CHIRP TYPE SAW SPREAD SPECTRUM MODEM, ITS CONSTITUTING METHOD, COMMUNICATION EQUIPMENT AND SYSTEM USING THE MODEM, CHIRP SIGNAL MULTIPLEXING METHOD, AND DETECTION OF CORRELATION FROM MULTIPLEXED CHIRP SIGNAL

摘要

PURPOSE: To suitably generate a chirp signal and to detect correlations between the chirp signal and a spread spectrum modulation signal by taking one electrode from electrodes constituting each of first and second SAW(surface acoustic wave) filters, which are formed on a piezoelectric substrate, as a common electrode and using the complex conjugate property of the frequency characteristic of the common electrode. ;CONSTITUTION: An input electrode 2 and an output electrode 4 are constituted on the surface of a piezoelectric substrate 1 where a SAW is propagated, and the first SAW filter which outputs the chirp signal from the output electrode 4 at the time of input of an impulse to the input electrode 2 and the second SAW filter which detects correlations between the chirp signal and a signal subjected to spread spectrum modulation at the time of input or this signal to the input electrode 2 are provided. One of electrodes 2 and 4 is constituted as a common electrode 3. That is, the complex conjugate property of frequency characteristics of the common electrode 3 is used to perform chirp signal generation and correlation detection on the single piezoelectric substrate 1.;COPYRIGHT: (C)1995,JPO