Abstract: A sampling capacitor interface circuit for storing charge on a sampling capacitor related to a sample of an input signal voltage during a charging phase and to transfer the stored charge to an output during a charge transfer phase, such input signal having bipolar voltages within a range above and below an input signal common mode voltage. The interface circuit includes a transistor having: an input electrode fed by the input signal; an output electrode coupled to the sampling capacitor; and, a control electrode. A controller is provided for producing a control signal having a first voltage during the charging phase and a second voltage during the charge transfer phase, such voltages being a unipolar voltage referenced to the input signal common mode voltage.

Abstract: An apparatus and a method for multiplying two time varying signals to produce a four quadrant, multiplied signal is provided. In one embodiment of the present invention, an apparatus for multiplying a first signal with a second signal includes an analog-to-digital converter that provides a first digital signal representative of the first signal, a first modulator that provides a first modulated signal representative of the second signal, a multiplier that multiplies the first digital signal by the first modulated signal and provides a second digital signal representative of a result of a multiplication of the first signal and the second signal, and a first filter having an input to receive the second digital signal and having an output that provides the multiplied signal.

Abstract: A voltage-to-frequency converter having an analog-to-digital converter, based on analog components, for converting samples of an analog signal into corresponding digital words and a digital-to-frequency converter, based on digital components, for converting the digital words into a train of pulses having a pulse repetition frequency related to the analog signal. With such an arrangement, the digital-to-frequency converter and the analog-to-digital converter are adapted to operate at different rates. Therefore, the analog-to-digital converter may be optimized at one operating rate while the digital-to-frequency converter is adapted to operate at a higher operating rate and over a wide range of operating rates. This arrangement thereby enables a slower, analog component based, analog-to-digital converter to be used fabricated with CMOS technology along with the higher, variable operating rate, digital component based, digital-to-frequency converter.

Abstract: A method and device for converting movement of an optical mouse on a surface having any random surface pattern of relatively light and dark areas separated by edges to electrical signals representing a direction of motion relative to two non-parallel axes. A plurality of prechargeable photon sensors are disposed on the mouse in a row along each axis and facing the surface periodically. The presence of an edge is periodically sensed in at least one preselected portion of each row of sensors, defining a sensor state for each axis for each period upon the sensing of an absence of an edge. Successive sensor states are compared to determine if movement has occurred relative to each axis and a signal representative of the movement determined is produced.

Abstract: A light pipe for use in an optical mouse comprises a block of light transmitting fibers comprising a plurality of parallel light transmissive regular polygonal fiber cores each surrounded by light transmissive cladding having a lower index of refraction than the core. The ratio of the width of the core to the thickness of the cladding ranges from 4 to 24.