Measurement Filter (Meas Filter On); Oversampling - R&S FSV-K8 Operating Manual

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R&S FSV-K8

2.6 Measurement Filter (Meas Filter On)

The RF Specification allows high distortion power in the first adjacent channels. The 3
MHz filter does not suppress this kind of distortion, which leads to a high interference
in modulation. Therefore a precise measurement of the frequency deviation is not pos-
sible.
In order to obtain correct deviation results, the spectrum analyzer supplies an optional
filter with a passband only appropriate for the channel to measure. This filter is used by
default. The Bluetooth spectrum has a bandwidth of 1 MHz. The filter is flat within 1.04
MHz (ripple: only 0.02 dB) and has steep edges. This measurement filter is not
dependent on the selected oversampling factor. As a result the displayed deviation
value is increased by 3.2%, but without the filter the displayed deviation value can
increase dramatically due to interference from adjacent channels. Generally the result
is more precise, if the displayed deviation is lower with filtering than without filtering. In
these cases the inaccuracy caused by the adjacent channel interference is higher than
the systematic inaccuracy caused by the filter.
Fig. 2-2: Selection of digital filters
Dashed–dotted curve: Standard filter with 4 points / symbol
Solid curve: Optional measurement filter, independent of the points / symbol setting

2.7 Oversampling

The number of samples per symbol is equivalent to the sampling rate in MHz (due to
the symbol length of 1 µs).
Operating Manual 1176.7610.02 ─ 02
Introduction to Bluetooth Measurements (K8)

Measurement Filter (Meas Filter On)

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