Rohde & Schwarz SML01 - Page 265

R&S®SML / R&S®SMV03 Test sequence
1090.3123.12 10.15 E-6
Settings on the R&S
SML02/03 / R&S SMV03
- FREQ:
9 MHz, 50 MHz, 200 MHz, 350 MHz, every 20 MHz to 2200 MHz or
3300 MHz
- LEVEL:
8 dBm, 3 dBm, - 2 dBm, - 7 dBm
Settings on the test receiver - S
pectrum analyzer mode
- C
enter frequency = FREQ (R&S SML)
- Span = 0 Hz
- Reference level = LEVEL (R&S SML)
- Resolution bandwidth and video bandwidth = 10 kHz
- Linear level scale
- Sweep time = 30 ms
Settings on the second test
transmitter
- Frequency = FREQ (R&S SML) – 100 Hz
- RF OFF first
Measurement  Bring the line displayed on the test receiver due to changing the
reference level to roughly the middle of the screen, read off the level
as the reference level and make a note of it.
 Unscrew the bridge from the R&S SML / R&S SMV03 and increase
the level on the second test transmitter until the reference level is
again being measured on the analyzer.
 Screw the bridge or directional coupler back onto the R&S SML / R&S
SMV03.
 The spectrum analyzer now shows a more or less wavy line
which represents the VSWR of the R&S SML / R&S SMV03. To
calculate the VSWR use the formula
VSWR = u
max
/ u
min
containing the maximum and minimum voltages.
Passive measurement of the VSWR for R&S SML / R&S SMV03 output levels below –25 dBm
Settings on R&S SML /
R&S SMV03
- FREQ: (far from the measurement frequency, > 10 MHz)
9 MHz, 50 MHz, 200 MHz, 350 MHz,
every 20 MHz to 1100 MHz or 2200 MHz / 3300 MHz (R&S
SML02/03)
- LEVEL:
- 30 dBm
Settings on the second test
transmitter
- Frequency = FREQ (R&S SML)
- Level = 10 dBm
Measurement  Unscrew the VSWR bridge from the DUT and note the level
measured on the analyzer as the reference value.
 Screw the bridge or directional coupler back on again and determine
the new level on the analyzer.
 The voltage ratio test level / reference level is the output
reflection coefficient r of the DUT.
 Use the formula
VSWR = (1 + r) / ( 1 – r)
to determine the standing wave ratio (VSWR).