Introduction to Software Defined Radios

photohomoeopathΤεχνίτη Νοημοσύνη και Ρομποτική

24 Νοε 2013 (πριν από 3 χρόνια και 7 μήνες)

138 εμφανίσεις

TAPR:

Tomorrow’s Ham Radio
Technology Today

John Ackermann, N8UR

Tucson Amateur Packet Radio, Inc.


Who am I?


A ham for 25+ years (ex
-
AG9V, WB9OWI)


A lawyer by trade, working for NCR Corp.


Active in DXing and Contesting, but
became interested in packet radio, joined
TAPR, and never looked back


Board member and VP since 1995


Elected President in 2000


Contact Information:

jra@febo.com or n8ur@tapr.org

http://www.febo.com

01 937 445
-
2966

What is TAPR?


Founded in Tucson, Arizona in early 1980s;
quickly became an international
organization


Today, over 2000 members worldwide


Contact Information:

8987
-
309 E. Tanque Verde Road

Tucson, AZ 85749
-
9399 USA

01 940 383
-
0000

tapr@tapr.org

http://www.tapr.org

Previous TAPR Projects/Products


TNC
-
1
--

the project that started it all


TNC
-
2
--

the “standard” TNC


OEM’d by AEA, MFJ, PacComm, and others


TrakBox (satellite antenna tracker, with
AMSAT)


DSP
-
93 (early DSP modem)


9600 Baud Modem


Many Others

TAPR Today


Focused on “Enabling Technology”


Tools that let hams continue to be on the
leading edge


Major Projects:


FHSS Spread Spectrum Radio


Software Defined Radio


PIC
-
based Project Kits


Co
-
Sponsor (with ARRL) of the annual
Digital Communications Conference

Current Products


PIC
-
E
--

Universal Packet Radio Encoder


T
-
238
--

One
-
Wire Weather Station


Compact Flash Adapter II


Totally Accurate Clock


METCON
-
2
--

Universal Remote
Control/Sensor


EZ
-
Trak
--

New Generation Satellite
Antenna Tracker

Books and Publications


PSR
--

TAPR’s Quarterly Journal


DCC Proceedings


Wireless Digital Communications: Design
and Theory

by Tom McDermott, N5EG


Networking Without Wires: TCP/IP over
Amateur Radio

by John Ackermann, N8UR


Spread Spectrum Update

edited by Greg
Jones, WD5IVD and Steve Bible, N7HPR


TAPR’s Online Presence


http://www.tapr.org


Mailing lists:


aprssig@lists.tapr.org (APRS)


netsig@lists.tapr.org (Packet Networking)


ss@lists.tapr.org (Spread Spectrum)


Many, many others


File Downloads


APRS software, etc.

What Is a Software Defined Radio
(SDR)?


Performs the majority of signal processing in the
digital domain using programmable DSPs and
hardware support, but some signal processing is still
done in the analog domain, such as in the RF and IF
circuits.

What Is a Software Radio (SW)?


The ultimate device, where the antenna is connected
directly to an A
-
D/D
-
A converter and all signal
processing is done digitally using fully
programmable high speed DSPs. All functions,
modes, applications, etc. can be reconfigured by
software.


Why Software Defined Radios?


Dale Hatfield, WØIFO,


Chief, Office of Engineering and Technology,

Federal Communications Commission



“This could stimulate a whole new generation of
amateur innovation that not only includes the
more spectrally efficient systems I mentioned
earlier, but also radios that could adapt to their
environment as well.”



Speech to AMRAD’s 25
th

Anniversary Dinner June 17, 2000

http://www.fcc.gov/Speeches/misc/dnh061700.html

Benefits of SDR


Flexible


Reduced Obsolescence


Enhances Experimentation


Brings Analog and Digital World Together


New Breed of Radio


Reprogrammable


Multiband/Multimode


Networkable


Simultaneous voice, data, and video


Full convergence of digital networks and radio
science.


Block Diagram

Software Defined Radio

Variable

Frequency

Oscillator

Local

Oscillator

(fixed)

Antenna

Bandpass

Filter

RF

IF

Baseband

ADC/DAC

DSP

Block Diagram

Software Defined Radio

Local

Oscillator

(fixed)

Antenna

RF

IF

Baseband

DSP

ADC/DAC

Block Diagram

Software Radio

Antenna

RF

IF

Baseband

DSP

ADC/DAC

Looking Ahead


Smart Radios

that
configure themselves to
perform the communications task requested (using
different frequency bands, modes, etc.)


Cognitive Radios

that learn about their
environment (e.g., other users nearby,
interference, location, elevation) to optimally
configure themselves to maximize efficiency and
reduce interference.

Technical Challenges


Dynamic Radio


ADC/DAC Speed


Smart Radio Algorithms


How to Build a SDR


DSP
-
10 by Bob Larkin, W7PUA


QST
-

Sep, Oct, Nov 1999


http://www.proaxis.com/~boblark/dsp10.htm


http://www.arrl.org/tis/info/vhfproj.html


R2
-
DSP by Rob Frohne, KL7NA


QST
-

Apr 1998


http://www.wwc.edu/~frohro/R2_DSP/R2
-
DSP.html


A Panoramic Transceiving System for PSK31

by Skip Teller, KH6TY and Dave Benson, NN1G


QST
-

Jun 2000


http://www.arrl.org/tis/info/psk31.html

(see also the new 80M “Whistler” radio by the same folks)

The DSP
-
10 As a SDR

DSP
-
10


Constructed by

Ernie Manly, W7LHL


TR SW

(D2)

U1,U2

TR SW

(D1)

U4,U5

Synthesizer

124.3 to 128.4 MHz

5 kHz Steps

Synthesizer

19.680 MHz

TR SW

(U11A,U11C)

Q1,

U10A

ADC

90

o

Arc Tangent

FM Detector

Sinewave BFO

12.5
-
17.5 kHz

90

o

SW

+ /
-

AGC

Audio

Filters

LMS

Denoise

DAC

U14

FFT Spectrum

Analyzer

FM

Squelch

SSB and CW

Detector

Analog Devices EZ
-
Kit Lite

Speaker

Serial Data

to PC

1024 Points

Audio

Power Amp

IF Amp

50 dB

ANT or

XVRTR

R

T

R

T

143
-

149 MHz

150 MHz

2
-
Pole

LC Filter

Low
-
Pass

Filter

40 dB

Transmit

RF Amp

Receive

RF Amp

32 dB

143
-

149 MHz

19.665 MHz

First

Mixer

(U3)

Second

Mixer

(U15)

28 kHz

Low
-
Pass Filter

4
-
Pole

Crystal Filter

4
-
Pole

LC Filter

TR

SW

(U11B)


U109B,

Q5,Q6

IF Driver

TR SW

(U12A,U12B)

Microphone

R

T

T

R

R

PTT

CW Key

10 MHz

Ext. Ref.

(Optional)

10
-
20 kHz

J212

J213

J211

J102

J103

J201

J204

Receiver Second IF

10
-
20 kHz


Single Yagi, 150 Watt 2
-
Meter EME QSO

W7SLB and W7PUA demonstrated a QSO on 2
-
meter EME, using the PUA43 mode of the DSP
-
10. Single Yagis and transmitter powers of
150 Watts or less were used on both ends of the contact. Details are available on the
weak signals page

and the linked text.


QRP 5
-
Watt 1296 EME QSO
On 25 February 2001 Ernie, W7LHL, and Larry, W7SZ, were successful with a PUA43 mode
QSO on 1296 MHz EME (Moon bounce). They were using a QRP power level of 5
-
Watts and backyard TVRO dishes of 10 and 12 feet.

Copy was Q5 as can be seen on the screen at the left (click on it for a bigger version). They were using a 28 character setti
ng
on PUA43 (see
below for more information on the PUA43 mode). The extra characters were being used for redundancy in portions of the message
. T
he
message would begin to appear in a few minutes, but Q5 copy was taking roughly 15 to 30 minutes per message. They exchanged c
all

signs,
grid squares, and confirmations both ways. Copy at W7LHL was not quite as good as for the other direction, but both stations
rec
eived a
complete message in the 28 characters. This was their first attempt at using the 5
-
Watt level for a QSO. As was reported earlier

they had
been successful at higher power during January.

None of those involved are aware of any previous 5 Watt 1296 MHz EME QSO's although this may well have been done using larger

antennas. Any information on this would be appreciated.

The PUA43 mode described below is ideal for this type of work. The limits of signal strength have yet to be fully explored. B
oth

Ernie and
Larry reported that they were kept busy with antenna pointing and playing screen "anagrams," so were not sure what their pati
enc
e level
might be if the power kept dropping. The nature of the mode is to trade
-
off time for increased sensitivity.











Single Yagi, 150 Watt 2
-
Meter EME QSO

W7SLB and W7PUA demonstrated a QSO on 2
-
meter EME, using the PUA43 mode of the DSP
-
10. Single Yagis and transmitter powers of
150 Watts or less were used on both ends of the contact. Details are available on the
weak signals page

and the linked text