Radio telemetry systems with channel selection
First Claim
1. A radio telemetry system comprising:
- a master station; and
a plurality of transponders, each transponder having a stand-by state in which it listens on each of a number of channels in turn, the master station listening on each of said number of channels in turn to establish a relatively quiet channel and then transmitting a wake-up signal on said relatively quiet channel, each transponder listening on said relatively quiet channel at the time the master station transmits said wake-up signal responding to receipt of said wake-up signal by transmitting an acknowledgement signal on said relatively quiet channel, the master station responding to receipt of one of the acknowledgement signals transmitted to receive data from the transponder which transmitted that one acknowledgement signal, thereafter that transponder ignoring further wake-up signals for a predetermined time, and the master station transmits a further wake-up signal after receipt of data from the transponder which transmitted said one acknowledgement signal.
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Accused Products
Abstract
A radio telemetry system for collecting the readings of consumer'"'"'s electricity consumption meters includes a master station (1) carried by a vehicle (1) and a plurality of transponders (3), each of which holds an electrical quantity indicative of an amount of electrical power consumed as measured by the meter associated with that transponder (3). The transponders (3) and the master station (1) communicate such that the transponders (3) transmit to the master station (1) signals containing information as to the values of the aforesaid electrical quantities held by them. Such communication takes place on a relatively quiet channel, of a number of channels, as determined by the master station (1) such that the system is capable of operating satisfactorily when the master station (1) and the transponders (3) utilise relatively low power transmitters (7, 19).
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Citations
12 Claims
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1. A radio telemetry system comprising:
- a master station; and
a plurality of transponders, each transponder having a stand-by state in which it listens on each of a number of channels in turn, the master station listening on each of said number of channels in turn to establish a relatively quiet channel and then transmitting a wake-up signal on said relatively quiet channel, each transponder listening on said relatively quiet channel at the time the master station transmits said wake-up signal responding to receipt of said wake-up signal by transmitting an acknowledgement signal on said relatively quiet channel, the master station responding to receipt of one of the acknowledgement signals transmitted to receive data from the transponder which transmitted that one acknowledgement signal, thereafter that transponder ignoring further wake-up signals for a predetermined time, and the master station transmits a further wake-up signal after receipt of data from the transponder which transmitted said one acknowledgement signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
- a master station; and
Specification