Software Manual for the R&S ZVL-K1 - Rohde & Schwarz

R&S ZVL-K1 Measurements on Modulated Signals
Standard dev /dB
0,35
0,3
0,25
0,2
0,15
0,1
0,05
0
Tx channel
ACPR IS95 Repeatability
Alternate channels
Adjacent channels
10 100 1000
Sweep tim e/m s
Fig. 2-22 Repeatability of adjacent channel power measurements on CDMA 2000 signals in
the fast ACP mode
Note on adjacent channel power measurements on 2000 MC1 base–station
signals:
When measuring the adjacent channel power of 2000 MC1 base–station signals, the
frequency spacing of the adjacent channel to the nominal transmit channel is specified
as ± 750 kHz. The adjacent channels are, therefore, so close to the transmit channel
that the power of the transmit signal leaks across and is also measured in the
adjacent channel if the usual method using the 30 kHz resolution bandwidth is
applied. The reason is the low selectivity of the 30 kHz resolution filter. The resolution
bandwidth, therefore, must be reduced considerably, e.g. to 3 kHz to avoid this. This
causes very long measurement times (factor of 100 between a 30 kHz and 3 kHz
resolution bandwidth).
This effect is avoided with the zero span method which uses steep IF filters. The
30 kHz channel filter implemented in the R&S ZVL-K1 has a very high selectivity so
that even with a ± 750 kHz spacing to the transmit channel the power of the useful
modulation spectrum is not measured.
1303.6573.42 2.27 E-5