SPA-900 Series User Manual 55
2.3.2.6
ΔM->Span
Set the span of the analyzer to the frequency difference between the two markers in Delta, or
Delta
Pair
marker type.
If
Normal
marker is selected, this function is invalid.
The function is invalid in Zero span mode.
2.3.2.7
ΔM->CF
Set the center frequency of the analyzer to the frequency difference between the two markers in
Delta
, or
Delta Pair
, marker type.
If
Normal
marker is selected, this function is invalid.
The function is invalid in Zero span mode.
2.3.3 Marker Fn
Special marker functions including Noise Marker, N dB BW and Freq Counter.
2.3.3.1
Select Marker
Select one of the four markers (1, 2, 3, 4) and the default is Marker1.
2.3.3.2
Noise Marker
Execute the Noise marker function for the selected marker and read the noise power spectral
density.
If the current marker is “
Off
” in the Marker menu, pressing
Noise Marker
will first set it to
Normal type automatically; then measure the average noise level at the marked point and
normalize this value to 1 Hz bandwidth. During this process, certain compensation is always
made on the basis of the detection and trace types. The measurement will be more precise if
RMS Avg or Sample detection type is used.
This function can be used for measuring the C/N ratio.
2.3.3.3
N dB BW
Enable the N dB BW measurement or set the value of N dB. The N dB BW denotes the frequency
difference between two points that are located on both sides of the current marker and with N dB
fall (N<0) or rise (N>0) in amplitude as shown in the figure on the next page.
Distributed by: Reliant EMC LLC, +1 408 916
‐
5750, info@reliantemc.com, www.reliantemc.com
