Data over voice transmission arrangement

• US 4,442,540 A
• Filed: 06/04/1981
• Issued: 04/10/1984
• Est. Priority Date: 06/04/1981
• Status: Expired due to Term

• Current Assignee: Bell Telephone Laboratories, Inc. (Nokia Corporation)
• Original Assignee: Bell Telephone Laboratories, Inc. (Nokia Corporation)
• Inventors: Allen, Jonathan B.
• Primary Examiner(s): Kemeny, E. S. Matt
• Application Number:
  US06/270,543
• Time in Patent Office: 1,041 Days
• Field of Search: 179/1.5 A, 179/15.55 R, 179/15.55 T, 179/1 D, 179/84 VF, 370/50, 370/81, 370/69, 370/69.1, 370/76, 358/142, 358/143, 358/257, 360/20, 381/31, 375/122
• US Class Current: 370/484
• CPC Class Codes: H04M 11/062 using different frequency bands for speech and other data

Abstract

A system for interpolating digital data signals to a frequency band above analog speech signals in a common transmission channel is disclosed. The system utilizes short time frequency analysis techniques to determine the cutoff frequency of the speech signal. Data signals temporarily held in storage within the system are thereafter modulated into an unused frequency band of the transmission channel above that needed for speech signals. The combined speech and data signals in the system are sent to a receiver which relays the respective speech and data signals to their appropriate locations. This system is compatible with digital signal processing techniques using Fast Fourier Transform Technology in conjunction with solid state logic elements.

Claims

1. A method for interpolating data and speech signals into a common transmission band comprising the steps of:

(a) converting the speech signal from analog to digital form,

(b) determining a frequency spectrum of the digital speech signal,

(c) determining a total energy content of the digital speech signal,

(d) determining the actual percentage of the total energy within each spectral line,

(e) summing the actual percentages of energy within a number of spectral lines,

(f) comparing the summed actual percentages of energy to the total energy content of the speech signal until a predetermined percentage is reached,

(g) determining the cutoff frequency of the digital speech signal when the predetermined percentage is reached,

(h) modulating the data signal to a position above the cutoff frequency of the speech signal, and

(i) sending the speech and modulated data signal to a receiver.

2. A system for interpolating digital data and analog speech signals into a common transmission band comprising

a first buffering means for holding digital data signals,

means for converting speech signals into digital form,

a second buffering means for holding digital speech signals received from the converting means,

processing means for determining the cutoff frequency of speech signals in response the first and second buffering means,

the processing means further comprising,

discrete Fourier transform means for determining the frequency spectrum of the digitized speech signal,

normalization means for determining the total energy of the frequency spectrum of the discrete Fourier transform means and for determining the actual percentage of energy within each spectral line of the speech signal,

summing means for accumulating the actual percentage of energy within each spectral line,

first latching register means for storing the accumulation of the actual percentage of energy within each spectral line and for feeding the actual percentage back to the summing means, and

comparator means for receiving the actual percentage of energy from the first register means and comparing it with a predetermined percentage from the second buffer means,

counting means for receiving the number of counts corresponding to the number of spectral lines from the normalization means,

second latching register means for receiving the number of counts corresponding to the number of spectral lines from the counting means,

read only memory means for converting the number of spectral lines from the second latching register means to the cutoff frequency of the speech signal,

the comparator means signaling a counting means when the actual percentage is smaller than the predetermined percentage,

the comparator means further inhibiting the counting means and signaling the second latching register means when the actual percentage is larger than the predetermined percentage,

the second register means sends the number of counts corresponding to the number of spectral lines obtained by accumulating the energy in the summing means to the read-only memory means,

modem means responsive to the cutoff frequency determined by the processing means for translating the data signals to a position in the transmission band above the cutoff frequency, and

filtering means responsive to the processing means for assigning the speech and the translated data signals within said transmission band respectively below and above the cutoff frequency.

3. A method for interpolating digital data and analog speech signals into a common transmission band comprising the steps of,

holding the digital data signal,

converting the analog speech signal into digital form,

determining the frequency spectrum of the digitized speech signal,

determining the total energy within the frequency spectrum,

determining the actual percentage of energy within each spectral line,

summing the actual percentage of energy within each spectral line in sequence,

comparing the summed actual percentage energy with a predetermined percentage of energy in sequence,

receiving a number of counts corresponding to the number of spectral lines in sequence,

converting the number of spectral lines to the cutoff frequency of the digitized speech signal when the predetermined percentage of energy is reached,

translating the digital signal to a position above the cutoff frequency of the digital speech signal, and

sending the digitized speech signal and the translated data signal to a receiver.

4. A system for interpolating digital data and analog speech signals into a common transmission band comprising:

a first buffering means for holding digital data signals,

means for converting speech signals into digital form,

a second buffering means for holding digital speech signals received from the converting means, and

processing means for determining the cutoff frequency of speech signals in response to the first and second buffering means;

said processing means further comprising

discrete Fourier transform means for determining the frequency spectrum of the digitized speech signal,

normalization means for determining the total energy of the frequency spectrum of the discrete Fourier of energy within each spectral line of the speech signal,

summing means for accumulating the actual percentage of energy within each spectral line,

first latching register means for storing the accumulation of the actual percentage of energy within each spectral line and for feeding the actual percentage back to the summing means,

comparator means for receiving the actual percentage of energy from the first register means and comparing it with a predetermined percentage from the second buffer means,

counting means for receiving the number of counts corresponding to the number of spectral lines from the normalization means,

second latching register means for receiving the number of counts corresponding to the number of spectral lines from the counting means,

read-only memory means for converting the number of spectral lines from the second latching register means to the cutoff frequency of the speech signal,

the comparator means signaling a counting means when the actual percentage is smaller than the predetermined percentage;

said comparator means further inhibiting the counting means and signaling the second latching register means when the actual percentage is larger than the predetermined percentage,

the second register means sends the number of counts corresponding to the number of spectral lines obtained by accumulating the energy in the summing means to the read-only memory means,

modem means responsive to the cutoff frequency determined by the processing means for translating the data signals to a position in the transmission band above the cutoff frequency, and the modem means further comprising a plurality of submodems, each submodem being associated wth a discrete cutoff frequency, and

filtering means responsive to the processing means for assigning the speech and the translated data signals within said transmission band respectively below and above the cutoff frequency.

5. A system for interpolating digital data and analog speech signals into a common transmission band comprising:

a first buffering means for holding digital data signals,

means for converting speech signals into digital form,

a second buffering means for holding digital speech signals received from the converting means, and

processing means for determining the cutoff frequency of speech signals in response to the first and second buffering means;

the processing means further comprising

discrete Fourier transform means for determining the frequency spectrum of the digitized speech signal,

normalization means for determining the total energy of the frequency spectrum of the discrete Fourier transform means and for determining the actual percentage of energy within each spectral line of the speech signal,

summing means for accumulating the actual percentage of energy within each spectral line,

first latching register means for storing the accumulation of the actual percentage of energy within each spectral line and for feeding the actual percentage back to the summing means,

comparator means for receiving the actual percentage of energy from the first register means and comparing it with a predetermined percentage from the second buffer means,

counting means for receiving the number of counts corresponding to the number of spectral lines from the normalization means,

second latching register means for receiving the number of counts corresponding to the number of spectral lines from the counting means,

read-only memory means for converting the number of spectral lines from the second latching register means, to the cutoff frequency of the speech signal,

the comparator means signaling a counting means when the actual percentage is smaller than the predetermined percentage,

the comparative means further inhibiting the counting means and signaling the second latching register means when the actual percentage is larger than the predetermined percentage,

the second register means sends the number of counts corresponding to the number of spectral lines obtained by accumulating the energy in the summing means to the read-only memory means,

modem means responsive to the cutoff frequency determined by the processing means for translating the data signals to a position in the transmission band above the cutoff frequency, and

filtering means responsive to the processing means for assigning the speech and the translated data signals within said transmission band respectively below and above the cutoff frequency;

the filtering means further comprising,

a complementary pair of time varying high-pass, low-pass filters,

the high-pass portion of the filtering means operating on the data signal from said modem means and

the low-pass portion of the filter operating on the speech signal from the second buffering means.

6. A system for interpolating digital data and analog speech signals into a common transmission band comprising:

a first buffering means for holding digital data signals,

means for converting speech signals into digital form,

a second buffering means for holding digital speech signals received from the converting means,

processing means for determining the cutoff frequency in response to the first and second buffering means;

said processing means further comprising,

discrete Fourier transform means for determining the frequency spectrum of the digitized speech signal,

normalization means for determining the total energy of the frequency spectrum of the discrete Fourier transform means and for determining the actual percentage of energy within each spectral line of the speech signal,

summing means for accumulating the actual percentage of energy within each spectral line,

first latching register means for storing the accumulation of the actual percentage of energy within each spectral line and for feeding the actual percentage back to the summing means,

comparator means for receiving the actual percentage of energy from the first register means and comparing it with a predetermined percentage from the second buffer means,

counting means for receiving the number of counts corresponding to the number of spectral lines from the normalization means,

second latching register means for receiving the number of counts corresponding to the number of spectral lines from the counting means,

read-only memory means for converting the number of spectral lines from the second latching register means, to the cutoff frequency of the speech signal,

the comparator means signaling a counting means when the actual percentage is smaller than the predetermined percentage,

the comparator means further inhibiting the counting means and signaling the second latching register means when the actual percentage is larger than the predetermined percentage,

the second register means sends the number of counts corresponding to the number of spectral lines obtained by accumulating the energy in the summing means to the read-only memory means,

modem means responsive to the cutoff frequency determined by the processing means for translating the data signals to a position in the transmission band above the cutoff frequency;

said modem means further comprising

a plurality of submodems, each submodem being associated with a discrete cutoff frequency, and

fittering means respnsive to the processing means for assigning the speech and the translated data signals within said transmission band respectively below and above the cutoff frequency;

the filtering means further comprising

a complementary pair of time-varying, high-pass, low-pass filters;

the high-pass portion of the filtering means operating on the data signal from said modem means and the speech signal from the second buffering means.