Fujitsu Corporation

Toshiro Nakazuru

Noboru Morita

Shigeaki Okutani

Keiji Sato

A cyclic equation setting unit transforms and sets a Taylor series equation for calculating a sine function into a single cyclic equation common to terms of the Taylor series equation, the single cyclic equation having a new known number Q that is defined by multiplying a known number Q and the square of a variable X, shifting the result by a shift number S and then adding a constant K thereto. An adjustment unit adjusts and prepares the shift number S such that within a variation range of the variable X the variable X has a maximum value 1 with the constant K being not greater than 1. A cyclic equation executing unit inputs and converts angle information i to the variable X, and executing the cyclic equation in sequence from higher order term to lower order term for the number of terms of the Taylor series equation to derive a sine function of the angle information i.

Arithmetic method and function arithmetic circuit for a fast fourier transform

Input data is divided into a plurality of blocks, and the blocks are corresponded to each address of the lookup table, and a block is divided into a plurality of sections according to the change of the output data, and at this time position information to indicates the boundary of the section, and output data in each section are stored in an address corresponding to each block, so that the memory capacity required for the lookup table can be decreased.

Lookup table and data acquisition method

A Fourier transform apparatus whose pipeline width is independent of transform point number of individual pipeline FFT circuits in each stage and composed of a preceding stage and a succeeding stage. Each of the stages includes M(power of 2)-point radix 2 pipeline FFT circuits each having two-parallel inputs/outputs in a number of a (divisor of M) which are equal in respect to the transform point number and data permutating means for data supply to the transform means of each stage so that the pipeline width of the Fourier transform apparatus is made independent of the transform point numbers of the individual pipeline FFT circuits in each stage.

Fourier transform apparatus

The present invention provides an access control device and a testing method that can simplify the software operations in an access control operation such as a JTAG control operation, and enable the hardware to perform a high-speed control operation. The access control device conducts a test or diagnosis on an object by accessing a serial interface based on a command and data that specify a testing or diagnosing route. Under the control of a processor, a control circuit in the access control device executes an access sequence in accordance with a command string and an input data string stored in a memory, and stores the data outputted from the object to be tested or diagnosed in the memory as an output data string. The control circuit sets a state transition route for each objective state in advance, so that a transition route can be readily determined for an objective state specified by the command string.

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Kawasaki, Japan

Toshiro Nakazuru