NIWLANA_RESULT_OFDM_DEMOD_IQ_GAIN_IMBALANCE_STANDARD_DEVIATION

NI WLAN Analysis Toolkit 18.0 Help

Edition Date: October 2018

Part Number: 373724K-01

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Data Type: float64
Access:read only
Functions:niWLANA_GetScalarAttributeF64
Description: Returns the standard deviation of the I/Q gain imbalance estimates. This value is expressed in dB. I/Q gain imbalance is the ratio of the mean amplitude of the in-phase (I) signal to the mean amplitude of the quadrature-phase (Q) signal.

If you set the NIWLANA_STANDARD attribute to NIWLANA_VAL_STANDARD_80211AG_OFDM, NIWLANA_VAL_STANDARD_80211J_OFDM, NIWLANA_VAL_STANDARD_80211P_OFDM or NIWLANA_VAL_STANDARD_80211G_DSSS_OFDM, you must use an empty string as the active channel string format to query this attribute.
If you set the NIWLANA_STANDARD attribute to NIWLANA_VAL_STANDARD_80211N_MIMO_OFDM or NIWLANA_VAL_STANDARD_80211AH_MIMO_OFDM, you must use 'channelx' as the active channel string format to query this attribute.
If you set the NIWLANA_STANDARD attribute to NIWLANA_VAL_STANDARD_80211AC_MIMO_OFDM, NIWLANA_VAL_STANDARD_80211AF_MIMO_OFDM or NIWLANA_VAL_STANDARD_80211AX_MIMO_OFDM, you must use '[segmentx/]channely' as the active channel string format to query this attribute. 'segment0/' is optional if the NIWLANA_NUMBER_OF_SEGMENTS attribute is set to 1.

Refer to the Configuring Active Channels (LabWindows/CVI) topic for more information about configuring active channels.

Note: The result of this attribute is invalid if you set the NIWLANA_OFDM_DEMOD_COMBINED_SIGNAL_DEMODULATION_ENABLED attribute to NIWLANA_VAL_TRUE.

Note: If the magnitude of the carrier or the Sample clock frequency offset is greater than 25 ppm, I/Q gain imbalance magnitude is greater than 3 dB, and quadrature skew magnitude is greater than 15 degrees, the estimates of these impairments might be inaccurate.

Note: If the cable connecting the device under test (DUT) and the NI-RFSA has significant low-pass characteristics or in-band ripple, measuring OFDM I/Q gain imbalance and quadrature skew may be adversely affected.

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