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Post subject: RF question
Unread postPosted: Sat Apr 02, 2005 12:42 pm
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.
The signal (in mV) at the antenna terminals required to produce an
output signal to noise ratio of 40 dB for
(i) a suburban area, (i) a
quiet semi-rural area.
(c) The corresponding electric field strength in the
(d) The improvement in S/N (for both cases (i) and (ii) above) which
- replacing the ribbon cable with a polyfoam cable, attenuation
- leaving the cable
the same, but fitting another antenna with a
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
thanks in advance.
Unread postPosted: Sat Apr 02, 2005 9:20 pm
Most tutors that help you
with college homework problems get paid. What are you offering?
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
Start with the cascaded Noise Factor
Ftotal = 1 + F1 + F2/G1 + F3/(G1*G2) + F4/(G1*G2*G3) + ...