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Orbital Systems LRD-200B Скачать руководство пользователя страница 9

LRD-200B Low-Rate Demodulator

LRD-200B Low-Rate Demodulator

©

Copyright 2012, Orbital Systems, Ltd.

9

Revision B.03

LRD-200B Low-Rate Data Demodulator

Figure 1 - LRD-200B Low-Rate Demodulator (Front View)

Figure 2 - LRD-200B Low-Rate Demodulator (Rear View)

SECTION 1

INTRODUCTION

The Orbital Systems, Ltd. LRD-200B demodulator is a versatile DSP (Digital Signal
Processing)-based receiver used for the following satellites that transmit in the L-band and S-
band:

•

Polar orbiting satellites

•

Geosynchronous weather satellites

•

EOS (earth observation satellites)

The LRD-200B supports selectable IF (Intermediate Frequency) inputs at both 140 MHz and
70 MHz for compatibility with Orbital Systems, Ltd. downconverters, IFDs (Integrated Feed
Downconverters), and third-party products.

The  LRD-200B  uses selectable SAW (Surface Acoustic Wave)  filters in  the IF to provide
superior  out-of-band signal  rejection.  This  function  is important  with  the  proliferation of
cellular phone and other wireless device signals in L-band and S-band.

The incoming signal is passed through a programmable attenuator to extend the input
dynamic range. It is converted to a 70 MHz first IF, and then converted to a 10 MHz IF for
processing by the digital demodulator. The signal is filtered and directly digitized at 100
MSPS (Million Samples Per Second) with 10-bit resolution.

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Содержание LRD-200B

Страница 1: ...al Systems Ltd 3807 Carbon Rd www OrbitalSystems com Irving TX 75038 USA LRD 200B Low Rate Demodulator Installation Operation and Maintenance Manual Manual P N MA 240 003 Revision B 03 Release Date 11 2 2015 ...

Страница 2: ...dulator LRD 200B Low Rate Demodulator Copyright 2012 Orbital Systems Ltd Revision B 03 2 Copyright 2012 Orbital Systems Ltd All rights reserved This document may be freely distributed Printed in the United States of America ...

Страница 3: ...enance Manual Document Number MA 240 001 Document Authors Robert Chuvarsky Document History Revision Number Date Revised By Purpose of Revision A 01 2008 12 05 Draft B 01 2012 01 10 R Chuvarsky Release Version B 02 2012 05 03 R Chuvarsky Added new command status requests and responses B 03 2 015 11 02 M Morgan Corrected Table 1 Data Values Approvals Revision Number Date Name ...

Страница 4: ...LRD 200B Low Rate Demodulator LRD 200B Low Rate Demodulator Copyright 2012 Orbital Systems Ltd Revision B 03 4 This page intentionally left blank ...

Страница 5: ... Status Indicators 24 3 1 2 Operational Display 25 3 1 3 Setup Buttons 26 3 2 OPERATIONAL FLOW OF THE SETUP BUTTONS 27 3 3 INSTRUCTIONS FOR CONFIGURING THE LRD 200B 29 3 3 1 RF Input Mode 29 3 3 2 Frequency 29 3 3 3 Demodulator Mode 30 3 3 4 Power Output 31 3 3 5 Input Attenuator 32 3 3 6 Clock Polarity 32 3 3 7 Data Polarity 33 3 3 8 Display Signal Level 33 3 3 9 Offset xxxx xxx MHz 34 3 3 10 Ser...

Страница 6: ...4 1 8 Receiver Operating Frequency 47 4 1 9 Status Requests and Responses 48 4 1 10 Commands 54 SECTION 5 MAINTENANCE 57 5 1 FUSE REPLACEMENT 57 5 1 1 Removing the Fuse Holder 58 5 2 PROBLEM RESOLUTION 59 SECTION 6 THEORY OF OPERATION 61 6 1 INPUT SELECTION AND CONVERSION TO 70 MHZ 61 6 2 DIGITAL DEMODULATOR 63 6 3 SYMBOL DECODING AND FORMATTING 64 6 4 USB INTERFACE 65 ...

Страница 7: ...gure 10 Front Panel 23 Figure 11 System Status Indicators 24 Figure 12 Operational Display and Description 25 Figure 13 Setup Buttons 26 Figure 14 Parameter Setup Flow Chart 28 Figure 15 140 MHz and 140 70 MHz RF Input Settings 29 Figure 16 Frequency Settings Select and Set Digits 29 Figure 17 Demodulator Modes 31 Figure 18 Power Output Settings 31 Figure 19 Input Attenuator Settings 32 Figure 20 ...

Страница 8: ...stems Ltd Revision B 03 8 Figure 34 Fuse Holder Release Tabs 58 Figure 35 Fuse Holder Removal 58 Figure 36 Theory of Operation 61 Figure 37 Input Selection and Conversion to 70 MHz 62 Figure 38 Digital Demodulator 63 Figure 39 Symbol Decoding and Formatting 64 Figure 40 USB Interface 65 ...

Страница 9: ...orts selectable IF Intermediate Frequency inputs at both 140 MHz and 70 MHz for compatibility with Orbital Systems Ltd downconverters IFDs Integrated Feed Downconverters and third party products The LRD 200B uses selectable SAW Surface Acoustic Wave filters in the IF to provide superior out of band signal rejection This function is important with the proliferation of cellular phone and other wirel...

Страница 10: ... and LVDS on a 15 pin D connector 50 ohm TTL versions on SMA connectors also are provided The LRD 200B supports direct connection to the SSEC SDI and to most other PC based data ingest interfaces The receiver command set supports complete operational control and status monitoring of receiver operation The command set also supports a compatibility mode for previous models of Orbital Systems Ltd rec...

Страница 11: ...I Output 0 to 3 5 VDC 30 mV dB nominal 50 dBm 2 3 VDC Demodulator DSP Demodulator Modes QPSK BPSK PSK Demodulator Implementation Loss 0 5 dB at 10E 6 BER QPSK BPSK 0 2 dB typical Baseband Filter Root Raised Cosine RRC variable alpha Data Supported Data Encoding NRZ L NRZ S NRZ M Biphase L Supported Symbol Rates 0 1 to 3 5 MSPS Convolutional Decoding Viterbi K 7 rate rate and dual rate G1 171 G2 13...

Страница 12: ...raming Electrical Mechanical Supply Voltage Power 100 to 240 VAC 30 watts Fuse 1 5 amp 5 x 20 mm Power Connector IEC C 13 3 conductor Downconverter Power Output 11 5 VDC 400 mA max Automatic current limit RF Input zero 0 only RF Input Connectors Type N female Signal Level Output Connector Type SMA female Size 48 cm 19 inch rack standard 1U high 254 mm 10 inches deep Support Fixed side rails Weight...

Страница 13: ...n be desktop or rack mounted It is designed to operate in a standard office environment 2 1 DESKTOP USE Four 4 rubber foot pads must be installed on the bottom of the LRD 200B for desktop use see Figure 3 Figure 3 Rubber Foot Pads and Screws The LRD 200B requires at minimum clearance of five 5 centimeters 2 inches for ventilation airflow Placing an Orbital Systems Ltd HRD or LRD receiver on top of...

Страница 14: ...n attach the rack supports using the fasteners shown in Figure 4 Mount the LRD 200B with rack supports into the rack enclosure Figure 4 Rack Mounting 2 3 CONNECTIONS 2 3 1 Power The LRD 200B contains a universal power supply that supports power input voltages from 100 to 240 VAC at 50 to 60 Hz The power input is a standard IEC C 13 type The LRD 200B usually is supplied with the appropriate power c...

Страница 15: ...net connection Use of a private network and not the user s local network is recommended for connecting the LRD 200B and other receiver components to the system control computer When used with a system that Orbital Systems Ltd has provided the LRD 200B is connected to an Ethernet 10 100 switch That switch is connected to a private network port on the Orbital Systems Ltd front end server FES Refer t...

Страница 16: ...efer to SECTION 3 in this manual or to the system documentation 2 3 3 RF Cables J01 supports 140 MHz J02 supports 70 MHz or 140 MHz Connect the 140 MHz RF cable to J01 or J02 on the rear panel If a 70 MHz RF cable is used connect it to J02 see Figure 7 Figure 7 RF Cable Connections Refer to the Operation section of this manual or system documentation to properly set the input attenuator for correc...

Страница 17: ...RZ data and clock connections are located on the rear panel These connections have RS 422 LVDS and 50 ohm TTL interfaces see Figure 8 These interfaces are active and can be used simultaneously Figure 8 Data Connections When used with an Orbital Systems Ltd front end server pre configured cables are provided for J04 Plug the cable into J04 and secure it using the screws retained in the connector se...

Страница 18: ...h your system Both RS 422 and LVDS signals are differential and require the use of twisted pair cables for optimal operation The length of these cables must as short as possible with a maximum length of two 2 meters 6 5 feet 2 3 7 50 Ohm TTL Connections Single end 50 ohm TTL data and clock signals are available on J06 and J07 These signals require the use of a high quality double shielded 50 ohm c...

Страница 19: ...m the LRD 200B correspond to the input requirements of the external data interface Refer to SECTION 3 to set the data and clock polarities as required After the LRD 200B has been installed and the cables have been connected route the cables in a manner appropriate for safety convenience and to prevent them from becoming damaged If the LRD 200B is mounted in a rack fastening the cables to the rails...

Страница 20: ...LRD 200B Low Rate Demodulator LRD 200B Low Rate Demodulator Copyright 2012 Orbital Systems Ltd Revision B 03 20 This page intentionally left blank ...

Страница 21: ...to receive data from different satellites The LRD 200B configuration parameters are shown in Table 3 LRD 200B Configuration Parameters Configurable Parameter Options Description RF Input J01 J02 This setting is used to select either J01 which supports a 140 MHz input J02 which supports a 70 MHz input or a 140 MHz input Demodulator Mode Satellites NOAA HRPT METOP AHRPT Feng Yung S VISSR COMS HRIT C...

Страница 22: ...ard setting The nominal receive signal level at the LRD 200B demodulator input should be minus 50 50 dBm If a larger reflector lower loss coaxial cable or a fiber optic link is used the signal level will increase which will require additional attenuation To determine the correct setting for the system consult the system designer This value typically is not changed and it is configured using the se...

Страница 23: ...MHz when receiving L band signals Consult the user system documentation for the correct setting The offset can be set only when input zero 0 is selected Disable Switches No Yes This setting is used to enable or disable the setup buttons 3 1 LRD 200B DEMODULATOR INDICATORS CONTROLS AND DISPLAY The following controls indicators and display are used to configure the demodulator see red highlighted ar...

Страница 24: ...dulator LRD 200B Low Rate Demodulator Copyright 2012 Orbital Systems Ltd Revision B 03 24 3 1 1 System Status Indicators Six 6 LED indicators are used to provide system status see Figure 11 Figure 11 System Status Indicators ...

Страница 25: ...tor Copyright 2012 Orbital Systems Ltd 25 Revision B 03 3 1 2 Operational Display The receive frequency input attenuator settings and demodulator lock status are indicated on the operational display see Figure 12 Figure 12 Operational Display and Description ...

Страница 26: ...utton is used to select the parameter option see Figure 14 Simultaneously pressing and holding both the upper and lower setup buttons sets all configuration parameters to default values If the setup buttons were disabled to prevent accidental changes to the LRD 200B settings two 2 methods are available to restore operation 1 Use a remote control command provided in SECTION 3 to enable the setup bu...

Страница 27: ...d again then Demodulator Mode would display and so on see Figure 14 Parameter Option Selection Lower Setup Button Example of Vertical Flow If Demodulator Mode were selected and NOAA HRPT were displayed and the user pressed the lower setup button METOP AHRPT would display If the user pressed the lower setup button again FENG YUN VISSR 3 would display and so on see Figure 14 If FY3 HRPT were display...

Страница 28: ...LRD 200B Low Rate Demodulator LRD 200B Low Rate Demodulator Copyright 2012 Orbital Systems Ltd Revision B 03 28 Figure 14 Parameter Setup Flow Chart ...

Страница 29: ...t will display 3 3 1 RF Input Mode RF Input mode is the first function to display during the setup process Press the lower setup button to select the 70 MHz input J01 or the 140 MHz 70 MHz input J02 see Figure 15 Figure 15 140 MHz and 140 70 MHz RF Input Settings 3 3 2 Frequency The Frequency function displays after RF Input Press the upper setup button to select the digits press the lower setup b...

Страница 30: ...he lower setup button to select one of the 15 modes in the following order see Figure 17 NOAA HRPT METOP AHRPT FENG YUN S VISSR COMS HRIT COMS LRIT GOES LRIT GOES GVAR MSG HRIT MSG LRIT MTSAT HRIT MTSAT LRIT METEOSAT PDUS FENG YUN CHRPT DMSP RTD FY 3 HRPT After the last satellite in the Demodulator Mode has been selected FY3 HRPT in this example the mode defaults to the first satellite NOAA HRPT ...

Страница 31: ...ator Copyright 2012 Orbital Systems Ltd 31 Revision B 03 Figure 17 Demodulator Modes 3 3 4 Power Output The Power Output function displays after Demodulator Mode Press the lower setup button to select ON or OFF see Figure 18 Figure 18 Power Output Settings ...

Страница 32: ... setup button to change the input attenuation in two 2 dB increments within a 30 dB range see Figure 19 Figure 19 Input Attenuator Settings 3 3 6 Clock Polarity The Clock Polarity function displays after Input Attenuator Press the lower setup button to select normal or inverted clock polarity to correspond to the user s hardware requirements see Figure 20 Figure 20 Normal or Inverted Clock Polarit...

Страница 33: ...Press the lower setup button to select normal or inverted data polarity to correspond to the user s hardware requirements see Figure 21 Figure 21 Data Polarity Setting 3 3 8 Display Signal Level The Display Signal Level function displays after Data Polarity Press the lower setup button to display the signal level as dBM volts or a count see Figure 22 Figure 22 Display Signal Level Setting ...

Страница 34: ...xxx MHz The Offset function displays after Display Signal Level Press the upper setup button to select the digit press the lower setup button to set the digit incrementally see Figure 23 Figure 23 Offset Setting 3 3 10 Serial Number The LRD 200B serial number is displayed after Offset see Figure 24 Figure 24 LRD 200B Serial Number ...

Страница 35: ...le or disable the setup buttons see Figure 25 Figure 25 Disable Switches Setting 3 3 12 Exit Setup Mode Use one of the following methods to exit the setup mode see Figure 26 Press lower switch when EXIT Setup is displayed Press and hold the upper setup button until the receive frequency and demodulator mode are displayed on the first line of the operational display Do not press any setup button fo...

Страница 36: ...LRD 200B Low Rate Demodulator LRD 200B Low Rate Demodulator Copyright 2012 Orbital Systems Ltd Revision B 03 36 This page intentionally left blank ...

Страница 37: ...CONTROL The LRD 200B provides an RG45 10 100 Ethernet port for remote control This interface uses a Lantronix Xport interface device which must have an IP address and serial protocol configuration assigned to it before it can operate The IP address is set to an appropriate value for the user s network The serial port parameters are set to the following values 9600 BAUD Eight 8 bit data No parity O...

Страница 38: ... server FES the IP address is set at the factory to 192 168 124 171 with telnet on port 10001 4 1 1 Configuring the IP Address The default Lantronix IP address is 192 168 124 171 If DeviceInstaller does not detect the Lantronix device close DeviceInstaller Manually configure the system IP address to 192 168 124 160 Make sure this IP address is available 4 1 2 Open DeviceInstaller After DeviceInsta...

Страница 39: ...ew IP Address 1 Select a device from the list see Figure 27 2 Click Assign IP on the toolbar see red highlighted area in Figure 28 Figure 28 Assigning an IP Address The Assign IP Address window opens see Figure 29 Figure 29 The Assign IP Address Window 3 If a device was not selected initially refer to Figure 27 a Device Identification prompt is displayed on the Assign IP Address window ...

Страница 40: ...30 Type the hardware address it should be on the product label into the field and then click Next Figure 30 Device identification Prompt 5 The Assignment Method window opens Select Assign a specific IP address and then click Next see red highlighted area in Figure 31 Figure 31 Assign a Specific IP Address 6 The IP Settings window opens see Figure 32 ...

Страница 41: ...zeros in the fields for dot quad numbers less than 100 For example if your IP address is 172 19 201 28 do not enter 028 for the last segment Subnet mask The subnet mask is the network segment where the device is located No default exists The subnet mask automatically displays based upon the IP address you entered you can however change it Default gateway IP address of the router for this network T...

Страница 42: ... fixed network configuration port number Windows telnet X X X X 9999 UNIX telnet X X X X 9999 3 Click OK The MAC Address window opens The following information is displayed MAC Address 4 Enter must be pressed within five 5 seconds to enter setup mode The Change Setup window opens Change Setup MAC address 00204AA5C8FC Software version V6 6 0 1RC2 080710 XPTEXE AES library version 1 8 2 1 Press Ente...

Страница 43: ...er The default setting for the telnet port is 10001 The range is 1 to 65535 with the exception of the port numbers listed in Table 5 Reserved Port Numbers Port Number Comments 1 to 1024 Reserved well known ports 9999 Telnet setup 14000 to 14009 Reserved for redirector 30704 Reserved 77FOh 30718 Reserved 77FEh Table 5 Reserved Port Numbers Baudrate 9600 I F Mode 4C Flow 00 Port No 10001 ConnectMode...

Страница 44: ...nt reflects the current released Firmware Version 8 Press Enter to confirm the port number settings The Change Setup window opens Change Setup 9 Save the new configuration option 9 The unit will reboot Change Setup 0 Server 1 Channel 1 3 E mail 5 Expert 6 Security 7 Defaults 8 Exit without save 9 Save and Exit Your choice _ ...

Страница 45: ...and with an invalid parameter 3 A response to the corresponding status request Responses begin with the character followed by a three 3 digit numeric code The numeric code for valid command response is followed by a separator and a single alphanumeric status or a delimited list of alphanumeric status values Responses are terminated with a return newline hex code 0x0D 0x0A or in C r n The three 3 d...

Страница 46: ... supports one or more operating modes that can be referenced using a three or four 3 or 4 character string LRD 200B Operating Modes String Description HRPT NOAA HRPT METP METOP AHRPT SVSR FENG YUN S VISSR CMHR COMS HRIT CMLR COMS LRIT GOLR GOES LRIT GVAR GOES GVAR MSHR MSG HRIT MSLR MSG LRIT MTHR MTSAT HRIT MTLR MTSAT LRIT PDUS METEOSAT PDUS CHRP FENG YUN CHRPT DMSP DMSP RTD FY3 FY3 HRPT Table 6 L...

Страница 47: ...z for L band reception and 2120 0 MHz for S band reception For typical operation the receiver downconverter offset offset command should be set to the same value as that used for the feed The receiver frequency is then set to the downlink frequency of the satellite To receive NOAA HRPT at 1698 0 MHz for example set the receiver offset offset command to 1556 0 MHz and then set the receiver frequenc...

Страница 48: ... mode set for input 1 104 xxxx All modes frequency What is the current receive frequency 105 xxxx xxx The 4 3 current frequency for example 1698 000 frequency_0 What is the current receive frequency set for input 0 106 xxxx xxx The 4 3 current frequency for example 1698 000 frequency_1 What is the current receive frequency set for input 1 107 xxxx xxx The 4 3 current frequency offset What is the c...

Страница 49: ...ty What is the data polarity for the current input 117 normal or 117 invert data_polarity_0 What data polarity is set for input 0 118 normal or 118 invert data_polarity_1 What data polarity is set for input 1 119 normal or 119 invert attenuator What is the current input attenuator setting 120 xx dB Where xx is 0 to 30 in 2 dB steps attenuator_0 What is the attenuator setting for input 0 121 xx dB ...

Страница 50: ...as GVAR report only LK Framed but non Viterbi formats such as HRPT should report FR Viterbi and framed formats such as METOP should report FR rssi_dbm What is the received signal level in dBm 151 xx x Where xx x is the dBm reading rssi_volts What is the received signal level in volts 152 x xx Where x xx is the voltage 2 3 volts 50 0 dBm Voltage increases with signal at 30 mV dB rssi_count What is ...

Страница 51: ...mode code Followed by the mode string s What is the receiver demodulator quick status short format 191 xx x yy Where xx x is the signal level in dBm and yy is the demodulator lock status i What is the receiver status long format 192 i m f o r l e Where i is the current input m is the current receive mode f is the current receive frequency o is the current downconverter offset r is the current rssi...

Страница 52: ...mod Eb No e is the current error status Fault status is 0 for no faults 1 for PLL unlocked 2 for overcurrent 3 for both serial_number What is the receiver serial number 198 xxxxxx Where xxxxxx is a six 6 alphanumeric character serial number product_info What is the product type serial number and firmware revision 199 AE 990 247 xxxxxx yy yy Where AE 990 247 is the Orbital Systems Ltd part number x...

Страница 53: ...c character serial number product_info What is the product type serial number and firmware revision 199 AE 990 247 xxxxxx yy yy Where AE 990 247 is the Orbital Systems Ltd part number xxxxxx is the serial number yy yy is the firmware revision For diagnostic purposes only demod_status_ bits Show individual demod lock bits 160 C S V F C carrier locked S symbol locked V Viterbi locked F frame synch n...

Страница 54: ...Description of Command x input x Set the current input x can be one of Zero 0 One 1 mode x Set the current receive mode X can be one of the supported mode codes or strings for example mode HRPT mode_0 x Set the receive mode for input 0 mode_1 x Set the receive mode for input 1 frequency xxxx xxx Set the current receive frequency The resulting receiver input is calculated by subtracting the offset ...

Страница 55: ...itch to 70 MHz offset xxxx xxx Set the current downconverter offset xxxx xxx can range from 0000 000 to 9999 999 offset_o xxxx xxx Set the downconverter offset for input 0 offset_1 xxxx xxx Set the downconverter offset for input 1 dc_power x Turn the downconverter power on input 0 x can be one of zero 0 one 1 clock_polarity x select the clock polarity for the current input x can be one of zero 0 n...

Страница 56: ...a_polarity_0 x select the data polarity for the input 0 x can be one of zero 0 normal one 1 or invert data_polarity_1 x select the data polarity for the input 1 x can be one of zero 0 normal one 1 invert attenuator x set the input attenuator for the current input x must be between zero 0 and 30 inclusive and will resolve to 2 dB resolution attenuator_0 x set the input attenuator value for input 0 ...

Страница 57: ...switch off the power and remove the AC line cord to prevent electrical shock SECTION 5 MAINTENANCE 5 1 FUSE REPLACEMENT Two 2 line input fuses are contained in the integrated power input module on the rear of the rack mount unit see Figure 33 The LRD 200B primary power input requires two 5 x 20mm fast acting fuses 1 5 amps Figure 33 Fuse Holder ...

Страница 58: ...ving the Fuse Holder 1 Locate the two 2 tabs on the fuse holder see Figure 34 Figure 34 Fuse Holder Release Tabs Figure 35 Fuse Holder Removal 2 Pinch together the retaining tabs and pull the fuse holder from the power input module see Figure 35 Remove and replace the fuses 3 Reinstall fuse holder in the power input module ...

Страница 59: ... B 03 5 2 PROBLEM RESOLUTION Our technical support team is available to resolve problems during normal business hours US Central Time GMT 006 by email support orbitalsystems com or by telephone 972 915 3669 To return a unit please contact the technical support team for a RMA number and shipping instructions ...

Страница 60: ...LRD 200B Low Rate Demodulator LRD 200B Low Rate Demodulator Copyright 2012 Orbital Systems Ltd Revision B 03 60 This page intentionally left blank ...

Страница 61: ...d is then sent to the digital demodulator The digital demodulator digitizes the 70 MHz IF and uses DSP techniques to decode the transmitted symbols The raw symbol output of the demodulator is applied as required to a Viterbi decoder sequencer and decode logic finally providing clock and NRZ Non Return to Zero data at the output 6 1 INPUT SELECTION AND CONVERSION TO 70 MHZ The input selection and c...

Страница 62: ...s either the 70 MHz input or the 70 MHz signal converted from the 140 MHz input for further processing This 70 MHz IF is filtered amplified and passed through a selectable three or six 3 or 6 MHz wide SAW filter to set the channel bandwidth for the digital demodulator The 70 MHz IF is passed to a logarithmic amplifier to provide a signal level indication It also is amplified in an AGC circuit to p...

Страница 63: ...d to the Digital Costas Loop The Digital Costas Loop is used to demodulate the transmitted symbols It provides an AGC signal to the input selection and conversion module to ensure that the analog to digital conversion is accomplished within an optimal dynamic range filling all 10 bits of the converter It also provides feedback to the Digital Quadrature Tuner to provide carrier tracking The Digital...

Страница 64: ...uired Depending upon the received signal only the I symbol could be used or both the I and Q could be used If the signal is convolutionally encoded the I or I and Q soft decision symbols are selected sequenced and provided to a Viterbi decoder as G1 and G2 symbols The output of the Viterbi decoder is then selected decoded if required and then sent to the output If the signal is not convolutionally...

Страница 65: ...he setup buttons It communicates to external devices through an RS 232 serial port a Lantronix Ethernet device or a USB interface 6 4 USB INTERFACE Figure 40 USB Interface The LRD 200B contains a USB 2 0 high speed interface which can be used to control the demodulator and to transmit the recovered data to a computer The USB interface receives the data and clock signals provided to the electrical ...

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