Abstract: Bias recording is used to record servo patterns on magnetic tape. With use of bias recording, a faster recording process may be provided relative to conventional pulse recording processes. A servo pattern recording method includes providing a servo band along at least a portion of a length of a tape. Bursts of a first signal are recorded in a first servo track of the servo band along the length of the tape and a second signal, e.g., a continuous signal, is recorded in at least a second servo track of the servo band along the length of the tape. The second servo track is recorded adjacent to the first servo track and at least one of the first signal and the second signal is recorded using a bias signal at a bias frequency summed with a record signal at a record frequency. A system for carrying out the bias recording of servo patterns is also described.

Abstract: An air valve actuated by an electric motor has a cylindrical inlet section. The inlet section defines a seating surface upstream of which is a support grid. A backplate to which the actuating motor is mounted is supported by a plurality of rods that extend downstream of the inlet section. A damper assembly includes a generally planar damper mounted for movement axial of the inlet section. The damper assembly includes a splined rod which extends upstream of the damper and into a cooperating spline in the support grid. A threaded spindle extends downstream of the damper plate through a cooperatively threaded motor-driven drive gear which is mounted for rotation on the backplate. Because a portion of the damper assembly is splined, the damper assembly cannot rotate and is driven axially within the valve by the rotation of the drive motor and drive gear.

Abstract: A normally open pneumatic air control valve includes an inlet section which defines a seating surface and a support grid. A support plate, located downstream of the inlet section, is itself supported by a plurality of rods extending from the inlet section. A damper assembly is disposed for movement axial of the inlet section and is supported for such movement between the inlet section support grid and the downstream support plate. The damper assembly is actuated by the admission of a pressurized gas to a chamber cooperatively defined by a housing fixed to the support plate and a diaphragm disposed therein. A spring acts on the fixed grid support of the inlet section and on the damper assembly to urge the damper assembly away from the inlet section so that the valve is biased to the open position.

Abstract: A normally closed pneumatically actuated air valve for use in a variable air volume air distribution system has a unitary inlet section which supports a damper assembly and actuator through a support grid disposed in the inlet section. The damper assembly is mounted for axial movement, on a fixed spindle and guide piston, under the impetus of the expansion of a pressure chamber defined by a portion of the damper assembly and a diaphragm which conformably surrounds the guide piston. A biasing spring acts on a surface of the fixed guide piston and on the damper assembly to bias the damper assembly toward a seating surface of the inlet section.