Textronix sbt250 spectrum analyzer
aug, 2005
resolution bandwidth, temperature:
The RBW is tied to the current span. You can
find the RBW by clicking on setup ->edit. The RBW for the current
span
will be display. The narrowest RBW is 100 Hz. A table of span
versus
RBW is:
| SPAN |
RBW |
| 100 Mhz |
1 Mhz |
| 10 Mhz |
100Khz |
| 5 Mhz |
30 Khz |
| 1 Mhz |
10 Khz |
| 100Khz |
1 Khz |
| 10 Khz |
100 Hz |
When nothing is plugged in Tsys is:
-
With 100 Hz RBW the Noise floor is -150 dbm/100 hz or -170dbm/hz
-
-198.6dbm/hz =1K so the the analyzer is 28.6 dbm above 1K.
-
Tsys= 10^(2.86)= 724 K.
Storing traces so they can be read back:
You can store a trace on the local disc in ascii.
Offline
you can read in the data and generate the x,y that was used for the
original
trace. This lets you computer process the data offline (rather than
just
having a screen dump plot to look at). The steps are:
-
File -> Save trace as
-
select tab separated txt (.txt)
-
enter the filename you want. You can bring up the keyboard using the
small
keyboard icon in the menu bar at the lower right. (can we save it
directly
to the floppy?)
-
got to start button start->progs->start floppy drive. Supposedly
this will
select floppy as the output device...
-
save
-
It the above wrote to the hard disc rather than the floppy, you can
copy
the file on the hard drive to the floppy with:
-
click on file, select the file you want to copy. Should be in the
directory:
MyNetTek -> yb250 ->?? -> appData->Results->filename
start -> programs -> start floppy drive
MyNetTek -> yb240 ->?? -> appData->Results->filename
copy command ???
paste to floppy
Reading the floppy in and generating the x,y array...
-
Read the floppy onto linux. I've had better luck with reading it from
windows
and then emailing it to myself on linux.
-
idl
-
@phil
-
filename='xxxxxxx.txt' .. the name of the file on linux
-
openr,lun,filename,/get_lun
-
ntraces=ybt250inp(lun,spc1,frq1,spc2,frq2,info=inpar,print=print)..
-
For more info see the idl
documentation for ybt250inp().
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