Chapter 15 - Spectrum analyzer 115
106 V3.2
Application
15.10.4
There are two basic applications.
„Line up“ a system:
A profile is created with the channels that are occupied in the system. Move the 1
st
cursor onto the
lowermost channel and the 2
nd
cursor onto the uppermost channel. First set the lowermost channel
to the desired absolute level. You then have two options.
No predistortion:
Set the level of the uppermost channel so that the reference line between the two cursors is
horizontal or raise the level display.
With predistortion:
Set the level of the uppermost channel appropriately higher.
The channels in between can then be “lined up” using the reference line.
Checking the tilt of the system:
A profile is created with the channels which are to be analyzed in the test. This may be fewer than
the number which are occupied in the system. Including fewer channels increases the repetition
rate.
Move the two cursors to the uppermost and the lowermost channels. Then check the level lines of
the channels in between using the reference line.
15.11
Switching to measuring receiver mode
In most modes you can switch directly from the analyzer to measuring receiver mode while in all
measuring ranges. The instrument uses the current cursor frequency to tune the measuring
receiver. In the ranges FM and RK direct switching is only possible in the lower spans, not
FULLSPAN. At TV is possible in channel mode only, but in every span. Press
ENTER
to trigger the
process.
SAT range
15.11.1
When the UNICABLE control is active, the frequency display always refers to the spectrum that
was converted by the UNICABLE unit.
Additional functions: With
MODE
you get a menu to select between "SAT SCAN"(Chapter 16.1)
and "TRANSPONDER SCAN". By pressing
ENTER
they can be started. For explanation please
look at next chapter.
15.11.1.1
Transponder SCAN
Depending on the respective SPAN, the following additional functions are executed when the
SCAN button is pressed.
At FULLSPAN: Starting from the current cursor position, the next maximum is searched and the
centre frequency of this transponder is determined. The analyzer then switches to
SPAN1(600MHz) with the frequency it has determined as the cursor position.
At every lower span than FULLSPAN the centre frequency of the next transponder is searched
and tuned to. In addition to the five or ten preset symbol rates, the entire range of the symbol rates
is searched from 2 to 45 MSym/s.
TV range in the channel input mode
15.11.2
As already mentioned in the "Chapter 15.4 - Cursor", the instrument can distinguish between
analog and digital channels based on the spectrum. This feature is used when switching into the
measuring receiver mode. When the instrument detects an ATV channel, the corresponding
measuring receiver mode is activated.
