Returns the measurement status, margin, margin-frequency, and absolute and relative power corresponding to the margin-frequency for lower offset segment. The relative power is relative to the peak power in the carrier.
Use "segment<n>/chain<k>/offset<<i>l</i>>" as the selector string to read results from this function.

Syntax

int32 __stdcall RFmxWLAN_SEMFetchLowerOffsetMargin(niRFmxInstrHandle instrumentHandle, char selectorString[], float64 timeout, int32 *measurementStatus, float64 *margin, float64 *marginFrequency, float64 *marginAbsolutePower, float64 *marginRelativePower)

Parameters

NameDirectionTypeDescription
instrumentHandle[in]niRFmxInstrHandle

This parameter specifies the RFmx session refnum. Instrument Handle In is obtained from the RFmxInstr_Initialize function or the RFmxInstr_InitializeFromNIRFSASessionArray function.

selectorString[in]char

This parameter specifies a Selector String comprising of the signal name, result name, segment number, chain number, and offset number. If you do not specify the signal name, the default signal instance is used. The default value is "segment0/chain0/offset0".
Example:
"segment0/chain0/offset0"
"signal::sig1/segment0/chain0/offset0"
"signal::sig1/result::r1/segment0/chain0/offset0"
"result::r1/segment0/chain0/offset0"
You can use the RFmxWLAN Build Offset String function to build the selector string.

timeout[in]float64

This parameter specifies the timeout for fetching the specified measurement. Set this value to an appropriate time, longer than expected for fetching the measurement. A value of -1 specifies that the function waits until the measurement is complete. This value is expressed in seconds. The default value is 10.

measurementStatus[out]int32 *

This parameter returns the lower offset (negative) segment measurement status, indicating whether the spectrum exceeds the SEM measurement mask limits in the lower offset segment.

Name

Value

Description

RFMXWLAN_VAL_SEM_LOWER_OFFSET_MEASUREMENT_STATUS_FAIL

0 (0x0)

Indicates that the measurement has failed.

RFMXWLAN_VAL_SEM_LOWER_OFFSET_MEASUREMENT_STATUS_PASS

1 (0x1)

Indicates that the measurement has passed.

margin[out]float64 *

This parameter returns the margin from the SEM measurement mask for the lower offset. This value is expressed in dB. Margin is defined as the maximum difference between the spectrum and the mask.

marginFrequency[out]float64 *

This parameter returns the frequency corresponding to the margin for the lower offset. This value is expressed in Hz.

marginAbsolutePower[out]float64 *

This parameter returns the absolute power corresponding to the margin for the lower offset. This value is expressed in dBm.

marginRelativePower[out]float64 *

This parameter returns the relative power corresponding to the margin for the lower offset. The relative power is relative to the peak power of the carrier channel. This value is expressed in dB.

Returns

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 RFmx 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 RFmxWLAN_GetError function.

The general meaning of the status code is as follows:

Value

Meaning

0

Success

Positive Values

Warnings

Negative Values

Errors