Pub Date : 1982-10-01DOI: 10.1109/MILCOM.1982.4805937
J. Handwerker
An interactive, real-time Voice System can provide on-line, intelligible, synthetic speech over a 75 bits-per-second (b/s) teletype Air Force Satellite Communications (AFSATCOM) channel. This flexible, cost-effective system operates in both clear and secure AFSATCOM operational modes. The demonstration hardware and software are described along with background information on the AFSArCOM system. The conclusion is that adding voice response to existing hard-copy teletype output over a limited capacity channel is feasible without modifying AFSATCOM hardware or software. In addition, such a Voice System appears attractive for other applications where channel capacity restricts operation to low data rates only.
{"title":"AFSATCOM-Compatible 75 b/s Voice System","authors":"J. Handwerker","doi":"10.1109/MILCOM.1982.4805937","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4805937","url":null,"abstract":"An interactive, real-time Voice System can provide on-line, intelligible, synthetic speech over a 75 bits-per-second (b/s) teletype Air Force Satellite Communications (AFSATCOM) channel. This flexible, cost-effective system operates in both clear and secure AFSATCOM operational modes. The demonstration hardware and software are described along with background information on the AFSArCOM system. The conclusion is that adding voice response to existing hard-copy teletype output over a limited capacity channel is feasible without modifying AFSATCOM hardware or software. In addition, such a Voice System appears attractive for other applications where channel capacity restricts operation to low data rates only.","PeriodicalId":179832,"journal":{"name":"MILCOM 1982 - IEEE Military Communications Conference - Progress in Spread Spectrum Communications","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1982-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122364439","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1982-10-01DOI: 10.1109/MILCOM.1982.4805905
M. A. Kader, A. El-Osmany
An analysis is presented of the performance of voice amplitude modulation (AM) and frequency modulation (FM) communication systems in the presence of direct-sequence (DS) spread spectrum (SS) signal. The effect of an interfering DS-SS signal on voice AM and FM receivers decreases by decreasing the DS signal power and/or its pseudo-noise (PN) code pulse duration (Tc).
{"title":"Interference Effects of Direct-Sequence Spread Spectrum Signal on Voice AM and FM Communication Systems","authors":"M. A. Kader, A. El-Osmany","doi":"10.1109/MILCOM.1982.4805905","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4805905","url":null,"abstract":"An analysis is presented of the performance of voice amplitude modulation (AM) and frequency modulation (FM) communication systems in the presence of direct-sequence (DS) spread spectrum (SS) signal. The effect of an interfering DS-SS signal on voice AM and FM receivers decreases by decreasing the DS signal power and/or its pseudo-noise (PN) code pulse duration (Tc).","PeriodicalId":179832,"journal":{"name":"MILCOM 1982 - IEEE Military Communications Conference - Progress in Spread Spectrum Communications","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1982-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115407098","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1982-10-01DOI: 10.1109/MILCOM.1982.4805984
E. Geraniotis
The preformance of asynchronous slow-frequency-hopped (SFH) spread-spectrum multiple-access (SSMA) communications over nonselective fading channels is examined. Binary phase-shift-keying (BPSK) modulation with coherent demodulation is employed. Bounds and approximations on the average bit error probability are first obtained for uncoded systems. Then the performance of various error-control coding schemes such as convolutional codes and Reed-Solomon codes with and without channel monitoring is compared. It is shown that error-control coding, in particular the use of Reed-Solomon codes, neutralizes channel fading and increases the multiple-access capability of SFH/SSMA systems.
{"title":"Coding for BPSK SFH/SSMA Communications over Fading Channels","authors":"E. Geraniotis","doi":"10.1109/MILCOM.1982.4805984","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4805984","url":null,"abstract":"The preformance of asynchronous slow-frequency-hopped (SFH) spread-spectrum multiple-access (SSMA) communications over nonselective fading channels is examined. Binary phase-shift-keying (BPSK) modulation with coherent demodulation is employed. Bounds and approximations on the average bit error probability are first obtained for uncoded systems. Then the performance of various error-control coding schemes such as convolutional codes and Reed-Solomon codes with and without channel monitoring is compared. It is shown that error-control coding, in particular the use of Reed-Solomon codes, neutralizes channel fading and increases the multiple-access capability of SFH/SSMA systems.","PeriodicalId":179832,"journal":{"name":"MILCOM 1982 - IEEE Military Communications Conference - Progress in Spread Spectrum Communications","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1982-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116707061","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1982-10-01DOI: 10.1109/MILCOM.1982.4806019
J. Pan, M. Kunz, J. Wilson, J. W. Breitmeier
The military satellite communications (MILSATCOM) terminals normally have multiple users with extensive distribution requirements containing analog and digital information. An increasing number of terminals contain their own computer information processing and display facilities. Conventionally, large diameter (and often expensive) coaxial and multiconductor cables are used to interconnect users for computer processing and display facilities, antenna servo and antenna structures, and between antenna converters, baseband demodulators, and modems. Besides weight and size disadvantages, conventional methods of cabling are troubled by EMI, noise pickup, ground loops, lightning, and RF isolation problems.
{"title":"Applications of Fiber Optics for MILSATCOM Earth Terminals","authors":"J. Pan, M. Kunz, J. Wilson, J. W. Breitmeier","doi":"10.1109/MILCOM.1982.4806019","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4806019","url":null,"abstract":"The military satellite communications (MILSATCOM) terminals normally have multiple users with extensive distribution requirements containing analog and digital information. An increasing number of terminals contain their own computer information processing and display facilities. Conventionally, large diameter (and often expensive) coaxial and multiconductor cables are used to interconnect users for computer processing and display facilities, antenna servo and antenna structures, and between antenna converters, baseband demodulators, and modems. Besides weight and size disadvantages, conventional methods of cabling are troubled by EMI, noise pickup, ground loops, lightning, and RF isolation problems.","PeriodicalId":179832,"journal":{"name":"MILCOM 1982 - IEEE Military Communications Conference - Progress in Spread Spectrum Communications","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1982-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115566972","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1982-10-01DOI: 10.1109/MILCOM.1982.4805973
S. Dhar, B. D. Perry
In this paper we discuss the use of skywave propagation paths in the HF band for spread spectrum communications involving coherent bandwidths of about one megahertz. We present experimental data describing wide-bandwidth one-hop F-layer links, discuss real-time adaptive equalization procedures for wideband spread spectrum signaling on these links, and conclude with some recent measurements over equalized paths of up to 2000 km. Two significant attributes of these equalized wideband channels are (1) time invariance over many seconds (typically ten), and (2) freedom from fading caused by the presence of multiple propagation modes. Both are dependent on achieving mode isolation in the receiver through the use of wideband waveforms. The measurement data was gathered in 1981 using MITRE's wideband HF test facility which consists of a mobile transmit terminal and a fixed receive terminal in Bedford, Massachusetts. The transmit terminal is capable of generating signals for channel measurement and data communications testing. The receive terminal is capable of real-time adaptive equalization over a 1.024 MHz bandwidth, signal processing, and data recording. The data presented here describes unequalized and equalized channel measurements.
{"title":"Equalized Megahertz-Bandwidth HF Channels for Spread Spectrum Communications","authors":"S. Dhar, B. D. Perry","doi":"10.1109/MILCOM.1982.4805973","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4805973","url":null,"abstract":"In this paper we discuss the use of skywave propagation paths in the HF band for spread spectrum communications involving coherent bandwidths of about one megahertz. We present experimental data describing wide-bandwidth one-hop F-layer links, discuss real-time adaptive equalization procedures for wideband spread spectrum signaling on these links, and conclude with some recent measurements over equalized paths of up to 2000 km. Two significant attributes of these equalized wideband channels are (1) time invariance over many seconds (typically ten), and (2) freedom from fading caused by the presence of multiple propagation modes. Both are dependent on achieving mode isolation in the receiver through the use of wideband waveforms. The measurement data was gathered in 1981 using MITRE's wideband HF test facility which consists of a mobile transmit terminal and a fixed receive terminal in Bedford, Massachusetts. The transmit terminal is capable of generating signals for channel measurement and data communications testing. The receive terminal is capable of real-time adaptive equalization over a 1.024 MHz bandwidth, signal processing, and data recording. The data presented here describes unequalized and equalized channel measurements.","PeriodicalId":179832,"journal":{"name":"MILCOM 1982 - IEEE Military Communications Conference - Progress in Spread Spectrum Communications","volume":"69 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1982-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125412666","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1982-10-01DOI: 10.1109/MILCOM.1982.4805960
J. Luecke, R. Yost
This paper presents a decision directed non-coherent AFC scheme for use with M-ary Frequency Shift Keying (MFSK) where accurate tracking and noise/jitter performance under large dynamics are required. The AFC uses a linear discriminator to obtain good tracking performance with an associated small degradation in noise performance. Analysis is performed to examine the effects of noise on the linear discriminator and AFC loop and comparisons are made between this linear AFC and nonlinear FFT based schemes under the influence of noise and large dynamics. This AFC is intended for use with any MFSK system and specifically for a frequency-hopping system employing MFSK as a modulation technique. The AFC may also be easily generalized to any orthogonal modulation technique such as M-ary Code Shift Keying or M-ary Time Shift Keying.
{"title":"Decision Directed AFC for Noncoherent Detectors Experiencing Large Signal Dynamics","authors":"J. Luecke, R. Yost","doi":"10.1109/MILCOM.1982.4805960","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4805960","url":null,"abstract":"This paper presents a decision directed non-coherent AFC scheme for use with M-ary Frequency Shift Keying (MFSK) where accurate tracking and noise/jitter performance under large dynamics are required. The AFC uses a linear discriminator to obtain good tracking performance with an associated small degradation in noise performance. Analysis is performed to examine the effects of noise on the linear discriminator and AFC loop and comparisons are made between this linear AFC and nonlinear FFT based schemes under the influence of noise and large dynamics. This AFC is intended for use with any MFSK system and specifically for a frequency-hopping system employing MFSK as a modulation technique. The AFC may also be easily generalized to any orthogonal modulation technique such as M-ary Code Shift Keying or M-ary Time Shift Keying.","PeriodicalId":179832,"journal":{"name":"MILCOM 1982 - IEEE Military Communications Conference - Progress in Spread Spectrum Communications","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1982-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125529215","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1982-10-01DOI: 10.1109/MILCOM.1982.4805963
H. Fruehauf
Since the advent of miniature Rubidium atomic oscillators, the long sought-after concepts of one-way ranging systems have become fully realized. From the decade-old OMEGA concepts to the future NAVSTAR-GPS network, the miniature atomic oscillator has become, and will continue to be, the heart of the navigation systems. In recent years, however, the spread spectrum communication technology has surfaced and is also becoming more and more integrated with atomic oscillators, reaching formidable A-J (antijam) and systems C3/NAV capabilities through the use of such devices. This paper describes the types of precision oscillators available and compares all the major parameters to help designers select the proper hardware for such systems. In addition, some applications of precision oscillators in existing C3/NAV systems will be given as well as what systems designers can expect from this technology in the near future.
{"title":"A Look at Navigation and Secure AJ Communications Technology and their Relation to Precision Oscillators","authors":"H. Fruehauf","doi":"10.1109/MILCOM.1982.4805963","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4805963","url":null,"abstract":"Since the advent of miniature Rubidium atomic oscillators, the long sought-after concepts of one-way ranging systems have become fully realized. From the decade-old OMEGA concepts to the future NAVSTAR-GPS network, the miniature atomic oscillator has become, and will continue to be, the heart of the navigation systems. In recent years, however, the spread spectrum communication technology has surfaced and is also becoming more and more integrated with atomic oscillators, reaching formidable A-J (antijam) and systems C3/NAV capabilities through the use of such devices. This paper describes the types of precision oscillators available and compares all the major parameters to help designers select the proper hardware for such systems. In addition, some applications of precision oscillators in existing C3/NAV systems will be given as well as what systems designers can expect from this technology in the near future.","PeriodicalId":179832,"journal":{"name":"MILCOM 1982 - IEEE Military Communications Conference - Progress in Spread Spectrum Communications","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1982-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123320521","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1982-10-01DOI: 10.1109/MILCOM.1982.4805964
M. Simon, Charles C. Wang
This paper presents a performance analysis of frequency-hopped (FH) spread spectrum systems for narrowband digital FM with limiter-discriminator (L/D) detection and integrate-and-dump post-detection filtering. The performance improvement provided by using coding and subsymbol diversity is illustrated. It is also demonstrated that a more robust, less complex system can perform better than the conventional system in partial band noise jamming and multipath environments.
{"title":"Limiter/Discriminator Detection of Narrowband FM in Jamming and Multipath Environments","authors":"M. Simon, Charles C. Wang","doi":"10.1109/MILCOM.1982.4805964","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4805964","url":null,"abstract":"This paper presents a performance analysis of frequency-hopped (FH) spread spectrum systems for narrowband digital FM with limiter-discriminator (L/D) detection and integrate-and-dump post-detection filtering. The performance improvement provided by using coding and subsymbol diversity is illustrated. It is also demonstrated that a more robust, less complex system can perform better than the conventional system in partial band noise jamming and multipath environments.","PeriodicalId":179832,"journal":{"name":"MILCOM 1982 - IEEE Military Communications Conference - Progress in Spread Spectrum Communications","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1982-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132617229","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1982-10-01DOI: 10.1109/MILCOM.1982.4805918
Frank S. Gutleber
The contents of this paper comprises a treatise on spread spectrum multiplexed noise codes. Multiplexed noise codes are codes formed with mate code pairs which when orthogonally multiplexed, transmitted, and detected in a matched filter possess an impulse autocorrelation function (i.e., noise like codes which compress to a single impulse containing no sidelobes). The fundamental requirement for achieving this desirable result is that the autocorrelation function of the two codes forming a mate pair must be of equal magnitude and opposite sense for all values of time outside of the main lobe. The various fundamental concepts which define the requirements for obtaining lobeless compression, an orthogonal noise code subclass, and basic general code expansion concepts are described and theoretically verified. In addition, a relatively complete coverage of the various unique attributes inherent in multiplexed noise codes are disclosed. In essence, a practical unified theory and explanation of these codes is presented to teach the principles involved and illustrate the magnitude of the gains that are realizable from codes that are capable of compressing to a lobeless impulse and which are available in abundance. The theoretical treatment demonstrates that the concepts and applications are all technically sound. Utilizing the various concepts established, an orthogonal subset of multiplexed noise codes (32 bit mate pair codes) was implemented actively using shift registers and tested in appropriate test configurations to verify that the theoretical performance can be obtained with practical hardware.
{"title":"Spread Spectrum Multiplexed Noise Codes","authors":"Frank S. Gutleber","doi":"10.1109/MILCOM.1982.4805918","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4805918","url":null,"abstract":"The contents of this paper comprises a treatise on spread spectrum multiplexed noise codes. Multiplexed noise codes are codes formed with mate code pairs which when orthogonally multiplexed, transmitted, and detected in a matched filter possess an impulse autocorrelation function (i.e., noise like codes which compress to a single impulse containing no sidelobes). The fundamental requirement for achieving this desirable result is that the autocorrelation function of the two codes forming a mate pair must be of equal magnitude and opposite sense for all values of time outside of the main lobe. The various fundamental concepts which define the requirements for obtaining lobeless compression, an orthogonal noise code subclass, and basic general code expansion concepts are described and theoretically verified. In addition, a relatively complete coverage of the various unique attributes inherent in multiplexed noise codes are disclosed. In essence, a practical unified theory and explanation of these codes is presented to teach the principles involved and illustrate the magnitude of the gains that are realizable from codes that are capable of compressing to a lobeless impulse and which are available in abundance. The theoretical treatment demonstrates that the concepts and applications are all technically sound. Utilizing the various concepts established, an orthogonal subset of multiplexed noise codes (32 bit mate pair codes) was implemented actively using shift registers and tested in appropriate test configurations to verify that the theoretical performance can be obtained with practical hardware.","PeriodicalId":179832,"journal":{"name":"MILCOM 1982 - IEEE Military Communications Conference - Progress in Spread Spectrum Communications","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1982-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128052182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1982-10-01DOI: 10.1109/MILCOM.1982.4806017
R. Varley, J. Conn
The Department of Defense (DOD) MILSATCOM community is rapidly moving toward deployment of Extremely High Frequency (EHF) earth terminals by the late 1980's. As a result, the communications system tradeoffs have solidified into more meaningful terminal specifications, including antenna requirements. Some aspects of antenna requirements at the selected EHF have not been encountered or emphasized in earlier SATCOM applications. It is the objective of this paper to review the system factors of antenna performance and to discuss some of the more pertinent tradeoffs leading to affordable solutions. This paper is aimed at the practicing antenna systems engineer and engineering management personnel of both equipment contractors and procuring agencies. The discussion attempts to distinguish between mobile and fixed platform applications, and concludes with a mobile antenna example at 20/45 gigahertz (GHz) which has been designed, built, and tested.
{"title":"EHF SATCOM Terminal Antennas","authors":"R. Varley, J. Conn","doi":"10.1109/MILCOM.1982.4806017","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4806017","url":null,"abstract":"The Department of Defense (DOD) MILSATCOM community is rapidly moving toward deployment of Extremely High Frequency (EHF) earth terminals by the late 1980's. As a result, the communications system tradeoffs have solidified into more meaningful terminal specifications, including antenna requirements. Some aspects of antenna requirements at the selected EHF have not been encountered or emphasized in earlier SATCOM applications. It is the objective of this paper to review the system factors of antenna performance and to discuss some of the more pertinent tradeoffs leading to affordable solutions. This paper is aimed at the practicing antenna systems engineer and engineering management personnel of both equipment contractors and procuring agencies. The discussion attempts to distinguish between mobile and fixed platform applications, and concludes with a mobile antenna example at 20/45 gigahertz (GHz) which has been designed, built, and tested.","PeriodicalId":179832,"journal":{"name":"MILCOM 1982 - IEEE Military Communications Conference - Progress in Spread Spectrum Communications","volume":"260 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1982-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127366578","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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