Patent ID: 6058137
Filing Date: 2000-05-02
Classification: H04B

Abstract:
A radio transmission system comprising of a radio receiver and a plurality of radio transmitters using frequency hopping modulation to intermittently transmit messages indicative of a status of operation associated with the transmitters;wherein each said transmitter includes a control logic means to change the carrier frequency according to a predetermined pattern and a time interval generator means for activating said transmitter at predetermined time intervals, said intervals may be set at a predetermined nominal value or changed according to a predetermined pattern; andwherein said receiver includes a frequency selective radio circuit that can be programmed to a desired frequency to receive and demodulate the transmitted carriers; andwherein said receiver includes a plurality of digital counters or memory registers means to hold data indicative of (a) the time of the next transmission occurrence for each said transmitter and (b) the frequency of the next transmission occurrence for each said transmitter, and wherein said receiver includes a receiver control logic means to change the receiver frequency according to said data in said digital counters or memory registers and to change said data in said digital counters or memory registers in response to the received messages; andwherein, said receiver control logic is operative to change the data in said digital counters or memory registers based on the time of arrival, the carrier frequency and the content of a message received from a transmitter for subsequent use for the determination of the time and frequency of the future transmissions for said transmitter, said determination is made individually for each transmitter of said plurality of transmitters, thus allowing the receiver to receive messages from many unsynchronized frequency hopping transmitters.