Correlation measurement method for determining complex envelope of time dispersion function in radio channel - correlating received base band signal with second code signal having higher symbol rate

The correlation method involves producing a first code signal is produced in a transmitter. The autocorrelation of the code signal is free of neighbouring correlation peaks. The first code signal is converted by a baseband clock signal to have a symbol rate of 1/TA. The base band signal is shifted to a carrier frequency and transmitted to the receiver. The received baseband signal is correlated with a second code signal, produced in the receiver at an increased symbol rate 1/TB, an integer number multiple of the first symbol rate 1/TA. USE/ADVANTAGE - Investigating local, time dependent and frequency-selective characteristics of radio communications paths. Insensitive to interference. With given minimal resolution of echo signal delays, requires small bandwidth of transmitter signal.