Instrument Function
R&S
®
SMBV100A
273Operating Manual 1407.6062.32 ─ 08
Example:
Fig. 5-18: 3GPP FDD signal (chip rate 3.84 Mcps, root-cosine filter 0.22).
The complex useful bandwidth of a signal which has been filtered using a root-cosine
filter with roll off alpha is calculated as follows:
f
use
= (1+ alpha) * f
symbol
f
symbol
= the symbol rate or chip rate of the signal.
In the example the complex useful bandwidth is calculated as follows:
f
use
= (1+ 0.22) * 3.84 MHz = 4.6848 MHz.
So as to comply with the condition requiring a maximum I/Q bandwidth of 40 MHz, the
valid range of values for the frequency offset is then:
-60MHz + 4.6848MHz/2 <= f
offset
<= 60MHz - 4.6848MHz/2 or
-57.6576MHz <= f
offset
<= 57.6576MHz
In the case of ARB signals, the output clock rate can be used for estimating the maximum
I/Q bandwidth of the waveform.
SCPI command:
[:SOURce<hw>]:BB:FOFFset on page 504
Phase Offset
Enter the relative phase offset for the baseband signal.
The phase offset affects the signal on the "Baseband block" output.
SCPI command:
[:SOURce<hw>]:BB:POFFset on page 505
Baseband Signal - Baseband Block
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