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Project
1. A Graduation project on
Wireless RF Transceiver
Presented by
Ain Sham Univer sit y
s
Ahmad Ibrahim
Facul t y Of Engineer ing Hazem Mohammad
Graduation Project 2001 Mohammad Atef
Mohammad Khalifa
Sherif Sobhi
Presented to
Dr. Khaled Sharaf
2. شكر
نتقدم بخالص الشكر و التقدير
للدكتور/ خالد شرف لما بذله معنا من
جهد ووقت كان فيهما خير قدوة فى
الدب و العلم و نحسبه على خير
ول نزكي على ال أحدا
3. Introduction
• Tx transmits at a centre frequency of
950MHz with a 20MHz B.W.
• Rx receives at a centre frequency of
1GHz with a 20MHz B.W.
6. Heterodyne vs. homodyne
• Heterodyne receiver is preferred over
homodyne Rx by its superior selectivity &
sensitivity.
• Heterodyne requires off-chip filters.
• Heterodyne requires greater area & so cost.
• However it is still used it is too much easier to
design.(no oscillator isolation problem)
10. Frequency Stability
• How to improve frequency stability ?
- Reduce noise
- Follow the oscillator with a buffer
- Thermally isolate the oscillator
- Use crystal to control the frequency
11. Voltage controlled oscillator
• If the output frequency can be adjusted by a
voltage, then we have a VCO.
• The tank capacitance can be replaced by a
reverse-biased diode (varactor)
12. Oscillator’s Parameters
• Phase Noise in LC circuits
- It may affect both the frequency and
amplitude of the output signal.
- The higher the Q of the tank, the lower the
phase noise.
13. Oscillator’s Parameters
• Phase Noise in VCO
Depends on the path into which the noise is
injected.
- Noise in signal path
- Noise in control path
• Another source of noise is generated by the
active device.
14. Oscillator’s parameters
• Oscillator Pulling
- Coupling from the power amplifier
- The desired signal is accompanied by a
large interferer
- The load pulling
• Oscillator Pushing
30. Transmitter VCO
• Negative Resistance Cell
- Uses active feedback network
-2(1/gm +RE)
instead of passive Vcc
network used in other Q4 Q3
topologies Q1 Q2
RE RE
{
Q5 Q6 Q7
CURRENT SOURCE Vcs
R4 R5 R3
0 0 0 0
-R cell
31. Transmitter VCO
• Verification of –R cell by Simulation
-0.016KV 200V
N N
e e
g g
a a
t -0.250KV t
i (950M,-66.844) i
v v 0V
e e
R -0.500KV R
e e
s s
i i
s s -200V
t t
-0.750KV (954M,-320.383)
a a
n n
c c
e e
-1.000KV -400V
1.5MHz 10MHz 100MHz 1.0GHz 10GHz 100GHz 30.6MHz 100.0MHz 1.00GHz 10.0GHz 28.6GHz
VR(Q21:c,Q23:c) Vr(Q23:c,Q22:b)
Frequency Frequency
Without tank With tank
32. Transmitter VCO
• The Tank Circuit
- Used to select the frequency
- Used to change the frequency
• The Output Buffer
- Acts as an isolation stage
33. Transmitter VCO
• Simulation Results
3 4 9 mV 5 0 mV
A
M
P
L
I
T
2 0 0 mV
U
D
E
0V
0V
- 5 0 mV
- 1 4 9 mV
0s 0. 5us 1. 0us 1. 5us 2. 0us 2. 5us 3. 0us 3. 00802us 3. 01000us 3. 01200us 3. 01400us 3. 01600us
V( C9 : 2 ) V( R4 0 : 1 )
T i me T i me
4 0 mV
A
M
P
L
I
T
U
D
E
2 0 mV
0V
9 5 5 . 0 5 MHz 9 6 0 . 0 0 MHz 9 6 5 . 0 0 MHz 9 6 9 . 6 0 MHz
V( R4 0 : 1 )
Fr e q u e n c y
34. Transmitter VCO
• Tuning Range
- The tuning range of the VCO is 20MHz
while Vcontrol is from 0 to 2.7v
39. Transmitter Section
• Output Signal
3 0 0 mV
2 0 0 mV
1 0 0 mV
0V
9 4 6 . 0 0 MHz 9 4 8 . 0 0 MHz 9 5 0 . 0 0 MHz 9 5 2 . 0 0 MHz 9 5 3 . 9 8 MHz
V( L 3 0 : 1 , MNMN) V( R2 3 : 2 , C3 : 2 )
Fr e q u e n c y
40. LNA
• LNA main charactaristics
- Noise figure
- Gain
- linearity
- S-parameters
- Power consumption
41. LNA input stage topologies
Vcc Vcc
Zc
Rb Zc
Output
Output
Vb Input
Input
Rs
bias Ze
Common base Common emitter
-better isolation 0 -poor isolation 0
-high unavoidable (Miller capacitance)
noise for 50Ohm -lower NF
input match((gm) -1 = 50)
42. Cascode amplifier
Vcc
Zc
-Better isolation than CE Output
o/p
(no Miller) Vb match.
-Less components than cascade
-Easily converted to differential
Input
i/p
match.
Ze
&
bias
0
56. Mixer topologies
• Passive mixer
- Microwave frequency
- No conversion gain
- high power consumption
- Transformer coupling
- Good linearity
57. Mixer topologies
Active mixer: Vcc
LO
LO
- Provides conversion gain
- Low power from LO port RF
- Excellent isolation Vbias
- No matching problem
58. Single balanced vs double
balanced
Vcc Vcc
LO
LO
LO LO
RF RF RF
Vbias Vbias Vbias
0
-Poor port to port isolation -perfect isolation
-Less noise contribution -higher noise contribution
60. Common emitter
• Consists of:
- Driver stage
- Switcher stage
- Load
Driver stage have the main effect in the mixer
linearity and noise figure
61. Gain
18
18
16
16
14 14
12 12
Gain
Gain
10 10
8 8
6 6
4 4
2 2
1 2 3 4 5 6 7 8 9 0 5 10 15 20 25 30 35
Idc
driverarea
Gain with biasing current gain with driver area
62. Noise figure
12 10.5
10
11
9.5
10
9
9
NF(dB)
8.5
NF(DB)
8 8
7 7.5
7
6
6.5
5
0 5 10 15 20 25 30
6
driver area 1 2 3 4 5 6 7 8 9 10
switch area
NF against driver area NF against switches area
63. Shot noise
11
10.5
10
9.5
9
NF(dB)
8.5
8
7.5
7
6.5
6
1 2 3 4 5 6 7 8 9 10
bias current
NF against bias current
Base noise will be more effected at high bias current
68. Simulation result
1 . 0 mV
I F s i gnal
0V
RF s i g n a l
- 1 . 0 mV
152. 5ns 156. 0ns 160. 0ns 164. 0ns 168. 0ns 172. 0ns
V( R1 9 : 1 , OUT 2 ) V( N1 0 1 9 8 3 , N1 0 6 9 0 8 )
T i me
1 . 0 mV
out put I F c o mp o n e n t
( 1 0 0 . 0 0 0 M, 8 2 2 . 4 6 4 u )
I nput RF c o mp o n e n t
( 1 . 0 0 0 0 G, 1 0 3 . 1 6 7 u )
100uV
10uV
1 0 MHz 3 0 MHz 1 0 0 MHz 3 0 0 MHz 1 . 0 GHz 3 . 0 GHz
V( R1 9 : 1 , OUT 2 ) V( N1 0 1 9 8 3 , N1 0 6 9 0 8 )
Fr e q u e n c y
70. Why IF ?
Selecting a
narrow channel
at RF , means
very high Q for
f0
the filters , so a
down shift in Q=
frequency is ∆f
needed to relax
the channel
select filter’s Q .
72. Automatic Gain Control
(AGC)
AGC means high gain for weak signals ,
and lower gain for relatively strong
signals , in order to maintain a near
constant output level, and to To buffer
the receiver electronics from change in
input signal strength .
87. FSK Demodulator
Quadrature detector :
• Most common for IC applications.
• Used for non I-Q Reception.
• Converts the FM signal to a PM signal ,then
detected by a PM detector .
