R&S FSV-K8, Руководство по эксплуатации, Страница: 15 / 135

Introduction to Bluetooth Measurements (K8)
R&S
®
FSV-K8
15 Operating Manual 1176.7610.02 ─ 02
ture stability by sampling the IF signal and converting it digitally down into the base
band (I/Q area).
The measurements are performed by passing the following signal processing steps:
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LAP (Lower Address Part) trigger detection
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Resampling
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Channel filtering
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Automated packet and bit pattern detection
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Limit check
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Parallel display of measurement curves and numeric results on the screen
The figure 2-1 shows the R&S FSV hardware from the IF to the processor. The analog
IF filter is fixed to 20MHz. The A/D converter samples the 20 MHz IF signal with a sam-
pling frequency of 65.83 MHz.
Low pass filtering is performed after the signal has been down–converted into the com-
plex base band and the data rate is reduced in the sequence. The amount of decima-
tion depends on the selected oversampling factor = points / symbol. The default setting
is 4, resulting in a 4 MHz sampling rate. For EDR–measurements, the oversampling
factor is always fixed to 4. The resulting I/Q data are stored in a memory of 512 k
words for I and Q respectively. The hardware trigger (external or IF power) controls the
memory access.
Fig. 2-1: Block diagram of the signal processing architecture of the R&S FSV
2.5 Bandwidths
The Bluetooth RF Specification defines a minimal bandwidth of 3 MHz. The digital
bandwidth depends on the selected oversampling factor (= points / symbol). With the
default setting of 4, the digital bandwidth is 3 MHz. This digital filter has a flat amplitude
characteristics and does not affect the frequency deviation of the signal.
Bandwidths