초록 ▼

A data collection system in which, in communications between each of terminal units and a data collector through a power line, the data collector subjects a polling signal generated by a polling generating circuit to spread spectrum modulation by a spreading section, and superimposes the spread sign

A data collection system in which, in communications between each of terminal units and a data collector through a power line, the data collector subjects a polling signal generated by a polling generating circuit to spread spectrum modulation by a spreading section, and superimposes the spread signal on the power line, while each of the terminal units subjects the incoming spread signal thereto superimposed on the power line to de-spread spectrum demodulation and recognizes it, and superimposes the data subjected to spread spectrum modulation on the power line after a certain period of time different from that in other terminal unit has passed. The data collector collects the data obtained by subjecting spread signals successively coming thereinto each by being superimposed on the power line to de-spread spectrum demodulation according to the polling.

대표청구항 ▼

[ What is claimed is:] [1.] A data collection system comprising:a plurality of terminal units each having a memory for storing therein data to be collected by the data collection system;a data collector; anda power line connecting each of said plurality of terminal units to said data collector with

[ What is claimed is:] [1.] A data collection system comprising:a plurality of terminal units each having a memory for storing therein data to be collected by the data collection system;a data collector; anda power line connecting each of said plurality of terminal units to said data collector with data communication being executed between each of said plurality of terminal units and said data collector via said power line,each terminal unit includinga modulating circuit configured to read out data from the memory of the respective terminal unit according to a common request signal transmitted from said data collector and subject said data to spread spectrum modulation, anda data transmitting circuit configured to transmit via said power line data modulated by said modulating circuit to said data collector, andsaid data collector includinga request signal transmitting circuit configured to transmit said common request signal via said power line to each of said plurality of terminal units,a demodulating circuit configured to subject data from each of said plurality of terminal units received via said power line, after transmission from said request signal transmitting circuit, to spread spectrum demodulation, anda data collecting circuit configured to collect data according to the data demodulated by said demodulating circuit, whereinsaid plurality of terminal units execute spread spectrum modulation using a common specified spread code in said modulating circuit and said demodulating circuit is a shared reversely spreading circuit for subjecting data modulated by each of said plurality of terminal units to reverse spread spectrum demodulation using said specified spread code.