# US 12,181,497 B2 · Voltage measurement and/or overvoltage protection circuit for a measurement instrument > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,181,497 B2 - Document ID: US12181497B2 - Status: Granted - Kind: B2 - Application number: 18/058,644 - Filed: 2022-11-23 - Published: 2024-05-23 - Granted: 2024-12-31 - Earliest claimed: 2022-11-23 - Assignees: Rohde & Schwarz GmbH & Co. KG - Applicants: Rohde & Schwarz GmbH & Co. KG - Inventors: Franz Strasser - Web page: https://patentgrep.com/patent/US12181497B2 ## CPC - G01R 1/36: Overload-protection arrangements or circuits for electric measuring instruments - G01R 15/04: Voltage dividers - G01R 15/125: {for digital multimeters} - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) ## Abstract A voltage measurement and/or overvoltage protection circuit for a measurement instrument comprising a measurement channel with at least one termination resistor and a measurement port is provided. Said voltage measurement and/or overvoltage protection circuit comprises at least one resistor. In this context, the voltage measurement and/or overvoltage protection circuit is contactable to the measurement port via said at least one resistor. In addition to this, a resistance of the at least one resistor is higher than a maximum resistance of the at least one termination resistor. ## Claims ### Claim 1 A voltage measurement or overvoltage protection circuit or any combination thereof for a measurement instrument comprising a measurement channel with at least one termination resistor and a measurement port, said voltage measurement or overvoltage protection circuit or any combination thereof comprising: at least one resistor, wherein the voltage measurement or overvoltage protection circuit or any combination thereof is contactable to the measurement port via said at least one resistor, and wherein a resistance of the at least one resistor is higher than a maximum resistance of the at least one termination resistor. ### Claim 2 (depends on 1) The voltage measurement or overvoltage protection circuit or any combination thereof according to claim 1, wherein the resistance of the at least one resistor is selected from at least 10 times higher, at least 15 times higher, at least 20 times higher, or at least 25 times higher, than the maximum resistance of the at least one termination resistor. ### Claim 3 (depends on 1) The voltage measurement or overvoltage protection circuit or any combination thereof according to claim 1, wherein the at least one resistor comprises at least a first resistor for contacting the measurement port and a second resistor following said first resistor. ### Claim 4 (depends on 3) The voltage measurement or overvoltage protection circuit or any combination thereof according to claim 3, wherein the first resistor comprises or is of a first construction form, wherein the second resistor comprises or is of a second construction form, and wherein the first construction form is smaller than the second construction form. ### Claim 5 (depends on 1) The voltage measurement or overvoltage protection circuit or any combination thereof according to claim 1, said voltage measurement or overvoltage protection circuit or any combination thereof further comprising: an amplifier for dividing a voltage provided by the at least one resistor according to a defined factor, or buffering said voltage provided by the at least one resistor in order to provide a divided or buffered voltage, or any combination thereof. ### Claim 6 (depends on 5) The voltage measurement or overvoltage protection circuit or any combination thereof according to claim 5, said voltage measurement or overvoltage protection circuit or any combination thereof further comprising: an analog-to-digital converter for digitizing the divided or buffered voltage or any combination thereof in order to provide a digitized voltage. ### Claim 7 (depends on 6) The voltage measurement or overvoltage protection circuit or any combination thereof according to claim 6, wherein the analog-to-digital converter is configured to provide the digitized voltage for the measurement instrument. ### Claim 8 (depends on 6) The voltage measurement or overvoltage protection circuit or any combination thereof according to claim 6, said voltage measurement or overvoltage protection circuit or any combination thereof further comprising: a processor for determining at least one measurement value on the basis of the digitized voltage. ### Claim 9 (depends on 8) The voltage measurement or overvoltage protection circuit or any combination thereof according to claim 8, wherein the processor is configured to provide the at least one measurement value for the measurement instrument. ### Claim 10 (depends on 8) The voltage measurement or overvoltage protection circuit or any combination thereof according to claim 8, wherein, when the at least one termination resistor is switchable between at least a first termination resistor comprising a first termination resistance and a second termination resistor comprising a second termination resistance being lower than said first termination resistance, the processor is configured to control the measurement instrument to switch to the first termination resistor if a defined voltage threshold is exceeded. ### Claim 11 (depends on 8) The voltage measurement or overvoltage protection circuit or any combination thereof according to claim 8, wherein, when the at least one termination resistor is switchable between at least a first termination resistor comprising a first termination resistance and a second termination resistor comprising a second termination resistance being lower than said first termination resistance, the processor is configured to control the measurement instrument to forbid switching to the second termination resistor if a defined voltage threshold is exceeded. ### Claim 12 (depends on 8) The voltage measurement or overvoltage protection circuit or any combination thereof according to claim 8, said voltage measurement or overvoltage protection circuit or any combination thereof further comprising: an additional analog-to-digital converter, wherein, when the at least one termination resistor is switchable between at least a first termination resistor comprising a first termination resistance and a second termination resistor comprising a second termination resistance being lower than said first termination resistance, the additional analog-to-digital converter is configured to digitize a voltage provided by the first termination resistor if a defined voltage threshold is exceeded in order to provide an additional digitized voltage. ### Claim 13 (depends on 12) The voltage measurement or overvoltage protection circuit or any combination thereof according to claim 12, wherein the processor is configured to determine at least one additional measurement value, in the form of a direct component, a frequency, a root mean square value, or any combination thereof, on the basis of the additional digitized voltage. ### Claim 14 (depends on 13) The voltage measurement or overvoltage protection circuit or any combination thereof according to claim 13, wherein the processor is configured to provide the at least one additional measurement value for the measurement instrument. ### Claim 15 (depends on 1) A measurement instrument comprising: the measurement channel with the at least one termination resistor and the measurement port, and the voltage measurement or overvoltage protection circuit or any combination thereof according to claim 1 being contacted to the measurement port. ### Claim 16 (depends on 15) The measurement instrument according to claim 15, wherein the measurement instrument comprises or is an oscilloscope, a voltmeter, a power meter, a spectrum analyzer, or any combination thereof. ### Claim 17 (depends on 15) The measurement instrument according to claim 15, said measurement instrument further comprising: a display for displaying at least one measurement value. ### Claim 18 (depends on 15) The measurement instrument according to claim 15, wherein the voltage measurement or overvoltage protection circuit or any combination thereof is active if the measurement channel is inactive. ### Claim 19 (depends on 15) The measurement instrument according to claim 15, wherein the measurement port comprises or is a coaxial connector, or wherein the at least one termination resistor comprises at least a first termination resistor comprising a first termination resistance and a second termination resistor comprising a second termination resistance being lower than said first termination resistance, or wherein the measurement channel comprises a termination resistor switch for switching between at least a first termination resistor comprising a first termination resistance and a second termination resistor comprising a second termination resistance being lower than said first termination resistance, or any combination thereof. ### Claim 20 An overvoltage protection method for operating a measurement instrument comprising a measurement channel with at least one termination resistor, a measurement port, and a voltage measurement or overvoltage protection circuit or any combination thereof being contacted to the measurement port, said at least one termination resistor being switchable between at least a first termination resistor comprising a first termination resistance and a second termination resistor comprising a second termination resistance being lower than said first termination resistance, said overvoltage protection method comprising the steps of: measuring a voltage with respect to the measurement port via at least one resistor, a resistance of said at least one resistor being higher than a maximum resistance of the at least one termination resistor, switching to the first termination resistor if a defined voltage threshold is exceeded with respect to the second termination resistor, or forbidding switching to the second termination resistor if the defined voltage threshold is exceeded with respect to the second termination resistor.