# US 11,307,231 B2 · Measurement system and method for determining a phase and amplitude influence of a device under test > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,307,231 B2 - Document ID: US11307231B2 - Status: Granted - Kind: B2 - Application number: 16/723,213 - Filed: 2019-12-20 - Published: 2020-06-25 - Granted: 2022-04-19 - Earliest claimed: 2018-12-21 - Assignees: Rohde & Schwarz GmbH & Co. KG - Applicants: Rohde & Schwarz GmbH & Co. KG - Inventors: Christian Kuhn; Werner Held - Web page: https://patentgrep.com/patent/US11307231B2 ## CPC - G01R 27/28: Measuring attenuation, gain, phase shift or derived characteristics of electric four pole networks, i.e. two-port networks; Measuring transient response (in line transmission systems H04B3/46) - G01R 31/2839: {using signal generators, power supplies or circuit analysers (G01R31/2879 takes precedence; multimeters G01R15/12, network analysers G01R27/28)} - G01R 31/31917: {Stimuli generation or application of test patterns to the device under test [DUT]} - G06F 1/022: {Waveform generators, i.e. devices for generating periodical functions of time, e.g. direct digital synthesizers (G06F1/025, G06F1/03 take precedence)} - H03H 17/06: Non-recursive filters - H03L 7/0814: {the phase shifting device being digitally controlled} - G01R 31/2837: {Characterising or performance testing, e.g. of frequency response (transient response G01R27/28)} - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) - H03H: IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS (waveguides, resonators, lines or other devices of the waveguide type H01P) - H03L: AUTOMATIC CONTROL, STARTING, SYNCHRONISATION OR STABILISATION OF GENERATORS OF ELECTRONIC OSCILLATIONS OR PULSES (generation of oscillations H03B) ## Abstract A measurement system for determining a phase and amplitude influence of a device under test, comprising a measurement instrument having a signal generator, a local oscillator, a first mixer and an analysis unit is disclosed. The signal generator is configured to generate a source signal with a predetermined source frequency and a source phase, and to forward the source signal to the device under test, wherein the source signal is altered by the device under test in at least one of amplitude and phase, such that a measurement signal is generated and forwarded to the first mixer. The local oscillator is configured to generate a local oscillator signal with a predetermined local oscillator frequency and a local oscillator phase, and to forward the local oscillator signal to the first mixer. The first mixer is configured to mix the measurement signal and the local oscillator signal, thereby generating a first mixer signal. The analysis unit is located downstream of the first mixer and is configured to analyze the first mixer signal or a processed version of the first mixer signal. The measurement instrument is configured to perform at least two measurements of the phase and amplitude influence of the device under test by analyzing the first mixer signal or the processed version of the first mixer signal, wherein at least one of the source phase and the local oscillator phase is altered between the at least two measurements. ## Claims ### Claim 1 A measurement system for determining a phase and amplitude influence of a device under test, comprising a measurement instrument having a signal generator, a local oscillator, a first mixer and an analysis unit, the signal generator being configured to generate a source signal with a predetermined source frequency and a source phase, and to forward said source signal to the device under test, wherein the source signal is altered by the device under test in at least one of amplitude and phase, such that a measurement signal is generated and forwarded to the first mixer, the local oscillator being configured to generate a local oscillator signal with a predetermined local oscillator frequency and a local oscillator phase, and to forward said local oscillator signal to the first mixer, the first mixer being configured to mix said measurement signal and said local oscillator signal, thereby generating a first mixer signal, the analysis unit being located downstream of the first mixer and being configured to analyze the first mixer signal or a processed version of said first mixer signal, and the measurement instrument being configured to perform at least two measurements of the phase and amplitude influence of the device under test by analyzing said first mixer signal or said processed version of said first mixer signal, wherein at least one of the source phase and the local oscillator phase is altered between the at least two measurements, wherein the measurement instrument is configured to alter at least one of the source phase or the local oscillator phase between the at least two measurements in such a way that the difference between the source phase and the local oscillator phase is changed by 90°. ### Claim 2 (depends on 1) The measurement system of claim 1, wherein the measurement instrument is configured to alter the source phase by 90° between the at least two measurements or to alter the local oscillator phase by 90° between the at least two measurements. ### Claim 3 (depends on 1) The measurement system of claim 1, wherein the analysis unit is configured to average over the at least two measurements. ### Claim 4 (depends on 1) The measurement system of claim 1, further comprising a numerically controlled oscillator and a second mixer, the numerically controlled oscillator being configured to generate a numerical oscillator signal with a predetermined numerical oscillator frequency and a numerical oscillator phase, and the numerically controlled oscillator being configured to forward said numerical oscillator signal to the second mixer, the second mixer being located downstream of the first mixer and upstream of the analysis unit, and the second mixer being configured to mix said numerical oscillator signal with said first mixer signal or with a processed version of said first mixer signal. ### Claim 5 (depends on 4) The measurement system of claim 4, wherein the numeric oscillator is configured to generate the numeric oscillator signal with a numeric oscillator phase being equal to the difference of the local oscillator phase and the source phase. ### Claim 6 (depends on 1) The measurement system of claim 1, wherein a low-pass filter is provided downstream of the first mixer immediately after the first mixer. ### Claim 7 (depends on 6) The measurement system of claim 6, wherein an analog-to-digital converter is provided downstream of the low-pass filter immediately after the low-pass filter. ### Claim 8 (depends on 1) The measurement system of claim 1, wherein the measurement instrument is configured to perform three or four measurements of the phase and amplitude influence of the device under test, wherein the measurement instrument is configured to alter at least one of the source phase and the local oscillator phase between the measurements in such a way that the difference between the source phase and the local oscillator phase is changed by 90° every time. ### Claim 9 (depends on 1) The measurement system of claim 1, comprising said device under test. ### Claim 10 (depends on 1) The measurement system of claim 1, wherein the measurement instrument is established as a vector network analyzer. ### Claim 11 A method for determining a phase and amplitude influence of a device under test, comprising the following steps: generating a source signal with a predetermined source frequency and a source phase, and forwarding said source signal to the device under test, wherein the source signal is altered by the device under test in at least one of amplitude and phase such that a measurement signal is generated, generating a local oscillator signal with a predetermined local oscillator frequency and a local oscillator phase, mixing said measurement signal and said local oscillator signal, thereby generating a first mixer signal, and analyzing the first mixer signal or a processed version of said first mixer signal in order to determine the phase and amplitude influence of the device under test, wherein the measurement defined by the steps above is performed at least twice, wherein at least one of the source phase and the local oscillator phase is altered between the two measurements, wherein at least one of the source phase or the local oscillator phase is altered between the at least two measurements in such a way that the difference between the source phase and the local oscillator phase is changed by 90°. ### Claim 12 (depends on 11) The method of claim 11, the source phase is altered by 90° between the at least two measurements or the local oscillator phase is altered by 90° between the at least two measurements. ### Claim 13 (depends on 11) The method of claim 11, wherein an average is taken over the at least two measurements. ### Claim 14 (depends on 11) The method of claim 11, wherein a numerical oscillator signal with a predetermined numerical oscillator frequency and a numerical oscillator phase is generated and mixed with said first mixer signal or said processed version of said first mixer signal. ### Claim 15 (depends on 14) The method of claim 14, wherein the numeric oscillator signal is generated with a numeric oscillator phase being equal to the difference of the local oscillator phase and the source phase. ### Claim 16 (depends on 11) The method of claim 11, wherein the measurement of the phase and amplitude influence of the device under test is performed three or four times, wherein at least one of the source phase and the local oscillator phase is altered between the individual measurements in such a way that the difference between the source phase and the local oscillator phase is changed by 90° every time. ### Claim 17 A measurement system for determining a phase and amplitude influence of a device under test, comprising a measurement instrument having a signal generator, a local oscillator, a first mixer and an analysis unit, the signal generator being configured to generate a source signal with a predetermined source frequency and a source phase, and to forward said source signal to the device under test, wherein the source signal is altered by the device under test in at least one of amplitude and phase, such that a measurement signal is generated and forwarded to the first mixer, the local oscillator being configured to generate a local oscillator signal with a predetermined local oscillator frequency and a local oscillator phase, and to forward said local oscillator signal to the first mixer, the first mixer being configured to mix said measurement signal and said local oscillator signal, thereby generating a first mixer signal, the analysis unit being located downstream of the first mixer and being configured to analyze the first mixer signal or a processed version of said first mixer signal, and the measurement instrument being configured to perform at least two measurements of the phase and amplitude influence of the device under test by analyzing said first mixer signal or said processed version of said first mixer signal, wherein at least one of the source phase and the local oscillator phase is altered between the at least two measurements, wherein the measurement instrument is configured to alter the source phase by 90° between the at least two measurements or to alter the local oscillator phase by 90° between the at least two measurements.