Electrical Communications Systems ECE.09.433 Spring 2019 Lab 3: Pre-lab Instruction Shreekanth Mandayam ECE Department Rowan University http://engineering.rowan.edu/~shreek/spring19/ecomms/

ECOMMS: Topics

Plan FM Signal and Spectrum FM Detection FM Generation Slope Detector FM Generation Voltage Controlled Oscillator (VCO) Phase Locked Loop (PLL) Lab Project 3

FM Signal & Spectrum Single-tone FM Signal Single-tone FM Spectrum 0 fc-3fm fc-2fm fc-fm fc fc+fm fc+2fm fc+3fm |S(f)| / (Ac/2) f J0(b) J1(b) J2(b) J3(b)

FM Detection FM Signal, We need a frequency-voltage converter Slope Detector

Slope Detector Frequency- AM voltage Detector converter LPF Envelope Detector |H(f)| f t fi(t) vo(t)

FM Generation Voltage Controlled Oscillator f0=fc m(t) Control Instantaneous Frequency m(t)

Oscillators: Principle b S Signal Source Amplifier Feedback Network Output + - vi vs vo Barkhausen Criteria for oscillation: Ab = -1

Oscillators Waveforms Schmitt Trigger Oscillator

Phase Locked Loop Phase Detector VCO LPF A fi fvco fi -fvco vo fo f Loop Filter vo Hold (lock) Range, fH Capture Range, fC fo f

Lab Project 3: Frequency Modulation and Detection http://users.rowan.edu/~shreek/spring19/ecomms/labs/lab3.html

Summary