Abstract: An electrical device such as a pressure guide wire (700) which has a resistive pressure sensor, such as a piezoresistive sensor (208), uses a precision interconnect in order to provide proper pressure measurement readings. The precision interconnect helps avoid the effects of contact and line resistance on the measurement of the pressure sensor's resistors (402 and 404). The precision interconnect uses high input impedance device's such as differential operational amplifiers (902, 904) in order to overcome the effect of any changes in the contact resistance. Further, an interface switch (1110) which is responsive to a control signal (1106) automatically determines what type of pressure guide wire (10 or 700) is attached to the interface circuit (1200).

Abstract: A digital acquisition system for use in a computerized radiation tomography system employs track and hold means associated with each channel of the radiation detector in the tomography system. Each channel of the radiation detector is connected to a voltage follower transistor and resistor. A signal from the voltage follower transistor and resistor is applied through a Butterworth filter and amplifier to a transconductance amplifier which provides a signal for application to a charge storage capacitor. The capacitor is connected to the detector channel except during each limited period of time when the charge is held for measurement and conversion to a digital form. The data acquisition system has fewer components, and the simplicity of the circuitry increases the circuit reliability.