Litepoint Corporation

Qingjie Lu

Christian Volf Olgaard

Ruizu Wang

Chen Cao

An example method includes following operations: (i) receiving a device signal from a device under test (DUT); (ii) setting an attenuation value; (iii) applying the attenuation value to the device signal to produce an attenuated device signal for a frequency spectrum analyzing device, where the frequency spectrum analyzing device produces a noise signal and intermodulation interference; (iv) obtaining a power spectral density value, where the power spectral density value comprises a power, at a frequency value, of a combined signal that is based on the attenuated device signal, the noise signal, and the intermodulation interference; (v) repeating operations (ii), (iii), and (iv) one or more times to produce multiple power spectral density values; (vi) repeating operations (i), (ii), (iii), (iv), and (v) one or more times to add power spectral density values to the multiple power spectral density values; and (vii) obtaining a power spectral density of the device signal.

Removing test equipment intermodulation interference and noise from power spectral density measurements

An example method includes the following operations: (i) receiving a device signal from a device under test (DUT); (ii) setting an attenuation value; (iii) applying the attenuation value to the device signal to produce an attenuated device signal for a frequency spectrum analyzing device, where the frequency spectrum analyzing device produces a noise signal; (iv) obtaining a power spectral density value using the frequency spectrum analyzing device, where a power spectral density comprises a power, at a frequency value, of a combined signal that is based on the attenuated device signal and the noise signal; (v) repeating operations (ii), (iii), and (iv) one or more times to produce multiple power spectral density values; (vi) repeating operations (i), (ii), (iii), (iv), and (v) one or more times to add power spectral density values to the multiple power spectral density values; and (vii) obtaining a power spectral density of the device signal.

Removing test equipment noise from power spectral density measurements

An example process determines a first error vector magnitude (EVM) of a signal output by a device under test (DUT). The process includes adding attenuation on a signal path between the DUT and a vector signal analyzer (VSA), where the attenuation is changeable: measuring, at the VSA, at least two second EVMs for different values of attenuation of the signal output by the DUT, where the at least two second EVMs are corrupted by noise from the VSA, and where each of the at least two second EVMs is based on two or more measurements; and determining the first EVM based on a linear relationship that is based on the first EVM, the at least two second EVMs, and a function based on the attenuation, where the first EVM is without at least some of the noise from the VSA.

Correcting error vector magnitude measurements

An example test system includes memory (e.g., one or more memory devices) storing (i) instructions that are executable, and (ii) a mapping function that relates first error vector magnitudes (EVMs) for first symbols to second EVMs for the first symbols, where the first EVMs are corrupted by radio frequency (RF) noise and the second EVMs are corrupted by both RF noise and symbol decoding errors. The test system also includes a decoder to receive a signal from a device under test, and to obtain a third EVM for a second symbol that is based on the signal, where the third EVM is corrupted by both RF noise and a symbol decoding error. One or more processing devices are configured to execute the instructions to adjust the third EVM using the mapping function to correct the symbol decoding error in the third EVM.

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Shanghai, China

Qingjie Lu