USING THE COMBISCOPE INSTRUMENTS 3 - 53
SUMMARY OF CALCULATED OFFSET VALUES:
Note: The PROGRAM EXAMPLE on the next page shows how it is
programmed.
TRACE POINT FREQUENCIES:
The horizontal frequency values (in Hz per point) are calculated from the trace
sample index (point number of the sample in the trace), the acquisition length
(TRACe:POINts), and the MTB (calculated from the SENSe:SWEep:TIME) by the
following equation:
Fs = (<sample_index>
*
1250) / (TRACe:POINts
*
MTB
*
50)
Restriction: Only trace sample data can be queried from trace memories; no
trace administration data, such as acquisition length and MTB value.
This means that these values must be queried from the actual input
channel signal, which is taken as the source for the FFT process. So,
take care that the acquisition length nor the MTB is changed between
activating the post processing function and reading the trace memory
where the post processing trace is stored.
ATTENUATOR
SETTING:
Vrms:
dBm-50
Ω
:
dBm-600
Ω
:
dB
µ
V:
5
V/div
2
,,
1
,,
+
11.18034
+
4.4721359
+
2.236068
+
33.9794
+
26.0206
+
20.0
+
23.187588
+
15.228787
+
9.2081872
+
140.9691
+
133.0103
+
126.9897
0.5
,,
0.2
,,
0.1
,,
+
1.118034
+
0.4472136
+
0.2236068
+
13.9794
+
6.0206
0.0
+
3.1875874
-
4.771213
-
10.791813
+
120.9691
+
113.0103
+
106.9897
50
mV/div
20
,,
10
,,
+
0.1118034
+
0.0447214
+
0.0223607
-
6.0206
-
13.979392
-
20.0
-
16.812413
-
24.771206
-
30.791813
+
100.9691
+
93.010308
+
86.989708
5
,,
2
,,
+
0.0111803
+
0.0044721
-
26.020632
-
33.97947
-
36.812444
-
44.771282
+
80.96907
+
73.01023