Periodic bandwidth widening for inductive coupled communications

摘要

In described examples, a method of inductive coupled communications includes providing a first resonant tank (first tank) and a second resonant tank (second tank) tuned to essentially the same resonant frequency, each having antenna coils and switches positioned for changing a Q and a bandwidth of their tank. The antenna coils are separated by a distance that provides near-field communications. The first tank is driven to for generating induced oscillations to transmit a predetermined number of carrier frequency cycles providing data. After the predetermined number of cycles, a switch is activated for widening the bandwidth of the first tank. Responsive to the oscillations in the first tank, the second tank begins induced oscillations. Upon detecting a bit associated with the induced oscillations, a switch is activated for widening the bandwidth of the second tank and a receiver circuit receiving an output of the second tank is reset.

主权项

1. A method of resonant inductive coupled communication, responsive to oscillations generated by a modulated carrier signal from a first resonant tank (first tank) that is tuned to a first resonant frequency and that includes first antenna coils, a first capacitor coupled in parallel to the first antenna coils, a first resistor coupled in series between the first antenna coils, and a first switch coupled in series between the first antenna coils, the first antenna coils transmitting a predetermined number of carrier frequency cycles for providing data that is first transition coded, and the first switch being activated for widening a bandwidth and changing a Q factor of the first tank after the predetermined number of carrier frequency cycles, the method comprising:
responsive to the oscillations in the first tank, beginning induced oscillations in a second resonant tank (second tank) tuned to a second resonant frequency essentially equal the first resonant frequency and that includes: a second antenna coil that is separated from the first antenna coils by a distance that provides near-field communications; a second capacitor coupled in parallel to the second antenna coil; and a second switch coupled in parallel to the second antenna coil; and with a receiver sense circuit, responsive to detecting a bit associated with the induced oscillations of the second tank, activating the second switch for widening a bandwidth and changing a Q factor of the second tank, and resetting the receiver sense circuit.