US5548338A — Compression of an electronic programming guide

Claim 1

Independent Claim 154 words

A method for compressing an electronic programming guide, comprising: assembling data representative of said electronic programming guide and comprising a plurality of characters; determining a number of bits required to represent each of said characters in Huffman code; selecting a plurality of candidate character strings from said data, said candidate character strings occurring more than a threshold number of times in said data and comprising at least two said characters; calculating a savings value for each of said candidate character strings using at least said number of bits required to represent in Huffman code each of said characters comprising said candidate character string; selecting at least one replacement character string from said candidate character strings based on said savings values; preparing a Huffman table comprising Huffman codes for each of said plurality of characters and each of said at least one replacement character strings; and compressing said electronic programming guide using said Huffman table.

Claim 2

Independent Claim 154 words

A method for compressing an electronic programming guide, comprising: assembling data representative of said electronic programming guide and comprising a plurality of characters; determining a number of bits required to represent each of said characters in Huffman code; selecting a plurality of candidate character strings from said data, said candidate character strings occurring more than a threshold number of times in said data and comprising at least two said characters; calculating a savings value for each of said candidate character strings using at least said number of bits required to represent in Huffman code each of said characters comprising said candidate character string; selecting at least one replacement character string from said candidate character strings based on said savings values; preparing a Huffman table comprising Huffman codes for each of said plurality of characters and each of said at least one replacement character strings; and compressing said electronic programming guide using said Huffman table.

Claim 3

Dependent Claim 36 words

The method of claim 1, wherein said threshold number for each of said candidate character strings equals a median frequency of said plurality of characters, divided by the number of characters in said candidate character string.

Claim 4

Dependent Claim 19 words

The method of claim 1, wherein at least 10 but no more than 50 replacement character strings are selected.

Claim 5

Dependent Claim 65 words

The method of claim 1, wherein each of said savings values is equal to the number of times said candidate character string occurs in said data multiplied by the difference between said number of bits required to represent in Huffman code each of said characters comprising said candidate character string and an estimated number of bits comprising a Huffman code for said candidate character string.

Claim 6

Dependent Claim 13 words

The method of claim 1, wherein said data comprises said electronic programming guide.

Claim 7

Dependent Claim 146 words

A set-top box for receiving and decompressing a signal comprising an electronic programming guide in compressed form, said electronic programming guide comprising a plurality of characters, said set-top box comprising: means for receiving said signal and providing data comprising a digital representation of said electronic programming guide in compressed form; a first storage space for storing a Huffman tree, said Huffman tree including at least one terminal branch representing a character string, said character string comprising at least two characters; a second storage space for storing application software for use with said Huffman tree to perform a decompression operation; a third storage space for storing said data; and a microcontroller connected to said receiver means and to said first, second, and third storage spaces for causing said application software to perform said decompression operation on said data to obtain said electronic programming guide in decompressed form.

Claim 8

Dependent Claim 146 words

A set-top box for receiving and decompressing a signal comprising an electronic programming guide in compressed form, said electronic programming guide comprising a plurality of characters, said set-top box comprising: means for receiving said signal and providing data comprising a digital representation of said electronic programming guide in compressed form; a first storage space for storing a Huffman tree, said Huffman tree including at least one terminal branch representing a character string, said character string comprising at least two characters; a second storage space for storing application software for use with said Huffman tree to perform a decompression operation; a third storage space for storing said data; and a microcontroller connected to said receiver means and to said first, second, and third storage spaces for causing said application software to perform said decompression operation on said data to obtain said electronic programming guide in decompressed form.

Claim 9

Dependent Claim 18 words

The set-top box of claim 6, wherein said receiver means comprises a receiver, a demodulator, and a buffer.

Claim 10

Dependent Claim 22 words

The set-top box of claim 6, wherein said first, second, and third storage spaces and said microcontroller comprise an integrated circuit chip.

Claim 11

Dependent Claim 26 words

The set-top box of claim 6, wherein said first and second storage spaces comprise a non-volatile memory and said third storage space comprises a volatile memory.

Claim 12

Dependent Claim 29 words

The set-top box of claim 9, wherein said first storage space is a ROM, said second storage space is an EEPROM, and said third storage space is a RAM.

Claim 13

Dependent Claim 19 words

The set-top box of claim 9, wherein said first and second storage spaces comprise a battery backed-up static RAM.

Claim 14

Dependent Claim 17 words

The set-top box of claim 9, wherein said first and second storage spaces comprise a flash memory.

Claim 15

Dependent Claim 27 words

The set-top box of claim 6, wherein said data is provided serially and said microcontroller further comprises an input pin on which to receive said serial data.

Claim 16

Dependent Claim 30 words

The set-top box of claim 6, wherein said data is provided in parallel and said microcontroller further comprises a plurality of input pins on which to receive said parallel data.

Claim 17

Dependent Claim 11 words

The set-top box of claim 6 further comprising an analog tuner.

Claim 18

Dependent Claim 12 words

The set top box of claim 6 further comprising a digital demultiplexer.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1999-08-20	2000-02-19	2000-08-20	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2003-08-20	2004-02-19	2004-08-20	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2007-08-20	2008-02-19	2008-08-20	$7700.00	Window Closed / Lapsed

Compression of an electronic programming guide

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