Abstract
A holder which converts the discrete input signal into continuous form by interpolation or extrapolation of the input pulse train is used frequently as an accessory of a digital computer.And this so called zero-order holder is commonly used.
The purpose of this paper is to find a systematic procedure for obtaining the transfer function of higher-order holders from Lagrange's interpolation formula connected with directly sampled values and to show the characteristics of the systems thus found.
A general method is made for the technique of realizing the higher-order holders. The Nthorder holders thus obtained are composed of a zeroorder holder, N integrators and several potentiometers. The frequency response and the error characteristic of the higher-order holder are given.
The instantaneous error and the mean squared errer of each holder to the sinusoidal input have been measured by using higher-order holders constructed on a hybrid computer.Then the maximum instantaneous errors of the holders to the sinusoidal input are estimated theoretically and experimentally. The experimental results show that the instantaneous errors and signal to noise ratios are improved remarkably by increasing the order of the holders.
