Communications Baseband PDR Communications Baseband Project 05500

Communications Baseband PDR Members  Advisors:  Dr. Joe Delorenzo  Dr. Eli Saber  Dr. Sohail Dianat  Team Members:  Leland Smith (Team Leader)  Jason Riesbeck (Chief Engineer)  Jonathan Hutton

Communications Baseband PDR Introduction  Communications Baseband is a project created by several professors in order to stimulate student’s practical understanding of communication systems.  Sponsor: Rochester Institute of Technology Department of Electrical Engineering

Communications Baseband PDR Project Overview  Modulate/Demodulate using Amplitude Modulation, Frequency Modulation, and Pulse Code Modulation  Receive analog or digital transmission approximately a classrooms distance and demodulate  Output original signal to see/hear successful recovery

Communications Baseband PDR Team Work Breakdown

Communications Baseband PDR Fundamental Design Objectives Specifications Weight Can be completed in allotted time. 10 Communicates AM, FM, and PCM across a classroom 9 Suitable for evaluation in a laboratory 7 Affordable for customer. 6 Easy to Use. 4 Minimal amount of external equipment 4

Communications Baseband PDR Preliminary Design Concept #1  Digital data rate  Not truly PCM  Usefulness Universal AM/FM/ASK/FSK System  Versatile   Two distanced RF channels Digital and analog signals utilize common modulators

Communications Baseband PDR Preliminary Design Concept #2  Not a PCM solution  Requires extra lab equipment  Duplex communication Analog Voice and Wireless RS232  Reasonable Bandwidth   Analog AM and FM maintained Serial link established

Communications Baseband PDR Preliminary Design Concept #3  Difficult to implement  Requires extra lab equipment  Duplex communication Analog Voice and Wireless USB  Impressive Bandwidth  Mbps  Analog AM and FM maintained USB link established

Communications Baseband PDR Preliminary Design Concept #4 Analog Voice and Streaming PCM Audio ◦Impressive Bandwidth ◦Comparison of modulation schemes ◦No external equipment  All modulations have independent communication systems All schemes have a common audio source

Communications Baseband PDR Concept Analysis

Communications Baseband PDR System Development Divided into 12 subsystems Specification developed for each

Communications Baseband PDR Feasibility  Assessed at a subsystem level.  Depends on the resources available  To maintain feasibility, subsystems should:  Satisfy design objectives  Economical  Comply with time constraints

Communications Baseband PDR FCC Considerations CountryFrequencyNotesStandards US GHzISM Band 1W802.11/11b MHzISM Band (Used by GSM in most countries) GHzISM Band GHzU-NII (Unlicensed - National Information Infrastructure) max. 200 mw EIRP a GHzU-NII max. 1w EIRP802.11a GHzU-NII max. 4w EIRP802.11a Unlicensed Bands (FCC b.4) All other bands 100mW or less Antenna gain can be as much as 6dB.

Communications Baseband PDR Audio Subsystem  Block Diagram

Communications Baseband PDR Anti-Aliasing Filter  Specifications:  0-5V Input  Pass-band 20 kHz  Stop-band 22 kHz  Attenuation 20 dB  Butterworth Filter  Elliptical Filter

Communications Baseband PDR Low Pass Filter -17dB 22.1 kHz

Communications Baseband PDR AM Modulation  Concept Development  Discrete Parts  IC  Transceiver IC  Feasibility Assessment

Communications Baseband PDR Design Objectives and Synthesis  Clock Oscillator  1 MHz Sine Wave  RLC Filter

Communications Baseband PDR Clock Oscillator

Communications Baseband PDR AM Receiver  AM Receiver  Demodulates Signal  Amplifies the Signal by 18 dB

Communications Baseband PDR FM Systems  Complicated to engineer  Could take months in industry Transmitter Receiver

Communications Baseband PDR Radio IC’s  A simple and effective solution

Communications Baseband PDR Choosing an FM IC ObjectivesWeight Part availability10 Comprehensive design resources8 Application examples7 Performance6 Price5 Low parts count5

Communications Baseband PDR FM Feasibility TaskTime in Hours Schematic Creation15 Performance Analysis5 Specification Formation13 Parts List8 General Documentation10 Board Layout12 Board assembly7 Functional Test12 Integration4 Tweaking and Repair20 Total106 Completed51 Remaining55 Meets design requirements Able to be complete in allotted time Low cost

Communications Baseband PDR FSK Systems  Similar to analog FM systems  Also very complicated

Communications Baseband PDR FSK Feasibility Nordic NRF2401 Transmits data at 1Mbps 2.4GHz ISM band

Communications Baseband PDR FSK Link Analysis  NRF2401 Specification ○ 0dBm output power ○ -80dBm receiver sensitivity  Link Budget Analysis ○ 60dB of attenuation at 10m (with 0dB antenna gain)

Communications Baseband PDR TaskTime in Hours Part Research8 Schematic Creation7 Performance Analysis5 Specification Formation8 Parts List8 Timing Information10 Board Layout12 Board assembly7 Functional Test13 Integration15 Tweaking and Repair20 Total113 Completed46 Remaining67 FSK Feasibility Meets project needs Only $4 with few external parts Reasonable time budget

Communications Baseband PDR PCM and Control Subassembly  Transmit Side  Conversion of Analog to Digital  Apply Protocol to Digital Data  Manage Memory and Data Flow to FSK Chip  Receive Side  Provide Control to FSK Chip  Receive and Manage FSK Chip Data  Control and Send Data to DAC

Communications Baseband PDR Interface Specifications  Rail to rail (0-3.3V) analog signal input  Desire ~44 kHz Sample Rate  1 Mbps transmit rate to FSK chip  Send samples to Digital to Analog Converter at sample rate

Communications Baseband PDR Microcontroller Specifications  At least 10 I/O pins  UART (clocked serial data transfer)  Support 1 Mbps

Communications Baseband PDR Solutions  PICmicro Microcontroller  Analog Devices DAC  10-bit  No overhead bits  Serial

Communications Baseband PDR Capabilities  PIC offers 10-bit AD  PIC provides I/O ports  USART (Synchronous/Asynchronous Communications)  Many I/O Ports for control lines  Provides 1MHz USART  Data storage and management

Communications Baseband PDR System Diagram

Communications Baseband PDR Communications Protocol  PIC must manage data from 10-bit samples to exact 1 Mbps output  USART sends 8-bit words  Start and Stop bit  Must hold at least 2 samples in PIC memory to transfer

Communications Baseband PDR IN  PIC  OUT  Known: What goes in must come out – and at the same rate.  Therefore: The rate the PIC can sample at is governed by the FSK communications protocol.  Sampling rate must be some integer number of the outgoing packet rate

Communications Baseband PDR Protocol Options Protocol TypeFSK Chip Mode SynchronousShockBurst AsynchronousDirect

Communications Baseband PDR Synchronous Option

Communications Baseband PDR Asynchronous Option 1

Communications Baseband PDR Asynchronous Option 2

Communications Baseband PDR Choice Protocol  Asynchronous – 1 Sample per 2 Frames

Communications Baseband PDR The Plan for May  Purchase all components  Build systems to spec  Test individual systems  Integrate Systems

Communications Baseband PDR Preliminary Cost Analysis ItemPrice ($) Board Layout100 FM Transmitter Parts40 FM Receiver Parts30 GFSK Transceiver Parts30 Audio Section parts25 AM Receiver Parts30 AM Transmitter Parts30 PIC Implementations15 Power Supply15 RF Cables30 Misc. Prototype Materials20 Total365

Communications Baseband PDR Possible Upgrades

Communications Baseband PDR Questions ?

Communications Baseband PDR Speaker Driver  High Power Op-Amp  Have enough power to drive a speaker  LM Ω 2 W

Communications Baseband PDR Audio Subsystem Specifications InputUnits Input Voltage0-5V Input Jack¼”- Output Voltage0-5V Output Jack0.1” Header-

Communications Baseband PDR Preliminary System Design