Abstract: The present invention provides a memory control device and a semiconductor processing apparatus which can be flexibly made adapted to a plurality of kinds of semiconductor memories. An SDRAM controller has: a register unit to which a command to be issued and a minimum interval (wait time) between issue of the command and issue of the next command are written by a CPU; and a command issuing unit that stops issue of the next command until the minimum interval written in the register elapses since issue of the command written in the register. Therefore, by changing software for the CPU, the SDRAM controller can be flexibly adapted to a plurality of kinds of SDRAMs.
Abstract: The present invention provides a memory control device and a semiconductor processing apparatus which can be flexibly made adapted to a plurality of kinds of semiconductor memories. An SDRAM controller has: a register unit to which a command to be issued and a minimum interval (wait time) between issue of the command and issue of the next command are written by a CPU; and a command issuing unit that stops issue of the next command until the minimum interval written in the register elapses since issue of the command written in the register. Therefore, by changing software for the CPU, the SDRAM controller can be flexibly adapted to a plurality of kinds of SDRAMs.
Abstract: The present invention relates to a direct digital frequency synthesizer using a variable sine wave-weighted digital to analog converter with improved size and efficiency and a synthesizing method thereof. The direct digital frequency synthesizer and the synthesizing method thereof are capable of simplifying a configuration for matching output data of a phase accumulator to sine wave amplitude without increase in complexity of a DAC by applying a nonlinear DAC for directly generating a current corresponding to base points with sine weights and a variable sine wave-weighted DAC for generating fine currents to be combined with variable weights based on the base points. Accordingly, it is possible to provide a high quality output, reduce a size and power consumption, and increase a speed.
Type:
Grant
Filed:
December 27, 2009
Date of Patent:
April 19, 2011
Assignees:
Chung-Ang University Industry—Academy Cooperation Foundation, ZARAMTECHNOLOGY Co. Ltd.
Abstract: A novel and useful apparatus for and method of local oscillator (LO) generation with non-integer multiplication ratio between the local oscillator and RF frequencies. The LO generation schemes presented are operative to generate I and Q square waves at a designated frequency while avoiding the well known issue of harmonic pulling. An input baseband signal is interpolated and upconverted in the digital domain to an IF. The LO operates at a frequency which is a n/m division of the target RF frequency fRF. The IF frequency is configured to ½ of the LO frequency. The upconverted IF signal is then converted to the analog domain via digital power amplifiers followed by voltage combiners. The output of the combiners is band pass filtered to extract the desired replica.
Abstract: A novel and useful apparatus for and method of local oscillator (LO) generation with non-integer multiplication ratio between the local oscillator and RF frequencies. The LO generation schemes presented are operative to generate I and Q square waves at a designated frequency while avoiding the well known issue of harmonic pulling. The signal is input to a synthesizer timed to a rational multiplier of the RF frequency fRF. The signal is then divided to generate a plurality of phases of the divided signal. A plurality of combination signals are generated which are then multiplied by a set of weights and summed to cancel out some undersired products. The result is filtered to generate the LO output signal.
Abstract: A novel and useful apparatus for and method of local oscillator (LO) generation with non-integer multiplication ratio between the local oscillator and RF frequencies. The LO generation schemes presented are operative to generate I and Q square waves at a designated frequency while avoiding the well known issue of harmonic pulling. The use of analog mixers of the prior art is avoided and replaced with an XOR gate configured to generate the correct average frequency. The edges are dynamically adjusted by ±T/12 or zero based on the state of the controlled oscillator down-divided clock.
Abstract: An inband signaling modem communicates digital data over a voice channel of a wireless telecommunications network. An input receives digital data. An encoder converts the digital data into audio tones that synthesize frequency characteristics of human speech. The digital data is also encoded to prevent voice encoding circuitry in the telecommunications network from corrupting the synthesized audio tones representing the digital data. An output then outputs the synthesized audio tones to a voice channel of a digital wireless telecommunications network.
Type:
Grant
Filed:
March 6, 2002
Date of Patent:
May 22, 2007
Assignee:
Airbiquity, Inc.
Inventors:
Dan A. Preston, Joseph Preston, Robert Leyendecker, Wayne Eatherly, Rod L. Proctor
Abstract: A novel and improved method and apparatus for a fast-slewing pseudorandom noise sequence generator is described. One or more loadable PN generators are controlled by a DSP or microprocessor in conjunction with a free-running counter which maintains a reference offset count. The PN generator will typically be part of a finger or searcher. The DSP or microprocessor may assist in other finger or searcher functions as well as the slew function, and can control one or more fingers and/or searchers. Each PN generator is comprised of a loadable linear feedback shift register (LFSR) or its equivalent, a loadable counter for maintaining an index of the state of that particular PN generator, and a slew control device capable of receiving a slew command and controlling the LFSR and index counter to enact an advance or a retard of a certain offset distance.
Type:
Grant
Filed:
November 23, 1998
Date of Patent:
November 28, 2000
Assignee:
Qualcomm Incorporated
Inventors:
Qiuzhen Zou, Gilbert C. Sih, Avneesh Agrawal