# US 2018/0026737 A1 · Determining ambient noise in a device under test electromagnetic compatibility test environment > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0026737 A1 - Document ID: US20180026737A1 - Status: Published application - Kind: A1 - Application number: 15/217,577 - Filed: 2016-07-22 - Published: 2018-01-25 - Earliest claimed: 2016-07-22 - Assignees: The DIRECTV Group, Inc. - Applicants: The DIRECTV Group, Inc. - Inventors: William Kucheravy - Web page: https://patentgrep.com/patent/US20180026737A1 ## CPC - H04J 11/0023: {Interference mitigation or co-ordination (direct sequence spread spectrum [DSSS] systems H04B1/7097; frequency hopping H04B1/713; allocation criteria for ingress interference avoidance H04L5/0062; frequency allocation criteria for requirements on out-of-channel emissions H04L5/0066; arrangements for removing intersymbol interference or baseband equalisers H04L25/03006; peak power aspects in multicarrier modulation H04L27/2614; power management H04W52/00; traffic scheduling H04W72/54, H04W72/541)} - G01R 31/001: {Measuring interference from external sources to, or emission from, the device under test, e.g. EMC, EMI, EMP or ESD testing (measuring electromagnetic fields G01R29/08; circuits for generating HV pulses in dielectric strength testing G01R31/14)} - H04B 17/102: {Power radiated at antenna} - H04L 1/24: Testing correct operation - H04L 1/242: {by comparing a transmitted test signal with a locally generated replica} - H04L 1/248: {Distortion measuring systems (measurement of non-linear distortion G01R23/20; measuring characteristics of individual pulses, e.g. deviation from pulse flatness, rise time, duration G01R29/02)} - G01R 29/0814: {Field measurements related to measuring influence on or from apparatus, components or humans (EMC, EMI and similar testing in general G01R31/001), e.g. in ESD, EMI, EMC, EMP testing, measuring radiation leakage; detecting presence of micro- or radiowave emitters; dosimetry; testing shielding; measurements related to lightning} - G01R 29/26: Measuring noise figure; Measuring signal-to-noise ratio - G01R 31/002: {where the device under test is an electronic circuit} - G01R 31/31709: {Jitter measurements; Jitter generators (measuring jitter, noise figure or signal-to-noise ratio per se G01R29/26; analysis of tester signals G01R31/31901)} - H04J: MULTIPLEX COMMUNICATION (transmission in general H04B; peculiar to transmission of digital information H04L5/00; systems for the simultaneous or sequential transmission of more than one television signal H04N7/08; in exchanges H04Q11/00; stereophonic systems H04S) - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) - H04B: TRANSMISSION - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract Determining ambient noise in a device under test electromagnetic compatibility test environment is presented herein. A method can include determining, by a system comprising a processor via a radio frequency input port of the system, an ambient electromagnetic noise corresponding to the system; and in response to determining, by the system via the radio frequency input port, a radio frequency signature of a device under test, subtracting, by the system, the ambient electromagnetic noise from the radio frequency signature to obtain a normalized value representing an electromagnetic emission of the device under test. In an example, an antenna/coaxial cable has been connected to the radio frequency input port, the ambient electromagnetic noise can be determined using the antenna/coaxial cable, and a radiated/conducted electromagnetic characteristic of the device under test representing the radio frequency signature of the device under test can be determined using the antenna/coaxial cable. ## Claims ### Claim 1 A method, comprising: determining, by a system comprising a processor via a radio frequency input port of the system, an ambient electromagnetic noise corresponding to the system; and in response to determining, by the system via the radio frequency input port, a radio frequency signature of a device under test, subtracting, by the system, the ambient electromagnetic noise from the radio frequency signature to obtain a normalized value representing an electromagnetic emission of the device under test. ### Claim 2 (depends on 1) The method of claim 1, further comprising: storing, by the system, an ambient noise value representing the ambient electromagnetic noise in a storage medium of the system, wherein the subtracting comprises: retrieving the ambient electromagnetic noise value from the storage medium; and subtracting the ambient electromagnetic noise value from the radio frequency signature to obtain the normalized value representing the electromagnetic emission of the device under test. ### Claim 3 (depends on 1) The method of claim 1, wherein the operations further comprise: electronically coupling the radio frequency input port to the processor using a radio frequency switch. ### Claim 4 (depends on 1) The method of claim 1, wherein an antenna has been connected to the radio frequency input port, and wherein the determining the ambient electromagnetic noise comprises determining, via the antenna, the ambient electromagnetic noise corresponding to the system. ### Claim 5 (depends on 4) The method of claim 4, wherein the determining the radio frequency signature of the device under test comprises determining, via the antenna, a radiated electromagnetic characteristic of the device under test representing the radio frequency signature of the device under test. ### Claim 6 (depends on 1) The method of claim 1, wherein a coaxial cable has been connected to the radio frequency input port, and wherein the determining the ambient electromagnetic noise comprises determining, via the coaxial cable, the ambient electromagnetic noise corresponding to the system. ### Claim 7 (depends on 6) The method of claim 6, wherein the coaxial cable has been connected between the radio frequency input port and the device under test, and wherein the determining the radio frequency signature of the device under test comprises determining, via the coaxial cable, a conducted electromagnetic characteristic of the device under test representing the radio frequency signature of the device under test. ### Claim 8 A system, comprising: a processor; and a memory that stores executable instructions that, when executed by the processor, facilitate performance of operations, comprising: in response to receiving, during a first configuration of the system, a first input signal via a radio frequency port of the system, determining a noise floor of a measurement environment of the system; and in response to receiving, during a second configuration of the system via the radio frequency port, a second input signal representing an electromagnetic characteristic of a device under test, subtracting the noise floor from the electromagnetic characteristic to obtain an electromagnetic emission of the device under test. ### Claim 9 (depends on 8) The system of claim 8, wherein the operations further comprise storing a background noise value representing the noise floor in a storage medium of the system, and wherein the subtracting comprises: retrieving the background noise value from the storage medium; and subtracting the background noise value from the electromagnetic characteristic to obtain the electromagnetic emission of the device under test. ### Claim 10 (depends on 8) The system of claim 8, wherein the operations further comprise: coupling the radio frequency port to an electrical interface coupled to the processor using a radio frequency switch. ### Claim 11 (depends on 8) The system of claim 8, wherein an antenna has been connected to the input port, and wherein the determining the noise floor comprises determining, using the antenna, the noise floor of the measuring environment of the system. ### Claim 12 (depends on 11) The system of claim 11, wherein the receiving the second input signal comprises: receiving, using the antenna, the second input signal; and based on the second input signal, determining a radiated characteristic of the device under test representing the electromagnetic characteristic of the device under test. ### Claim 13 (depends on 8) The system of claim 8, wherein a coaxial cable has been connected to the input port, and wherein the determining the noise floor comprises determining, using the coaxial cable, the noise floor of the measuring environment of the system. ### Claim 14 (depends on 13) The system of claim 13, wherein the receiving the second input signal comprises: receiving, using the coaxial cable, the second input signal; and based on the second input signal, determining a conducted characteristic of the device under test representing the electromagnetic characteristic of the device under test. ### Claim 15 A machine-readable storage medium, comprising executable instructions that, when executed by a processor, facilitate performance of operations, comprising: electronically coupling an input port to an electrical interface communicatively coupled to the processor; determining, via the input port, background electromagnetic noise; and in response to determining, via the input port, an electromagnetic characteristic of a device under test, subtracting the background electromagnetic noise from the electromagnetic characteristic to obtain an electromagnetic emission of the device under test. ### Claim 16 (depends on 15) The machine-readable storage medium of claim 15, wherein the operation further comprise storing a background noise value representing the background electromagnetic noise in a memory, and wherein the subtracting comprises: retrieving the background noise value from the memory; and subtracting the background noise value from the electromagnetic noise characteristic to obtain the electromagnetic emission of the device under test. ### Claim 17 (depends on 15) The machine-readable storage medium of claim 15, wherein the determining the background electromagnetic noise comprises determining, using an antenna that has been connected to the input port, the background electromagnetic noise. ### Claim 18 (depends on 17) The machine-readable storage medium of claim 17, wherein the determining the electromagnetic characteristic comprises determining, using the antenna, a radiated electromagnetic characteristic of the device under test. ### Claim 19 (depends on 15) The machine-readable storage medium of claim 15, wherein the determining the background electromagnetic noise comprises determining, using a coaxial cable that has been connected to the input port, the background electromagnetic noise. ### Claim 20 (depends on 19) The machine-readable storage medium of claim 19, wherein the determining the electromagnetic characteristic comprises determining, using the coaxial cable, a conducted electromagnetic characteristic of the device under test.