ELEC 470, Spring 2004
Prof. Rich Kozick

Homework 8

Date Assigned: Tuesday, March 23, 2004
Date Due: Tuesday, March 30, 2004

  1. Reading: Please continue studying Chapter 4 of the Lathi text on amplitude modulation, particularly Sections 4.7 and 4.8. I suggest that you read Section 4.9 on television. We will not discuss Section 4.9 in class, but it is a good application of the AM topics in Chapter 4.

    Please begin reading Chapter 5 on angle modulation.

  2. Special Topic Reports: Check the list of topics on the course web page, and if your topic is a duplicate, then send me your new topic choice by Thursday, March 25.

  3. Problems: Please solve the following problems in the Lathi text and submit your solutions on March 30.
    4.8-1 and 4.8-2.

  4. Please run the Simulink program costas_demo.mdl, which is available on the course home page under Demonstrations and Class Notes.

    In the DSB-SC demodulator using a Costas phase-locked loop in program costas_demo.mdl, what is the effect of the "Slider Gain" that amplifies the signal prior to being input to the VCO? What happens if this gain is too small? What happens if this gain is too large? Consider the filter that immediately precedes the Slider Gain: what signal is this filter designed to remove?

    Recall that in this program, you can change the phase and the frequency in the "TX Carrier" to cause the Costas loop to hunt for a new frequency-lock and phase-lock.

Thank you.