SDR TX ProjectHardware / Software Update

Jerry Boyd, WB8WFK

(Hardware and FPGA VHDL )

Mike Pendley, K5ATM (PIC Software)

October 2008

This is an ARTS Project

Software defined ARDF radio transmitter

New approach to solve a reoccurring problem

– A need exists for an easy to build “NO-Tune” reliable ARDF transmitter that does not require any complex test equipment other then a DVM , wattmeter and receiver to verify operation after assembly

– Simple Alignment (tune RF output stage)– As a result of this development effort Other ham radio related

applications are possible•A short list of possible applications

–APRS–PSK–RF Signal generator for equipment testing

The Problem

Our Current FOX Boxes are

– LARGE and heavy– Tend to fall out of sync– Limited to 2m FM MCW and 80m CW– Programming switches and radios need to

be adjusted to change frequencies and configuration.

The ProblemRoot cause

– All problems can be traced to systems that are wired together using mutable connectors, cables and equipment interconnected to function as an ARDF transmitter

– RF gets into and upsets controller– Radios are not designed for high duty cycle– Equipment not designed for this application– Wires can get caught in equipment during

transport to location and interruptoperation

– Lots of opportunity for somethingto go wrong

The Solution A Software Defined Radio That can

– Dynamically change frequency– Dynamically change modulation modes– Conserve power during “down” time– Use SI station “real time clock” to stay in sync and “auto

recover” if power is interrupted after sync– Phone home with state of health information– A user interface that is easy to configure– Shielded enclosure that protects all electronics– Radio designed for continuous duty cycle (homing beacon

mode)– Every thing contained in one hardware package with power

input, SI input and antenna connections

The Solution

A Software Defined Radio

– First Generation WB8WFK K5ATM SDR (w/o PA amps) demonstrated at 2005 ARDF championships

– Used as homing transmitter for the 2005 USA ARDF championships

Tools used

• Recent changes in industry ( free tools for download from the internet) make a project like this possible

Free development environments

• Xilinx– WWW.Xilinx.com Webpack ISE development

environment for development of VHDL and FPGA code

• JAVA IDK– Sun Microsystems. Used to develop lookup ROMs, I

wrote Java code that automatically writes VHDL code to define modulation parameters

• Microchip– PIC ISE development environment for generating PIC

controller code

Purchased Items

• PIC dim II card development kit and PIC programmer. I took part in a group buy by the Albuquerque Yahoo PIC group

• BASYS Digiletinc.com Xilinx eval board. purchased last Christmas

• SI score keeping system Purchased Summer 2008 by Albuquerque transmitter hunters

2nd Generation Prototype

Signal Processor FPGA ($10 Xilinx chip). FPGA, regulators , clock and boot ROM are only features being used on $59 eval board

Mixer

Class C RF amp

OP amp for D/A, AM Modulator & RF power control

Pre driver

Voltage regulator

Open Bench testing of SI interface

PIC DIM2 card and Xilinx FPGA eval board used for SI interface concept testing. Next steep is to produce ~ 3 inch X 4 inch PCB board with all processing and I/O support electronics combined to finish development

SI pinch data (Time and Stick number) displayed on PIC dim LCD0x23 = station 35 or MO5 for FJWW score keeping software

02B8F3 = SI stick Number 247347 was punched8 33 6 =Punch time was 8:33 06 PM

2nd generation Block Diagram of today's demo hardware

Signal processor using Xilinx FPGA

Simple bandpass

Filter

Driver PAClass C

ModulatorPower Control

8

LO

RF

VHF

Mixer

HF not used in today's demo

FM modulatorAM modulator

SynthesizerHF and VHF

Packet modem (TX only)Control Logic

PICFox

Controller

Simple Block Diagram

RS-232 to SI station

130MHz

15.565

145.565

The hart of the system• Phase accumulators operating at 200 MHz

– Generates both HF and VHF signals• VHDL state machines

– Generate modulation formats and handles DSP control• VHF signals generated at HF then mixed up to VHF

– FPGA generates LO (130 MHz) and formatted transmit IF signal (14 to 18 MHz) that represents modulated up converted144 to 148 MHz carrier

– AM modulation is the one exception and that’s done under FPGA digital control of the Class C VHF Power amp

– Sample output from Java code for configuring phase accumulators VHF DDS phase inc is 309022897 counts for 144.3900 Mhz; DDS set to 14.39000000 Mhz

VHF DDS phase inc is 334255830 counts for 145.5650 Mhz; DDS set to 15.56500000 Mhz VHF DDS phase inc is 355730666 counts for 146.5650 Mhz; DDS set to 16.56500000 Mhz VHF DDS phase inc is 377205503 counts for 147.5650 Mhz; DDS set to 17.56500000 Mhz

• HF signals (80 meters) are direct generated– Sample output from Java code configuring phase accumulators

HF DDS phase inc is 76879915 counts for 3.5800 Mhz HF DDS phase inc is 81604379 counts for 3.8000 Mhz HF DDS phase inc is 76020921 counts for 3.5400 Mhz HF DDS phase inc is 75806173 counts for 3.5300 Mhz

Software2m (VHF) Transmission modes to be

supported– FM MCW Cont carrier– FM MCW keyed carrier– AM MCW Cont carrier– CW– AM MCW keyed carrier– FM packet (1200 baud)– APRS tracker?

145.565 VHFAM Modulation

Software (cont)2m Transmission modes to be supported

-Sport ID data packet sent while TX is off cycle

-VHF TX would be used during a HF hunt to support SI data

-Panic button located at each control station to request medical assistance

K0OV photo

First SI data sent Via Packet• First on air test of SI reporting KPC3 TNC was decoding packets. Each SI

punch event is sent 4 times (binary data) to aid reception at finish line

• Note 0X02 = STX and OX03 = ETX

57 42 38 57 46 4B 2D 31 3E 41 50 54 44 44 53 2D WB8WFK-1>APTDDS- 31 2C 57 49 44 45 32 2D 32 3A 20 3C 55 49 3E 3A 1,WIDE2-2: <UI>: 0D 0A 02 53 21 23 10 02 B8 F3 10 00 2A C7 10 03 ...S!#..¸ó..*Ç.. A6 10 0A 03 0D 0A 57 42 38 57 46 4B 2D 31 3E 41 ¦.....WB8WFK-1>A 50 54 44 44 53 2D 31 2C 57 49 44 45 32 2D 32 3A PTDDS-1,WIDE2-2: 20 3C 55 49 3E 3A 0D 0A 02 53 21 23 10 02 B8 F3 <UI>:...S!#..¸ó 10 00 2A C7 10 03 A6 10 0A 03 0D 0A 57 42 38 57 ..*Ç..¦.....WB8W 46 4B 2D 31 3E 41 50 54 44 44 53 2D 31 2C 57 49 FK-1>APTDDS-1,WI 44 45 32 2D 32 3A 20 3C 55 49 3E 3A 0D 0A 02 53 DE2-2: <UI>:...S 21 23 10 02 B8 F3 10 00 2A C7 10 03 A6 10 0A 03 !#..¸ó..*Ç..¦... 0D 0A 57 42 38 57 46 4B 2D 31 3E 41 50 54 44 44 ..WB8WFK-1>APTDD 53 2D 31 2C 57 49 44 45 32 2D 32 3A 20 3C 55 49 S-1,WIDE2-2: <UI 3E 3A 0D 0A 02 53 21 23 10 02 B8 F3 10 00 2A C7 >:...S!#..¸ó..*Ç 10 03 A6 10 0A 03 0D 0A ..¦.....

First packet send via RF on 9/21/2008Red indicates enbedded SI punch data

Our SI system

SoftwareOther Transmission modes

– Special modes for car hunts are possible• Random on time• Variable and random

power output• Short TX times• Keyed carrier modes• Different modulation formats

This is a transmitter used on an Albuquerque T hunt by Mike Pendley K5ATM

SoftwareOther Transmission modes

– HF side• 80M CW used for 80 meter ARDF

HF CW 3.58 MHz

What next• BASIC concept is verified using open bench setup! I am

happy with signal processor operation• Now its time to:

– Develop 2 X 3 inch Circuit board and User interface– Write SPI based interface VHDL code for signal processor FPGA

to allow full control of signal processor by the PIC processor (Modulation Mode and frequency selection). Currently done using dip switches

– Develop panic button interface to allow runners to call for medical help at any control point

– Field test prototype with all of the above functions• Design of the PC board with necessary I/O to support the

above is now in process. Schedule will allow testing design over Christmas holiday break

• There will be another PCB before the final design is done to develop PA board (HF and VHF) that mounts on top of the signal processor board ~ January 2009 time frame

3 X 4 inch PCB Board layout has started

Demo

• Demonstrate Generation 2 prototype system

Some Other Projects

Questions