Digital data transmitter, transmission line encoding method, and decoding method
First Claim
1. A digital data transmission apparatus comprising:
- a data coding device operable to convert digital data into a signal level corresponding to a symbol that is assigned to the digital data in each symbol cycle as a prescribed unit cycle;
a first digital filter having a first sampling cycle that is shorter than a unit cycle of a signal level string that has been obtained by said data coding device, and being operable to allow only predetermined frequencies to pass;
a D/A converter operable to convert a digital data stream that has passed through said first digital filter, into an analog signal;
a low-pass filter operable to eliminate folding distortion of said first digital filter from the analog signal that has been obtained by said D/A converter, the folding distortion being determined in the first sampling cycle;
a differential driver operable to convert an output from said low-pass filter, into two signals having opposite polarities relative to a predetermined reference potential, and to input the two signals into a twisted pair cable;
a differential receiver operable to receive transmission signals transmitted through the twisted pair cable, and to convert a difference in potential between two wires of the twisted pair cable into a signal;
an A/D converter operable to convert the signal outputted from said differential receiver into a digital signal value in each second sampling cycle;
a second digital filter operable to allow only a predetermined frequency band of a digital data stream that has been obtained by sampling with said A/D converter, to pass; and
a level evaluator operable to evaluate a symbol value from a level of a signal in symbol timing, including a symbol in the signal, based on an output from said second digital filter, and to convert the symbol value into corresponding digital data,wherein said first and second digital filters both have low-pass characteristics, and said first digital filter has frequency characteristics of cutting off at least frequency data which are higher than a frequency band in which electromagnetic waves emitted from the respective two signals that pass through the twisted pair cable cancel each other out, thereby to eliminate emission of electromagnetic waves to outside the twisted pair cable.
1 Assignment
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Accused Products
Abstract
A digital data transmission apparatus includes a transmitting end (100) that includes: a binary/quadrary conversion unit (110) for converting a data stream; a coding unit (120) for mapping the converted data to be coded; a digital filter (130); a D/A conversion unit (140); a low-pass filter (150) for eliminating a high-band signal; a differential driver (160) for inputting an analog signal that has passed through the low-pass filter into a twisted pair cable (300), and a receiving end (200) that includes: a low-pass filter (210) for eliminating noises from both wires of the twisted pair cable; a receiver (220) for receiving the signals that have passed through the low-pass filter; an A/D conversion unit (230); a digital filter (240); an evaluation unit (250) for evaluating a signal level of a received signal; a decoding unit (260) for decoding the signal level into receipt data; and a synchronization unit (270) for generating a clock.
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Citations
43 Claims
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1. A digital data transmission apparatus comprising:
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a data coding device operable to convert digital data into a signal level corresponding to a symbol that is assigned to the digital data in each symbol cycle as a prescribed unit cycle; a first digital filter having a first sampling cycle that is shorter than a unit cycle of a signal level string that has been obtained by said data coding device, and being operable to allow only predetermined frequencies to pass; a D/A converter operable to convert a digital data stream that has passed through said first digital filter, into an analog signal; a low-pass filter operable to eliminate folding distortion of said first digital filter from the analog signal that has been obtained by said D/A converter, the folding distortion being determined in the first sampling cycle; a differential driver operable to convert an output from said low-pass filter, into two signals having opposite polarities relative to a predetermined reference potential, and to input the two signals into a twisted pair cable; a differential receiver operable to receive transmission signals transmitted through the twisted pair cable, and to convert a difference in potential between two wires of the twisted pair cable into a signal; an A/D converter operable to convert the signal outputted from said differential receiver into a digital signal value in each second sampling cycle; a second digital filter operable to allow only a predetermined frequency band of a digital data stream that has been obtained by sampling with said A/D converter, to pass; and a level evaluator operable to evaluate a symbol value from a level of a signal in symbol timing, including a symbol in the signal, based on an output from said second digital filter, and to convert the symbol value into corresponding digital data, wherein said first and second digital filters both have low-pass characteristics, and said first digital filter has frequency characteristics of cutting off at least frequency data which are higher than a frequency band in which electromagnetic waves emitted from the respective two signals that pass through the twisted pair cable cancel each other out, thereby to eliminate emission of electromagnetic waves to outside the twisted pair cable. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. A transmission channel coding method comprising:
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when transmitting digital data as one symbol having of an arbitrary number of bits, providing a number of signal levels which is greater than a number of kinds of symbols; and assigning a signal level that represents a symbol in a symbol transmission timing to one of the signal levels other than a previous signal level in an immediately preceding symbol transmission timing. - View Dependent Claims (24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36)
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37. A data transmission apparatus comprising:
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a data coding device operable to convert digital data into a signal level corresponding to a symbol that is assigned to the digital data in each symbol cycle as a prescribed unit cycle; a first digital filter having a first sampling cycle that is shorter than a unit cycle of a signal level string which has been coded by said data coding device, and being operable to allow only predetermined frequencies to pass; a D/A converter operable to convert a digital data stream that has passed through said first digital filter, into an analog signal; a low-pass filter operable to eliminate folding distortion of said first digital filter from the analog signal that has been obtained by said D/A converter, the folding distortion being determined in the first sampling cycle; and a differential driver operable to convert an output of said low-pass filter, into two signals having opposite polarities relative to a predetermined reference potential, and to input the two signals into a twisted pair cable, wherein said first digital filter has frequency characteristics of cutting off at least frequency data which are higher than a frequency band in which electromagnetic waves emitted from the respective two signals that pass through the twisted pair cable cancel each other out, thereby to eliminate emission of electromagnetic waves to outside the twisted pair cable.
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38. A data receiving apparatus for receiving transmission signals that are transmitted from a data transmission apparatus including:
- a data coding device operable to convert digital data into a signal level corresponding to a symbol that is assigned to the digital data in each symbol cycle as a prescribed unit cycle;
a first digital filter having a first sampling cycle that is shorter than a unit cycle of a signal level string that has been obtained by the data coding device, and being operable to allow only predetermined frequencies to pass;
a D/A converter operable to convert a digital data stream that has passed through the first digital filter, into an analog signal;
a low-pass filter operable to eliminate folding distortion of the first digital filter from the analog signal that has been obtained by the D/A converter, the folding distortion being determined in the first sampling cycle;
a differential driver operable to convert an output from the low-pass filter, into two signals having opposite polarities relative to a predetermined reference potential, and to input the two signals into a twisted pair cable, wherein the first digital filter has low-pass characteristics of cutting off at least frequency data which are higher than a frequency band in which electromagnetic waves emitted from the respective two signals that pass through the twisted pair cable cancel each other out, thereby to eliminate emission of electromagnetic waves to outside the twisted pair cable, the data receiving apparatus comprising;a differential receiver operable to receive transmission signals transmitted through the twisted pair cable, and to convert a difference in potential between two wires of the twisted pair cable into a signal; an A/D converter operable to convert the signal outputted from said differential receiver into a digital signal value in each sampling cycle; a second digital filter operable to allow only lower frequency components of a digital data stream that has been obtained by sampling with said A/D converter, to pass; and a level evaluator operable to evaluate a symbol value from a level of a signal in symbol timing, including a symbol in the signal, based on an output from said second digital filter, and to convert the symbol value into corresponding digital data.
- a data coding device operable to convert digital data into a signal level corresponding to a symbol that is assigned to the digital data in each symbol cycle as a prescribed unit cycle;
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39. A data transmission/receiving apparatus for receiving data outputted from a data transmission apparatus including:
- a data coding device operable to convert digital data into a signal level corresponding to a symbol that is assigned to the digital data in each symbol cycle as a prescribed unit cycle;
a first digital filter having a first sampling cycle that is shorter than a unit cycle of a signal level string that has been obtained by the data coding device, and being operable to allow only predetermined frequencies to pass;
a D/A converter operable to convert a digital data stream that has passed through the first digital filter, into an analog signal;
a low-pass filter operable to eliminate folding distortion of the first digital filter from the analog signal that has been obtained by the D/A converter, the folding distortion being determined in the first sampling cycle;
a differential driver operable to convert an output from the low-pass filter, into two signals having opposite polarities relative to a predetermined reference potential, and to input the two signals into a twisted pair cable;
a differential receiver operable to receive transmission signals transmitted through the twisted pair cable, and to convert a difference in potential between two wires of the twisted pair cable into a signal;
an A/D converter operable to convert the signal outputted from the differential receiver into a digital signal value in each second sampling cycle;
a second digital filter operable to allow only a predetermined frequency band of a digital data stream that has been obtained by sampling with the A/D converter, to pass; and
a level evaluator operable to evaluate a symbol value from a level of a signal in symbol timing, including a symbol in the signal, based on an output from the second digital filter, and to convert the symbol value into corresponding digital data, wherein the first and second digital filters both have low-pass characteristics, and the first digital filter has frequency characteristics of cutting off at least frequency data which are higher than a frequency band in which electromagnetic waves emitted from the respective two signals that pass through the twisted pair cable cancel each other out, thereby to eliminate emission of electromagnetic waves to outside the twisted pair cable, the data transmission/receiving apparatus comprising;a transmission/receiving controller operable to judge whether the digital data outputted from the level evaluator of the data transmission apparatus is to be retransmitted, output the digital data that is not to be retransmitted as received data, and multiplex transmission data inputted from outside with the digital data that is to be retransmitted, thereby to be inputted to the data coding device.
- a data coding device operable to convert digital data into a signal level corresponding to a symbol that is assigned to the digital data in each symbol cycle as a prescribed unit cycle;
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40. A signal processing method for processing transmission signals that are transmitted from a data transmission apparatus including:
- a data coding device operable to convert digital data into a signal level corresponding to a symbol that is assigned to the digital data in each symbol cycle as a prescribed unit cycle;
a first digital filter having a first sampling cycle that is shorter than a unit cycle of a signal level string that has been obtained by the data coding device, and being operable to allow only predetermined frequencies to pass;
a D/A converter operable to convert a digital data stream that has passed through the first digital filter, into an analog signal;
a low-pass filter operable to eliminate folding distortion of the first digital filter from the analog signal that has been obtained by the D/A converter, the folding distortion being determined in the first sampling cycle;
a differential driver operable to convert an output from the low-pass filter, into two signals having opposite polarities relative to a predetermined reference potential, and to input the two signals into a twisted pair cable, wherein the first digital filter has frequency characteristics of cutting off at least frequency data which are higher than a frequency band in which electromagnetic waves emitted from the respective two signals that pass through the twisted pair cable cancel each other out, thereby to eliminate emission of electromagnetic waves to outside the twisted pair cable, the data coding device is operable to convert data comprising two or more bits per symbol cycle, into a symbol to be transmitted, the data coding device includes;
a previous signal level storage device operable to store a previous signal level; and
a coding device operable to decide a signal level corresponding to a symbol to be transmitted, based on the previous signal level and the symbol to be transmitted, the coding device is operable to assign a symbol in a symbol transmission timing to a signal level having a predetermined difference from the previous signal level that is stored in the previous signal level storage device, the signal processing method comprising;obtaining a difference between a signal level in a first symbol receipt timing and a signal level in a second symbol receipt timing; and establishing a symbol to correspond to the difference to decode a signal level in the first symbol receipt timing. - View Dependent Claims (41)
- a data coding device operable to convert digital data into a signal level corresponding to a symbol that is assigned to the digital data in each symbol cycle as a prescribed unit cycle;
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42. A signal processing method for processing transmission signals that are transmitted from a data transmission apparatus including:
- a data coding device operable to convert digital data into a signal level corresponding to a symbol that is assigned to the digital data in each symbol cycle as a prescribed unit cycle;
a first digital filter having a first sampling cycle that is shorter than a unit cycle of a signal level string that has been obtained by the data coding device, and being operable to allow only predetermined frequencies to pass;
a D/A converter operable to convert a digital data stream that has passed through the first digital filter, into an analog signal;
a low-pass filter operable to eliminate folding distortion of the first digital filter from the analog signal that has been obtained by the D/A converter, the folding distortion being determined in the first sampling cycle;
a differential driver operable to convert an output from the low-pass filter, into two signals having opposite polarities relative to a predetermined reference potential, and to input the two signals into a twisted pair cable, wherein the first digital filter has low-pass characteristics of cutting off at least frequency data which are higher than a frequency band in which electromagnetic waves emitted from the respective two signals that pass through the twisted pair cable cancel each other out, thereby to eliminate emission of electromagnetic waves to outside the twisted pair cable, the data coding device includes a number of signal levels which is greater than a number of kinds of symbols to be transmitted per symbol cycle, the data coding device is operable to assign a symbol in a symbol transmission timing to one of the signal levels, the data coding device includes;
a previous signal level storage device operable to store a previous signal level; and
a coding device operable to decide a signal level corresponding to a symbol to be transmitted, based on the previous signal level and the symbol to be transmitted, the coding device is operable to assign a symbol in a symbol transmission timing to a signal level having a predetermined difference from the previous signal level that is stored in the previous signal level storage device, the signal processing method comprising;obtaining a difference between a signal level in a first symbol receipt timing and a signal level in a second symbol receipt timing; and establishing a symbol to correspond to the difference to decode a signal level in the first symbol receipt timing. - View Dependent Claims (43)
- a data coding device operable to convert digital data into a signal level corresponding to a symbol that is assigned to the digital data in each symbol cycle as a prescribed unit cycle;
Specification