niWLANG_ChannelNumberToCarrierFrequency80211af

NI WLAN Generation Toolkit 18.0 Help

Edition Date: October 2018

Part Number: 373725J-01

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int32 __stdcall niWLANG_ChannelNumberToCarrierFrequency80211af (float64 channelStartingFrequency, float64 channelBandwidth, int32 channelNumber, int32 TVHTMode, float64 *carrierFrequency);

Purpose

Calculates the carrier frequency of 802.11af channels, as defined in section 23.3.14 of IEEE Standard 802.11af-2013.

Parameters

Input
Name Type Description
channelStartingFrequency float64 Specifies the start frequency of the frequency band. The default value is 45 MHz. The channel start frequency is given by the following formula:

Channel Starting Frequency (Hz) = Channel Starting Factor * 500 kHz This value is expressed in Hz.
channelBandwidth float64 Specifies the channel bandwidth used for transmitting the signal. The default value is 6 MHz. This value is expressed in Hz.
channelNumber int32 Specifies the offset of the center frequency, in increments of the channel bandwidth used for transmitting the signal. This value is expressed in Hz. The default value is 1 MHz.
TVHTMode int32 Specifies the mode of the 802.11af signal transmission.

The default value is NIWLANG_VAL_TVHT_MODE_4.

NIWLANG_VAL_TVHT_MODE_1(0) Specifies the TVHT mode representing a single Basic Channel Unit (BCU).
NIWLANG_VAL_TVHT_MODE_2C(1) Specifies the TVHT mode representing two contiguous BCUs.
NIWLANG_VAL_TVHT_MODE_2N(2) Specifies the TVHT mode representing two noncontiguous BCUs.
NIWLANG_VAL_TVHT_MODE_4C(3) Specifies the TVHT mode representing four contiguous BCUs.
NIWLANG_VAL_TVHT_MODE_4N(4) Specifies the TVHT mode representing two noncontiguous frequency segments, each of which are composed of two BCUs.
Output
Name Type Description
carrierFrequency float64* Returns the carrier frequency. This value is expressed in Hz.

The function calculates the carrier frequency using the following equation:

carrier frequency (Hz) = channel starting frequency (Hz) + (TVHT_W * channel number + channel center frequency correction (Hz)

where channel center frequency correction (Hz) is used to adjust the carrier frequency in the different TVHT modes. It is 0 for NIWLANG_VAL_TVHT_MODE_1 and NIWLANG_VAL_TVHT_MODE_2N, 0.5 * TVHT_W for NIWLANG_VAL_TVHT_MODE_2C and NIWLANG_VAL_TVHT_MODE_4N and 1.5 * TVHT_W for NIWLANG_VAL_TVHT_MODE_4C.

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 the function to determine if an error occurred.

To obtain a text description of the status code, call the niWLANG_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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