10 likes | 99 Views
VIP Software Defined Radio Team: USRP FM Tranceiver. Projects on the Transmitter Side. Faculty Advisor: Chih -Chun Wang Graduate Asst : Joon Young Kim. Students: Ben Vondersaar , Andrew Hall, Zeyu Zhou, Jiyu Lu, Jian Sun. Digital Communication.
E N D
VIP Software Defined Radio Team: USRP FM Tranceiver Projects on the Transmitter Side Faculty Advisor: Chih-Chun Wang Graduate Asst: Joon Young Kim Students: Ben Vondersaar, Andrew Hall, Zeyu Zhou, Jiyu Lu, Jian Sun Digital Communication • Send music files with RBDS information through FM Goal 1) any frequency range 2) play from file 3) play from microphone 4) volume control bit string: 0 1 1 0 1 1 0 0 …… Music file with simple cosine function t Projects on the receiver side FM Radio Broadcast Data System (RBDS) Doppler effect Observed frequency changes with position • Embeds small amounts of digital information in an FM broadcast • e.g. station identification and program information • Bitrate: 1,187.5 bps • Sent along the 57kHz subcarrier FM Transmission of cosine function Conceptual waves Design analog waveform Challenges: Compensating the frequency shift of the Doppler effect Tool: Costas Loop Task: Implement Costas Loop by Matlab, C++ Transmission Steps Source sends string of bits Bits differentially encoded Converted to polar impulses Converted to biphase symbols Shaping filter Placed on 57kHz subcarrier and added to baseband signal USRP: Universal Software Radio Peripheral • USRP allows general purpose computers to function as high bandwidth software radio. • Priced around $ 1700 - relatively cheap • 4 ADCs • 64 million sample per second • 4 DACs • 128 million samples per second • Motherboard and daughterboard provide great flexibility of clocking • Open sourced implementation Block diagram of radio-data equipment at the transmitter (source: UNITED STATES RBDS STANDARD April 9, 1998) Sampling Cite[source:http://michaelgellis.tripod.com/mixerscom.html] USRP Application for the Graduate Research • Travel Time Estimation for Intelligence Transportation Systems • USRP sniffs Bluetooth signals from inductive loop transmitters. • Each time and frequency estimation can identify various types of cars. Source:http://www.chmag.in/article/dec2011/gsm Travel Time Estimation USRP processing Actual EM waves