[SOLVED] Can u kindly rougly tell me passband regions for these two graphs

[moonnightingale]

Can u kindly rougly tell me passband regions for these two graphs

 

[devilwar]

Cut the largest lobe with a line perpendicular to y-axis at -3db. The two points at which the line cuts the lobe gives you the passband.

Fig 1. 1.3 to 1.4(approx)
Fig 2. 0.65-0.8(Approx)

 

[moonnightingale]

Thanks a lot
Devilwar
Can anybody second him and confirm his answer

 

[devilwar]

Actually the passband is assumed from where power is greater than or equal to half. So voltage/ current becomes 1/root(2). Now 1/root(2) is -3db in log scale.
log(10) 2= 0.3010
20 log(10) root(2)=10 log(10) 2= 3.010
almost = 3db