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SDR Architectures, Remote Radio and FlexRadio Update
Ham-Com: June 13, 2015
Stephen Hicks, N5AC VP Engineering, FlexRadio Systems
SDR, Remote HF, FlexRadio Agenda
What is an SDR? History of Amateur SDR Technologies that make an SDR
Remote HF and Maestro FlexRadio Update Other presentations today
What is an SDR?
SDR is a spectrum
Some radios are clearly NOT
Other radios clearly ARE
Many permutations in-between
So what makes up an SDR?
Engineering Design Process
Draw a block diagram
Simulate
Draw a schematic
Simulate
Build
Measure and adjust
Engineering Design Process
Does the circuit match the simulation exactly? NO … WHY?
Components are not “ideal” There are losses not modeled Component variance Component capabilities
Result: Never as good as the simulation
Can’t we account for component differences?
In some cases, YES
Some materials work better in some cases
Compensating circuits can be added
In some cases, NO
There will always be issues
Components and ProblemsResistors Capacitors Inductors Transistors Mixers Amplifiers Crystals Filters
Lot Variance Parasitics Non-linearities Thermal variance Electrically induced variance IMD Manufacturing variance The list goes on…
Block Diagram Key
Yellow blocks are
Green blocks are DIGITAL
ANALOG
123 346 767 1134
001 1010 1011 110 010
455 913 21
2394 23
Filter Design: SimulationSampled signals passed through simulated ideal components
Results could even be played out a speaker
123 346 767 1134 1582 1204 895 431 208
150 300 600 1200 1500 1200 600 300 150
FILTER SIMULATION DAC
Filter Design: Simulation Limits
Analog: 20-30 poles
Digital: unlimited … except for latency. Maybe 200, 1000, more!
Could a computer run the simulation IN THE RADIO?
ADC DACFILTER SIMULATION
DEFINITIONS: Software Defined vs. Controlled
CONTROLLED
Computer Control of Fixed Capabilities(frequency, band, etc)
DEFINED
Modulation, Demodulation, filtering, and processing; as well as Control Capabilities Software Defined and Upgradeable
500 Hz Brick Wall Filter
6dB Bandwidth 487 Hz, 60dB Bandwidth 660 Hz, Shape Factor ~1.35 4096 Bin FFT and 2048 Tap Filter
2.8KHz SSB Filter Spectrum
6dB Bandwidth 2587 Hz, 60dB Bandwidth 2756 Shape Factor ~1.06, 2048 Tap Filter
Software Demodulation and Baseband
New demod schemes added later!
Precise Filtering
Advanced Noise Reduction
DEMOD
IF AMP
AUDIO AMP
FILTER DAC
ADC
Economics 101
What is the marginal cost of a 2nd receiverin an analog radio?
ANSWER: the cost of the added parts (plus amortized engineering)
What if I want 2 RX?
LO
DEMOD
FILTER IF AMP
AUDIO AMP
MIXER
FILTER
2x analog components ≈ $2x
ADC
DAC
DEMODADC
FILT
ER
What are we trying to achieve?
Remove distortion
Better performance
Flexibility to change or add features
Ability to tailor the radio quickly
Never before possible noise mitigation
Never before possible capabilities
Can we do more?
LO
DEMOD
FILTER IF AMP
AUDIO AMP
MIXER
FILTER
Why doesn’t everyone do Direct Sampling?192kHz @ 64bits =
12Mbps192kHz
DAC
ADC
Direct Sampling
LO
DEMOD
FILTER
AUDIO AMP
MIXER
FILTER
Now, THAT’s an SDR!
250MHz @ 16bits = 4Gbps
250MHz
DAC
ADC
4Gbps is…
40 - 100Mbps cables4 - 1Gbps cables
That’s a LOT of data! The most modern home networking you can buy, can’t handle this …
Economics 101
What is the marginal cost of a 2nd receiverin an digital radio (SDR)?
ANSWER: the cost of the extra processing power (plus amortized engineering) … think Moore’s law
Processing Power = FPGA
Direct Sampling
LO
DEMOD
FILTER
AUDIO AMP
MIXER
FILTER
Now, THAT’s an SDR!
ALL of HF digitizedALL of HF
DAC
ADC
Direct Sampling Benefits
+ Distortion minimized (ADC @ antenna): best signal clarity + n-Receivers, n-Panadapters and varying widths
see more bands, more receivers + Extremely high dynamic range: operate in worst
conditions + Extreme flexibility through reprogrammability (ultimate
SDR): future benefits – Technically challenging to design
F A T
“Our Choices Determine Our Destiny” — A.R. Benard
Shortcut to the finish line:
Direct Sampling Receiver A
PowerSDR et. al.
Rapidly bring up a direct sampling receiver
Each 192kHz receiver uses 10+ Mbps
A full 1MHz of bandwidth panadapter: 73 Mbps
Not scalable
DAY
TON
201
2
“Our Choices Determine Our Destiny” — A.R. Benard
Building for the future:
FLEX-6000 SmartSDR
New software, much more work in the radio
A full-screen panadapter: <1 Mbps AT ANY WIDTH
Scalable, Remotable
DAY
TON
201
2
Spectrum Display BW
1MHz <500kbps
1MHz 77Mbps
150:1 Bandwidth Difference
10MHz <500kbps
1500:1 Bandwidth Difference
10MHz 770Mbps
SmartSDR APIs
FLEX-6XXX
Windows Computer
UDP TCP
FlexLib
SmartSDR Ethernet API
SmartSDR FlexLib API
SmartSDR
SmartSDR-Windows
© 2 0 1 5 F L E X R A D I O S Y S T E M S
Continued to hear that knobs/buttons are important Often, existing products maligned for complexity Station reconfiguration time frustrating Integration in SO2R, M/1, M/2, M/M stations a problem The dream of simple remote operation…
Maestro The interviews…
© 2 0 1 5 F L E X R A D I O S Y S T E M S
Maestro Control surface and more
Essentially a remotable SmartSDRwith knobs & buttons Can be used in place of a computer to run any FLEX-6000 Optimized to have just frequently used controls Let’s take a closer look …
© 2 0 1 5 F L E X R A D I O S Y S T E M S
Maestro Display
WXGA (1280x800) 8” IPS Cap Touch Can show one or two panafalls Up to two slices Cap touch, pinch to zoom, buttons and pop-up menus Built on SmartSDR API
© 2 0 1 5 F L E X R A D I O S Y S T E M S
Maestro Capabilities
Integrated CW keyer Mic, headphones, line in/out ~6 hours of battery life or plug-in (12V nom.) WiFi (802.11 a/b/g/n) and wired Ethernet (1GbE) VESA mount for Public Safety comms, mobile use, etc
© 2 0 1 5 F L E X R A D I O S Y S T E M S
Maestro What’s next?
Control of a computer and large display (fairly easy) Multiple Maestros on a single radio WAN use (away from the shack) Who knows …
SmartSDR v1.3 August 2014
CWX Transverter operation Contest Logger return focus Profile manager Diversity
SmartSDR v1.4 March 2015
LAN Remote FM / DFM Memories Performance Optimizations CW Enhancements DAX Enhancements CAT Improvements
SmartSDR v1.4.3 April 2015
Binaural receive Digital transmit monitor TX Audio play/record FlexControl Enhancements
DXing and Contesting
Focus Return for loggers SO2R Integration (N1MM) SO2R in a single radio ! FlexRadio Systems 1.5kW Solid State Amplifier
Other Presentations Today
1300 Contest Luncheon, Grokking HF Receiver Performance (Room 9) 1400 SmartSDR API and applications (Room 3)
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