Hi there.
I wish to get your attention for a strange behaviour about my Rigol DSA815TG just to know if my instrument have a trouble or I am forgotting something.
Yesterday I tried to check the response curve of a simple 145MHz cavity filter (first picture) by two different ways:
1) by my Rigol DSA815TG scalar network integrated system;
2) by HP8595E spectrum analyzer + Wiltron 6621B programmable sweep generator (two instruments run independently so they are no syncronized; Wiltron generator runs faster at 10ms of sweep and HP8959E has a slow sweep at 20 seconds - see the second picture).
The curves of the same cavity with the same cables are different. Two spectrum analyzers are set in the same mode:
-Center frequency 145MHz
-Span 200MHz
-Ref. level 0dBm
-ampl. scale 10dB/div.
Wiltron:
-start freq. 10MHz to 12.5GHz
-level 0dBm
Of course I have just normalized the DSA815's tracking generator before.
As you can see both show the peak at 150MHz but the Rigol doesn't show the negative peak afterwards (red arrow on the third picture)
What do you think about?
Rgds
auato