Abstract: A rotational speed measurement system may include a rotational speed measuring device for measuring a rotational speed of a motor or component thereof. The downhole rotational speed measuring device may include a magnet and a magnetic sensor. A telescoping unit may position the magnetic sensor into sensing proximity of the magnet. A method for measuring downhole rotational speed may include coupling a rotational speed measuring device to a measurement assembly and a motor. The rotational speed measuring device may include a magnet and a magnetic sensor. The position of the magnetic sensor, the magnet, or both, may be adjusted with a telescoping unit to place the magnetic sensor into sensing proximity of the magnet.

Abstract: In a two-way paging system including a paging terminal, a plurality of paging transmitters, a plurality of paging receivers, and a plurality of two-way paging units, the plurality of two-way paging units transmitting reverse channel messages to the paging receivers in a time division multiplexed protocol, the protocol including a frame with a plurality of reverse channel time slots, a method of assigning reverse channel time slots to the paging units is disclosed. The method comprises: (a) determining a set of transmitting paging units from the plurality of two-way paging units, the set of transmitting paging units being those of the plurality of two-way paging units that are to transmit a reverse channel message; and (b) randomly assigning each of the transmitting paging units in the set of transmitting paging units one of the reverse channel time slots in the frame.