Abstract: An improved method and apparatus for non-invasive determination of blood pressure is disclosed. The oscillometric technique is employed, wherein a valve representative of the blood pressure is derived from a signal representative of the pressure oscillations in a cuff, where the value is derived for a plurality of cuff pressures, and where the cuff pressure corresponding to the maximum of the values derived from the pressure oscillations is taken to be the mean arterial pressure. The instant method uses as the value the complementary oscillation index which is defined to be the area bounded by a line connecting successive peaks in the signal and the signal beneath the line, divided by the time between peaks. Apparatus employing both digital and analog circuitry is employed.

Abstract: A telemetry receiver for demodulating subcarrier frequencies is disclosed. The flexibility of the receiver permits it to decode signals from a wide variety of transmitters. In the preferred embodiment, a biomedical digital telemetry subcarrier demodulator employs microprocessor control of a variable bandpass filter and cycle counter. The bandpass of the filter is set by the microprocessor to pass frequencies at and around the center frequency of the desired subcarrier frequency. The counter is preset for the desired number of cycles. In operation, the desired subcarrier frequency is passed by the filter, through a signal shaper, and to the counter. Upon receiving the first cycle, the counter activates a timer, which measure the period of the predetermined number of cycles. The desired signal is the percentage deviation of the subcarrier period from the average subcarrier period.

Abstract: A digital magnetic recording tape cartridge has a housing that permits use of up to 1/4-inch wide tape which, in turn, increases data recording packing density over standard 0.150-inch tape cartridges. The tape cartridge is the belt-driven type having a flexible elastic endless belt that applies tension to tape on the supply and take-up reels to move the tape. Rotation of a driving roller causes the belt to drive the tape reels and move the tape between the reels. A magnetic head of the tape transport engages an exposed portion of the tape in the cartridge for reading or writing data on the tape. In a preferred embodiment, the tape is 1/4-inch wide. The number of data tracks is substantially increased by the wider 1/4-inch tape. The cartridge housing has a base plate with a stepped down recess that accommodates the wider 1/4-inch tape and the wider supply and take-up reels, tape guide rollers, and tape guide pins.

Abstract: A digital magnetic recording tape cartridge has a housing that permits use of greater than 1/4-inch wide tape which, in turn, increases data recording packing density over standard 1/4-inch tape cartridges. The tape cartridge is the belt-driven type having a flexible elastic endless belt that applies tension to tape on the supply and take-up reels to move the tape. Rotation of a driving roller causes the belt to drive the tape reels and move the tape between the reels. A magnetic head of the tape transport engages an exposed portion of the tape in the cartridge for reading or writing data on the tape. In a preferred embodiment, the tape is 1/2-inch wide. The number of data tracks is substantially increased by the wider 1/2-inch tape. The cartridge housing has a base plate with a stepped on recesses that accommodates the wider 1/2-inch tape and the wider supply and take-up reels, tape guide rollers, and tape guide pins.

Abstract: A tape cartridge drive having a movable read/write head has a fail-safe locking mechanism for preventing removal of the cartridge when the head is in contact with the tape. The tape cartridge has a door on the cartridge housing for opening to expose a portion of the tape prior to moving the head into contact with the tape. The cartridge door has a tripping arm which is rotated for opening the cartridge door. The door of the tape drive has a cam that contacts an interposer latch inside the tape drive housing for rotating the tripping arm to open the cartridge door when the door of the tape drive is closed. A pawl latch locks the door of the tape drive and a head moving mechanism moves the head to its operative position. During the first portion of the head movement, a locking pin is placed behind the interposer latch. This locks the latch in position to prevent the possible ejection of the cartridge while the head is in contact with the tape.

Abstract: A tape drive has a movable read/write head. A tape cartridge is inserted endwise into a receptacle in the tape drive housing. The read/write head is moved to a retracted position away from the envelope of the cartridge so the read/write head avoids interference with the cartridge when the cartridge is inserted into the receptacle. The cartridge includes a magnetic tape and a door on the cartridge housing for opening to expose a portion of the tape once the tape is locked in the tape drive receptacle. The read/write head is then moved to an operative position in contact with the tape. The head-moving mechanism includes a support on which the head is carried, an elongated swing arm on which the head support slides vertically toward and away from the elevation of the tape, a rotatable cam, and a cam follower on the head support in contact with the rotatable cam for causing the head support to slide along the swing arm when the cam is rotated.

Abstract: A door opening mechanism in a tape drive opens a door on a tape cartridge to expose a portion of the tape for contact with a movable read/write head. The cartridge is inserted endwise into a receptacle in the tape drive housing. The head is moved to a retracted position away from the cartridge so the head avoids interference with the cartridge being inserted into the receptacle. The door opening mechanism includes a rotating lever having outwardly projecting door sensing and cartridge door opening fingers. The two fingers project from the lever at different elevations and angles. A pivot mounts the lever to rotate about an axis essentially normal to the plane of travel of the cartridge into the receptacle. The lever is retained in an inoperative position with the cartridge sensing finger positioned for contact with a portion of the cartridge housing as the cartridge is inserted toward an operating position in the tape drive.

Abstract: A receptacle for a tape cartridge includes cartridge guide rails for engaging opposite sides of the cartridge housing to guide insertion and removal of the cartridge. The cartridge includes a magnetic tape and a door on the cartridge housing for opening to expose a portion of the tape prior to moving the cartridge into a locked position for engaging the tape with the head. The door is normally spring-biased to a closed position, and one of the guide rails has a door control rail that trips the door open against the bias of the return spring as the cartridge passes along the guide rail. The control rail also includes a ramped recessed portion which engages the door tripping arm and reduces the force applied against the bias of the return spring to permit the door to move inwardly through an angle to a partially open position during the latter portion of its travel into the receptacle.

Abstract: An improved tape cartridge includes a housing having a rigid base member and means for covering the base member. The base member is a one-piece structure having a bottom of flat-cross-section and a plurality of holes extending through the bottom. The base member includes three side walls with two side walls being opposed and the side walls extending upwardly generally perpendicular to the bottom. Preferably, the base member is die casted and made from aluminum alloy. The housing includes a resilient cover, preferably made from plastic which does not distort the base member's flatness upon assembly. The cover has a front wall which extends downward generally perpendicular to a top portion of the cover and the front wall has an open face. Means for connecting the cover and base member are included.

Abstract: A tape transport includes a fixed support for receiving a tape cartridge having a tape drive roller engaged with a bi-directional capstan. The capstan, together with a reversible capstan drive motor and a heat sink surrounding the motor, comprise an integral unit which is mounted to the cartridge support through biasing springs which enable the unit to pivot about its center of gravity relative to the support. The capstan, through its c.g. mount, applies a constant force to the tape drive roller indpendently of external forces acting on the tape drive unit. The electrical drive circuit for the capstan motor includes power transistors which are an integral part of the heat sink for maximizing use of the heat sink as a means for dissipating heat generated by operation of the capstan drive motor and power transistors.