Service manual

WLAN TX Measurements
R&S
®
FSV-K91/91n/91ac/91p
35Operating Manual 1176.7649.02 ─ 04
parameter and the accuracy of the estimates is lower than the accuracy of the estima-
tions achieved by (17). If the EVM value is dominated by Gaussian noise this method
yields similar results as (18).
3.4.2 Literature of the IEEE 802.11b Application
[1] Institute of Electrical and Electronic Engineers, Part 11: Wireless LAN Medium Access Control
(MAC) and Physical Layer (PHY) specifications, IEEE Std 802.11-1999, Institute of Electrical and
Electronic Engineers, Inc., 1999.
[2] Institute of Electrical and Electronic Engineers, Part 11: Wireless LAN Medium Access Control
(MAC) and Physical Layer (PHY) specifications: Higher-Speed Physical Layer Extensions in the
2.4 GHz Band, IEEE Std 802.11b-1999, Institute of Electrical and Electronic Engineers, Inc., 1999.
3.5 802.11b RF Carrier Suppression
Definition
The RF carrier suppression, measured at the channel center frequency, shall be at
least 15 dB below the peak SIN(x)/x power spectrum. The RF carrier suppression shall
be measured while transmitting a repetitive 01 data sequence with the scrambler disa-
bled using DQPSK modulation. A 100 kHz resolution bandwidth shall be used to per-
form this measurement.
Comparison to IQ offset measurement in R&S FSV-K91/91n list mode
The IQ offset measurement in R&S FSV-K91/91n returns the actual carrier feed
through normalized to the mean power at the symbol timings. This measurement
doesn't need a special test signal and is independent of the transmit filter shape.
The RF carrier suppression measured according to the standard is inversely propor-
tional to the IQ offset measured in R&S FSV-K91/91n list mode. The difference (in dB)
between the two values depends on the transmit filter shape and should be determined
with one reference measurement.
The following table lists exemplary the difference for three transmit filter shapes (±0.5
db):
Transmit filter – IQ-Offset [dB] – RF-Carrier-Suppression [dB]
Rectangular 11 dB
Root raised cosine, "α" = 0.3
10 dB
Gaussian, "α" = 0.3
9 dB
802.11b RF Carrier Suppression