Pub Date : 1990-02-04DOI: 10.1109/AERO.1990.109082
A. Madni
The author presents a novel design approach for a VFC (voltage-to-frequency converter) based on a digital technique which utilizes an analog-to-digital converter, programmable read-only-memory, latch, divide-by-n chip, and associated control circuitry. The unique aspect of this design is the fact that the ratio between the maximum and minimum frequency rates is programmable by the user, and the performance is highly repeatable. This technique was developed in order to provide a drive circuitry for a 5-b digital phase shifter which was being serrodyned in order to create deception jamming functions for electronic countermeasures applications. A circuit diagram of the digital VFC is presented.<>
{"title":"Digitally programmable voltage-to-frequency converter","authors":"A. Madni","doi":"10.1109/AERO.1990.109082","DOIUrl":"https://doi.org/10.1109/AERO.1990.109082","url":null,"abstract":"The author presents a novel design approach for a VFC (voltage-to-frequency converter) based on a digital technique which utilizes an analog-to-digital converter, programmable read-only-memory, latch, divide-by-n chip, and associated control circuitry. The unique aspect of this design is the fact that the ratio between the maximum and minimum frequency rates is programmable by the user, and the performance is highly repeatable. This technique was developed in order to provide a drive circuitry for a 5-b digital phase shifter which was being serrodyned in order to create deception jamming functions for electronic countermeasures applications. A circuit diagram of the digital VFC is presented.<<ETX>>","PeriodicalId":141316,"journal":{"name":"IEEE Conference on Aerospace Applications","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114975486","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 : 1990-02-04DOI: 10.1109/AERO.1990.109091
A. Jackson
The author reviews the requirements placed on the controller in real-time aerospace control applications and compares them with those found in the digital signal processing (DSP) field. The application of a family of powerful DSP microchips to the field of aerospace control systems is studied. An example of a simple control system is used to present the basic concepts and to show the effects of data sampling rate. The code sequence required to implement the control law is shown for a floating-point DSP microchip, and the timing is also given. It is concluded that DSP microchips, such as the Motorola DSP56001 and DSP96002, are extremely powerful and have the speed necessary for real-time control applications. Their instruction sets easily meet the requirements for real-time operating systems. Fixed-point units, such as the DSP56001 with 24-b precision, are more than adequate for many applications. For complicated control systems, like those using Kalman filtering to predict the state of the system, DSP microchips with floating-point capability, such as the 32-b DSP96002, would be the logical choice, for they increase dynamic range and are much easier to use.<>
{"title":"Digital signal processor microchips applied to aerospace control systems","authors":"A. Jackson","doi":"10.1109/AERO.1990.109091","DOIUrl":"https://doi.org/10.1109/AERO.1990.109091","url":null,"abstract":"The author reviews the requirements placed on the controller in real-time aerospace control applications and compares them with those found in the digital signal processing (DSP) field. The application of a family of powerful DSP microchips to the field of aerospace control systems is studied. An example of a simple control system is used to present the basic concepts and to show the effects of data sampling rate. The code sequence required to implement the control law is shown for a floating-point DSP microchip, and the timing is also given. It is concluded that DSP microchips, such as the Motorola DSP56001 and DSP96002, are extremely powerful and have the speed necessary for real-time control applications. Their instruction sets easily meet the requirements for real-time operating systems. Fixed-point units, such as the DSP56001 with 24-b precision, are more than adequate for many applications. For complicated control systems, like those using Kalman filtering to predict the state of the system, DSP microchips with floating-point capability, such as the 32-b DSP96002, would be the logical choice, for they increase dynamic range and are much easier to use.<<ETX>>","PeriodicalId":141316,"journal":{"name":"IEEE Conference on Aerospace Applications","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114686954","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 : 1990-02-04DOI: 10.1109/AERO.1990.109073
C. Tsang
The signal degradation of a BPSK (binary phase-shift keying) signal with NRZ (nonreturn to zero) and biphase baseband signaling formats in the presence of CW (continuous-wave) spur is analyzed. CW spur is usually due to unintentional interference, and the degradation is usually small. The degradation is a function of the frequency and phase differences, the signaling format, and the nominal value of the BER (bit error rate). A BER analysis is performed, and typical numerical results are provided. It is shown that the signal degradation depends on the phase difference between the signal and the CW interference. The NRZ signal is more sensitive to the interference than the biphase signal.<>
{"title":"Signal degradation of BPSK signal in the presence of CW spur","authors":"C. Tsang","doi":"10.1109/AERO.1990.109073","DOIUrl":"https://doi.org/10.1109/AERO.1990.109073","url":null,"abstract":"The signal degradation of a BPSK (binary phase-shift keying) signal with NRZ (nonreturn to zero) and biphase baseband signaling formats in the presence of CW (continuous-wave) spur is analyzed. CW spur is usually due to unintentional interference, and the degradation is usually small. The degradation is a function of the frequency and phase differences, the signaling format, and the nominal value of the BER (bit error rate). A BER analysis is performed, and typical numerical results are provided. It is shown that the signal degradation depends on the phase difference between the signal and the CW interference. The NRZ signal is more sensitive to the interference than the biphase signal.<<ETX>>","PeriodicalId":141316,"journal":{"name":"IEEE Conference on Aerospace Applications","volume":"105 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115806811","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 : 1900-01-01DOI: 10.1109/AERO.1990.109078
F. Manshadi
The application of the scalar wave-fast Fourier transform (SW-FFT) technique to the computation of the propagation characteristics of some complex optical fiber structures is presented. The SW-FFT technique is based on the numerical solution of the scalar wave equation by a forward-marching fast Fourier transform method. This solution yields the spatial configuration of the fields as well as its modal characteristics in and around the guiding structure. The following are treated by the SW-FFT method: analysis of coupled optical fibers and computation of their odd and even modes and coupling length; the solution of tapered optical waveguides (transitions) and the study of the effect of the slope of the taper on mode conversion; and the analysis of branching optical fibers and demonstration of their mode-filtering and/or power-dividing properties.<>
{"title":"Propagation characteristics of optical fiber structures with arbitrary shape and index variation","authors":"F. Manshadi","doi":"10.1109/AERO.1990.109078","DOIUrl":"https://doi.org/10.1109/AERO.1990.109078","url":null,"abstract":"The application of the scalar wave-fast Fourier transform (SW-FFT) technique to the computation of the propagation characteristics of some complex optical fiber structures is presented. The SW-FFT technique is based on the numerical solution of the scalar wave equation by a forward-marching fast Fourier transform method. This solution yields the spatial configuration of the fields as well as its modal characteristics in and around the guiding structure. The following are treated by the SW-FFT method: analysis of coupled optical fibers and computation of their odd and even modes and coupling length; the solution of tapered optical waveguides (transitions) and the study of the effect of the slope of the taper on mode conversion; and the analysis of branching optical fibers and demonstration of their mode-filtering and/or power-dividing properties.<<ETX>>","PeriodicalId":141316,"journal":{"name":"IEEE Conference on Aerospace Applications","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114449456","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 : 1900-01-01DOI: 10.1109/AERO.1990.109080
N. Mysoor
A voltage-controlled 8415-MHz FET oscillator stabilized by a dielectric resonator is described. The oscillator provides over 3.2-MHz linear electronic tuning range with a flat power output equal to +1.8 dBm (27 degrees C, nominal), a single-sideband noise-to-carrier ratio of -68 dBc/Hz at 1 kHz off carrier, and a frequency-temperature coefficient of 0.54 parts per million/ degrees C over a -24 degrees C to 75 degrees C range. The oscillator withstood 150 Krads (Si) of gamma radiation with no significant performance degradation. The overall performance of the FET oscillator is far superior in many ways to that of an equivalent bipolar oscillator for space applications. For space applications, the FET dielectric resonator oscillator (DRO) is preferred over bipolar DRO because of its lower DC power consumption, better thermal frequency stability, linear electronic tunability. and higher RF output power capability.<>
{"title":"An electronically tuned, stable 8415 MHz dielectric resonator FET oscillator for space applications","authors":"N. Mysoor","doi":"10.1109/AERO.1990.109080","DOIUrl":"https://doi.org/10.1109/AERO.1990.109080","url":null,"abstract":"A voltage-controlled 8415-MHz FET oscillator stabilized by a dielectric resonator is described. The oscillator provides over 3.2-MHz linear electronic tuning range with a flat power output equal to +1.8 dBm (27 degrees C, nominal), a single-sideband noise-to-carrier ratio of -68 dBc/Hz at 1 kHz off carrier, and a frequency-temperature coefficient of 0.54 parts per million/ degrees C over a -24 degrees C to 75 degrees C range. The oscillator withstood 150 Krads (Si) of gamma radiation with no significant performance degradation. The overall performance of the FET oscillator is far superior in many ways to that of an equivalent bipolar oscillator for space applications. For space applications, the FET dielectric resonator oscillator (DRO) is preferred over bipolar DRO because of its lower DC power consumption, better thermal frequency stability, linear electronic tunability. and higher RF output power capability.<<ETX>>","PeriodicalId":141316,"journal":{"name":"IEEE Conference on Aerospace Applications","volume":"122 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133626437","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 : 1900-01-01DOI: 10.1109/AERO.1990.109079
S. Mobasser, D. Weisenberg
The combination of a Sun sensor called a Sun gate (SG) and a digital programmable signal processor on the Galileo spacecraft attitude and articulation control subsystem (AACS) will orient the rotation axis of the spacecraft toward the Sun to satisfy a new requirement imposed by the new spacecraft trajectory. The combination will continuously monitor the pointing direction of the rotation axis, and any off-Sun excursions of more than a preset threshold will be detected, triggering appropriate actions by the flight software to prevent off-Sun cone angles of more than 14 degrees . The design of the SG is described in detail, its principle of operation is given, and the flight software processing of the SG output is discussed.<>
{"title":"A Sun gate for Galileo spacecraft attitude control","authors":"S. Mobasser, D. Weisenberg","doi":"10.1109/AERO.1990.109079","DOIUrl":"https://doi.org/10.1109/AERO.1990.109079","url":null,"abstract":"The combination of a Sun sensor called a Sun gate (SG) and a digital programmable signal processor on the Galileo spacecraft attitude and articulation control subsystem (AACS) will orient the rotation axis of the spacecraft toward the Sun to satisfy a new requirement imposed by the new spacecraft trajectory. The combination will continuously monitor the pointing direction of the rotation axis, and any off-Sun excursions of more than a preset threshold will be detected, triggering appropriate actions by the flight software to prevent off-Sun cone angles of more than 14 degrees . The design of the SG is described in detail, its principle of operation is given, and the flight software processing of the SG output is discussed.<<ETX>>","PeriodicalId":141316,"journal":{"name":"IEEE Conference on Aerospace Applications","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130887233","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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