Rohde & Schwarz R&S FSP Series, Operating Manual

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R&S FSP Getting Started
Noise Measurements
2.18 Operating Manual 1164.4556.12 - 06
Fig. 2-1 Measurement of the R&S FSP’s intrinsic noise power in a 1.23 MHz channel
bandwidth.
5. Stabilizing the measurement result by increasing the sweep time
➢
Press the SWEEP TIME softkey and enter 1 s .
By increasing the sweep time to 1 s, the trace becomes much smoother
thanks to the RMS detector and the channel power measurement display is
much more stable.
6. Referring the measured channel power to a bandwidth of 1 Hz
➢
Press the CHAN PWR / Hz softkey.
The channel power is referred to a bandwidth of 1 Hz. The measurement is
corrected by -10 · log (ChanBW), with ChanBW being the channel bandwidth
that was selected.
Method of calculating the channel power
When measuring the channel power, the R&S FSP integrates the linear power
which corresponds to the levels of the pixels within the selected channel. The
R&S FSP uses a resolution bandwidth which is far smaller than the channel band-
width. When sweeping over the channel, the channel filter is formed by the pass-
band characteristics of the resolution bandwidth (see
Fig. 2.16 ).
Fig. 2.16 Approximating the channel filter by sweeping with a small resolution bandwidth
The following steps are performed:
Channel bandwith
Resolution filter
-3 dB
Sweep