Abstract: Preamplifying circuitry amplifies sound signals for input into a computer system. A first stage common-emitter amplifier provides high-gain amplification of the input signal, while a second stage amplifier comprising an operational amplifier is suitable for driving a cable with the amplified sound signal. A low-cost constant voltage source comprising a diode and an operational amplifier supplies a voltage reference to both amplifier stages with a very high rejection of system noise. The circuitry and methods of the present invention provide a low-cost, easily manufactured preamplifier suitable for sound input in desktop computing devices.

Abstract: A method of conveniently making a selection from a set of options available in a computer program is described. As successive letters which make up the proposed selection are entered, successively smaller lists of options corresponding to the entered letters are displayed. At any point, the user makes a selection by moving a cursor to a desired selection and pressing a button or key to indicate that the selection has been made.

Abstract: Apparatus and methods for reducing the quantization error in shift-matrix finite impulse response (FIR) filters (210) operate on a sampled analog signal (11) converted to a sequence of digital signal samples (13). A weight conversion device (23) converts a weight signal W comprising a sequence of tap weights W.sub.i into both a corresponding series of logarithmically-encoded weights W'.sub.i and a series of weight error values .DELTA.W.sub.i. A multiplication device (30) multiplies each of the digital signal samples (13) with the first series of logarithmically-encoded weights W'.sub.i and provides the results to an accumulator (26). A signal encoding device (40) converts the digital signal samples (13) into a sequence of logarithmically-encoded digital signal samples (42). A quantization error correction device (220) multiplies each of the weight error values .DELTA.W.sub.i by the logarithmically-encoded digital signal samples (42) and also provides the results simultaneously to the accumulator (26).

Abstract: An ion processing unit (10) comprising a series of M perforated electrode sheets (12), driving electronics (14,16) and a central processing unit (18), allow formation, shaping and translation of multiple effective potential wells (42). Ions, trapped within a given effective potential well (42), can be isolated, transferred, cooled or heated, separated, and combined. Measurement of induced image currents allows measurement and typing of ion species by their respective mass-to-charge ratios. The combination of many electrode sheets (12), each having N multiple perforations (22), creates any number of parallel ion processing channels (26). The ion processing unit (10) provides an N by M massively parallel ion processing system, furnishing means for processing large numbers of ions in parallel in the same manner, but with different ion processes deployed at different sections of each ion processing channel (26).

Abstract: Methods and apparatus for sealing perforations in windows, curtain wall and other building fixtures are disclosed. The present invention enables the construction of building exteriors impervious to water leakage through holes in sills and other building exterior components. a molded plastic cap [10] is secured around each exterior hole [20] and fastener [16,18] with an adhesive [22]. The cap prevents water from leaking through the exterior hole into the building interior while allowing sills and exterior sections to move in response to thermal, seismic and other mecahnical changes. By not coming into contact with the fastener [16,18] and hole [20], the seal [10] avoids any possible contamination and chemical degradation from the fastener materials.