ECEN 658 HW2
Xin Wang 721006226
f upper
1. Since
U 2 (t ) >t = S (f ) df
f lower
,
4 k B T R s ( f upper f lower )
U 2 (t ) > =
=4 k B T R s
f
f
S ( f )=
2. Since U=IR ,
S i ( f )=
I=U rms /R s and
1
S ( f )=4 k B T / Rs
R2
s

Sitong Zhai 321008470
ECEN658
Frequency is 0.1 Hz10000 Hz
10
4
10
4
U th 4 KTR df = 4 1.38 1023 300 10000 df =1.66 1012 V 2 ,
2
0.1
10
U
2
flicker
0.1
4
u2 r 2 /(2.3 f ) df =3.13 1010 V 2 ,
0.1
10
U
2
shot
4
2 I d e r 2 df =8.57 1016 V 2 ,
d
0.1
2
2
U

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Homework (due on Tuesday, January 28, 2014)
1. At thermal equilibrium, the rms thermal noise voltage on an open-circuit ideal resistor Rs at
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U rms = 4 k B T Rs
(f upper f lower )
(1)
where k

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Homework (due to Wednesday, 2/4/2013)
1. A student measured the power density spectrum with a circuitry. The noise bandwidth is 500
(
)
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Give the characteristic values of the input noise generators of an amplifier with
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1. How large will be the effective noise voltage at the output of the diode-based circuit
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