Rohde & Schwarz R&S SMU200A, Руководство по обслуживанию

Страница: 35 / 294

Preparation, Recommended Test Frequencies and Levels R&S SMU200A
1007.9845.82 1.8
E-12
Preparation, Recommended Test Frequencies and Levels
To ensure proper conditions for the performance test and prevent setting errors, the instrument must be
prepared as follows:
•
Allow for a minimum warm-up time of 30 minutes at ambient temperature.
•
Carry out all internal adjustments (see operating manual, chapter 4, section "Internal Adjustment -
Setup-System").
•
Press
PRESET
to establish a defined initial state before configuring a new measurement.
The following sections describe the procedures for checking the rated values. The values are specified in
the data sheet. Additional uncertainties introduced by the measurement equipment must be taken into
account when checking the rated values.
The following table lists the important internal switchpoint frequencies and the recommended measurement
frequencies derived from these frequencies. We recommend measurements at these frequencies unless
particular test frequencies are specified. In the following, RF
max
is the maximal settable RF (depending on
installed options).
Table 1-4 Range limits, main test frequencies
Range Frequency/ MHz Hardware switching points Recommended test frequencies in MHz
Mixer 0.3 to 200 0.3, 0.5, 1, 2, 5, 10, 20, 50, 100, 199.9
Divider /4 >200 to 375 Lowpass filter 285 MHz 200.1, 280, 290, 374.9
Divider /2 >375 to 750 Lowpass filters, 436, 705.0 MHz 375.1, 435.9, 436.10, 704.9, 705.1, 749.9
Base octave >750 to 1500 Lowpass filter, 1110 MHz,
Oscillator limits 890, 1070, 1285 MHz 750.1, 889.9, 890.1, 1069.9, 1070.1, 1109.9,
1110.1, 1284.9, 1285.1, 1499.9
Doubler >1500 to 3000 Lowpass filter, 1809.0 MHz 1500.1, 1808.9, 1809.1, 2999.9
R&S B106 >3000 to 6000 Bandpass filters 3780, 4500, 4760 3000.1, 3779.9, 3780.1, 4399.9, 4400.1,
4759.9, 4760.1, 6000
For high-resolution measurements in the entire frequency range, a logarithmic frequency grid in 1-2-5
sequence is recommended up to 50 MHz; above this value, linear 50 MHz steps should be used up to
the upper limit frequency.
The recommended test levels are at the upper and lower switching threshold of the attenuator. The
electronic attenuator of the DUT is switched depending on frequency, modulation parameters and level
according to an internal stored table in approximately 5 dB steps. The switching thresholds can be
detected under
Attenuator fixed range in the Level menu. After setting all other parameters, the
threshold level can be detected by level variation. The level at which the attenuator fixed range changes
is the threshold. By measuring at the last level setting of one range and the first level setting of the next
range, the internal setting range borders are used. In the following,
P
min
is the lowest level before
switching the attenuator, and P
max
the highest. For best measurement results, levels at the crossover
from 0 to 5 dB attenuation are recommended.