摘要:
A digital architecture for a pulse generator includes a triggerable voltage controlled oscillator (VCO) with two alternative sources of frequency control voltage, an internal DAC or a phase frequency comparison with an external timebase. In a top octave of operation, the output of the triggerable VCO is used to produce output pulses whose edge locations are then adjusted by small digital increments or "slivers" and very small analog increments or "verniers". In lower octaves of operation, the contents of a pattern RAM serve to frequency divide the triggerable VCO output frequency by powers of two. The RAM contents are converted to a serial bit stream that imposes the coarse pulse width and period as an integral number of top octave periods, or quanta. The edge locations are then adjusted with slivers and verniers, as in the top octave. Automatic calibration facilities are included. This architecture provides controllable tolerances, permits accurate positioning of a trigger out signal relative to any pulse produced, allows the user to specify the trailing edge timing directly, and permits both pulse width and phase to be specified as a percentage of the overall period and automatically kept proportional when the frequency is varied. It also allows synchronized operation of different channels at rates related by powers-of-two, and permits the disabling of a channel at an operator determined voltage level. A means for determining, by the use of an external signal, when bursts of pulses synchronized to an external frequency source will begin, is also provided.
摘要:
A digital architecture for a pulse generator provides a method of synchronizing signals of the pulse generator. The pulse generator has a timebase card, a microprocessor and a plurality of pulse cards. The microprocessor controls the parameters of the timebase card and pulse cards, and the timebase card provides a common master clock signal to all of the pulse cards determined by a triggerable voltage controlled oscillator that has two sources of frequency control voltage, an internal DAC for absolute frequency and a frequency comparison circuit for synchronization with an external timebase. The pulse cards produce pulses, either singly or in bursts, with the leading and trailing edges being separately positionable using quantum, sliver and vernier controls. A pattern RAM on each pulse card provides a pulse pattern that provides an approximation of the desired pulses to one quantum, and repeated iterations through the pattern RAM provide bursts of pulses. Pattern RAMs on different pulse cards, where one pattern is related to the other by a power of two, may be synchronized since both channels use the same master clock from the timebase card. Likewise a burst of pulses may be synchronized with the external timebase since the master clock is synchronized with the external timebase, with a frame sync input signal being used to determine the relative phase between the burst of pulses and the external timebase.
摘要:
A digital architecture for a pulse generator includes a triggerable voltage controlled oscillator (VCO) with two alternative sources of frequency control voltage, an internal DAC or a phase frequency comparison with an external timebase. In a top octave of operation, the output of the triggerable VCO is used to produce output pulses whose edge locations are then adjusted by small digital increments or "slivers" and very small analog increments or "verniers". In lower octaves of operation, the contents of a pattern RAM serve to frequency divide the triggerable VCO output frequency by powers of two. The RAM contents are converted to a serial bit stream that imposes the coarse pulse width and period as an integral number of top octave periods, or quanta. The edge locations are then adjusted with slivers and verniers, as in the top octave. Automatic calibration facilities are included. This architecture provides controllable tolerances, permits accurate positioning of a trigger out signal relative to any pulse produced, allows the user to specify the trailing edge timing directly, and permits both pulse width and phase to be specified as a percentage of the overall period and automatically kept proportional when the frequency is varied. It allows synchronized operation of different channels at rates related by powers-of-two, and permits disabling of a channel at an operator determined voltage level. A means for determining, by the use of an external signal, when bursts of pulses synchronized to an external frequency source will begin, is also provided.
摘要:
A digital architecture for a pulse generator includes a triggerable voltage controlled oscillator (VCO) with two alternative sources of frequency control voltage, an internal DAC or a phase frequency comparison with an external timebase. In a top octave of operation, the output of the triggerable VCO is used to produce output pulses whose edge locations are then adjusted by small digital increments or "slivers" and very small analog increments or "verniers". In lower octaves of operation, the contents of a pattern RAM serve to frequency divide the triggerable VCO output frequency by powers of two. The RAM contents are converted to a serial bit stream that imposes the coarse pulse width and period as an integral number of top octave periods, or quanta. The edge locations are then adjusted with slivers and verniers, as in the top octave. Automatic calibration facilities are included. This architecture provides controllable tolerances, permits accurate positioning of a trigger out signal relative to any pulse produced, allows the user to specify the trailing edge timing directly, and permits both pulse width and phase to be specified as a percentage of the overall period and automatically kept proportional when the frequency is varied. It also allows synchronized operation of different channels at rates related by powers-of-two, and permits the disabling of a channel at an operator determined voltage level. A means for determining, by the use of an external signal, when bursts of pulses synchronized to an external frequency source will begin, is also provided.
摘要:
A digital architecture for a pulse generator includes a triggerable voltage controlled oscillator (VCO) with two alternative sources of frequency control voltage, an internal DAC or a phase frequency comparison with an external timebase. In a top octave of operation, the output of the triggerable VCO is used to produce output pulses whose edge locations are then adjusted by small digital increments or "slivers" and very small analog increments or "verniers". In lower octaves of operation, the contents of a pattern RAM serve to frequency divide the triggerable VCO output frequency by powers of two. The RAM contents are converted to a serial bit stream that imposes the coarse pulse width and period as an integral number of top octave periods, or quanta. The edge locations are then adjusted with slivers and verniers, as in the top octave. Automatic calibration facilities are included. This architecture provides controllable tolerances, permits accurate positioning of a trigger out signal relative to any pulse produced, allows the user to specify the trailing edge timing directly, and permits both pulse width and phase to be specified as a percentage of the overall period and automatically kept proportional when the frequency is varied. It allows synchronized operation of different channels at rates related by powers-of-two, and permits disabling of a channel at an operator determined voltage level. A means for determining, by the use of an external signal, when bursts of pulses synchronized to an external frequency source will begin, is also provided.
摘要:
The write disturb that occurs in polymer memories may be reduced by writing back data after a read in a fashion which offsets any effect on the polarity of bits in bit lines associated with the addressed bit. For example, each time the data is written back, its polarity may be alternately changed. In another embodiment, the polarity may be randomly changed.
摘要:
A method for dynamically balancing a serial data link is disclosed. The serial data link includes a first transmission line and a second transmission line. The method includes the steps of creating a DC offset voltage between the first and second transmission lines when the serial data link is in an idle state. When the serial data link is in use to carry data, the DC offset voltage between the first and second transmission lines is removed.
摘要:
The effects of a self-erase phenomenon when accessing imprinted ferroelectric memory cells that have non-conductive electrode interfaces that reduce remnant polarization and decrease signal margin are eliminated. A self-erase control pulse asserted after an access pulse is utilized. The self-erase control pulse has a magnitude sufficient to offset a remnant charge on the non-conductive electrode interfaces after the removal of the access pulse.
摘要:
A concurrent asynchronous USB 2.0 data stream destuffer and separator with variable-width bit-wise memory controller is described. A parallel stream bit destuffer module identifies in parallel one or more stuffed bits in a decoded data field of a received data stream using a six-bit sliding window. The stuffed bits are bits that were inserted into the received USB data stream by a transmitter to force data transitions in the received USB data stream. A data separator module separates the one or more stuffed bits from a plurality of valid data bits in the decoded data field. A memory module generates an incremental pointer value representative of the number of valid bits and writes the plurality of valid data bits from the decoded data field into a variable sized bit-wise memory structure.
摘要:
A device having a functionalized electrode having a probe molecule, wherein the device has an ability to electrically detect a molecular binding event between the probe molecule and a target molecule by a polarization change of the functionalized electrode is disclosed. The device could also include an unfunctionalized electrode that does not have the probe molecule and the device could have an ability to electrically detect the molecular binding event between the probe molecule and the target molecule by a polarization change between the functionalized electrode and the unfuctionalized electrode.