Abstract: In a system having an DSP, an ASIC and a memory, in which the ASIC generates a number of different competing interrupts for the DSP to service, the ASIC has an interrupt request control module which automatically provides the DSP with a vector pointing to the memory location of the interrupt service routine for the currently pending interrupt request having the highest priority of all pending requests. The DSP reads this vector and uses it to access the interrupt service routine in the memory. Reading of this vector causes the interrupt request to be de-asserted, which causes the next highest priority pending interrupt request to become the highest priority pending interrupt request. As a result, a new vector is presented for the next read by the DSP.

Abstract: A simplified algorithm for digital signal interpolation and a novel architecture to implement the algorithm in an integrated circuit (“IC”) with significant space constraints are presented. According to embodiments of the present invention, the interpolator is divided into two parts. The first part of the interpolator increases the sample rate by a factor of two and smoothes the signal using a half-band Infinite Impulse Response (“IIR”) filter. The second part of the interpolator increases the sample rate of the signal by a factor of thirty-two using a zero-order-hold (“ZOH”) circuit. In one embodiment, the half-band IIR filter is implemented using an all-pass lattice structure to minimize quantization effects. The lattice coefficients are chosen such that the structure can achieve all filter design requirements, yet is capable of being implemented with a small number of shifters and adders, and no multipliers.

Abstract: An apparatus and method for facilitating interaction during a communication session between an analog modem and a terminal adapter for conveying digital alert tones and control data therebetween is provided. The embodiments provide for a collateral digital communication path between a microcontroller of an analog modem and a microcontroller of a terminal adapter for selectively relaying digital alert tones and control data therebetween. One embodiment utilizes a cellular interface of an analog modem for tapping and evaluating information for the presence of control data. Upon successful identification of control data, the microcontroller of a terminal adapter is notified and the specific control data detected in identified. By providing a method of apparatus for digitally relaying control data, accuracy of identification of control data by a terminal adapter is enhanced by foregoing needless signal transformation and retransformation.

Abstract: A complex of a chelating agent is formed and labelled with technetium-99m. The chelating agent is either an ethylenediamine carboxylic acid or its salt having a phenolic group at each end of the molecule such as EDDHA and HBED or alternatively the phenolic amino carboxylic acid or its salt having a single phenolate group such as HBG or HBS. The complex is a stannous complex which when labelled with technetium-99m has a good balance of lipo-solubility and waater-solubility to permit hepato-biliary imaging. The radiopharmaceutical may be useful for assessing hepatobiliary function in animals including human beings. A particularly useful chelating agent is ethylene-bis-(.alpha.-imino-2-hydroxy-5-bromophenyl acetic acid).