Rohde & Schwarz R&S FSP Series, Operating Manual

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R&S FSP Instrument Functions
LO/IF ports for external mixers - Option R&S FSP-B21
4.280 Operating Manual 1164.4556.12 - 06
sured at a frequency too. As a result, the criterion for detecting unwanted signals is
not fulfilled. To blank out unwanted signals permanently an almost constant noise
indication is therefore required. This can be achieved by reducing the video band-
width. Since the average noise indication lies well below the generated noise peak
values, the minimum level diminishes. For identification using
AUTO ID signals
should have this minimum level.
Examining unwanted mixer products with small span
With large spans in which non-modulated sinewave signals are represented as sin-
gle lines, unwanted mixer products are generally completely blanked out. If the user,
however, examines closer the frequency range containing a blanked signal using a
small span, e.g. an image-frequency response, the spectrum represented in
Fig.
4.37 is obtained.
Fig. 4.37 Components of a mixer product blanked out with AUTO ID
There are components of a blanked signal the level difference of which is smaller
than the tolerance predefined with
AUTO ID THRESHOLD as compared with the
noise floor. These components are therefore not blanked out. The tolerance chosen
was 10 dB in this example which can be seen at the level difference between marker
and delta marker (display 'Delta 2 [T1]').
Using AUTO ID with large spans
As already described, the comparison of maximum peak values of test and refer-
ence sweep is performed for each sweep point. A trace comprises yyy…10000
sweep values the number of which is reduced to build the 625 pixels. Each pixel
contains the maximum value of the sweep points it consists of. Therefore a pixel can
contain information of a number of frequency steps.
R e f - 1 0 d B m
B
1 M H z / C e n t e r 5 9 . 1 5 2 3 6 6 6 7 G H z S p a n 1 0 M H z
R B W 2 0 0 k H z
S W T 2 0 m s
* V B W 1 0 0 k H z
1 S A
V I E W
- 1 1 0
- 1 0 0
- 9 0
- 8 0
- 7 0
- 6 0
- 5 0
- 4 0
- 3 0
- 2 0
- 1 0
1
M a r k e r 1 [ T 1 ]
- 8 1 . 7 9 d B m
5 9 . 1 5 1 9 6 6 0 2 6 G H z
2
D e l t a 2 [ T 1 ]
- 1 0 . 0 1 d B
9 6 . 1 5 3 8 4 6 0 8 5 k H z