Cover Sheet
ECE3434
Quiz #4
Noise and signal quality analysis
----------------------------------------------------------------------------------------------------------------------------Transistor topologies:
1. General Purpose topology
2. Voltage follower
3. Current follower
Noise BW 
Bandwidth

2
Parasitic (high freq) capacitances:
C   C JC
OX = .0345fF/m
C  C JE  g m   F
2
COX  W  L
3
 v 
'
C12
 C12  1  2 
 v1 
CGD  CGDO  W
Miller (capacitance multiplication) effect:
Noise:
1
 pH
4
 f 3dB 
Cs 
4kT = 1.6 x 10-20 J
{en2 }  4kTR
Noise temperature:
Te  T1  T2 G1  T3 (G1G 2 )    
Noise floor:
S i (min)  kT  B  F  (S / N ) out  Nf
Minimum detectable signal:
In general:
F = 1
Dynamic Range: DR =
- for MOSFET
(NSD = Noise spectral density)
{i n2 }  4kTG
2
Shot noise: (NSD) {in2 }  2qI for BJT
{in2 }  4kT  g m for FET
3
( S N ) in
Na
Te
Noise factor:
= 1
= 1
F
( S N ) out
Ni
T
Thermal noise (NSD)
- for BJT
vs(min)  4 Rs S i (min)
[{e n2 }  {i n2 } 
R S2 ]
4k TRS
2
log PI  log Nf 
3
RS (opt)  {en2 } {in2 }
{en2 }  {in2 }  R 2
Cover sheet #2 System Noise in packaged circuits: Harris Semiconductor
ECE3434
Quiz #4: Noise and signal quality Analysis
4 Dec 2009
----------------------------------------------------------------------------------------------------------------------Instrux: Show work in space provided Be neat, concise, encircle answers
Else –10 pts
----------------------------------------------------------------------------------------------------------------------Defaults:  F = 100, Resistances in k, T = 300K, 4kT = 1.6 x 10-20 J
----------------------------------------------------------------------------------------------------------------------Short Answer
SA-1: (4 pts) For the HA2544 video opamp (cover sheet) what is the equivalent input noise voltage and the
equivalent input noise current for operation at 100kHz?
{en} = ___________________
{in} = __________________
SA-2: (4 pts) For question SA-1, what is the optimum input resistance RS for minimum system noise factor?
RS(opt) = __________________
SA-3: (6 pts) What would the noise factor F and noise temperature be for question SA-2?
F = __________________
Te = __________________
C-1 (8 pts) What is the noise temperature and noise factor for the following system?
(a) Te __________
(b) F __________
C-2 (18pts) A metabolic ESP system consists of an amplifier/receiver connected to a halo antenna through a
cable with NF = 2dB and loss of –1.0dB. The amplifier has noise factor F = 2.5, gain G = 10dB and (tuned)
bandwidth 25kHz. The noise temperature of the antenna is 270oK. What is:
(a) noise temperature and noise factor of the (antenna +cable + receiver) system
(b) signal power Si(min) necessary for (S/N)out = 6 dB. Give answer in both dBW and in watts.
(c) minimum detectible ESP signal level (vs(min)) if the equivalent antenna source resistance = 100 and
the antenna and cable are matched.
C-3 (27 pts) A pressure-sensitive optical fiber loop antenna is configured in a loosely-laced spiral buried just
below the ground surface in the vicinity of a high-security installation. It is connected to security central by an
impedance-matched optical connector cable having loss 0.4 dB/km and noise figure 1.0dB. Noise analysis is
crucial since any intruders, even an innocent tabby, will be vaporized by the installation's weapons systems.
Find:
(a) System Te and noise factor F if an
optical fiber of length 5km is used.
(b) Total equivalent input noise power.
(c) Maximum allowed length connector
cable for system Te < 690K.
(d) Noise floor Si(min) for maximumlength cable system if it is required that (S/N)out
= 9dB. Give answer in both dBW and in watts.
(e) Dynamic range if the two-tone input
equivalent power level = -10dBW.
C-4 (a) (8 pts) Assume  F = 100, rB = 25CJC =
3pF, CJE = 4pF, F = 0.3ns. Determine the dominant
high frequency pole (in Mr/s) within 10% and the
corresponding noise bandwidth. If you can
accomplish these by inspection, so much for the better.
pH 
Bn ______________
Figure Q-1: General purpose (CE) configuration
(b) (12 pts) Figure Q-1: Determine the input noise spectral density (NSD) contribution {en2} at node
N1(base node of Q1) due to:
(1) RS _______________
(2) IB __________________
(3) IC__________________
B-1 (6pts) Determine noise factor F and noise Te for this circuit (Figure Q-1)
(a) F _______________
(b) Te __________________
B-2 (8pts) If vs = 100V determine
(a) (S/N)in _______________
(b) (S/N)out __________________
A-1:
(a) (4pts) What does the Spice Macro Max( NTOT(ONOISE))/ Max(NTOT(RS)) accomplish?
(b) (4pts) What does the Spice Macro Max(V(VL))* Max( V(VL))/ Max(S(NTOT(ONOISE))) accomplish?
A-2 (8) From your two simulation exercises on noise for the general purpose (also called the CE)
configuration, what is the effect of increase of Rs (the source resistance) on:
Decrease
(1)
(2)
(3)
(4)
Bandwidth
Shot noise contribution
S/N)out
Noise factor
(
(
(
(
)
)
)
)
No change
(
(
(
(
)
)
)
)
Increase
(
(
(
(
)
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)
)