Patent EP0795977A2 successfully refreshed from Google Patents.
EP0795977A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Method of transmitting an ADSL signal simultaneously with an ISDN signal
Assignee: NXP USA Inc
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Filing: 1997-02-28
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Granted: —
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Expires: 2017-02-28
Abstract
Abstract A flexible asymmetrical digital subscriber line (ADSL) transmitter is able to operate simultaneously with integrated services digital network (ISDN) terminal equipment (TE) using a common telephone line (18). The ADSL transmitter changes the frequency content of a frequency-encoded ADSL signal (104) so that its frequency content does not overlap the frequency content of the ISDN TE signal. A corresponding ADSL receiver located within a central office (CO) adapts to the changed frequency content, allowing the ADSL signal to be transmitted over the telephone line without substantial loss of signal integrity. In one embodiment, an ADSL transmitter (100) converts ADSL symbols making up the frequency-encoded ADSL signal (104) into a corresponding time domain signal. The transmitter (100) then interpolates the time domain signal and high pass filters the interpolated signal. This high pass filtered signal is then converted to analog form, bandpass filtered, and driven onto the telephone line (18).
Inventors
- 👤 Mathew A. Rybicki
- 👤 Michael R. May
- 👤 Matthew A. Pendleton
- 👤 Terance L. Johnson
- 👤 Peter R. Molnar
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 04:03
CPC Classifications
H; H04; H04Q; H04Q11/00; H04Q11/04; H04Q11/0428; H04Q11/0435; H04L; H04L27/00; H04L27/0002; H04L5/00; H04L5/02; H04L5/06; H04Q2213/00; H04Q2213/13034; H04Q2213/13107; H04Q2213/1313; H04Q2213/1319; H04Q2213/13199; H04Q2213/13209; H04Q2213/13376; H04Q2213/13396
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
249 words
An asymmetric digital subscriber line (ADSL) transmitter (100) for transmitting an upstream signal from a remote terminal (RT) (32) to a central office (CO) (40) via a telephone line (18), and adapted for use with a signal source (38) simultaneously conducting a signal with a first frequency content via the telephone line (18), comprising: a frequency-to-time converter (106) having an input for receiving a frequency-encoded ADSL data signal (104), and an output for providing a processed signal (108) with a second frequency content; an interpolator (110) having an input coupled to said output of said frequency-to-time converter (106), and an output for providing an interpolated output signal (112) with a third frequency content; a high pass filter (114) having an input coupled to said output of said interpolator (110), and an output for providing a high pass filtered output signal (116) with a fourth frequency content, a cutoff frequency of said high pass filter (114) being above said first frequency content; a digital-to-analog converter (DAC) (118) having an input coupled to said output of said high pass filter (114), and an output; and a bandpass filter (122) having an input coupled to said output of said DAC (118), and an output coupled to the telephone line (18) for providing the upstream signal with a fifth frequency content; wherein the upstream signal is representative of said frequency-encoded ADSL data signal (104) but has said fifth frequency content, and said fifth frequency content and said first frequency content are substantially nonoverlaping.
Claim 2
Dependent Claim
25 words
The ADSL transmitter (100) of claim 1 wherein said interpolator (110) operates at a rate equal to twice a rate of said frequency-to-time converter (106).
Claim 3
Dependent Claim
21 words
The ADSL transmitter (100) of claim 1 wherein said frequency-to-time converter (106) comprises an inverse fast Fourier transform (IFFT) signal processor.
Claim 4
Dependent Claim
263 words
An asymmetric digital subscriber line (ADSL) transmitter (130) for transmitting an upstream signal from a remote terminal (RT) (32) to a central office (CO) (40) via a telephone line (18), and adapted for use with a signal source (38) simultaneously conducting a signal with a first frequency content via the telephone line (18), comprising: a frequency-to-time converter (106) having an input for receiving a frequency-encoded ADSL data signal (104), and an output for providing a processed signal (108) with a second frequency content; an interpolator (110) having an input coupled to said output of said frequency-to-time converter (106), and an output for providing an interpolated output signal (112) with a third frequency content; a low pass filter (132) having an input coupled to said output of said interpolator (110), and an output for providing a low pass filtered output signal (134) with a fourth frequency content, a cutoff frequency of said low pass filter (132) being above said second frequency content; a multiplier (135) having a first input coupled to said output of said low pass filter (132), a second input for receiving a mixing signal, and an output (136); a digital-to-analog converter (DAC) (118) having an input coupled to said output of said multiplier (135), and an output; and a bandpass filter (122) having an input coupled to said output of said DAC (118), and an output coupled to the telephone line (18) for providing the upstream signal having a fifth frequency content, wherein said upstream signal is representative of said frequency-encoded ADSL data signal (104) but has said fifth frequency content.
Claim 5
Dependent Claim
21 words
The ADSL transmitter (130) of claim 4 wherein said frequency-to-time converter (106) comprises an inverse fast Fourier transform (IFFT) signal processor.
Claim 6
Dependent Claim
200 words
An asymmetric digital subscriber line (ADSL) transmitter (140) for transmitting an upstream signal from a remote terminal (RT) (32) to a central office (CO) (40) via a telephone line (18), and adapted for use with a signal source (38) simultaneously conducting a signal with a first frequency content via the telephone line (18), comprising: an frequency-to-time converter (106) having an input for receiving a frequency-encoded ADSL data signal (104), and an output for providing a processed signal (108) with a second frequency content; an interpolator (110) having an input coupled to said output of said frequency-to-time converter (106), and an output for providing an interpolated output signal (112) with a third frequency content; a digital-to-analog converter (DAC) (142) having an input coupled to said output of said interpolator (110), and an output; and a bandpass filter (144) having an input coupled to said output of said DAC (142), and an output coupled to the telephone line (18) for providing the upstream signal with a fourth frequency content, said bandpass filter (144) having a low frequency cutoff above said first frequency content, wherein the upstream signal is representative of said frequency-encoded ADSL data signal (104) but has said fourth frequency content.
Claim 7
Dependent Claim
195 words
An asymmetric digital subscriber line (ADSL) transmitter (150) for transmitting an upstream signal from a remote terminal (RT) (32) to a central office (CO) (40) via a telephone line (18), and adapted for use with a signal source (38) simultaneously conducting a signal with a first frequency content via the telephone line (18), comprising: a frequency-to-time converter (152) having a first input for receiving said frequency-encoded ADSL data signal, and an output for providing a processed signal (153) having a data rate which is an integer multiple of a data rate of said frequency-encoded ADSL data signal (104), said processed signal (153) having a third frequency content; a digital-to-analog converter (DAC) (154) having an input coupled to said output of said frequency-to-time converter (152), and an output; and a bandpass filter (158) having an input coupled to said output of said DAC (154), and an output coupled to the telephone line (18) for providing the upstream signal with a fourth frequency content, said bandpass filter (158) having a low frequency cutoff above said first frequency content, wherein the upstream signal is representative of said frequency-encoded ADSL data signal (104) but has said fourth frequency content.
Claim 8
Dependent Claim
43 words
The ADSL transmitter (150) of claim 7 wherein said frequency-to-time converter (152) further has a second input for receiving a reference signal, wherein said frequency-to-time converter (152) performs frequency-to-time conversion on an input formed from a combination of said first and second inputs.
Claim 9
Dependent Claim
125 words
In an asymmetric digital subscriber line (ADSL) transmitter (100), a method for allowing a second signal source (38) providing a signal with a first frequency content, to simultaneously use a telephone line (18), comprising the steps of: receiving a frequency-encoded ADSL data signal (104); converting (106) said frequency-encoded ADSL data signal (104) into a time domain signal (108) having a second frequency content substantially according to American National Standards Institute (ANSI) Standard ANS T1.43, wherein said second frequency content overlaps said first frequency content; changing (110/114) said second frequency content into a third frequency content, wherein said third frequency content does not substantially overlap any portion of said first frequency content; and transmitting the output signal having said third frequency content on the telephone line.
Claim 10
Dependent Claim
126 words
A remote terminal (RT) (32) for connection to a telephone line (18), comprising: a first terminal (104) adapted for being coupled to an asymmetric digital subscriber line (ADSL) signal source (11) having a first frequency content; a second terminal adapted for being coupled to a second signal source (38) having a second frequency content, wherein said second frequency content overlaps a portion of said first frequency content; and a transmitter (106/110/142/144) coupled to said first terminal (104), wherein said transmitter (106/110/142/144) changes said first frequency content into a third frequency content, wherein said third frequency content does not substantially overlap any portion of said second frequency content, wherein said ADSL signal source (11) and said second signal source (38) may simultaneously utilize the telephone line (18).
References Cited (Backward Citations)
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