1 / 11

Electrical Communications Systems ECE.09.433 Spring 2019

Electrical Communications Systems ECE.09.433 Spring 2019. Lecture 4a February 12, 2019. Shreekanth Mandayam ECE Department Rowan University http://engineering.rowan.edu/~shreek/spring19/ecomms/. Signals Systems. Modulation Index Efficiency Bandwidth Noise.

chavezm
Télécharger la présentation

Electrical Communications Systems ECE.09.433 Spring 2019

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Electrical Communications SystemsECE.09.433Spring 2019 Lecture 4aFebruary 12, 2019 Shreekanth Mandayam ECE Department Rowan University http://engineering.rowan.edu/~shreek/spring19/ecomms/

  2. Signals Systems Modulation Index Efficiency Bandwidth Noise Performance Transmitters Receivers Standards Time Domain Complex Envelope Spectrum Power Plan • DSB-SC Modulation • Costas Loop • QAM • Complex Envelope Representation • Spectrum of a bandpass signal

  3. ECOMMS: Topics

  4. |M(f)| -B 0+B Signals Systems Modulation Index Efficiency Bandwidth Noise Performance Transmitters Receivers Standards Time Domain Complex Envelope Spectrum Power DSB-SC Modulation Message Spectrum Matlab Demo http://engineering.rowan.edu/~shreek/spring11/ecomms/demos/dsbsc.m f DSB-SC Spectrum |S(f)| -fc-B -fc -fc+B 0fc-B fc fc+B f

  5. AM -m(t) -Accos2pfct DSB-SC: Balanced Modulator AM Accos2pfct m(t) S

  6. DSB-SC: Coherent Detector Product Modulator Baseband LPF v(t) s(t) Aocos2pfct Local Oscillator

  7. v1(t) Product Modulator Baseband LPF v3(t) v4(t) VCO LPF X s(t) -90o Phase Shift Phase Discriminator Product Modulator Baseband LPF v2(t) Synchronous Coherent Detection: Costas PLL I-Channel Q-Channel

  8. Product Modulator S s(t) m1(t) LPF Product Modulator Local Oscillator Local Oscillator -90o Phase Shift -90o Phase Shift Product Modulator LPF m2(t) Product Modulator Quadrature Amplitude Modulation (QAM) Rx Tx I-Channel Q-Channel

  9. message: m(t) carrier: c(t) Modulator s(t): radio signal Complex Envelope Representation • We want a common mathematical representation for • information transfer from baseband to bandpass • any bandpass signal • any time of modulation • signal/noise and signal+noise

  10. Spectrum of a Bandpass Signal

  11. Summary

More Related