Duplex bi-directional multi-mode remote instrument reading and telemetry system

摘要

The remote instrument reading and telemetry system of the present invention includes at least one instrument link interconnected to a data gathering device and a remote station interrogation apparatus. The interrogation apparatus and instrument link both include radio transmitters and receivers so information and instructions can be communicated between them. In the interrogation mode, the interrogation apparatus instructs the instrument link to transmit information (e.g., data from the data gathering device) in a specified manner, within certain time frames, and in a specific frequency channel. Before requesting the transmission of information, the interrogation apparatus determines which of the available reply radio channels is the best for transmission of information and instructs the instrument link to use this reply channel. In a preferred embodiment, the instrument link transmits information using spread spectrum modulation techniques, and the interrogation apparatus determines the spread spectrum parameters that optimize processing gain and the data transmission rate. The instrument link is also controlled so that parts of the instrument link (e.g., the transmitter's amplifier) are only powered up during specific periods of instrument link activity to conserve power.