US3763359A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for equalizing a transmission system
Assignee: AT&T Inc
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Filing: 1972-05-15
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Granted: 1973-10-02
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Expires: 1992-05-15
Abstract
Abstract A method of adjusting Bode network equalizers utilizes three pilot signals for each network to achieve a minimum mean-squared error in a transmission system. These pilot signals, which are located at the center frequency of the network and half way between it and the center frequencies of the adjacent networks, are passed through the system and compared with a reference signal in order to generate error terms. A method of manually minimizing the error terms according to an iterative process and apparatus for automatically reducing it according to a steepest descent process are used to produce the minimum mean-squared error.
Inventors
- 👤 Sung Cho Yo
- 👤 F Kelcourse
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 20:45
CPC Classifications
H; H04; H04B; H04B3/00; H04B3/02; H04B3/04; H04B3/14; H04B3/141
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
213 words
Apparatus for equalizing a segment of a transmission line comprising a transmitting means connected to one end of said segment of transmission line for introducing a plurality of pilot signals into said segment of said transmission line, an equalizer connected to the other end of said segment of transmission line comprising at least one adjustable Bode network, the said one Bode network being adapted to equalize a predetermined band of frequencies, said plurality of pilot signals comprising an individual signal at the center of the band of frequencies equalized by the said Bode network, and individual signals at the frequencies midway between the center frequency and the upper and lower limits of the band of frequencies equalized by the Bode network, comparing means connected to said equalizer for comparing the pilot signals after transmission through said equalizer and said segment of said transmission line with reference signals and generating a plurality of error signals therefrom, and means connected between said comparing means and said equalizer to adjust the gain of the Bode network so that the sum of the error signal at the center frequency of the Bode network and the error signals at its adjacent pilot frequencies, multiplied by the relative Bode network gain at these frequencies, is substantially equal to zero.
Claim 2
Dependent Claim
213 words
Apparatus for equalizing a segment of a transmission line comprising a transmitting means connected to one end of said segment of transmission line for introducing a plurality of pilot signals into said segment of said transmission line, an equalizer connected to the other end of said segment of transmission line comprising at least one adjustable Bode network, the said one Bode network being adapted to equalize a predetermined band of frequencies, said plurality of pilot signals comprising an individual signal at the center of the band of frequencies equalized by the said Bode network, and individual signals at the frequencies midway between the center frequency and the upper and lower limits of the band of frequencies equalized by the Bode network, comparing means connected to said equalizer for comparing the pilot signals after transmission through said equalizer and said segment of said transmission line with reference signals and generating a plurality of error signals therefrom, and means connected between said comparing means and said equalizer to adjust the gain of the Bode network so that the sum of the error signal at the center frequency of the Bode network and the error signals at its adjacent pilot frequencies, multiplied by the relative Bode network gain at these frequencies, is substantially equal to zero.
Claim 3
Dependent Claim
126 words
Apparatus in accordance with claim 1 wherein said equalizer comprises a plurality of adjustable Bode networks, each of said Bode networks being adapted to equalize an individual predetermined band of frequencies having a center frequency and an upper frequency and a lower frequency, the center frequency of adjacent Bode networks being respectively at the upper and lower frequencies of said individual predetermined band of frequencies to provide continuous equalization over the entire frequency spectrum to be equalized, said plurality of pilot signals comprising an individual signal at the center frequency of each of said plurality of Bode networks and individual signals at frequencies midway between the center frequency and the upper and lower frequencies of said individual band of frequencies of each of said Bode networks.
Claim 4
Dependent Claim
23 words
Apparatus as claimed in claim 1 wherein the relative Bode network gain equals one-half at the pilot frequencies adjacent to the center frequencies.
Claim 5
Dependent Claim
118 words
Apparatus as claimed in claim 1 wherein said means for adjusting the gain comprises a steepest descent circuit, comprising: means for generating a first sum signal by adding the error signal at the center frequency of the said Bode network to half the error signals at its adjacent pilot frequencies; means for integrating the first sum signal to obtain an integrated first sum signal; means for generating a first gain signal representing the gain setting of the said Bode network; means for generating a second sum signal by adding the integrated first sum signal to the first gain signal; and means for varying the gain setting of the said Bode network in response to the second sum signal.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-10-01 | 1977-04-02 | 1977-10-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-01 | 1981-04-02 | 1981-10-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-01 | 1985-04-02 | 1985-10-02 | $7700.00 | Window Closed / Lapsed |