Post subject: RF question
Unread postPosted: Sat Apr
02, 2005 12:42 pm
A television receiver tuned to a channel
at 220 MHz comprises a front end
amplifier (G = 18 dB, F = 2.5
dB), mixer (G = 16 dB, F = 12 dB) and IF
amplifier (F = 2 dB,
Bn = 6 MHz). It is connected to an antenna of gain 6 dB
of 300 ohm ribbon lead with an attenuation of 0.12 dB/m. Calculate
(a) The noise figure of the receiver.
(b) The signal (in mV)
at the antenna terminals required to produce an
to noise ratio of 40 dB for (i) a suburban area, (i) a
(c) The corresponding electric field strength
in the neighbourhood of
(d) The improvement in
S/N (for both cases (i) and (ii) above) which
would result from
- replacing the ribbon cable with a polyfoam cable, attenuation
- leaving the cable the same, but fitting another antenna
gain of 10 dB
- leaving the cable and antenna as originally
and fitting a masthead
amplifier with F = 2 dB and G = 20 dB.
Assume in each case that the signal field strength is the same.
Anyone gives some hints for solving this question
Unread postPosted: Sat Apr 02, 2005 9:20 pm
that help you with college homework problems get paid. What are
Unread postPosted: Sun Apr 03, 2005 3:02 am
Do I have to
show my work?
Unread postPosted: Wed May 18, 2005 10:07 pm
the cascaded Noise Factor calculation...
Ftotal = 1 + F1
+ F2/G1 + F3/(G1*G2) + F4/(G1*G2*G3) + ...