IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
US-0374385
(1989-06-30)
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발명자
/ 주소 |
- Lee Robert A. (Fairborn OH)
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출원인 / 주소 |
- The United States of America as represented by the Secretary of the Air Force (Washington DC 06)
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인용정보 |
피인용 횟수 :
5 인용 특허 :
2 |
초록
▼
An analyzer recorder collects sonic boom information of supersonic aircraft and launch vehicles, for use to validate Environmental Impact Statements that contain supersonic aircraft activity. The device comprises a 16-bit microprocessor, a random access memory (RAM) storage, a data retrieval unit (D
An analyzer recorder collects sonic boom information of supersonic aircraft and launch vehicles, for use to validate Environmental Impact Statements that contain supersonic aircraft activity. The device comprises a 16-bit microprocessor, a random access memory (RAM) storage, a data retrieval unit (DRU), and a microcomputer. It samples and captures in digital form any loud impulse noise from background noise. The unattended device can discern a sonic boom from the normal background noise and capture it in permanent solid RAM storage for later analysis. The RAM modules can then be transferred with the DRU and the information on the DRU transferred to the microcomputer. The microprocessor displays each recorded event, time of occurrence and summary information for all the stored data.
대표청구항
▼
A method of analyzing and recording boom events, discerning the boom event from other noisy events with a boom screening methodology, in which sound levels are digitized with positive values for compression parts and negative values for rarefaction parts of sound waves, said method having an initial
A method of analyzing and recording boom events, discerning the boom event from other noisy events with a boom screening methodology, in which sound levels are digitized with positive values for compression parts and negative values for rarefaction parts of sound waves, said method having an initialization phase, a data acquisition phase, and a evaluation phase; wherein the initialization phase includes providing parameters which include a low trigger set to an absolute value of the sound pressure, so that there is a positive value and an equal negative value for the low trigger, a higher trigger having a value for a level which an event must exceed to be considered a good event, an event timer time duration which is preset to a predetermined value for a typical boom duration, a cycle timer time duration of shorter duration than that for the event timer, a positive pulse time, a negative pulse time, and a value for pressure rise and a value for a period of time which together define a rise time standard; down crossings being defined as the absolute value of the pressure data going from greater than the absolute value of the low trigger value to less, up crossings being defined as the absolute value of the pressure data going from less than the absolute value of the low trigger value to more; wherein the data acquisition phase starts following completion of the initialization phase and comprises the steps of continuously monitoring a noise environment and digitizing a noise signature to provide digitized values for sound levels at fixed intervals, examining the sound levels with a data acquisition routine which starts at the beginning of each of said fixed intervals and ends by returning, and then waiting for the beginning of the next interval; wherein the data acquisition routine comprises getting the digitized value for the sound level and using it as a current data value, determining if the absolute value of the current data value is greater than the absolute value of the low trigger, and if so, flagging the start of an event, starting the event timer, storing the current data value in memory as a data point, also storing the current data value as a peak value, and returning; for subsequent intervals, event collection being in progress, storing the current data value in memory as a data point, determining if the current data value is greater than the previous peak value and if so updating the peak value, determining if the current data indicates a down crossing and if so starting the cycle timer, determining if the current data indicates an up crossing and if so stopping the cycle timer, if the current data value is negative determining if it is a negative peak value and if so storing the value as a negative peak value; determining if either the event timer or the cycle timer has timed out by reaching its preset value, and if so starting the evaluation phase; wherein the evaluation phase comprises the steps of (1) determining if the peak value is greater than said higher trigger value, (2) determining if all of the data points from the peak forward for said positive pulse time are greater than the positive value of the low trigger, and determining if all of the data points checked backward from the negative peak indicated by the fifth flag for said negative pulse time have an absolute value greater than the absolute value of the low trigger, and (3) determining if any rise time before said peak meets a predetermined criteria using said rise time standard; and declaring a valid boom event if all of the above tests of the evaluation phase are passed, and otherwise declaring it not a valid boom event.
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