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12 QPSK EVM Measurement
The quadrature phase shift keying (QPSK) error vector magnitude (EVM) measurement is a measure of
phase and amplitude modulation quality that relates the performance of the actual signal compared to an
ideal signal as a percentage, as calculated over the course of the ideal constellation. These phase and
frequency errors are measures of modulation quality for the W-CDMA (3GPP) system, and can be
quantified through QPSK EVM measurements. For measurement results and views, see “View/Display”
on page 836.
This topic contains the following sections:
“Measurement Commands for QPSK EVM” on page 779
“Remote Command Results for QPSK EVM Measurement” on page 779
Measurement Commands for QPSK EVM
The general functionality of CONFigure, FETCh, MEASure, and READ are described at the beginning
of this section. See the SENSe:EVMQpsk commands for more measurement related commands.
:CONFigure:EVMQpsk
:CONFigure:EVMQpsk:NDEFault
:FETCh:EVMQpsk[n]?
:READ:EVMQpsk[n]?
:MEASure:EVMQpsk[n]?
For more measurement related commands, see the SENSe subsystem, and the section “Remote
Measurement Functions” on page 1031.
Remote Command Results for QPSK EVM Measurement
n Results Returned
0 Returns unprocessed I/Q trace data, as a series of comma-separated trace points, in volts.