US 4,908,721 A · Improved decoder

Abstract

A data decoding system includes a data retrieval device which retrieves encoded data from a mass-storage device and transmits the data to a serial-to-parallel shift register. The shift register, operating at the data transfer rate, converts the encoded data to a parallel stream of bit-pairs. The bit-pairs are then transmitted, over parallel lines, to a second shift register which is operating at one-half the data transfer rate. The second shift register stores a sufficient number of the bit-pairs to constitute a byte of binary data when decoded. Once enough bit-pairs are stored, a ROM, operating at a rate which is slower than the data transfer rate, decodes the information to form a byte of binary data. The system utilizes a data retrieval system with a high data transfer rate and processing circuitry with a reduced bandwidth requirement to produce decoded data at a rate which is comparable to the data transfer rate.

Claims8

Dependent claims

A decoder for decoding data which is in the form of code words, said decoder comprising:

A. a p-bit shift register for receiving encoded bits;
B. means for shifting the encoded bits from said p-bit shift register each time said shift register receives p bits;
C. a second shift register consisting of a predetermined number of p-bit stages connected to receive a predetermined number of the bits shifted from said p-bit shift register by said shifting means, said second shift register including at least q stages, with the stages together being capable of storing a number of bits corresponding to one or more code words;
D. decoding means for receiving signals corresponding to the bits stored in said second shift register and providing in response thereto corresponding decoded data;
and
E. means for supplying said signals to said decoding means each time said second shift register receives a predetermined number of bits from said p-bit shift register.

3 more elements

Dependencies are inferred from the claim text.

Improved decoder

Life of this patent

Improved decoder

Life of this patent

Abstract

Claims8