Abstract:
Provided are a rate 13/15 MTR code encoding/decoding method and apparatus. The encoding method includes: generating a predetermined rate-13/15 MTR code in which 13-bit data corresponds to 15-bit data; outputting input 13-bit data as a 15-bit codeword according to the rate-13/15 MTR code; checking whether codewords satisfy a predetermined constraint condition by connecting the 15-bit codeword and a subsequent 15-bit codeword; and converting specific bits of the codewords if the codewords violate the constraint condition and not converting the codewords if the codewords do not violate the constraint condition. The rate-13/15 MTR (j=2, k=8) code includes: 8192 codewords obtained to prevent the number of consecutive transitions from becoming 3 at code boundaries in a modulation coding process. Data can be reliably reproduced with high write density, and a large amount of data can be stored in and reproduced from a magnetic recording information storage medium.
Abstract:
A signal delay control circuit for use in a semiconductor memory device is disclosed. The circuit includes a first reference voltage generating unit for generating a first reference voltage; a second reference voltage generating unit for generating a second reference voltage that is lower than the first reference voltage; a control signal generating unit for generating a clock signal to drive input and output operations of internal circuits; and an impedance circuit in circuit with the first and second reference voltage generating units for generating a plurality of reference voltages to be applied to the internal circuits wherein the reference voltages are set in accordance with a distance between the control signal generating unit and the respective one of the internal circuits.
Abstract:
A voltage generator for a semiconductor memory device that improves the drivability of an output driver by controlling a gate of the output driver to vary between an internal power supply voltage and a ground voltage, is disclosed. The voltage generator includes an output voltage controller to generate a pull-up signal for controlling a pull-up operation and a pull-down signal for controlling a pull-down operation, the pull-up signal having a level substantially equivalent to an internal power supply voltage if a cell plate voltage is higher than a cell plate reference voltage, and having a level below the cell plate voltage if the cell plate voltage is lower than the cell plate reference voltage. The voltage generator further includes an output driver to generate a stable cell plate voltage in response to the pull-up signal and the pull-down signal.
Abstract:
The present invention relates to a gain controlled amplifier, and more particularly, to a gain controlled amplifier using active feedback and variable resistance. It is an object of the present invention to provide a gain controlled amplifier minimizing the gain and the degradation of power characteristics generated when adjusting gain in a variable gain amplifier which receives signals having different power levels, amplifies them in accordance with each power level and outputs output signals in a constant power level. In order to achieve the above object, a gain controlled amplifier in accordance with the present invention comprises an amplifier and an active feedback means for negative feedbacking the output of the amplifier to the input of the amplifier, and further has a feedback amount controller inputting the controlled feedback signal to the amplifier by controlling the feedback amount of said active feedback means.
Abstract:
A gate voltage control circuit of a power amplifier for reducing the power dissipation by improving the efficiency at an average output power and for enhancing the linearity of the power amplifier at a maximum output power, the gate voltage control circuit comprising an input terminal for receiving an output power signal from a power amplifier; an output power detecting circuit for detecting the output power signal and for converting the detected output power signal to a DC voltage signal; a voltage dividing circuit comprising at least two resistors for dividing a voltage difference between the DC voltage signal and a negative voltage in a ratio of resistances of the resistors; and an output terminal for supplying the divided voltage as a gate voltage control signal.
Abstract:
There is disclosed a bidirectional data input/output circuit of a synchronous memory device and the method for controlling the same according to the present invention. The synchronous memory device according to the present invention is aimed at solving a data confusion problem generated when a write operation subsequent to a data read operation is performed in a data input/output line. Though the data line is a bidirectional bus data line by which an input/output is also performed, it can be applied to a circuit construction in which high and low potential data are inputted/outputted through an independent dedicated line. In addition, there is provided an internal buffer for inputting a write data into the memory device. The circuit according to the present invention further includes a memory for storing a data signal generated upon a read operation, when a read operation subsequent in time to a write operation is performed; and a device for selecting as a write data the opposite signal of the data signal generated upon a read operation when the two data lines both become active.
Abstract:
A method for correcting a high frequency measurement error which can exactly correct the high frequency measurement error even with the use of a standard devices of which characteristic have not been verified by calculating the characteristic impedance of the correction device from the characteristics of an auxiliary measuring device calculated by using a general error correction method, and calculating again the once calculated characteristics of the auxiliary measuring device. The method in accordance with the present invention comprises the steps of modelling an auxiliary measuring device used for measuring a high frequency charateristics of the device under test by two transmission lines connected in series between two terminals and a parasitic component connected in parallel between a junction of the two transmission lines and a ground; and moving a reference measurement point to the junction of the two transmission lines by using a phase angle of each transmission line and calculating a reference impedance at the terminal of the auxiliary measuring device to which an object to be measured is connected by using the difference of the resultant reflection coefficients of each port.
Abstract:
A semiconductor memory device comprising a memory cell array for storing input data therein, a data output buffer for outputting the data stored in the memory cell array externally, an output terminal for transferring the output data from the data output buffer externally, a data input buffer for transferring the output data from the data output buffer to the memory cell array, a data register for temporarily storing the transferred data from the data input buffer, and a multiplexer connected among the memory cell array, the data register and the data output buffer, for selecting one of the data stored in the memory cell array and the data stored in the data register and transferring the selected data to the data output buffer. In the normal case, the multiplexer selects the data stored in the memory cell array and transfers the selected data to the data output buffer. In a specific case where the input data to the memory cell array have the same values or a regularity, the multiplexer selects the data stored in the data register and transfers the selected data to the data output buffer.
Abstract:
A signal input unit for a semiconductor memory device comprising a signal input terminal, an electrostatic discharge protection circuit for discharging an electrostatic signal of high level from the input terminal to a ground voltage source, a signal transfer circuit connected in parallel to the electrostatic discharge protection circuit, for switching a normal input signal from the input terminal, a signal transfer control circuit for controlling a switching operation of the signal transfer circuit, and a signal input circuit for buffering an output signal from the electrostatic discharge protection circuit or the signal transfer circuit and transferring the buffered signal to an internal circuit of the semiconductor memory device. The electrostatic discharge protection circuit sufficiently discharges the external electrostatic signal to the ground voltage source in a standby mode of the semiconductor memory device. The signal transfer circuit is connected in parallel to the electrostatic discharge protection circuit so that the normal input signal can be transferred directly to the signal input circuit in an operation mode of the semiconductor memory device with no delay by the electrostatic discharge protection circuit. Therefore, a signal delay can be prevented.
Abstract:
Disclosed herein is a direct current (DC) uninterruptible power supply system. The DC uninterruptible power supply system is connected to a DC power conversion system converting prevailing alternating current (AC) power into DC power, supplies the DC power to a load, charges an internal auxiliary power supply device with the DC power, and continuously supplies power to the load from the auxiliary power supply device while cutting off an electric connection with the DC power conversion system when the DC power conversion system short-circuits due to a leakage current or damage thereof or is disconnected.