Abstract: A feedforward amplifier (150) according to the present invention uses a direct coupling of an amplifier stage (158) with the amplifier's load (RL). The main amplifier (202) is coupled through a transmission line (210) to the load. This direct coupled amplifier stage (158) is driven by a signal that induces a very low impedance in parallel with the load to the error signal, but appears as an open circuit to the desired signal so that the desired signal from the main amplifier is substantially unaffected.

Abstract: A feedforward amplifier and notch filter (150) according to the present invention uses a direct coupling of an amplifier stage (158) with the amplifier's load (RL). The main amplifier (202) is coupled through a transmission line (210) to the load. This direct coupled amplifier stage (158) is driven by an signal that induces a very low impedance in parallel with the load at the receive frequency, but appears as an open circuit at the desired frequencies so that the desired signal from the main amplifier is virtually unaffected while output components at the receive frequency are cancelled.

Abstract: An evacuation sheath assembly and method of treating occluded vessels which reduces the risk of distal embolization during vascular interventions is provided. The evacuation sheath assembly includes an elongated tube defining an evacuation lumen having proximal and distal ends. A proximal sealing surface is provided on a proximal portion of the tube and is configured to form a seal with a lumen of a guided catheter. A distal sealing surface is provided on a distal portion of the tube and is configured to form a seal with a blood vessel. Obturator assemblies and infusion catheter assemblies are provided to be used with the evacuation sheath assembly. A method of treatment of a blood vessel using the evacuation sheath assembly includes advancing the evacuation sheath assembly into the blood vessel through a guide catheter. Normal antegrade blood flow in the blood vessel proximate to the stenosis is stopped and the stenosis is treated.

Abstract: A medical device comprising a support member adjacent to a first member and a second member, the first and second members may be laser welded to one another by directing radiation absorbable by the first and second members at the first and second members. The support member is provided adjacent to the first member and is constructed and arranged to substantially reflect or substantially transmit radiation at one or more frequencies absorbable by at least one of the first member and the second member.

Abstract: The present invention provides a balloon catheter with a length compensator, which can be an accordion section or a slipping sleeve section. In the accordion section embodiment of the invention, the outer shaft of the catheter includes an accordion section positioned proximally of the balloon. In this embodiment the length compensator is comprised of the accordion section and the outer shaft between the accordion section and the point where the proximal end of the balloon is attached to the outer shaft. The distal end of the balloon is attached to an inner shaft. As the balloon is inflated the accordion section expands to adjust the axial length of the length compensator to compensate for the movement of the two ends of the balloon towards each other. In the slipping sleeve embodiment of the invention, the inner shaft of the catheter includes a slipping sleeve section positioned proximally of the point where the distal end of the balloon is connected to the inner shaft.

Abstract: A compensated signal source (210, 220) utilizes baseband signals and a radio frequency carrier signal to generate a set of source output signals (226, 227) which are coupled to a particular circuit (230, 240, 250). The signal source (210, 220) is operable in a characterizing mode in which a test configuration is applied, and outputs from the signal source and the particular circuit measured to develop parameters representing imperfections within the signal source and within the particular circuit. The signal source (210, 220) is operable in a normal mode, in which compensation based on the measured parameters is applied to account for the imperfections. In a preferred embodiment, the particular circuit (230, 240, 250) and compensated signal source (210, 220) form part of an amplifier (200) that implements linear amplification using nonlinear components (LINC) techniques.

Abstract: An apparatus (100) uses power recovery from a combining circuit (125) to improve efficiency. A power combiner (125) generates multiple output signals (127, 133) from a combination of input signals (113, 114). One of the output signals from the power combiner is coupled to a power recovery circuit (135), and energy is recovered and preferably stored for later use.

Abstract: An amplifier (100) has first and second operation modes. The amplifier (100) includes an amplifier input portion (110) and an amplification gain stage. The amplification stage has two gain paths (120, 140) coupled in parallel to the amplifier input portion (110). At least one of the gain paths (120) has an amplification component (121) that in part forms a switch to select between the first and second operation modes.

Abstract: The present invention provides an improved stent delivery catheter. The stent delivery system comprises a catheter having a stent receiving portion adapted to receive a stent near the distal end of the catheter and a stent concentrically arranged around the catheter within the stent receiving portion. The stent delivery system further comprises a proximal outer sheath, a retractable distal sheath surrounding at least a portion of the stent and containing the stent in its reduced delivery configuration and a pull back means connected to the retractable distal sheath. The system further comprises a collapsible sheath concentrically arranged around the catheter and located between the retractable distal sheath and the proximal outer sheath, whereby when the pull back means is pulled proximally the distal sheath is retracted, causing the collapsible sheath to collapse and freeing the stent for delivery.