# US 11,029,437 B2 · System, method and apparatus for providing an in-line buried wire guidance amplifier > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,029,437 B2 - Document ID: US11029437B2 - Status: Granted - Kind: B2 - Application number: 16/409,924 - Filed: 2019-05-13 - Published: 2019-11-14 - Granted: 2021-06-08 - Earliest claimed: 2018-05-14 - Assignees: Valmont Industries, Inc. - Applicants: Valmont Industries, Inc. - Inventors: Lowell Imhof - Web page: https://patentgrep.com/patent/US11029437B2 ## CPC - G01V 3/08: operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices (with electromagnetic waves G01V3/12) - G01V 3/12: operating with electromagnetic waves {(operating with millimetre waves G01V8/005)} - G01V 3/16: specially adapted for use from aircraft (G01V3/165 - G01V3/175 take precedence) - G01R 29/085: {for detecting presence or location of electric lines or cables (fault detection G01R31/50; fault location G01R31/08)} - G01V: GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS (means for indicating the location of accidentally buried, e.g. snow-buried, persons A63B29/02) - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) ## Abstract The present invention provides a filter which is configured to filter frequencies created by noise outside of the band of interest and to then amplify the filtered signal to allow a weaker signal to be used for guidance. According to a first preferred embodiment, the filter of the present invention includes a 5th order active high pass filter cascaded with a 5th order active low pass filter. According to a further preferred embodiment, the filter of the present invention preferably provides a cutoff of frequencies below 700 Hz and above 1500 Hz. According to a further preferred embodiment, the filter of the present invention further uses a voltage amplifying circuit to amplify the filtered signal. ## Claims ### Claim 1 A system for detecting a location of a buried wire, wherein the system comprises: an antenna array, wherein the antenna array is comprised of a first steering antenna, a second steering antenna; and a reference antenna; wherein the reference antenna is positioned between the first steering antenna and the second steering antenna; a guidance receiver, wherein the guidance receiver is configured to receive and process signals from the antenna array to determine the relative position of the antenna array to the buried wire; and a guidance receiver filter; wherein the guidance receiver filter is interposed between the antenna array and the guidance receiver; wherein the guidance receiver filter is comprised of a 5th order active high pass filter cascaded with a 5th order active low pass filter to produce a filtered signal; wherein the guidance receiver filter is configured to cutoff of frequencies below 700 Hz and above 1500 Hz; wherein the guidance receiver filter comprises a voltage amplifying circuit; wherein the guidance receiver filter comprises a rail splitting circuit; wherein the guidance receiver filter comprises an input signal buffer circuit; wherein the 5th order active high pass filter comprises a 5th order high pass filter/amplifier circuit; wherein the 5th order active low pass filter comprises a 5th order low pass filter/amplifier circuit; wherein the rail splitting circuit comprises a voltage divider and a first non-inverting operational amplifier; wherein the voltage divider comprises a first resistor and a second resistor connected in series between a supply voltage and a grounding element; wherein the rail splitting circuit further comprises a first capacitor connected in parallel with the first resistor and a second capacitor connected in parallel with the second resistor; wherein the 5th order high pass filter/amplifier circuit comprises a 1st order high pass filter/amplifier circuit cascaded with a first 2nd order high pass filter circuit and a second 2nd order high pass filter circuit. ### Claim 2 (depends on 1) The system of claim 1, wherein the 1st order high pass filter/amplifier circuit comprises an RC network formed by a third capacitor and a third resistor. ### Claim 3 (depends on 2) The system of claim 2, wherein the 1st order high pass filter/amplifier circuit comprises a variable resistor which is configured to adjust the gain of the 1st order high pass filter/amplifier circuit. ### Claim 4 (depends on 3) The system of claim 3, wherein the first 2nd order high pass filter circuit comprises an RC network formed by a fourth resistor, a fourth capacitor, a fifth capacitor, a first operational amplifier and a first feedback resistor. ### Claim 5 (depends on 4) The system of claim 4, wherein the second 2nd order high pass filter circuit comprises an RC network formed by a fifth resistor, a sixth capacitor, a seventh capacitor, a second operational amplifier and a second feedback resistor. ### Claim 6 (depends on 5) The system of claim 5, wherein the 5th order low pass filter/amplifier circuit is configured to receive input directly from the 5th order high pass filter/amplifier circuit. ### Claim 7 (depends on 6) The system of claim 6, wherein the 5th order low pass filter/amplifier circuit comprises a first low pass filter/amplifier circuit cascaded with a first 2nd order low pass filter circuit and a second 2nd order lowpass filter circuit. ### Claim 8 (depends on 7) The system of claim 7, wherein 5th order low pass filter/amplifier circuit comprises an output connected to a resistor network comprising a fixed resistor and an adjustable resistor. ### Claim 9 (depends on 8) The system of claim 8, wherein the resistance of the adjustable resistor is configured to adjust the voltage gain of the 2nd order low pass filter/amplifier circuit. ### Claim 10 A system for detecting a location of a buried wire, wherein the system comprises: an antenna array, wherein the antenna array is comprised of a first steering antenna, a second steering antenna; and a reference antenna; wherein the reference antenna is positioned between the first steering antenna and the second steering antenna; a guidance receiver, wherein the guidance receiver is configured to receive and process signals from the antenna array to determine the relative position of the antenna array to the buried wire; and a guidance receiver filter; wherein the guidance receiver filter is interposed between the antenna array and the guidance receiver; wherein the guidance receiver filter is comprised of a 5th order active high pass filter cascaded with a 5th order active low pass filter to produce a filtered signal; wherein the guidance receiver filter is configured to cutoff of frequencies below 700 Hz and above 1500 Hz; wherein the guidance receiver filter comprises a voltage amplifying circuit; wherein the 5th order active high pass filter comprises a 5th order high pass filter/amplifier circuit; wherein the 5th order active low pass filter comprises a 5th order low pass filter/amplifier circuit; wherein the 5th order high pass filter/amplifier circuit comprises a 1st order high pass filter/amplifier circuit cascaded with a first 2nd order high pass filter circuit and a second 2nd order high pass filter circuit. ### Claim 11 (depends on 10) The system of claim 10, wherein the guidance receiver filter comprises a rail splitting circuit; wherein the guidance receiver filter comprises an input signal buffer circuit. ### Claim 12 (depends on 11) The system of claim 11, wherein the rail splitting circuit comprises a voltage divider and a first non-inverting operational amplifier. ### Claim 13 (depends on 12) The system of claim 12, wherein the voltage divider comprises a first resistor and a second resistor connected in series between a supply voltage and a grounding element. ### Claim 14 (depends on 13) The system of claim 13, wherein the rail splitting circuit further comprises a first capacitor connected in parallel with the first resistor and a second capacitor connected in parallel with the second resistor.