US 6,275,520 B1Granted

Pseudo-noise generating apparatus

AssigneeFujitsu Limited

InventorsTakaharu Nakamura, Kazuo Kawabata, Kazuhisa Obuchi, Hajime Hamada

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Abstract

A pseudo-noise generating apparatus capable of starting a pseudo-noise sequence from an arbitrary phase using compact processing circuitry. Tap selection patterns corresponding to a plurality of phase shift amounts are stored in advance in a ROM. By giving a phase shift amount to the ROM and setting the corresponding tap selection pattern in AND gates, the pseudo-noise sequence generated by the pseudo-noise generator is shifted in phase, and is loaded into a shift register. After setting a new phase amount in the ROM, the contents of the shift register are transferred into a shift register in the pseudo-noise generator. By repeating this operation, the desired phase shift is accomplished as a sum of a plurality of phase shift amounts.

Claims5

Dependent claims

A pseudo-noise generating apparatus comprising:

a pseudo-noise generator having a plurality of delay elements connected in series:
a memory device for storing a plurality of selection patterns corresponding to a plurality of different phase shift amounts, and outputting a selection pattern corresponding to one phase shift amount specified from among said plurality of phase shift amounts;
a selector for selecting delay element outputs in said pseudo-noise generator in accordance with said selection pattern output from said memory device;
an adder for adding said delay element outputs selected by said selector, thereby outputting a phase-shifted version of a pseudo-noise sequence output from said pseudo-noise generator;
a shift register for storing therein said pseudo-noise sequence that said adder outputs;
and
a controller for accomplishing a desired phase shift as a sum of a plurality of phase shift amounts by issuing specification of a phase shift amount to said memory device and by transferring said pseudo-noise sequence stored in said shift register into said delay elements in said pseudo-noise generator.

4 more elements

Dependencies are inferred from the claim text.