Abstract: A scalable FIR filter architecture that requires fewer computations, less storage registers, and is capable of parallel processing, is presented. The scalable filter architecture reduces the number of computations (e.g., multiplication) by utilizing the inherent symmetry and reduces the number of storage elements required by utilizing what is known as the transpose-form (as compared to direct-form) filter architecture. The filter architecture is scalable to accommodate different complexity levels. In accordance to the present invention, a filter can be scaled up/down by adding/subtracting a processing block to/from the existing structure. Because these processing blocks can process signals independently and simultaneously, the filter architecture in accordance to the present invention allows for parallel and distributive processing thereby meeting the required performance requirements.

Abstract: A full-duplex communication device includes a transmit channel, a receive channel, and echo cancellers connected between the transmit channel and the receive channel. A plurality of control parameters and status indicators are defined for both channels. The plurality of control parameters are accessed via a writable interface for controlling operations of the communication device. Typically the control parameters are modified, enabled, and disabled based on an implemented control method and based on signal conditions, including noise, echo, tone, and other abnormal noise conditions. A writable access port enables a user to request tweaking, modification, enabling, and disabling of multiple features and controls. A readable/writable access port enables access to multiple status parameters that are indicative of the status of the communication device and channel operating conditions.

Abstract: A processor including a large register file utilizes a dirty bit storage coupled to the register file and a dirty bit logic that controls resetting of the dirty bit storage. The dirty bit logic determines whether a register or group of registers in the register file has been written since the process was loaded or the context was last restored and, if written generates a value in the dirty bit storage that designates the written condition of the register or group of registers. When the context is next saved, the dirty bit logic saves a particular register or group of registers when the dirty bit storage indicates that a register or group of registers was written. If the register or group of registers was not written, the context is switched without saving the register or group of registers. The dirty bit storage is initialized when a process is loaded or the context changes.

Abstract: A process controller implements an overall, user-developed control strategy in a process control network that includes distributed controller and field devices, such as Fieldbus and non-Fieldbus devices. A user defines the control strategy by building a plurality of function blocks and control modules and downloading or installing user-specified portions of the control strategy into the Fieldbus devices and the non-Fieldbus devices. Thereafter, the Fieldbus devices automatically perform the downloaded portions of the overall strategy independently of other portions of the control strategy. For example in a process control system that includes distributed field devices, controllers and workstations, portions of the control strategy downloaded or installed into the field devices operate independently of and in parallel with the control operations of the controllers and the workstations, while other control operations manage the Fieldbus devices and implement other portions of the control strategy.

Abstract: A system which builds an operating system-independent environment for executing utility programs is created by establishing a virtual drive that resides on a physical disk drive within the native file system of a native operating system. A virtual drive is a set of files on a physical disk drive that is configured to emulate a physical disk drive. The virtual drive can be deleted by a computer user and similarly can be re-established by the computer user. The virtual drive is bootable and activates an operating system that makes all system resources accessible to the utility programs and also allows the computer user to use the disk space that is allocated for the virtual drive, if desired.

Abstract: A signal communication structure for communicating signals between a base and a display of an electronic device, the base and display being connected in an axially hinged connection includes an axial member formed from a flexible material and includes a communication line for signal communication with the axial member adapted to flex about the axially hinged connection between the base and the display. The axial member also includes a plurality of appendage members connected to and extending from the axial member. The appendage members include a communication line coupled to the communication line of the axial member for signal communication between the plurality of appendage members via the axial member.

Abstract: For small angles that are near critical angle, a primary incident X-ray beam has excellent depth resolution. A series of X-ray fluorescence measurements are performed at varying small angles and analyzed for depth profiling of elements within a substrate. One highly useful application of the X-ray fluorescence measurements is depth profiling of a dopant used in semiconductor manufacturing such as arsenic, phosphorus, and boron. In one example, angles are be varied from 0.01° to 0.20° and measurements made to profile arsenic distribution within a semiconductor wafer. In one embodiment, measurements are acquired using a total reflection X-ray fluorescence (TXRF) type system for both known and unknown profile distribution samples. The fluorescence measurements are denominated in counts/second terms and formed as ratios comparing the known and unknown sample results. The count ratios are compared to ratios of known to unknown samples that are acquired using a control analytical measurement technique.

Abstract: A signal processing circuit includes a main input sampling structure with an integrator operational amplifier and input lines including a switched capacitor. The input lines have switched connections to input signal lines and reference signal lines. A replica sampling structure is used in combination with the main input sampling structure to eliminate or reduce signal-dependent current that is drawn from the input signal line and the reference signal line. The replica sampler includes buffered input lines and switched capacitor of the input sampling structure but the capacitors have switched connections to the reference signal lines such that the connections have opposite polarity to the connections of the reference signal line to the input sampling structure. The replica sampler eliminates or reduces signal-dependent current from the reference signal lines. Buffering of the input lines in the replica sampler eliminates or reduces the signal-dependent current drawn from the input signal lines.

Abstract: A sound or music synthesizer includes a reverberation simulator having a substantially reduced volatile storage, random access memory, or buffer size in comparison to conventional reverberation simulators by decimating the sound signal prior to applying the sound signal to a reverberator and then interpolating the sound signal generated by the reverberator to restore the sample frequency. The substantial reduction in buffer size enables the usage of the reverberator in low-cost, reduced size and single-chip environments.

Abstract: A linear approximation to an exponential decay function exploits the characteristic of an exponential function that, at equal time intervals, the ratio of a parameter value at the beginning of the interval to the parameter value at the end of the interval remains constant. The technique for linear approximation of an exponential decay includes selection of a constant period or interval of time and selection of a constant ratio between the parameter value at the beginning of the constant period and the parameter value at the end of the constant period. In one embodiment, the selected ratio is one-half to exploit a binary arithmetic implementation. For a ratio of one-half, the exponential decay has a "half-life" in which only half the parameter value at the beginning of a period is left at the end of the selected "half-life time period".

Abstract: An electronic circuit having a circuit stage, such as a switched capacitor stage or a 1-bit digital-to-analog converter and switched capacitor filter, that is loaded with a load impedance employs current feedforward to substantially cancel effects of the load impedance. A circuit includes a circuit stage and a load impedance following and connected to the circuit stage. A current feedforward circuit is connected to the load impedance, substantially cancelling the load impedance to improve linearity of the digital-to-analog converter or switched capacitor filter.

Abstract: A variable sample rate approximation technique is used for coding and recreating musical signals in a wavetable synthesizer. Many sounds inherently include one large fast transfer of energy followed by vibrations that dampen over time so that the bandwidth requirement of a musical sound is reduced with passing time. Using the variable sample rate approximation technique, musical sounds are classified into two categories, sustaining sounds and percussive sounds. A sustaining instrument creates a noisy stimulus then sustains the sound created by the noisy stimulus. A percussive instrument is also a noisy source and generates a sound signal having high frequencies that decay rapidly while sustaining instruments sustain at all frequencies nearly equally. The sustaining and percussive instruments have substantially different waveform characteristics but present similar conditions with respect to memory reduction.

Abstract: The present invention relates to a tone signal generator. The tone signal generator includes first tone signal generation means for producing a dual-tone, multi-frequency ("DTMF") audio signal; second tone signal means for producing a plurality of non-DTMF audio signals; storage means for storing data that represents at least one channel of an output audio tone signal; and selection means for selectively loading the DTMF signal into the storage means and for selectively accumulating the non-DTMF signals into the storage means so as to generate the output tone signal.

Abstract: A test circuit (200) furnishes a low battery level signal on the basis of a comparison between a first ratio of the battery potential when the battery (206) is unloaded and a second ratio of the loaded battery potential. The battery test circuit includes a potential divider (210), a comparator (250) and a potential sampler including a storage element (240), a controller (260), a control line (266) and a switch (268). The potential divider is coupled to the battery and includes a first tap (226) and a second tap (224). The potential sampler, which includes a storage element (240), is coupled to the first tap through a switch (268) so that a first ratiometric portion of the unloaded battery voltage is stored on the storage element. The comparator has a first input that is coupled to the storage element and a second input that is coupled to the second tap.