Demodulation:DF2:Results:Maximum Carrier Drift (Hz) Property

NI Bluetooth Analysis Toolkit 18.0 Help

Edition Date: January 2019

Part Number: 373431K-01

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Short Name: DF2 Maximum Carrier Drift (Hz)

Property of niBTAnalysis

Returns the maximum carrier frequency drift. This value is expressed in Hz.

The toolkit integrates the frequency of the FM demodulated signal starting from the center of the first preamble bit to the center of the first bit following the last preamble bit. For LE-LR-125k packets, the frequency integration is done from the start of the third preamble bit to the end of the 18th preamble bit. This value is recorded as f0 .

For LE-LR-125k packets, the frequency offsets are calculated also for the three 16-bit groups after the 18th bit in the preamble and are recorded as f1 , f2 , and f3 .

The toolkit then integrates the frequency deviation of every x bits in the payload starting from the yth payload symbol and it is repeated until the end of the payload duration. The integral sums are recorded as fn (n≥4 for LE-LR-125k and n≥1 for all other packets). The frequency drift is computed as the difference between the initial carrier frequency tolerance and fn . However, the sign is retained in the result. The toolkit finds the maximum of |f0 -fn | over different acquisitions and adds corresponding (f0 -fn ) sign to the result.

For LE-Enhanced packets, x = 20 and y = 2.

For LE-LR-125k packets, x = 16 and y = 27.

For BR and all other LE packets, x = 10 and y = 2.

Refer to section 5.1.11 of the Bluetooth Test Specification Radio Frequency Test Suite Structure (TSS) and Test Purposes (TP) Specification 1.2/2.0/2.0+EDR/2.1/2.1+EDR/3.0/3.0+HS for more information about BR packets, and sections 4.6.4, 4.6.9, and 4.6.11 of Bluetooth Test Specification 5.0.0 for more information about LE packets.

The toolkit averages this measurement, using peak hold averaging, over the number of acquisitions specified by the DF2 Number of Averages property.

Note  Maximum Carrier Drift results are not applicable for DM1, DM3, DM5, HV1, HV2, HV3, AUX1, EV4, and EV5 packets for DF2 measurements. The standard measurement procedure requires the payload test pattern 10101010 without any parity bits. For LE-LR-125k packets, coded bit sequence of 11110000 resulting from an LE payload pattern of 11111111 gives valid value for this measurement.

Remarks

The following table lists the characteristics of this property.

Datatype /images/reference/en-XX/help/373431K-01/cdbl.gif
PermissionsRead Only
High-level VIs niBT SA DF2 Get Maximum Carrier Drift
ResettableNo

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