Digital data over voice communication
AssigneeIntegrated Network Corporation
InventorDev V. Gupta
Life of this patent
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Abstract
A method and apparatus is described for transmitting and receiving data signals and voice band signals over a single pair of wires, wherein the energy content of the data signals in the voice bands is transferred to a higher frequency to avoid interference between the two. This is accomplished by sinusoidally encoding the data pulses in the frequency domain. The encoding is equivalently performed in the time domain by linearly combining weighted delayed and advanced versions of the data pulses, in accordance with a weighting formula. A transversal filter is used to multiple delayed and advanced versions of the data pulses by a scaling factor times the ratio of m!/(m-i)!i! factorial wherein i is the ith version being weighted, m is an integer greater than one and ! indicates the factorial function.
Claims28
Apparatus for encoding data signals for transmission at a predetermined rate over telephone lines in the presence of voice band telephone signals such that the frequency spectrum of the data signals is substantially removed from the voice band and is shifted to a higher frequency spectrum comprising:
- (a) generator means for generating pulsed data signals;
- (b) coding means for shifting the frequency spectrum of the data signals to produce encoded data signals by forming linear combinations of said pulsed data signals with delayed and advanced versions thereof to encode the pulses in the frequency domain in the form sin.sup.m .theta. wherein .theta.=.pi. fT/4;
- and wherein m is an integer greater than or equal to 1, f is a frequency variable and T is the reciprocal of the rate of the data being transmitted.
Telephone communication apparatus comprising an encoder responsive to AMI encoded pulsed data signals for forming linear combinations of said pulsed data signals to encode the pulses in the time domain resulting in a frequency domain spectrum in the form of sin.sup.m .theta. wherein .theta.=.pi. fT/4 and m is an integer equal to or greater than 1, f is a frequency variable and T is the reciprocal of the rate of data transmitted to transform energy in said pulses from a lower frequency region to a higher frequency region, thereby to avoid substantial interference with base band signals.
Apparatus for encoding data signals wherein the encoding is of the form sin.sup.m .theta. wherein .theta.=.pi. fT/4;
- and wherein m is an integer greater than or equal to 1, f is a frequency variable and T is the reciprocal of the rate of the data signals being transmitted to produce encoded data signals for transmission at a predetermined rate over telephone lines in the presence of voice band telephone signals such that the frequency spectrum of the data signals is substantially removed from the voice band and is spread over a higher frequency spectrum comprising:
- transversal filter means for linearly summing m+1 weighted, delayed and advanced versions of the data signals, which versions are weighted by the product of a constant and the ratio of m factorial divided by i factorial times (m-i) factorial wherein i is the ith version weighted and m is an integer.
A communication system comprising two nodes linked by a pair of conductors for concurrent transmissions of voice frequency signals and bursts of higher frequency encoded data signals from a first node to a second node and subsequent reception of concurrent transmissions of voice frequency signals and bursts of data signals from the second node to the first node over said pair of conductors;
- (a) said first node comprising:
- (i) first coupling means for coupling voice frequency signals transmitted over said conductors from said second node through a first low pass filter to a voice frequency communication system and higher frequency encoded data signals transmitted over said conductors through a first high pass filter;
- (ii) first equalizer means coupled to said first high pass filter for compensating said encoded data signals for signal losses incurred in transmission over said pair of conductors;
- (iii) first data receiver means for decoding the encoded received data signals;
- (iv) first encoder means for accepting time compressed multiplexed data signals and sinusoidally encoding said data signals by a function of sin.sup.m .theta.;
- wherein .theta.=.pi. fT/4 and m is an integer greater than unity, f is a frequency variable and T is the reciprocal of the data rate at which the data signals are transmitted to produce encoded data signals to substantially remove any signal energy in the voice frequency band;
- and
- (v) first means for passing said encoded data signals to said first high pass filter for transmission over said pair of conductors to said second node;
- (b) said second node comprising:
- (i) second coupling means for coupling voice frequency signals transmitted over said conductors from said first node through a second low pass filter to a voice frequency communication system and higher frequency encoded data signals from said conductors through a second high pass filter;
- (ii) second equalizer means coupled to said second high pass filter for compensating said encoded data signals for signal losses incurred in transmission over said pair of conductors;
- (iii) second data receiver means for decoding the encoded received data signals;
- (iv) second encoder means for accepting time compressed multiplexed data signals and sinusoidally encoding said data signals by a function of sin.sup.m .theta.;
- wherein .theta.=.pi. fT/4 and m is an integer greater than unity, f is a frequency variable and T is the reciprocal of the data rate at which the data signals are transmitted to produce encoded data signals to substantially remove any signal energy in the voice frequency band and second means for passing said encoded data signals to said second high pass filter for transmission over said pair of conductors to said first node.
A method for encoding data signals for transmission at a predetermined rate over telephone lines in the presence of voice band telephone signals such that the frequency spectrum of the data signals is substantially shifted from the voice band and is spread over a higher frequency spectrum comprising the steps of:
- (a) generating pulsed data signals;
- (b) forming linear combinations of said pulsed data signals with delayed and advanced versions thereof to sinusoidally encode the pulses in the frequency domain wherein the encoding is of the form sin.sup.m .theta. wherein .theta.=.pi. fT/4;
- and wherein m is an integer greater than or equal to 1, f is a frequency variable and T is the reciprocal of the rate of the data signals being transmitted to produce encoded data signals.
A method for encoding data signals for transmission at a predetermined rate over telephone lines in the presence of voice band telephone signals such that the frequency spectrum of the data signals is substantially removed from the voice band and is spread over a higher frequency spectrum wherein the encoding is of the form sin.sup.m .theta. wherein .theta.=.pi. fT/4;
- and wherein m is an integer greater than or equal to 1, f is a frequency variable and T is the reciprocal of the rate of the data signals being transmitted to produce encoded data signals comprising the steps of:
- (a) generating said data signals;
- and
- (b) linearly summing m+1 weighted, delayed and advanced versions of the generated data signals, which versions are weighted by the ratio of m factorial divided by i factorial times (m-i) factorial wherein i is the ith version weighted and m is an integer.
A method of communication in which two nodes are linked by a pair of conductors for transmissions of voice frequency signals and bursts of higher frequency encoded data signals wherein the encoding is of the form sin.sup.m .theta. wherein .theta.=.pi. fT/4;
- and wherein m is an integer greater than or equal to 1, f is a frequency variable and T is the reciprocal of the rate of the data signals being transmitted to produce encoded data signals from a first node to a second node and subsequent reception of transmissions of voice frequency signals and bursts of higher frequency data signals from the second node to the first node over said pair of conductors comprising the steps of:
- (a) at the first node:
- (i) coupling voice frequency signals transmitted over said conductors from said second node through a first low pass filter to a voice frequency communication system and higher frequency encoded data signals transmitted over said conductors through a first high pass filter;
- (ii) compensating said encoded data signals for signal losses incurred in transmission over said pair of conductors;
- (iii) decoding the encoded received data signals;
- (iv) accepting time compressed multiplexed data signals and sinusoidally encoding said data signals to substantially remove any signal energy in the voice frequency band;
- and
- (v) passing said encoded data signals to said first high pass filter for transmission over said pair of conductors to said second node;
- (b) at the second node:
- (i) coupling voice frequency signals transmitted over said conductors from said first node through a second low pass filter to a voice frequency communication system and higher frequency encoded data signals from said conductors through a second high pass filter;
- (ii) compensating said encoded data signals for signal losses incurred in transmission over said pair of conductors;
- (iii) decoding the encoded received data signals;
- and
- (iv) accepting time compressed multiplexed data signals and sinusoidally encoding said data signals to substantially remove any signal energy in the voice frequency band and second means for passing said encoded data signals to said second high pass filter for transmission over said pair of conductors to said first node.
Apparatus for encoding data signals in the form of sin.sup.m .theta. wherein .theta.=.pi. fT/4 and m is an integer equal to or greater than 1, f is a frequency variable and T is the reciprocal of the rate of data transmitted for transmission over telephone lines in the presence of voice band telephone signals such that the frequency spectrum of the data signals is substantially removed from the voice band and is shifted to a higher frequency spectrum comprising:
- (a) means for generating said data signals;
- and
- (b) means for shifting the frequency spectrum of the generated data signals to produce encoded data signals by linearly summing m+1 weighted, delayed and advanced versions of the generated data signals, which versions are weighted by the ratio of m factorial divided by i factorial times (m-i) factorial wherein i is the ith version weighted and m is an integer.
Dependencies are inferred from the claim text.