射频和VF设计的参考因素

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