초록 ▼

An apparatus for processing pulses in ATCRBS/Mode S interrogations includes an antenna for receiving a radio frequency interrogation signal. The radio frequency interrogation signal is downconverted by a downconverter to an intermediate frequency signal. The intermediate frequency signal is converte

An apparatus for processing pulses in ATCRBS/Mode S interrogations includes an antenna for receiving a radio frequency interrogation signal. The radio frequency interrogation signal is downconverted by a downconverter to an intermediate frequency signal. The intermediate frequency signal is converted to a digitized interrogation signal by an analog-to-digital converter. A processing unit, coupled to the analog-to-digital converter, detects a pulse peak in the digitized interrogation signal using a moving threshold to locate the peak pulse between a first fixed threshold and a second fixed threshold.

대표청구항 ▼

What is claimed: 1. A method for processing pulses from interrogations in a Mode S/ATCRBS transponder comprising the steps of: receiving a digitized interrogation signal from an analog-to-digital converter; determining a peak pulse of the digitized interrogation signal; and determining a type of th

What is claimed: 1. A method for processing pulses from interrogations in a Mode S/ATCRBS transponder comprising the steps of: receiving a digitized interrogation signal from an analog-to-digital converter; determining a peak pulse of the digitized interrogation signal; and determining a type of the peak pulse, wherein the step of determining a peak pulse further comprises: determining whether at least four samples of the digitized interrogation signal have a successive rise in signal strength of at least 1 dB; determining whether at least five samples of the digitized interrogation signal exceed a first predetermined threshold; and determining a moving threshold that increases as a peak pulse is detected. 2. The method of claim 1, further comprising the step of determining whether an ATCRBS rate limit is needed. 3. The method of claim 1, wherein the step of determining a peak pulse further comprises: if at least four samples of the digitized interrogation signal do not have a successive rise in signal strength of 1 dB, determining whether samples of the digitized interrogation signal exceed a signal threshold, the second threshold being lower than the first; and determining a moving threshold that increases as a peak pulse is detected. 4. The method of claim 1, further comprising: detecting a first peak pulse from an interrogation signal received at a top antenna; detecting a second peak pulse from the interrogation signal received at a bottom antenna; and selecting a peak pulse based on a comparison of signal strength of the first peak pulse and the second peak pulse. 5. The method of claim 1, wherein the step of determining a type of pulse further comprises determining that the pulse is a 6 dB type pulse. 6. The method of claim 1, wherein the step of determining a type of pulse further comprises determining that the pulse is a 3 dB type pulse. 7. The method of claim 3, wherein the moving threshold is reduced to a second threshold after the peak pulse is selected. 8. A method for processing pulses from interrogations in a Mode S/ATCRBS transponder comprising the steps of: receiving a digitized interrogation signal from an analog-to-digital converter; determining a peak pulse of the digitized interrogation signal; and determining a type of the peak pulse, wherein the step of determining a type of pulse further comprises: processing a delayed digitized interrogation signal; identifying a pulse as a 3 dB pulse if an amplitude of a sample of the delayed digitized interrogation signal is greater than a 3 dB and a MTL crossing flag is true; and identifying a pulse as a 6 dB pulse if an amplitude of a sample of the delayed digitized interrogation signal is greater than a 6 dB and a MTL crossing flag is true. 9. An apparatus for processing pulses in ATCRBS/Mode S interrogations comprising: an antenna for receiving a radio frequency interrogation signal; a downconverter for downconverting the radio frequency interrogation signal to an intermediate frequency signal; an analog-to-digital converter operable to convert the intermediate frequency signal to a digitized interrogation signal; and a processing unit coupled to the analog-to-digital converter, the processing unit configured to detect a pulse peak in the digitized interrogation signal using a moving threshold to locate the pulse between a first fixed threshold and a second fixed threshold, the processing unit determines whether at least four samples of the digitized interrogation signal have a successive rise in signal strength of at least 1 dB, determines whether at least five samples of the digitized interrogation signal exceed a first predetermined threshold, and determines a moving threshold that increases as a peak pulse is detected. 10. The apparatus of claim 9, wherein the processing unit is further configured to decay a signal strength value of the moving threshold after detecting a pulse. 11. The apparatus of claim 9, wherein the processing unit is further configured to determine if a pulse is a 3 dB pulse or a 6 dB pulse. 12. The apparatus of claim 9, wherein the processing unit is further configured to limit responses to ATCRBS interrogations. 13. The apparatus of claim 9, wherein the processing unit is further operable to select data from a first channel or a second channel. 14. The apparatus of claim 11, wherein the processing unit is further configured to: process a delayed digitized interrogation signal; identify a pulse as a 3 dB pulse if an amplitude of a sample of the delayed digitized interrogation signal is greater than 3 dB and a MTL crossing is true; and identify a pulse as a 6 dB pulse if an amplitude of a sample of the delayed digitized interrogation signal is greater than 6 dB and a MTL crossing is true. 15. The apparatus of claim 9, further comprising reply logic to generate a reply to an interrogation based on the peak pulse. 16. The apparatus of claim 9, wherein the processing unit is a field programmable gate array. 17. A method for processing pulses from ATCRBS/Mode S interrogations comprising: receiving a digitized interrogation signal from an analog-to-digital converter; determining whether at least four samples of the digitized interrogation signal have a successive rise in signal strength of at least 1 dB; determining whether at least five samples of the digitized interrogation signal exceed a first predetermined threshold; determining a moving threshold that increases as a peak pulse is detected; processing a delayed digitized interrogation signal; identifying a pulse as a 3 dB pulse if an amplitude of a sample of the delayed digitized interrogation signal is greater than 3 dB and a MTL crossing is true; and identifying a pulse as a 6 dB pulse if an amplitude of a sample of the delayed digitized interrogation signal is greater than 6 dB and a MTL crossing is true. 18. The method of claim 17, further comprising: detecting a first peak pulse from an interrogation signal received at a top antenna; detecting a second peak pulse from the interrogation signal received at a bottom antenna; and selecting a peak pulse based on a comparison of signal strength of the first peak pulse and the second peak pulse.