Making The Modulation Characteristics Measurement; Purpose; Measurement Method - Agilent Technologies ESA-E Series Measurement Manual

Making Bluetooth™ Measurements

Making the Modulation Characteristics Measurement

Making the Modulation Characteristics Measurement

Purpose

Modulation characteristics is a frequency deviation measurement which is
designed to verify both the modulator performance and the accuracy of the
pre-modulation 0.5BT Gaussian Filter.

Measurement Method

Two separate test signals are required for this measurement, each one containing
an 8-bit repeating sequence in the payload. These repeating sequences are
11110000 and 10101010.
The measurement is performed in 2 stages, each stage requiring a different packet:
one carrying the 11110000 payload, the other carrying the 10101010 payload.
Using the 11110000 payload
The average frequency over the first 8 bits in the payload is calculated and then the
maximum deviation from this average over bits 2,3,6 & 7 is measured. The
maximum for each repeating 8-bit sequence in the payload is measured in the same
way, each time calculating a new average frequency over the respective 8 bits.
Eventually, the average of all these maximums is calculated and shown in the
results window as ∆f1 Avg.
Using the 10101010 payload
The average frequency over the first 8 bits in the payload is calculated and then
the maximum deviation from this average over all 8 bits is measured. The
maximum for each repeating 8-bit sequence in the payload is measured in the same
way, each time calculating a new average frequency over the respective 8 bits.
Eventually the average of all these maximums is calculated and shown in the
results window as ∆f2 Avg.
Once the measurement has acquired values for ∆f1 Avg and ∆f2 Avg, the ratio of
∆f2 Avg to ∆f1 Avg is also displayed.
Since this measurement requires human interaction (to manually change test
signals), it will display only either ∆f1 Avg or ∆f2 Avg the first time it is run,
depending on the signal type. The first result must be "held" using the Hold Result
parameter and the measurement restarted. At this point the other signal type should
be supplied, and the measurement restarted.
If a remote query of all three results is requested after having obtained only one
result, then 3 values will be returned, although only 1 result will be correct and the
other 2 will contain NaN.
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