射频和VF设计的参考因素BROADCASTING DIVISION
Application Note
Reference factor between RF (referenced to sync top level) and VF
Products:
TV Demodulators and Video Analyzers
UAF + EFA 33 VSA + B10
7BM10_0E
Reference factor between RF (referenced to sync top level) and VF
Let us analyze a modulated signal:
0% 11 % 42 % 73 % 100 %
VF
100 % white
side band
50 % grey 0 % black - 43 % sync top
RF/IF
Level Percentages for RF/IF Signal with Reference to VF Signal
Now do the calculation: The sideband amplitude referenced to Upp (USB , LSB) is app (USB , LSB) = 73%-11% = 62% in case of double sideband modulation, as we have in VSB frequency range.
73 % Vision Carrier
ap (USB )=15.5 % ap (LSB)=15.5 %
42 % Vision Carrier at VF 50 % grey
ap (LSB)=15.5 % 11 %
ap (USB )=15.5 % a pp (LSB,USB) = 62 % 73 %
Vect……
