Patent ID: 7881155

Claim:
A system for communicating downhole information through a wellbore to a surface location comprising: a drill string with a drilling sub at an end thereof; a pumping means for pumping drilling mud into the wellbore, said drilling mud being fluid, said pumping means being positioned at the surface location and being in fluid connection with said drill string with said drilling sub; and a downhole electronics module positioned in said drilling sub, said downhole electronic module comprising: a valve means for providing a flow restriction to fluid passing through said drilling sub, said valve means being suitable for controlling a flow of drilling mud in said drilling sub; a sensor means positioned in the drilling sub for sensing a downhole condition in the wellbore; a brake means cooperative with the valve means for fixing said valve means in at least two static positions, during a start of said flow of drilling mud through said drilling sub and during opening of said valve means; and a detector means positioned at the surface location and cooperative with the fluid passing through said drilling sub for providing a measurement value at the surface location correlative to time between changes of pressure of the fluid in the drill string.