A TANK filter is provided for a lead wire of an active medical device (AMD). The TANK filter includes a capacitor in parallel with an inductor. The parallel capacitor and inductor are placed in series with the lead wire of the AMD, wherein values of capacitance and inductance are selected such that the TANK filter is resonant at a selected frequency. The Q of the inductor may be relatively maximized and the Q of the capacitor may be relatively minimized to reduce the overall Q of the TANK filter to attenuate current flow through the lead wire along a range of selected frequencies. In a preferred form, the TANK filter is integrated into a TIP and/or RING electrode for an active implantable medical device.

Tank filters placed in series with the lead wires or circuits of active medical devices to enhance mri compatibility

One or more inductors and one or more capacitors are physically disposed relative to one another in series and are electrically connected to one another in parallel to form a bandstop filter. Chip inductors and chip capacitors having spaced apart conductive terminals are physically arranged in end-to-end abutting relation to minimize electrical potential between adjacent conductive terminals. The bandstop filter may be hermetically sealed within a biocompatible container for use with an implantable lead or electrode of a medical device. The values of the inductors and the capacitors are selected such that the bandstop filter is resonant at one or more selected frequencies, such as an MRI pulsed frequency.

Capacitor and inductor elements physically disposed in series whose lumped parameters are electrically connected in parallel to form a bandstop filter

The present invention provides compensation for temperature in a transducer by connecting the adjustment resistors to the transducer itself to provide a correct transducer output. A number of switches are used to couple the adjustment resistors to the transducer circuit. An individual resistor may be coupled in parallel or in series with a transducer resistance. The control input for the switches are each coupled to a separate bit output of a multiple bit memory. The memory is programmed to control the duty cycle of the switches when addressed.

Programmable compensation of bridge circuit thermal response

A desired programmable complex analog bandpass filter (10) is replaced by a 'black box' that receives an analog continuous-time signal and delivers an analog continuous-time signal, just as the analog filter would, but internally realizes the programmability with a programmable discrete-time system. The transfer function of the 'black box' is the same as the transfer function of the analog filter. The 'black box' includes an anti-aliasing filter (12), an A/D-converter (14), a complex digital bandpass filter (16), a D/A-converter (18) and an anti-imaging filter (20).

Programmable analog bandpass filtering apparatus and method and design method for a discrete time filter

Apparatus for equalizing a soundfield comprises an amplifier and a gain control circuit for selectively adjusting the gain of the amplifier as a function of frequency in response to data values received by the gain control circuit. The apparatus has power supply terminals for supplying operating current from an external power source to the amplifier and the gain control circuit. In addition, the apparatus comprises an electronic storage device for storing data values and applying those data values to the gain control circuit. The stored data values are maintained in the apparatus upon interruption of the supply of operating current to the power supply terminals. The apparatus has an input port for applying data values to the storage device, and does not have manually actuable controls for selectively adjusting the stored data values.

Apparatus and method for equalizing a soundfield

A narrow-band RC active bandpass filter, in which the center frequency may be changed by changing the resistance values of certain resistive elements, has the certain resistive elements switchably connectable into and out of the RC network so that the ratio of time during which the resistors are connected to the network to the time during which resistors are not connected to the network determines the effective resistance thereof. A programmable timing circuit has a plurality of outputs with each output supplying a different number of equal width pulses during a predetermined like time period whereby each output corresponds to a different ratio. The timing circuit actuates and deactuates the switchable connection from a selected output thus deriving the required effective resistance for a predetermined center frequency. The bandwidth of the passband is set by a different resistive element and remains substantially unchanged as the center frequency is changed by changing the effective resistance of the certain resistive elements.

Gideon Willoner

Papers

Digitally programmable active RC bandpass filter with constant absolute bandwidth