Data converter with minimum phase FIR filter and method for calculating filter coefficients

Claim 2

A coder-decoder for sending and receiving signals comprising: an analog-to-digital converter for converting an incoming analog signal into a plurality of first digital signal samples; a digital antialiasing filter for receiving the plurality of first digital signal samples; a decimator for reducing the number of said first digital signal samples provided from said digital antialiasing filter to provide a digital output signal having a predetermined signal rate less than the rate of said first digital signal samples; a digital low pass reconstruction filter for receiving a plurality of second digital signal samples and for filtering images of the base band from said second digital signal samples; an interpolator for increasing the number of said second digital signal samples provided from said digital low pass reconstruction filter to provide a digital output signal having a predetermined signal rate, greater than the rate of said second digital signal samples; and an oversampling digital-to-analog converter for converting the digital output signal received from the interpolator into an analog signal for sending, wherein at least one of said filters is a minimum phase finite impulse response filter.

Claim 3

A coder-decoder as recited in claim 1, wherein said coder-decoder is employed as a front-end circuit for a modem.

Claim 4

A coder-decoder as recited in claim 1, wherein the analog-to-digital converter is an oversampling analog-to-digital converter, sampling at a rate higher than the Nyquist rate.

Claim 5

A coder-decoder as recited in claim 1, wherein the oversampling digital-to-analog converter is an oversampling sigma-delta modulator.

Claim 6

A coder-decoder as recited in claim 1, wherein the oversampling digital-to-analog converter is a noise shaping coder.

Claim 7

A coder-decoder as recited in claim 5, wherein the noise shaping coder is an oversampling sigma-delta modulator.

Claim 8

A coder-decoder as recited in claim 5, wherein the noise shaping coder further comprises a noise shaping filter.

Claim 9

A coder-decoder as recited in claim 7, wherein the noise shaping filter comprises a minimum phase finite impulse response filter.

Claim 10

A coder-decoder as recited in claim 8, wherein the minimum phase finite impulse response filter is an optimum minimum phase finite impulse response filter.

Claim 11

A coder-decoder for sending and receiving signals comprising: an oversampling analog-to-digital converter for convening an incoming analog signal into a plurality of first digital signal samples; a digital antialiasing filter for receiving the plurality of first digital signal samples; a decimator for reducing the number of said first digital signal samples provided from said digital antialiasing filter to provide a digital output signal having a predetermined signal rate less than the rate of said first digital signal samples; a digital low pass reconstruction filter for receiving a plurality of second digital signal samples and for filtering images of the base band from said second digital signal samples; an interpolator for increasing the number of said second digital signal samples provided from said digital low pass reconstruction filter to provide a digital output signal having a predetermined signal rate greater than the rate of said second digital signal samples; and a digital-to-analog converter for converting the digital output signal received from the interpolator into an analog signal for sending, wherein at least one of said filters is a minimum phase finite impulse response filter.

Claim 12

A coder-decoder for sending and receiving signals comprising: an oversampling analog-to-digital converter for convening an incoming analog signal into a plurality of first digital signal samples; a digital antialiasing filter for receiving the plurality of first digital signal samples; a decimator for reducing the number of said first digital signal samples provided from said digital antialiasing filter to provide a digital output signal having a predetermined signal rate less than the rate of said first digital signal samples; a digital low pass reconstruction filter for receiving a plurality of second digital signal samples and for filtering images of the base band from said second digital signal samples; an interpolator for increasing the number of said second digital signal samples provided from said digital low pass reconstruction filter to provide a digital output signal having a predetermined signal rate greater than the rate of said second digital signal samples; and a digital-to-analog converter for converting the digital output signal received from the interpolator into an analog signal for sending, wherein at least one of said filters is a minimum phase finite impulse response filter.

Claim 13

A coder-decoder as recited in claim 10, wherein said coder-decoder is employed as a front-end circuit for a modem.

Claim 14

A coder-decoder as recited in claim 10, wherein the oversampling analog-to-digital converter is an oversampling sigma-delta modulator.

Claim 15

A coder-decoder as recited in claim 10, wherein the oversampling analog-to-digital converter is a noise shaping coder.

Claim 16

A coder-decoder as recited in claim 13, wherein the noise shaping coder is an oversampling sigma-delta modulator.

Claim 17

A coder-decoder as recited in claim 13, wherein the noise shaping coder further comprises a noise shaping filter.

Claim 18

A coder-decoder as recited in claim 15, wherein the noise shaping filter comprises a minimum phase finite impulse response filter.

Claim 19

A coder-decoder as recited in claim 16, wherein the minimum phase finite impulse response filter is an optimum minimum phase finite impulse response filter.

Claim 20

A coder-decoder for sending and receiving signals comprising: an oversampling analog-to-digital converter for convening an incoming analog signal into a plurality of first digital signal samples and for shifting quantization noise out of the baseband of said incoming signal; a digital antialiasing filter for receiving the plurality of first digital signal samples and for filtering said quantization noise from said first digital signal samples; a decimator for reducing the number of said first digital signal samples provided from said digital antialiasing filter to provide a digital output signal having a predetermined signal rate less than the rate of said first digital signal samples; a digital low pass reconstruction filter for receiving a plurality of second digital signal samples and for filtering images of the base band from said second digital signal samples; an interpolator for increasing the number of said second digital signal samples provided from said digital low pass reconstruction filter to provide a digital output signal having a predetermined signal rate greater than the rate of said second digital signal samples; an oversampling digital-to-analog converter for converting the digital output signal received from the interpolator into an analog signal for sending; and a digital high pass filter for receiving the plurality of first digital signal samples from the digital antialiasing filter and for filtering low frequency noise from the first digital signal samples, wherein at least one of said filters is a minimum phase finite impulse response filter.

Claim 21

A coder-decoder for sending and receiving signals comprising: an oversampling analog-to-digital converter for convening an incoming analog signal into a plurality of first digital signal samples and for shifting quantization noise out of the baseband of said incoming signal; a digital antialiasing filter for receiving the plurality of first digital signal samples and for filtering said quantization noise from said first digital signal samples; a decimator for reducing the number of said first digital signal samples provided from said digital antialiasing filter to provide a digital output signal having a predetermined signal rate less than the rate of said first digital signal samples; a digital low pass reconstruction filter for receiving a plurality of second digital signal samples and for filtering images of the base band from said second digital signal samples; an interpolator for increasing the number of said second digital signal samples provided from said digital low pass reconstruction filter to provide a digital output signal having a predetermined signal rate greater than the rate of said second digital signal samples; an oversampling digital-to-analog converter for converting the digital output signal received from the interpolator into an analog signal for sending; and a digital high pass filter for receiving the plurality of first digital signal samples from the digital antialiasing filter and for filtering low frequency noise from the first digital signal samples, wherein at least one of said filters is a minimum phase finite impulse response filter.

Claim 22

A coder-decoder as recited in claim 18, wherein the minimum phase finite impulse response filter is an optimum minimum phase finite impulse response filter.

Claim 23

A modem for sending and receiving signals comprising: an oversampling analog-to-digital converter for convening an incoming analog signal into a plurality of first digital signal samples and for shifting quantization noise out of the baseband of said incoming signal; a digital antialiasing filter for receiving the plurality of first digital signal samples and for filtering said quantization noise from said first digital signal samples; a decimator for reducing the number of said first digital signal samples provided from said digital antialiasing filter to provide a digital output signal having a predetermined signal rate less than the rate of said first digital signal samples; a digital low pass reconstruction filter for receiving a plurality of second digital signal samples and for filtering images of the base band from said second digital signal samples; an interpolator for increasing the number of said second digital signal samples provided from said digital low pass reconstruction filter to provide a digital output signal having a predetermined signal rate greater than the rate of said second digital signal samples; an oversampling digital-to-analog converter for converting the digital output signal received from the interpolator into an analog signal for sending; and a transmitter for modulating received data into said plurality of second digital samples the transmitter, including a transmitter filter to filter the plurality of second digital samples, wherein at least one of said filters is a minimum phase finite impulse response filter.

Claim 24

A modem for sending and receiving signals comprising: an oversampling analog-to-digital converter for convening an incoming analog signal into a plurality of first digital signal samples and for shifting quantization noise out of the baseband of said incoming signal; a digital antialiasing filter for receiving the plurality of first digital signal samples and for filtering said quantization noise from said first digital signal samples; a decimator for reducing the number of said first digital signal samples provided from said digital antialiasing filter to provide a digital output signal having a predetermined signal rate less than the rate of said first digital signal samples; a digital low pass reconstruction filter for receiving a plurality of second digital signal samples and for filtering images of the base band from said second digital signal samples; an interpolator for increasing the number of said second digital signal samples provided from said digital low pass reconstruction filter to provide a digital output signal having a predetermined signal rate greater than the rate of said second digital signal samples; an oversampling digital-to-analog converter for converting the digital output signal received from the interpolator into an analog signal for sending; and a transmitter for modulating received data into said plurality of second digital samples the transmitter, including a transmitter filter to filter the plurality of second digital samples, wherein at least one of said filters is a minimum phase finite impulse response filter.

Claim 25

A modem as recited in claim 20, wherein the minimum phase finite impulse response filter is an optimum minimum phase finite impulse response filter.

Claim 26

A modem as recited in claim 20, wherein the oversampling analog-to-digital converter is an oversampling sigma-delta modulator.

Claim 27

A modem as recited in claim 20, wherein the oversampling digital-to-analog converter is an oversampling sigma-delta converter.

Claim 28

A modem for sending and receiving signals comprising: an oversampling analog-to-digital converter for converting an incoming analog signal into a plurality of first digital signal samples and for shifting quantization noise out of the baseband of said incoming signal; a digital antialiasing filter for receiving the plurality of first digital signal samples and for filtering said quantization noise from said first digital signal samples; a decimator for reducing the number of said first digital signal samples provided from said digital antialiasing filter to provide a digital output signal having a predetermined signal rate less than the rate of said first digital signal samples; a digital low pass reconstruction filter for receiving a plurality of second digital signal samples and for filtering images of the base band from said second digital signal samples; an interpolator for increasing the number of said second digital signal samples provided from said digital low pass reconstruction filter to provide a digital output signal having a predetermined signal rate greater than the rate of said second digital signal samples; an oversampling digital-to-analog converter for converting the digital output signal received from the interpolator into an analog signal for sending; and a receiver for receiving the first digital signal samples filtered by the digital high-pass filter, the receiver including a receiver filter to filter the received first digital signal samples, wherein at least one of said filters is a minimum phase finite impulse response filter.

Claim 29

A modem for sending and receiving signals comprising: an oversampling analog-to-digital converter for converting an incoming analog signal into a plurality of first digital signal samples and for shifting quantization noise out of the baseband of said incoming signal; a digital antialiasing filter for receiving the plurality of first digital signal samples and for filtering said quantization noise from said first digital signal samples; a decimator for reducing the number of said first digital signal samples provided from said digital antialiasing filter to provide a digital output signal having a predetermined signal rate less than the rate of said first digital signal samples; a digital low pass reconstruction filter for receiving a plurality of second digital signal samples and for filtering images of the base band from said second digital signal samples; an interpolator for increasing the number of said second digital signal samples provided from said digital low pass reconstruction filter to provide a digital output signal having a predetermined signal rate greater than the rate of said second digital signal samples; an oversampling digital-to-analog converter for converting the digital output signal received from the interpolator into an analog signal for sending; and a receiver for receiving the first digital signal samples filtered by the digital high-pass filter, the receiver including a receiver filter to filter the received first digital signal samples, wherein at least one of said filters is a minimum phase finite impulse response filter.

Claim 30

A modem as recited in claim 24, wherein the minimum phase finite impulse response filter is an optimum minimum phase finite impulse response filter.

Claim 31

A modem for sending and receiving signals comprising: an oversampling analog-to-digital converter for converting an incoming analog signal into a plurality of first digital signal samples and for shifting quantization noise out of the baseband of said incoming signal; a digital antialiasing filter for receiving the plurality of first digital signal samples and for filtering said quantization noise from said first digital signal samples; a decimator for reducing the number of said first digital signal samples provided from said digital antialiasing filter to provide a digital output signal having a predetermined signal rate less than the rate of said first digital signal samples; a digital low pass reconstruction filter for receiving a plurality of second digital signal samples and for filtering images of the base band from said second digital signal samples; an interpolator for increasing the number of said second digital signal samples provided from said digital low pass reconstruction filter to provide a digital output signal having a predetermined signal rate greater than the rate of said second digital signal samples; an oversampling digital-to-analog converter for converting the digital output signal received from the interpolator into an analog signal for sending; and a transmitter for modulating received data into said plurality of second digital samples the transmitter, including a transmitter filter to filter the plurality of second digital samples; a receiver for receiving the first digital signal samples filtered by the digital high pass filter, the receiver including a receiver filter to filter the received first digital signal samples, wherein at least one of said filters is a minimum phase finite impulse response filter; and an echo canceler, the echo canceler for receiving the filtered plurality of second digital samples provided by the transmitter, and for receiving the first digital signal samples also received by the receiver, said echo canceler for canceling from the first digital signal samples the type of energy sent by the transmitter whereby echo is canceled from the plurality of first digital signal samples, the echo canceler providing as an output to a summing junction the plurality of first digital signal samples from which the echo was canceled, the summing junction adding said plurality of first digital signal samples to the plurality of first digital signal samples received from the digital high pass filter and providing the summed plurality of first digital signal samples to the receiver.

Claim 32

A modem for sending and receiving signals comprising: an oversampling analog-to-digital converter for converting an incoming analog signal into a plurality of first digital signal samples and for shifting quantization noise out of the baseband of said incoming signal; a digital antialiasing filter for receiving the plurality of first digital signal samples and for filtering said quantization noise from said first digital signal samples; a decimator for reducing the number of said first digital signal samples provided from said digital antialiasing filter to provide a digital output signal having a predetermined signal rate less than the rate of said first digital signal samples; a digital low pass reconstruction filter for receiving a plurality of second digital signal samples and for filtering images of the base band from said second digital signal samples; an interpolator for increasing the number of said second digital signal samples provided from said digital low pass reconstruction filter to provide a digital output signal having a predetermined signal rate greater than the rate of said second digital signal samples; an oversampling digital-to-analog converter for converting the digital output signal received from the interpolator into an analog signal for sending; and a transmitter for modulating received data into said plurality of second digital samples the transmitter, including a transmitter filter to filter the plurality of second digital samples; a receiver for receiving the first digital signal samples filtered by the digital high pass filter, the receiver including a receiver filter to filter the received first digital signal samples, wherein at least one of said filters is a minimum phase finite impulse response filter; and an echo canceler, the echo canceler for receiving the filtered plurality of second digital samples provided by the transmitter, and for receiving the first digital signal samples also received by the receiver, said echo canceler for canceling from the first digital signal samples the type of energy sent by the transmitter whereby echo is canceled from the plurality of first digital signal samples, the echo canceler providing as an output to a summing junction the plurality of first digital signal samples from which the echo was canceled, the summing junction adding said plurality of first digital signal samples to the plurality of first digital signal samples received from the digital high pass filter and providing the summed plurality of first digital signal samples to the receiver.

Claim 33

A modem as recited in claim 24, wherein the minimum phase finite impulse response filter is an optimum minimum phase finite impulse response filter.

Claim 34

A modem as recited in claim 26, wherein the echo canceler is adaptive.

Claim 37

A modem as recited in claim 20, further comprising: a digital high pass filter for receiving the plurality of first digital signal samples from the digital antialiasing filter and for filtering low frequency noise from the first digital signal samples.

Claim 38

A modem as recited in claim 24, further comprising: a digital high pass filter for receiving the plurality of first digital signal samples from the digital antialiasing filter and for filtering low frequency noise from the first digital signal samples.

Claim 39

A modem as recited in claim 26, further comprising: a digital high pass filter for receiving the plurality of first digital signal samples from the digital antialiasing filter and for filtering low frequency noise from the first digital signal samples.