeaker in the frequency range between 20 Hz and 20,000 Hz. A fast Fourier transform (FFT) is applied on the recorded signal to transform from time domain to frequency domain and the frequency spectrum is obtained. From the frequency spectrum, first six frequency band and it corresponds the total energy are computed and chosen for further analysis. The total energy of the each frequency band signal are obtained and used as features for training the neural network. A simple neural network model is developed for the automatic detection of loudspeaker faults. From the result it is observed that the proposed method is able to classify the faults with an accuracy level of 84%.
Integrated two-beam antenna array featuring dual-circular polarization
A concept of an integrated antenna array featuring two independent beams and dual circular polarization has been described. The antenna array consists of two radiating elements which are excited at two orthogonally placed feeding ports with the use of four appropriately connected 3-dB/90° directional couplers. Therefore, such an array generates two symmetrically located beams having right-handed circular polarization (RHCP) and identical two beams having left-handed circular polarization (LHCP). The presented concept has been verified by the design and measurements of an antenna array operating at 2.4 GHz frequency range.