Patent ID: 7808859

Claim:
A mud pulse telemetry tool configured for use in a drillstring having a drilling fluid flowing therein, comprising: a pulser configured to be disposed in the drillstring for generating pressure pulses downhole, the pulser having: a non-rotating stator including a fluid flow path; a rotor proximate the stator; a motor coupled to the rotor, wherein rotation of the motor rotates the rotor in a controllable rotationally oscillating motion to obstruct flow of the fluid through the stator to generate pressure pulses in the drilling fluid, the motor controlling at least one characteristic of the rotor oscillating motion according to an encoding scheme to transmit an encoded signal using the pressure pulses; and a spring device coupled to the motor configured to affect a torque of the rotor to reduce power use of the motor when the motor rotates the rotor to generate the pressure pulses.