Abstract
For the evaluation of the characteristics of a continuous linear system is known correlation function technique which is based essentially upon the following simple relation:
φyz(τ)=∫T0g(s)φmz(τ-s)ds where g(s) is an impulse response, m(t) is an M-sequence input with a basic clock pulse interval Δ and a total pulse number N in a period T, y(t) is an output and φyz(τ) is a cross correlation function between the output y(t) and an appropriate function z(t).
In the conventional correlation method, z(t) is an M-sequence signal, while, in the persent paper, it is proposed that z(t) be z(t)=NΣk=1{m(t)+c}δ(t-kΔ+Δ/2) where δ(t) is the delta function and c is an appropriate constant.
For processing the output data to evaluate an estimate of the impulse response is derived a simple computational algorithm which, by proper choice of the constant c, is made to reduce to a minimum the effect of additive noises present at the M-sequence input and at the measured output. Furthermore, an analysis of error introduced by non-ideal input transducer is also developed.
The error estimate is given when the above algorithm is applied to a second order system. The experimental results through an analog computer simulation are in good agreement with the calculated estimate.
