Communications: electrical – Continuously variable indicating – Plural transmitters
Reexamination Certificate
1998-03-30
2001-02-06
Horabik, Michael (Department: 2735)
Communications: electrical
Continuously variable indicating
Plural transmitters
C340S870030, C340S870100, C246S16900S, C246S18200B
Reexamination Certificate
active
06184798
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to telemetry systems and more particularly to telemetry systems for remote data acquisition.
BACKGROUND OF THE INVENTION
Telemetry systems used for remote data monitoring are known in a variety of different applications including “Local LAN” Systems for example hospital record keeping, and “Body LAN”, for example monitoring soldier biological vital signs in a battlefield situation. Conventionally, data telemetry employs a bi-directional communications link wherein both a network controller and transmitting sensors each operate as transponders. Conventional telemetry systems include time and frequency division multiplexing systems. In a conventional telemetry system, the network controller receives a radio signal from the transmitting sensors and converts the signal to a digital format providing the measured data. The network controller also operates to transmit synchronization and/or acknowledgment information to the transmitting sensors. The transmitting sensors operate to receive the synchronization and/or acknowledgment information as well as to transmit the radio signal measured data. Accordingly, in a conventional telemetry system, the remote transmitting sensors also act as receivers and the central receiver also acts as a transmitter. The communication link between the central receiver and the transmitting sensors, therefore, is bi-directional and synchronously communicates, typically, in time or frequency or both.
U.S. Pat. No. 5,537,397 issued Jul. 16, 1996 entitled “Spread ALOHA For CDMA Data Communications” discloses a method of providing multiple access to a data communications channel wherein transmitters spread a data signal spectrum according to a code spreading sequence. In order to simplify the system by obviating the need for multiple receivers in a receiving hub for interpreting differently coded data transmissions, the hub station transmits a control signal which is received by the transmitters to advance or retard the timing of the data transmission in order to reduce the probability of fatal interference between two or more transmitted signals. Accordingly, the transmitters operate as transponders and a single receiver is able to receive the transmitted data serially. As can be appreciated by one of ordinary skill in the art, both the network controller and the transmitters operate as transponders. Disadvantageously, a transponder is more costly to implement and requires more power to operate than a pure transmitter. As the number of sensors to monitor increases, so does the cost and power required for implementation of a bi-directional telemetry system. There is a need, therefore, for a lower cost, lower power telemetry system, that maintains the robust transmission performance of the known synchronized and acknowledged telemetry systems.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a low cost monitoring system.
It is a further object of the present invention to provide a system for remote monitoring of a plurality of sensors from a single receiver.
It is a further object to provide a robust and reliable unidirectional telemetry system for remote data acquisition.
A telemetry system comprises a plurality of transmitters operating autonomously relative to each other, each transmitter transmitting a packet over a first predetermined transmit time duration. A monitoring receiver receives the packet within a second predetermined receive time duration. The first predetermined transmit time duration is less than the second predetermined receive time duration and there is an absence of an acknowledgment signal from the receiver to the transmitter.
It is a feature of the present invention that a plurality of beacons transmit data to a receiver and the beacons do not receive synchronization or acknowledgment information, thereby providing a lower cost telemetry system due to the exclusive transmit operation of the beacons.
Advantageously, a system according to the teachings of the present invention provides a low cost, robust, and reliable unidirectional telemetry system for remote monitoring of a plurality of sensors.
REFERENCES:
patent: 3676875 (1972-07-01), Adams et al.
patent: 4316175 (1982-02-01), Korber et al.
patent: 4340886 (1982-07-01), Boldt et al.
patent: 4356475 (1982-10-01), Neumann et al.
patent: 4442426 (1984-04-01), Heuschmann et al.
patent: 4582280 (1986-04-01), Nichols et al.
patent: 4724435 (1988-02-01), Moses et al.
patent: 5272476 (1993-12-01), McArthur
patent: 5374015 (1994-12-01), Bezos et al.
patent: 5377938 (1995-01-01), Bezos et al.
patent: 5383717 (1995-01-01), Fernandez et al.
patent: 5446451 (1995-08-01), Grosskopf, Jr.
patent: 5537397 (1996-07-01), Abramson
patent: 5539396 (1996-07-01), Mori
patent: 5594871 (1997-01-01), Hiyama
patent: 0627841 A2 (1994-05-01), None
patent: 2297663 (1996-08-01), None
PCT International Application No.: PCT/US95/03911, dated Oct. 12, 1995; International Publication No.: WO 95/27272.
PCT International Search Report, International application No.: PCT/US98/06204, International filing dated Mar. 30, 1998.
Dinicola Brian K.
Horabik Michael
The Whitaker Corporation
Wong Albert K.
LandOfFree
Unidirectional telemetry system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Unidirectional telemetry system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Unidirectional telemetry system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2578177