Agilent Technologies E4445A PSA Series, Руководство пользователя, Страница: 71 / 74

Chapter 5 71
Hints and Tips
FAQs and Helpful Hints and Tips
Hints
an
d Tip
s
asking the source to start its sweep at
−
0.8 GHz. In this case:
But
−
0.8 GHz is not in the range of the signal source.
So you can either:
• increase the offset to
≤ −
3 GHz
or
• reduce the stop frequency to
≤
2.8 GHz
Example 5: Offset Causes Bad Source Stop Frequency
Using PSA (13.2 GHz and above) and a 6 GHz source (for example, an
E4438C):
PSA settings:
• Start Freq = 10 GHz
• Stop Freq = 12 GHz
• Sweep Points = 101
• Offset =
−
5 GHz, On
• Harmonic = OFF
This will cause the “Freq range of ext src exceeded” error.
Reason:
The signal source is being asked to sweep outside its frequency range.
In this case:
Source Start Freq
2.5E 9
( )
2.8E 9
( )
–
( )
+
3.0E 9
( )
2.5E 9
( )
–
101 1 –
---------------------------------------------
⎝ ⎠
⎛ ⎞
–
1
--------------------------------------------------------------------------------------------------------------- 0.8E 9
( )
= –0.8 GHz – = =
Source Stop Freq
3.0E 9
( )
2.8E 9
( )
–
( )
+
3.0E 9
( )
2.5E 9
( )
–
101 1 –
---------------------------------------------
⎝ ⎠
⎛ ⎞
+
1
--------------------------------------------------------------------------------------------------------------- 0.2E 9
( )
= 200 MHz = =
Source Start Freq
10E 9
( )
5E 9
( )
–
( )
+
12E 9
( )
10E 9
( )
–
101 1 –
------------------------------------------
⎝ ⎠
⎛ ⎞
–
1
------------------------------------------------------------------------------------------------------ 4.98E 9
( )
= 4.98 GHz = =