Scribd
Upload
71 views27 pages

Lecture5 3TLW PDF

This document discusses mixer concepts in radio frequency system design. Mixers are used to translate signals between different frequencies through frequency mixing. There are three main types of mixers discussed: single-ended mixers, single-balanced mixers, and double-balanced mixers. Key considerations in mixer design include noise figure, isolation between local oscillator and radio frequency ports, nonlinearity, and conversion loss or gain between input and output signal powers.

Uploaded by

rushitaa
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF, TXT or read online on Scribd
71 views27 pages

Lecture5 3TLW PDF

This document discusses mixer concepts in radio frequency system design. Mixers are used to translate signals between different frequencies through frequency mixing. There are three main types of mixers discussed: single-ended mixers, single-balanced mixers, and double-balanced mixers. Key considerations in mixer design include noise figure, isolation between local oscillator and radio frequency ports, nonlinearity, and conversion loss or gain between input and output signal powers.

Uploaded by

rushitaa
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF, TXT or read online on Scribd
You are on page 1/ 27

Unit 5

RF System Design Concepts


Mixers
Session Meta Data

Author Ramprabhu S
Version No. 1.1
Release Date 10-03-2020
Reviewer
Revision History

Date of Revision Details Version Number


10 March 2020 1.1
Session Objectives

 To introduce the concepts of Mixer.


Session Outcomes

At the end of the session, students will be able to

 Understand the use of mixer and its types.


Outline

 Mixer

 Single Ended Mixer

 Single Balanced Mixer

 Double Balanced Mixer


Mixer
• Mixers are commonly used to multiply signals of
different frequencies in an effort to achieve frequency
translation.

• Mixers help reduce the Q factors by the concept of


down-conversion.

• The best known systems is the down-conversion in a


heterodyne receiver
Mixer
Basic Mixer Concept
Basic Mixer Concept
• Shockley diode equation is given by

• For a MESFET

• Input voltage applied is


Basic Mixer Concept
• Current output characteristics of non-linear
device is given by Taylor series
Basic Mixer Concept
• Cosine terms are rewritten using trigonometric
identity taylor
series representation up to third term i.e., upto
second-order inter-modular product is given by
Frequency Domain Considerations
• Up-conversion process is associated with the
modulation in a transmitter, whereas the down-
conversion is encountered in a receiver
Frequency Domain Considerations
Frequency Domain Considerations
Problem of Image Frequency
• The desired RF signal transforms as

• The image frequency transforms as

• To suppress the image frequencies image filters


are used
Problem of Image Frequency
Single-Ended Mixer
Conversion Loss & Noise Figure
The conversion loss (CL) of a mixer is generally
defined in dB as the ratio of supplied input power
PRF over the obtained IF power PIF

Noise Figure of a mixer is given by


Single-Ended Mixer
Single-Balanced Mixer
Single-Balanced Mixer
Double-Balanced Mixer
Summary

• Important considerations in the mixer design are


Noise Figure, Isolation between LO and RF
signal ports, Nonlinearity, Conversion Loss or
gain between the RF and IF signal powers
Test Your Understanding
• Write short notes on types of mixers
References
1. John D Ryder, “Networks, lines and fields”, 2nd
Edition, Prentice Hall India, 2015.

2. Mathew M. Radmanesh, “Radio Frequency &


Microwave Electronics”, Pearson Education Asia,
Second Edition, 2002.

3. Reinhold Ludwig and Powel Bretchko, “RF Circuit


Design - Theory and Applications”, Pearson Education
Asia, First Edition, 2001.

You might also like