niWLANA_GetOFDMDemodSampleClockOffset

NI WLAN Analysis Toolkit 18.0 Help

Edition Date: October 2018

Part Number: 373724K-01

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int32 __stdcall niWLANA_GetOFDMDemodSampleClockOffset (niWLANAnalysisSession session, char channelString[], float64 *clockOffset);

Purpose

Returns the estimated Sample clock offset. The Sample clock offset is the difference between the Sample clocks at the digital-to-analog converter (DAC) of the transmitting device under test (DUT) and the digitizer. This value is expressed in parts per million (ppm).

If the clock offset value is more than 25 ppm, the estimated value might be inaccurate. The clock offset measurement follows section 17.3.9.5 of IEEE Standard 802.11a-1999 and section 20.3.21.6 of IEEE Standard 802.11n-2009, section 22.3.18.3 of IEEE Standard 802.11ac-2013, section 24.3.16.3 of IEEE P802.11ah/D1.3, and section 28.3.18.3 of IEEE P802.11ax/D3.0.

To understand which active channel strings are required to configure this function, refer to the NIWLANA_RESULT_OFDM_DEMOD_SAMPLE_CLOCK_OFFSET_AVERAGE attribute.

Note  If the magnitude of the carrier or the sample clock frequency offset is greater than 25 ppm the estimated value may be inaccurate.

Parameters

Input
Name Type Description
session niWLANAnalysisSession Specifies the niWLAN analysis session refnum.
channelString char[] Set this parameter to "" (empty string) or NULL.
Output
Name Type Description
clockOffset float64* Returns the estimated Sample clock offset The estimated offset is the difference between the Sample clocks at the DAC of the transmitting DUT and the digitizer. If the clock offset value is greater than 25 ppm, the estimated value may be inaccurate. This value is expressed in ppm.

Return Value

Name Type Description
status int32 Returns the status code of this operation. The status code either indicates success or describes an error or warning condition. Examine the status code from each call to an niWLAN function to determine if an error has occurred.

To obtain a text description of the status code and additional information about the error condition, call the niWLANA_GetErrorString function.

The general meaning of the status code is as follows:

Value Meaning
0 Success
Positive Values Warnings
Negative Values Errors

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