| 摘要 |
<p>A flexible drive cable body (10) includes a flexible, counter-wound coil (12) including an outer coil (14) and an inner coil (16). A support tube (18) is received within a central lumen (20) of the counter-wound coil (12), and a pair of twisted electrically insulated wires (22) are, in turn, received within a lumen of the support tube (18). The support tube (18) is usually liquid impermeable to maintain an air gap around the wire pair (22). The air gap improves shielding and maintains a constant overall impedance across the drive cable. The drive cable may be combined with an ultrasonic transducer at its distal end to form an ultrasonic transmission core.</p> |
