Abstract: A rectangular wave for determining a range of a weight function is transformed to frequency domain by an FFT or the like, and after being multiplied by a window function (BlackmanHarris window function, for example) generated on a frequency axis by a multiplier, the frequency domain is transformed again to the time domain by an IFFT or the like thereby to generate a weight function.

Abstract: A transponder (12) transmits a reply in response to an interrogation input thereto, the interrogation including twin pulses, and a monitoring processor (13) transmits to the transponder a pseudo interrogation identical in format to the interrogation, receives from the transponder a reply responding to the pseudo interrogation, and monitors a performance of the transponder, the monitoring processor (13) including a pulse spacing adjuster (131c) operable to adjust a pulse spacing of twin pulses along with generation of the pseudo interrogation, and a monitor (134b) operable to output an alarm in response to a failed reception or a delayed reception of a reply from the transponder after transmission of a pseudo interrogation with a compliant pulse spacing, and further to output an alarm in response to a reception of a reply from the transponder after transmission of a pseudo interrogation with an uncompliant pulse spacing.

Abstract: A transmitter 122 transmits interrogations to aircraft airborne in a coverage, a receiver 123 receives signals transmitted from aircraft airborne in the coverage, reply analyzers 132b and 133b analyze a reply responding to an interrogation transmitted from the transmitter, as the reply is detected from signals received by the receiver, and a squitter analyzer 132d analyzes an extended squitter, as the extended squitter is detected from the signals received by the receiver.

Abstract: A pulse detecting equipment includes a log compression processor (105) for logarithm-converting signal levels of a reception signal received at an antenna and input therefrom, with maintained frequency components of the reception signal as input, an AD converter (106) for converting the reception signal as logarithm-converted in signal level, from an analog form into a digital form, a first detector (110) for limiting the reception signal as converted into the digital form to a band of a prescribed first frequency, to obtain a signal, to detect signal levels thereof, a second detector (111) for limiting the reception signal as converted into the digital form to a band of a prescribed second frequency smaller than the first frequency, to obtain a signal, to detect signal levels thereof, and a pulse detector (113) for use of a result of comparison between signal levels detected at the first detector and signal levels detected at the second detector, to detect pulses of a prescribed frequency as a signal transmi

Abstract: A transponder (12) transmits a reply in response to an interrogation input thereto, the interrogation including twin pulses, and a monitoring processor (13) transmits to the transponder a pseudo interrogation identical in format to the interrogation, receives from the transponder a reply responding to the pseudo interrogation, and monitors a performance of the transponder, the monitoring processor (13) including a pulse spacing adjuster (131c) operable to adjust a pulse spacing of twin pulses along with generation of the pseudo interrogation, and a monitor (134b) operable to output an alarm in response to a failed reception or a delayed reception of a reply from the transponder after transmission of a pseudo interrogation with a compliant pulse spacing, and further to output an alarm in response to a reception of a reply from the transponder after transmission of a pseudo interrogation with an uncompliant pulse spacing.

Abstract: A pulse detecting equipment includes a log compression processor (105) for logarithm-converting signal levels of a reception signal received at an antenna and input therefrom, with maintained frequency components of the reception signal as input, an AD converter (106) for converting the reception signal as logarithm-converted in signal level, from an analog form into a digital form, a first detector (110) for limiting the reception signal as converted into the digital form to a band of a prescribed first frequency, to obtain a signal, to detect signal levels thereof, a second detector (111) for limiting the reception signal as converted into the digital form to a band of a prescribed second frequency smaller than the first frequency, to obtain a signal, to detect signal levels thereof, and a pulse detector (113) for use of a result of comparison between signal levels detected at the first detector and signal levels detected at the second detector, to detect pulses of a prescribed frequency as a signal transmi

Abstract: A transmitter 122 transmits interrogations to aircraft airborne in a coverage, a receiver 123 receives signals transmitted from aircraft airborne in the coverage, reply analyzers 132b and 133b analyze a reply responding to an interrogation transmitted from the transmitter, as the reply is detected from signals received by the receiver, and a squitter analyzer 132d analyzes an extended squitter, as the extended squitter is detected from the signals received by the receiver.

Abstract: It is related to a mode S secondary surveillance radar system for carrying out a target (aircraft) surveillance with a high reliability, where a surveillance processor 39 produces a detection report of a acquisition surveillance by a scan of an antenna thereafter by adopting the mode A code information with coinciding code data among mode A code information acquired by scans of a plurality of times. In this way, the efficient utilization of RF channels during the roll-call period can be maintained while improving the reliability of a target detection report.

Abstract: A DC-DC converter includes a switching circuit having first and second switching elements to which a direct current voltage is supplied, the first and second switching elements periodically operated so that one of the switching elements is turned on while the other one is turned OFF during a period other than a dead time period, a serial circuit in which a first capacitor, and primary windings of first and second inductance elements are connected in series, and a connection is made between an output point of the switching circuit and a reference potential point (or input voltage point), and output circuits including rectifier elements, each of which rectifies a voltage induced by secondary windings of the first and second inductance elements, the output circuits obtaining a direct current output voltage.

Abstract: A secondary surveillance radar system comprising a including a ground system which observes an observation area where an aircraft equipped with a mode S transponder and an aircraft equipped with an ATCRBS transponder possibly coexist, wherein the ground system comprises includes a transmit processor which transmits to the observation area an all-call interrogation signal specific for mode S including an identification code of the ground system, a receive processor which receives a reply signal to the interrogation signal transmitted by the transmit processor, and a recognition processor which recognizes the reply signal as a processing target when identification information included in the reply signal received by the receive processor coincides with the identification code of the ground system, and wherein the recognition processor recognizes the reply signal as the processing target also when the identification information included in the reply signal received by the receive processor coincides with null in

Abstract: It is related to a mode S secondary surveillance radar system for carrying out a target (aircraft) surveillance with a high reliability, where a surveillance processor 39 produces a detection report of a acquisition surveillance by a scan of an antenna thereafter by adopting the mode A code information with coinciding code data among mode A code information acquired by scans of a plurality of times. In this way, the efficient utilization of RF channels during the roll-call period can be maintained while improving the reliability of a target detection report.

Abstract: There are provided a differential processing unit which performs differential processing for a Mode S transponder transmission signal, an auto correlation arithmetic operation unit which performs an arithmetic operation of a degree of auto correlation between an increasing change rate and decreasing change rate of a power level in the signal which has been subjected to the differential processing, a pulse regeneration unit which regenerates a pulse based on the degree of auto correlation, which has been obtained by the auto correlation arithmetic operation processing, a pulse phase locked loop unit which performs gate processing and phase locked processing for the regenerated pulse, and a pulse decoding unit which decodes the Mode S transponder transmission signal based on the pulse which has been subjected to the gate processing and the phase locked processing.

Abstract: An interrogation transmission method of a secondary surveillance radar compares prediction angle ranges for transmitting interrogations with a beam-width of an antenna, and transmits the interrogations at every roll-call period if the prediction angle ranges for transmitting interrogations are narrower than the beam-width of the antenna. In contrast, if the prediction angle ranges for transmitting the interrogations are wider than the beam-width of the antenna, the radar respectively sets a period to transmit the interrogations and a period not to transmit the interrogations until responses can be received, and transmits interrogations at every roll-call period after the responses can be received (even if a receiving error or downlink occurs).

Abstract: There are provided a differential processing unit which performs differential processing for a Mode S transponder transmission signal, an auto correlation arithmetic operation unit which performs an arithmetic operation of a degree of auto correlation between an increasing change rate and decreasing change rate of a power level in the signal which has been subjected to the differential processing, a pulse regeneration unit which regenerates a pulse based on the degree of auto correlation, which has been obtained by the auto correlation arithmetic operation processing, a pulse phase locked loop unit which performs gate processing and phase locked processing for the regenerated pulse, and a pulse decoding unit which decodes the Mode S transponder transmission signal based on the pulse which has been subjected to the gate processing and the phase locked processing.

Abstract: There are provided a differential processing unit which performs differential processing for a Mode S transponder transmission signal, an auto correlation arithmetic operation unit which performs an arithmetic operation of a degree of auto correlation between an increasing change rate and decreasing change rate of a power level in the signal which has been subjected to the differential processing, a pulse regeneration unit which regenerates a pulse based on the degree of auto correlation, which has been obtained by the auto correlation arithmetic operation processing, a pulse phase locked loop unit which performs gate processing and phase locked processing for the regenerated pulse, and a pulse decoding unit which decodes the Mode S transponder transmission signal based on the pulse which has been subjected to the gate processing and the phase locked processing.

Abstract: A DC-DC converter comprises a switching circuit having first and second switching elements to which a direct current voltage is supplied, the first and second switching elements making a periodic operation so that one of the switching elements is turned on while the other one is turned OFF during a period other than a dead time period, a serial circuit in which a first capacitor, and primary windings of first and second inductance elements are connected in series, and a connection is made between an output point of the switching circuit and a reference potential point (or input voltage point), and output circuits including rectifier elements, each of which rectifies a voltage induced by secondary windings of the first and second inductance elements, the output circuits obtaining a direct current output voltage.

Abstract: A secondary surveillance radar system for use in surveillance of an airspace, which reliably achieves surveillance of the airspace even when an aircraft including a mode S transponder and an aircraft including an ATCRBS transponder are both located in the airspace, wherein both of a time interval between time when transmission of an all-call interrogation signal specific for mode S is completed and time when the transmission of an all-call interrogation signal specific for mode A is started and a time interval between time when transmission of the all-call interrogation signal specific for mode S is completed and time when transmission of an all-call interrogation signal specific for mode C is started is varied in units of one all-call time period.

Abstract: A secondary surveillance radar system comprising a ground system which observes an observation area where an aircraft equipped with a mode S transponder and an aircraft equipped with an ATCRBS transponder possibly coexist, wherein the ground system comprises a transmit processor which transmits to the observation area an all-call interrogation signal specific for mode S including an identification code of the ground system, a receive processor which receives a reply signal to the interrogation signal transmitted by the transmit processor, and a recognition processor which recognizes the reply signal as a processing target when identification information included in the reply signal received by the receive processor coincides with the identification code of the ground system, and wherein the recognition processor recognizes the reply signal as the processing target also when the identification information included in the reply signal received by the receive processor coincides with null information.

Abstract: There are provided a differential processing unit which performs differential processing for a Mode S transponder transmission signal, an auto correlation arithmetic operation unit which performs an arithmetic operation of a degree of auto correlation between an increasing change rate and decreasing change rate of a power level in the signal which has been subjected to the differential processing, a pulse regeneration unit which regenerates a pulse based on the degree of auto correlation, which has been obtained by the auto correlation arithmetic operation processing, a pulse phase locked loop unit which performs gate processing and phase locked processing for the regenerated pulse, and a pulse decoding unit which decodes the Mode S transponder transmission signal based on the pulse which has been subjected to the gate processing and the phase locked processing.

Abstract: An interrogation transmission method of a secondary surveillance radar compares prediction angle ranges for transmitting interrogations with a beam-width of an antenna, and transmits the interrogations at every roll-call period if the prediction angle ranges for transmitting interrogations are narrower than the beam-width of the antenna. In contrast, if the prediction angle ranges for transmitting the interrogations are wider than the beam-width of the antenna, the radar respectively sets a period to transmit the interrogations and a period not to transmit the interrogations until responses can be received, and transmits interrogations at every roll-call period after the responses can be received (even if a receiving error or downlink occurs).