RADIO MODE SELECTIVITY BLOCK FOR A DETECTOR FOR DETECTING A BURIED CURRENT CARRYING CODUCTOR
First Claim
1. A radio mode selectivity block for a detector for detecting very low frequency magnetic emissions from a buried current carrying conductor, the detector having magnetic sensors for converting the magnetic emissions into field strength signals and an analogue to digital converter for digitising the field strength signals, the radio mode selectivity block comprising:
- a plurality of beat frequency oscillators to centre the bandwidth of detection of the field strength signals of the detector on target very low frequency (VLF) frequency bands;
summing means for summing the outputs of the beat frequency oscillators; and
multiplying means for multiplying the output of the summing means with said digitised signal.
1 Assignment
0 Petitions
Accused Products
Abstract
A radio mode selectivity block 41 for a detector 1 for detecting a buried current carrying conductor comprises a plurality of beat frequency oscillators 53 to centre the bandwidth of detection of the detector 1 on target very low frequency (VLF) frequency bands. The frequencies of the beat frequency oscillators are chosen to fall within the VLF frequency bands used in a number of countries, so that the detector 1 can be used in radio mode in these countries without the need for local configuration.
-
Citations
6 Claims
-
1. A radio mode selectivity block for a detector for detecting very low frequency magnetic emissions from a buried current carrying conductor, the detector having magnetic sensors for converting the magnetic emissions into field strength signals and an analogue to digital converter for digitising the field strength signals, the radio mode selectivity block comprising:
-
a plurality of beat frequency oscillators to centre the bandwidth of detection of the field strength signals of the detector on target very low frequency (VLF) frequency bands; summing means for summing the outputs of the beat frequency oscillators; and multiplying means for multiplying the output of the summing means with said digitised signal. - View Dependent Claims (2, 3, 4, 5, 6)
-
Specification