Low-complexity direct conversion receiver for delay-and-correlate

Abstract

A direct conversion receiver for a delay-and-correlate transmitted reference spread spectrum signaling method and apparatus is based on minimal component digital circuitry instead of analog delay and multiplier circuits. The method allows direct RF to baseband conversion and eliminates the need for an IF stage. The receiver includes an RF converter for converting a received direct sequence spread spectrum signal to baseband. An analog-to-digital converter samples the baseband signal at a rate greater than the chipping rate of the direct sequence spread spectrum signal. A delay stage coupled to the output of the analog-to-digital converter generates a delayed signal. Multiplier logic receives output signals from the analog-to-digital converter and the delay stage and, in response, generates control output signals. A counter responsive to the control output signals increments or decrements a count or recycles, depending on the decoded control output signals.