Low Rate Software Based LRIT Receiver

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14432 Albemarle Point Place Chantilly VA
20151 Phone [phone] Fax (703)
488-2555 www.avtec.com
EMWIN S/W Receiver April 27, 2004
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Presentation Agenda

• EMWIN System Introduction
• EMWIN Demodulator Software Overview
• System Requirements
• Installation Instructions Overview
• Prototype Demonstration
• On-going Work / Potential Upgrades

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EMWIN-N S/W Receiver Introduction

• S/W Demodulation, Bit-Synchronization
• CCSDS Concatenated R-S Convolution, Bitstream
  Service
• Signal must be acquired for coding gain to apply
• EMWIN-N Reduced TX Power Performance Goals
• 3 dB Margin with 1 meter antenna _at_ 5 degree
  elevation
• BER 10-6 _at_ 5 degree elevation
• Implementation Goals
• Support EMWIN-I Series FSK EMWIN-N Series BPSK
• S/W Loading lt 25 CPU (1 GHz P4)
• Re-use Antenna RF components
• Additional H/W costs lt 300
• Current Test Results
• 4.5 dB Margin with 1 meter antenna _at_ 5 degree
  elevation achievable
• Link Margin enough to support transition to 2x
  data rate QPSK

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EMWIN Receiver Architecture
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EMWIN Demodulator Software Overview
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System Requirements
 
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Installation Overview

• Download S/W and Manuals from NWS
• Antenna / LNB Amplifier
• IF Adapter
• Consumer PC / Sound card / Serial card
• EMWIN Demodulator
• EMWIN data processing display S/W

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(a) Antenna/LNB Amplifier

1. Assemble the dish and position the antenna.
2. Connect the LNB to the antenna.

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(b) IF Adapter

• Construct or Purchase UHF/VHF Frequency Adapter.
• Connectorized component version.
  Surface/through hole
• schematic available.

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(b) UHF/VHF Frequency Adapter (cont.)

1. Connect the UHF/VHF Frequency adapter to the LNB
   using an SMA or appropriate RF cable. Note 60
   dBm maximum input for the reference design.
2. Connect the adapter to an A/D or soundcard when
   installed. If using the Avtec Data Source
   Service, channel 0 of the soundcard must be used
   at this time.
3. Connect the power supply to the rear power jack.
4. Turn on the DC BIAS for the adapter.
5. Turn main power on.

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(c) Consumer PC / Sound Card / Serial Card

1. Install Windows 2000 or XP and corresponding
   service packs on PC if not already pre-installed.
2. Install Sound card or A/D converter.
3. Install Serial expansion card if the PC does not
   contain two RS-232 com ports and connect loop
   back cable.
4. Login to the system as the local administrator
   and install necessary device drivers. Insure
   TCP/IP Protocol stack is active.

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(c) Consumer PC / Sound Card / Serial Card (cont.)

1. Configure the A/D or Sound card and test
   operation by recording and playing audio.

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(c) Consumer PC / Sound Card / Serial Card (cont.)

1. Configure the Serial card if necessary. Test
   using HyperTerminal.

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(d) EMWIN Demodulator

1. Unpack the archived EMWINSetup.exe to a temporary
   directory and verify.
2. Initiate EMWIN installer.

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(d) EMWIN Demodulator (cont.)
17. Review and acknowledge the welcome
screen. 18. Review and acknowledge the license
agreement.
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(d) EMWIN Demodulator (cont.)
19. Review and acknowledge the information
screen. 20. Select program location.
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(d) EMWIN Demodulator (cont.)
21. Select the installation type. 22. Select
icon access location.
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(d) EMWIN Demodulator (cont.)

• 23. Install EMWIN Demodulator Services.
• 24. Reboot the PC.
• 25. Verify EMWIN Data Source and Demodulator
  Service are active.
• Select START-gtEMWIN Demodulator-gtEMWIN Config.
• Select Data Source Service Tab and note activity
  icon.
• Select Demodulator Service Tab and note activity
  icon.

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(d) EMWIN Demodulator (cont.)
Pertinent Data Source Parameters Input Device
Selects the desired sound card. Input Gain
Selects the sound card gain value. Data range is
between -32768 and 32768. TCP Port Number
Selects a valid TCP/IP Port. Port range is
between 1 to 65535. Avoid system reserved ports.
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(d) EMWIN Demodulator (cont.)
Pertinent Demodulator Parameters Data Source
Host IP address that the Data Source Service
resides at. IP address 127.0.0.1 represents the
local systems address. Signal Format Selects
between EMWIN I (0) or EMWIN N (1). COM Port
Number Defines the desired COM port to write
out for the EMWIN display software. TCP Port
Number Selects a valid TCP/IP Port. Must match
the Data Source Service assigned port address.
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(d) EMWIN Demodulator (cont.)
Pertinent FSK Demodulator Parameters Sample Rate
The sample rate will be 96 KHz for the sound
card solution. Signal Present Threshold The
threshold which used to indicate whether a valid
signal is present. AGC Gain The gain bandwidth
setting value that corresponds to about a 10 Hz
bandwidth at the given input sample rate. Tuner
Frequency Initial tuner frequency that
represents the frequency as seen by the A/D
converter. The nominal center frequency has been
designed for approximately 25 KHz.
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(d) EMWIN Demodulator (cont.)
Pertinent FSK Symbol Parameters Symbol Rate
Specifies the number of symbols that are
transmitted in one second. EMWIN I requires a
symbol rate of 9600. Error Threshold Maximum
allowable number of errors before the demodulator
symbol tracker is reset.
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(d) EMWIN Demodulator (cont.)
Pertinent BPSK Demodulator Parameters Sample
Rate The sample rate will be 96 KHz for the
sound card solution. Signal Present Threshold
The threshold which used to indicate whether a
valid signal is present. AGC Gain The gain
bandwidth setting value. Tuner Frequency
Initial tuner frequency that represents the
frequency as seen by the A/D converter.
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(d) EMWIN Demodulator (cont.)
Pertinent BPSK Symbol Parameters Symbol Rate
Specifies the number of symbols that are
transmitted in one second. EMWIN I requires a
symbol rate of 22000. Error Threshold Maximum
allowable number of errors before the demodulator
symbol tracker is reset.
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(e) COTS EMWIN S/W
26. Install EMWIN data processing display S/W.
Register license. 27. Start EMWIN S/W, configure
serial com ports (if used) and file
repository. 28. Start EMWIN Ingest and process
EMWIN service products.
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Ongoing Efforts

• De-Couple RX layer from Coding layer
• Allows use of RX function only, or decoder only
• Provide example application that interfaces with
  the EMWIN S/W RX
• Example S/W that allows users/vendors to build
  on-top of S/W RX
• Control and monitor examples, indicates receiver
  performance
• Available in 1-2 Weeks
• Modify EMWIN S/W RX to allow use with lower
  performance Sound Cards
• Use both L R channels
• Minimal (lt 15 in components) changes to IF
  Adapter H/W design
• IQ Recombination in S/W
• Higher data rate options
• QPSK
• CCSDS Turbo Convolution Codes
• Low Density Parity Check

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Questions?
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Backup - S/W Demod BitSync Block Diagram
A/D
I Q used to simplify tracking
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Backup - Software FSK Demod/Bitsync Module

• Acquires data from TCP socket connection
• Required for EMWIN-I reception and decoding

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Backup - Bit Synchronizer and Matched Filter

• Performs bit clock recovery and soft symbols for
  PSK and BPSK signals
• Outputs Soft symbols to second processor through
  Global Memory

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Backup - Frame Synch and Bit Decoding

• Soft symbols are input from Demod BitSync
• If required, Viterbi decoding is performed
  followed by a frame synchronizer function
• Application software is not a deliverable item,
  but if supplied GFE will be included