Transceiver Architectures

1
Transceiver Architectures

• General Consideration
• Receiver Architectures
• Super-heterodyne
• Homodyne
• Low IF
• Transmitter Architectures
• Direct Conversion
• Two Step

2
General Consideration

• Adjacent channel reject

3
General Consideration

• nonlinearity and spurious respone

4
General Consideration

• Dynamic range design
• AGC (for large signal)
• Isolation between TX and RX(for small signal)
• PA design
• noise immunity and supply reject

5
Receiver Architectures

• Super-heterodyne Receiver
• easy to design
• problem of image
• problem of half if

6
Problem of image

• Need image rejection filter
• Choose a suitable IF (high is good)

7
Problem of image

• How about the IF frequency?

8
Problem of Half IF

• Second harmonic problem

9
Homodyne Receivers

• Easy to single chip
• Channel Selection
• DC offsets
• I/Q Mismatch
• Even-Order Distortion
• Flick Noise
• choose a suitable code
• LO Leakage

10
Channel Selection

• Different placement of three block

11
DC offsets

• Self-mixing problem

12
I/Q Mismatch
13
Even-Order Distortion
14
Low-IF Receivers

• Possible way to implant digital IF
• Low-IF cause image reject problem

15
Digital IF

• Subsampling Receivers

16
Image reject filter

• Hartley Architecture

17
Hartley Architecture
18
Image reject filter

• Weaver Architecture

19
Weaver Architecture
20
Transmitter Architectures

• Direct-Conversion Transmitters

21
Transmitter Architectures

• Two-Step Transmitters