Rohde & Schwarz SML01 - Page 261

R&S®SML / R&S®SMV03 Test sequence
1090.3123.12 10.11 E-6
the mixer being used.
 For calibration purposes lower the level of the DUT by 40 dB and
detune one test transmitter by 20 kHz. Check the signal for
harmonics; the second and third harmonics must be more than 30 dB
below the fundamental. Use the analyzer to measure the reference
value at 20 kHz and make a note of this value.
 Cancel the detuning and set the phase quadrature. Restore the level
of the DUT and detune the phase offset at the auxiliary transmitter.
Observe the output voltage from the mixer on the oscilloscope, until
the voltage reaches 0.
 Read off the noise voltage from the analyzer, normalized to 1 Hz
bandwidth (noise level).
Analysis Note the difference compared to the reference level and increase the
offset found by a further 6 dB for the second sideband measured at the
same time (correlated) and 40 dB for the level switchover. If the signal-to-
noise ratio of the second test transmitter is not at least 10 dB better than
that of the DUT, the noise component of the reference transmitter must
also be determined and due allowance must be made.
 The corrected signal-to-noise ratio is the required measured value.
Example: Let the reference level be measured as 12 dBm. At 20 kHz a
noise level of -78 dBm (1 Hz) is determined. The difference is
90 dB. Adding in the correction for the second sideband (6
dB) and the level switchover (40 dB) gives a signal-to-noise
ratio of -136 dB or a noise level of -136 dBc (dB referenced to
the carrier power).
Wideband noise
Test setup  Test setup 1, spectrum analyzer mode
Settings on R&S SML /
R&S SMV03
- UTILITIES  REF OSC  SOURCE EXTERN
- LEVEL: 5.1 dBm
- FREQ:
5 MHz, 10 MHz, 76 MHz, 76.000 000 1 MHz, 151.312 500 1 MHz,
255. 250 000 1 MHz,
605.250 000 MHz, 605.250 000 1 MHz,
700 MHz, 807 MHz, 807.000 000 1 MHz, 950 MHz,
1 076 MHz,
1 076.000 000 1 MHz, 1 100 MHz, 1 250 MHz,
1 800 MHz,
2 010 MHz, 2 200 MHz, 2 655 MHz,
2 655.000 000 1 MHz,
2 800 MHz, 2 800.000 000 1 MHz, 3 300 MHz
Settings on the test receiver - R
eference level = 7 dBm
- C
enter frequency = FREQ (R&S SML) or FREQ + 5 MHz
- Span = 50 kHz
- MEAS  CHANPWR/ACP  CP/ACP CONFIG  CHANNEL
BANDWITH = 30 kHz
Measurement principle The measurement method is based on the channel power measurement.
First the carrier power is determined, then the measurement channel is
moved to a corresponding store and the channel power is likewise