Patent ID: 8687674

Claim:
An apparatus for receiving a spread-spectrum (SS) signal transmitted at a radio-frequency (RF) and recovering information coded therein, comprising: (a) a first surface acoustic wave (SAW) correlator having an input and an output, with the input of the first SAW correlator being operatively connected to an antenna to receive the SS signal; (b) a first RF envelope detector connected to the output of the first SAW correlator to rectify the output of the first SAW correlator; (c) a second SAW correlator with the input thereof operatively connected to the antenna to receive the SS signal; (d) a second RF envelope detector connected to the output of the second SAW correlator to rectify the output of the second SAW correlator; (e) a first pulse-shaping circuit connected to the first RF envelope detector to receive the rectified output of the first SAW correlator and to produce therefrom a first bipolar pulse signal having a first period inversely related to a first intermediate frequency, with the first intermediate frequency being lower than a carrier frequency of the SS signal; (f) a second pulse-shaping circuit connected to the second RF envelope detector to receive the rectified output of the second SAW correlator and to produce therefrom a second bipolar electrical pulse signal having a second period inversely related to a second intermediate frequency, with the second intermediate frequency being lower than the carrier frequency of the SS signal; and (g) a third correlator operatively connected to receive the first and second bipolar electrical pulse signals at an input thereof and to provide at an output thereof a low-frequency output signal containing the information in a decoded state.