Demodulation:CFO:Results:Maximum Carrier Drift Rate (Hz) Property

Short Name: CFO Maximum Carrier Drift Rate (Hz)

Property of niBTAnalysis

Returns the maximum carrier frequency drift rate and it is denoted by |f_n -f_n-3 |_max for LE-LR-125k and |f_n -f_n-5 |_max for all other packets. 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 18^th 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 18^th 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 y^th payload symbol and it is repeated until the end of the payload duration. The integral sums are recorded as f_n (n≥4 for LE-LR-125k and n≥1 for all other packets). The frequency drift rate is computed as the absolute difference between two x-bit groups separated by z microseconds. The maximum of all these difference values over different acquisitions is the maximum carrier frequency drift rate.

For LE-Enhanced packets, x = 20, y = 2, and z = 50.

For LE-LR-125k packets, x = 16, y = 27, and z = 48.

For BR and all other LE packets, x = 10, y = 2, and z = 50.

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 CFO Number of Averages property. The absolute value in each iteration is used for peak hold averaging.

Note  The results of this property are not applicable for DM1, DM3, DM5, HV1, HV2, HV3, AUX1, EV4, and EV5 packets for carrier frequency offset (CFO) measurements. The standard measurement procedure requires the payload test pattern of 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
Permissions	Read Only
High-level VIs	niBT SA CFO Get Maximum Carrier Drift Rate
Resettable	No