Abstract: An RF step attenuator topology is optimized for use with GaAsFET switching devices, exploiting their high isolation while minimizing the effects of their relatively high insertion loss. The attenuator includes an attenuation network that has two inputs and two outputs, permitting four different attenuation levels to be selected by use of just one input switch and one output switch. The detailed embodiments feature high levels of attenuation (up to 140 dB in 10 dB steps), a minimum number of switches in the through-path (four), very wide band operation (250 KHz-2 GHz), and economical design.

Abstract: A coaxial reverse power protection relay using a conductive elastomeric tube and a conductive body. The relay includes a reed switch enclosed within the central channel of the conductive body. The tube concentrically surrounds the reed switch within the channel. The tube retains the reed switch in place and serves as a conformal ground. A magnetic coil is wound around a portion of the body. When energized the coil produces a magnetic field which closes the reed switch. When de-energized, the coil's magnetic field ceases, opening the reed switch. The reed switch, along with center contacts form a center conductor within the channel of the relay body. The body and elastomeric tube form an outer conductor. The relay is impedance matched to RF connector and instrument transmission line impedances. A nonuniform impedance occurring along the length of the reed switch is balanced by the conforming tube walls. The internal wall of the conductive body has a retention thread in the vicinity of the reed switch.

Abstract: The connection and shielding system for modular RF circuits encases modular circuitboards (10) within five-sided enclosures (11). The sixth side of each enclosure is provided by the top ground plane of a base circuitboard (20) that supports and electrically interconnects the components of the modular circuitboards (10). Enclosures (11) are fixed to a grounded metal socket formed by fence strips (22) and metal inserts (23) which form upwardly open slots including yieldable longitudinal gaskets (50). Gaskets (50) yieldably grip the open end of enclosures (11) and seal them against escaping radiation. Further radiation shielding is provided about the base circuitboard (20) by the fact that the conductive signal traces provided in it are sandwiched between two continuous ground planes and run between plated-through vias joining the ground planes. The ends of each enclosure are provided with double wall baffles (17, 18) which provide airflow to the interior and RFI shielding through offset open apertures (13).

Abstract: The connection and shielding system for modular RF circuits encases modular circuitboards (10) with five-sided enclosures (11). The sixth side of each enclosure is provided by the top ground plane of a base circuitboard (20) that supports and electrically interconnects the components of the modular circuitboards (10). Enclosures (11) are fixed to a grounded metal socket formed by fence strips (22) and metal inserts (23) which form upwardly open slots including yieldable longitudinal gaskets (50). Gaskets (50) yieldably grip the open end of enclosures (11) and seal them against escaping radiation. Further radiation shielding is provided about the base circuitboard (20) by the fact that the conductive signal traces provided in it are sandwiched between two continuous ground planes and run between plated-through vias joining the ground planes. The ends of each enclosure are provided with double wall baffles (17, 18) which provide airflow to the interior and RFI shielding through offset open apertures (13).

Abstract: The connection and shielding system for modular RF circuits encases modular circuitboards (10) within five-sided enclosures (11). The sixth side of each enclosure is provided by the top ground plane of a base circuitboard (20) that supports and electrically interconnects the components of the modular circuitboards (10). Enclosures (11) are fixed to a grounded metal socket formed by fence strips (22) and metal inserts (23) which form upwardly open slots including yieldable longitudinal gaskets (50). Gaskets (50) yieldably grip the open end of enclosures (11) and seal them against escaping radiation. Further radiation shielding is provided about the base circuitboard (20) by the fact that the conductive signal traces provided in it are sandwiched between two continuous ground planes and run between plated-through vias joining the ground planes. The ends of each enclosure are provided with double wall baffles (17, 18) which provide airflow to the interior and RFI shielding through offset open apertures (13).

Abstract: A cursor controller has a handle having first and second perpendicular slots disposed in different parallel planes. A first cross-slide is slidably mounted in the first slot and guides the motion of the handle along an x axis. A second cross-slide is slidably mounted in the second slot and guides the motion of the handle along a y axis. A first encoder strip mounted to the first cross-slide is provided together with a quadrature detector for sensing the direction and magnitude of movement of the handle along the y axis. A second encoder strip mounted to the second cross-slide is provided together with a quadrature detector for sensing the direction and magnitude of movement of the handle along the x axis. Signals from the quadrature detectors are processed and coupled to a computer to provide cursor control on the computer's display screen.