Abstract
It is well known that impulse response of a linear system subject to an M-sequence input can be approximately obtained by correlating the input with the output.
A new delay method of M-sequence is proposed, showing that the j-th delayed versions are given by mk-j=yjTxk when the basic sequences are defined by mk=y0Txk13:35 2009/02/03. Here x and y are the state vectors of basic and adjoint shift registers, respectively. The subscripts 0, k and j are the sampling numbers. Then the error of approximation is evaluated theoretically, investigating the relation between the crosscorrelation and the impulse response. And it is shown that no steady state error exists in the measurement of impulse response.
On these principles, a portable correlating apparatus which is simple in the construction is trially built. Measurement and recording of the correlation are made automatically by this apparatus. The experimental results on the analogue simulated system are in good agreement with the theoretical prediction.
