Patent ID: 7079591
Filing Date: 2006-07-18
Classification: G01V,H03D

Abstract:
1. A data recovery subsystem for use in a receive system configured to receive a magnetic field signal including a carrier component usable for locating an underground object and at least one modulation sideband, the data recovery subsystem comprising: a first mixer adapted to mix a Radio Frequency (RF) signal representative of the magnetic field signal with a first Local Oscillator (LO) signal to produce an Intermediate Frequency (IF) signal representative of the magnetic field signal, the IF signal including an IF carrier component and an IF modulation sideband; a Phase Locked Loop (PLL) adapted to phase-lock a second LO signal to the IF carrier component of the IF signal; a second mixer adapted to synchronously mix the IF signal with the second LO signal to produce a baseband signal including a demodulated sideband, the demodulated sideband corresponding to the modulation sideband of the magnetic field signal a baseband filter adapted to filter the baseband signal and thereby produce a filtered baseband signal including the demodulated sideband; a signal squarer following the baseband filter and adapted to derive a logic signal from the filtered baseband signal, the logic signal being representative of information conveyed by the demodulated sideband a local oscillator for generating a local clock; and a data synchronizer adapted to