Apparatus for measuring transmission time utilized for data collection system

• US 5,740,200 A
• Filed: 03/20/1996
• Issued: 04/14/1998
• Est. Priority Date: 03/20/1995
• Status: Expired due to Fees

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Kamata, Shigeo
• Primary Examiner(s): Chin, Stephen
• Assistant Examiner(s): GHAYOUR, MOHAMMAD H
• Application Number:
  US08/619,967
• Time in Patent Office: 755 Days
• Field of Search: 375/224, 370/519, 370/517
• US Class Current: 375/224
• CPC Class Codes: H04B 3/462 Testing group delay or phase shift, e.g. timing jitter

Abstract

An apparatus for measuring transmission time is utilized for a data collection system including an observation station situated in a given wide-ranging region, and a collection station for collecting data from the observation station over a transmission line, and is designed for measuring the transmission time necessary for a signal to propagate through a transmission path. The apparatus is configured to have a signal detecting unit for taking out, from a signal indicating unit which indicates the states of various signals to be transmitted through a transmission path of a transmission line using light emitting devices or the like, and for detecting a first signal sent from a collection station in order to start data collection and a second signal returned from an observation station in order to notify that the first signal has been received, in a state in which the data collection system is kept running and the electrically uncoupled state relative to the transmission path is retained; and a transmission time calculating unit for calculating the transmission time of a signal propagating through the transmission path on the basis of a difference between the time instant at which the first and second signals are detected.

Claims

1. An apparatus for measuring transmission time that is utilized for a data collection system including an observation station situated in a given region, a collection station for collecting data from said observation station over a transmission line, and a signal indicating unit for indicating the states of arbitrary signals to be transmitted through a transmission path within said transmission line, and that is designed for measuring the transmission time necessary for said signal to propagate through said transmission path, comprising:

a signal detecting means for taking out, from said signal indicating unit, and detecting a first signal to be sent from said collection station to said observation station in order to start data collection, and a second signal to be returned from said observation station to said collection station in order to notify that said first signal has been received, in a state in which said data collection system is kept operating and the electrically uncoupled state relative to said transmission line is retained;

a transmission time calculating mean for calculating the transmission time of a signal propagating through said transmission path on the basis of a difference between the time instant at which said first and second signals are detected; and

wherein said signal indicating unit includes light emitting devices for indicating said states of signals in said transmission path by means of lights, wherein said signal detecting means includes light receiving units for receiving light signals emanating from said light emitting devices and converting them into electrical signals, and comparing means for comparing patterns of electrical signals supplied from said light receiving units with a given pattern registered in advance and checking if both patterns coincide with each other, and when said both patterns coincide with each other, it is recognized that at least one of said first and second signals has been detected.

2. An apparatus according to claim 1, wherein the results of detection of said first and second signals performed by said signal detecting means are output in the form of electrical signals.

3. An apparatus according to claim 1, wherein the results of detection of said first and second signals performed by said signal detecting means are output in the form of light emissions from associated light emitting devices.

4. An apparatus according to claim 1, further comprising an instantaneous synchronization timing generating means for generating a timing signal, which is used to sample data sent from said observation station, on the basis of said first and second signals within a predetermined time interval.

5. An apparatus according to claim 2, further comprising an instantaneous synchronization timing generating means for generating a timing signal, which is used to sample data sent from said observation station, on the basis of said first and second signals within a predetermined time interval.

6. An apparatus according to claim 3, further comprising an instantaneous synchronization timing generating means for generating a timing signal, which is used to sample data sent from said observation station, on the basis of said first and second signals within a predetermined time interval.

7. An apparatus for measuring transmission time that is utilized for a data collection system including an observation station situated in a given region, a collection station for collecting data sent from said observation station over a transmission line, and a signal indicating unit for indicating the states of arbitrary signals to be transmitted through a transmission path within said transmission line, and that is designed for measuring the transmission time necessary for said signal to propagate through said transmission path, said apparatus for measuring transmission time comprising:

a signal detecting means for taking out, from said signal indicating unit, and detecting a specific signal relevant to data collection in a state in which said data collection system is kept operating and the electrically uncoupled state relative to said transmission path is retained, said signal detecting means inputting a reference signal that is different from said signal relevant to data collection, wherein said apparatus for measuring transmission time further comprises;

a transmission time calculating means or calculating the transmission time of a signal propagating through said transmission path on the basis of a difference between the time instant at which said specific signal is detected and the time instant at which said reference signal is detected; and

wherein said signal indicating unit includes a light emitting device for indicating said state of a signal in said transmission path by means of lights, wherein said signal detecting means includes a light receiving unit for receiving a light signal emanating from said light emitting device and converting it into an electrical signal, and a comparing means for comparing the pattern of an electrical signal supplied from said light receiving unit with a given pattern registered in advance and checking if both the patterns coincide with each other, and when both the patterns coincide with each other, it is recognized that said specific signal relevant to data collection has been detected.

8. An apparatus according to claim 7, wherein said reference signal is input as an electrical signal to said signal detecting means.

9. An apparatus according to claim 7, wherein said reference signal is a light signal stemming from light emissions and said light signal is input to said signal detecting means.

10. An apparatus according to claim 7, further comprising an instantaneous synchronization timing generating means for generating a timing signal, which is used to sample data sent from said observation station, on the basis of said specific signal relevant to data collection and said reference signal within a predetermined time interval.

11. An apparatus according to claim 8, further comprising an instantaneous synchronization timing generating means for generating a timing signal, which is used to sample data sent from said observation station, on the basis of said specific signal relevant to data collection and said reference signal within a predetermined time interval.

12. An apparatus according to claim 9, further comprising an instantaneous synchronization timing generating means for generating a timing signal, which is used to sample data sent from said observation station, on the basis of said specific signal relevant to data collection and said reference signal within a predetermined time interval.

13. An apparatus for measuring transmission time that is utilized for a data collection system including an observation station situated in a given region, a collection station for collecting data from said observation station over a transmission line, and a signal indicating unit for indicating the states of arbitrary signals to be transmitted through a transmission path within said transmission line, and that is designed for measuring the transmission time necessary for said signal to propagate through said transmission path, comprising:

a signal detecting means for taking out, from said signal indicating unit, and detecting a first signal to be sent from said collection station to said observation station in order to start data collection, and a second signal to be returned from said observation station to said collection station in order to notify that said first signal has been received, in a state in which said data collection system is kept operating and the electrically uncoupled state relative to said transmission line is retained;

a transmission time calculating mean for calculating the transmission time of a signal propagating through said transmission path on the basis of a difference between the time instant at which said first and second signals are detected;

an instantaneous synchronization timing generating means for generating a timing signal, which is used to sample data sent from said observation station, on the basis of said first and second signals within a predetermined time interval; and

wherein said signal indicating unit includes light emitting devices for indicating said states of signals in said transmission path by means of lights, wherein said signal detecting means includes light receiving units for receiving light signals emanating from said light emitting devices and converting them into electrical signals, and comparing means for comparing patterns of electrical signals supplied from said light receiving units with a given pattern registered in advance and checking if both patterns coincide with each other, and when said both patterns coincide with each other, it is recognized that at least one of said first and second signals has been detected.

14. An apparatus for measuring transmission time that is utilized for a data collection system including an observation station situated in a given region, a collection station for collecting data sent from said observation station over a transmission line, and a signal indicating unit for indicating the states of arbitrary signals to be transmitted through a transmission path within said transmission line, and that is designed for measuring the transmission time necessary for said signal to propagate through said transmission path, said apparatus for measuring transmission time comprising:

a signal detecting means for taking out, from said signal indicating unit, and detecting a specific signal relevant to data collection in a state in which said data collection system is kept operating and the electrically uncoupled state relative to said transmission path is retained, said signal detecting means inputting a reference signal that is different from said signal relevant to data collection;

a transmission time calculating means or calculating the transmission time of a signal propagating through said transmission path on the basis of a difference between the time instant at which said specific signal is detected and the time instant at which said reference signal is detected;

an instantaneous synchronization timing generating means for generating a timing signal, which is used to sample data sent from said observation station, on the basis of said specific signal relevant to data collection and said reference signal within a predetermined time interval,

wherein said signal indicating unit includes a light emitting device for indicating said state of a signal in said transmission path by means of lights, wherein said signal detecting means includes a light receiving unit for receiving a light signal emanating from said light emitting device and converting it into an electrical signal, and a comparing means for comparing the pattern of an electrical signal supplied from said light receiving unit with a given pattern registered in advance and checking if both the patterns coincide with each other, and when both the patterns coincide with each other, it is recognized that said specific signal relevant to data collection has been detected.