AN ESTIMATION OF ACOUSTIC PARAMETERS OF PIEZOELECTRIC TELEPHONE BY MONTE-CARLO METHOD

A problem in the telephone handset is that there is no design formula that can relate the values of the parameters in the acoustic equivalen t circuit (acoustic parameters) of the earphone system directly to the shape (dimensions) of the actual handset. As a result, the design of the handset has been made very difficult. To derive such a formula, th e values of the acoustic parameters must be estimated accurately from the actual measurement of the handset. Previously, the authors have es timated that acoustic parameters, using the nonlinear optimization tec hnique, but a problem is still left that the number of parameters that can be simultaneously estimated is limited. This paper tries to solve this problem and proposes an estimation technique using the Monte Car lo method, which can also realize a high estimation accuracy. In the p roposed method, an allowable range for the actual response is defined and the acoustic parameters are estimated by modifying the upper and t he lower limits of each acoustic parameter so that the response stays within the allowable range. The proposed method has the advantages tha t the number of parameters to be estimated is not limited, a good agre ement can be realized with the actual response, and the decision can b e made without intuition. The approach also provides a useful means fo r the design of the whole system. Although this paper discusses the es timation for the piezoelectric telephone handset, the proposed method can be applied effectively to any type of telephone handset.