Rohde & Schwarz R&S SMU200A, Руководство по обслуживанию, Страница: 48 / 294

R&S SMU200A Test Procedures
1007.9845.82 1.21
E-12
Level Data
Level Uncertainty
Test method
The level uncertainty is measured in two steps. First, the frequency response
is measured at a fixed level with high frequency resolution. Then the level
dependant uncertainty is measured at fixed frequencies over the specified
range.
Test equipment - Power meter (Table 1-2, item 8)
-
Spectrum analyzer (Table 1-1, item 24)
- Low-noise preamplifier (Table 1-1, item 10)
Test method for levels in measurement range of power meter
Test setup
Connect power meter to RF output socket.
Measurement
Setting on DUT:
- Level:
1. the maximum specified level versus frequency, unmodulated
2. 3 dB below the maximum specified level, unmodulated
3. 0 dBm, unmodulated
Measure the level at output frequencies of 300 kHz to RF
max
.
The level error is the deviation of the measured level from the set value.
Recommended test frequencies
for the level frequency response
measurement 300 k, 1 M, 3 M, 5 M, 9 M, 15 M, every 10 M up to 1495 M, 1505 M,
from 1520 M every 20 M up to 6000 M (all in Hz)
Recommended test frequencies
and levels for the level
dependant measurement.
1 MHz, 500 MHz, 1 GHz, 1.5 GHz, 2 GHz, 3 GHz, 4 GHz, 5 GHz, 6 GHz.
Test level: from the maximum specified level in 5 dB steps down to the
minimum specified level.
Test method for low levels
Test principle Levels below the measurement range of the power meter can be
determined by means of a relative measurement referred to the
measurements performed with the power meter, using a high-linearity
spectrum analyzer (digital IF).
After switching the analyzer attenuator a continuity calibration is to be
carried out. It is therefore recommended to switch the attenuator not until
reaching approx. 50 dB under full scale, since the linearity errors are very
small in the range up to -50 dBfs (referred to full scale). If the measurement
is started at (P
max
–40) dBm, no error occurs due to alternating internal
impedance of the DUT.
Test setup
Connect the spectrum analyzer to the RF output of the DUT with
hermetically sealed RF measurement cables .