US3624299A
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Apparatus and method
Assignee: Applied Digital Data Systems Inc
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Filing: 1969-11-13
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Granted: 1971-11-30
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Expires: 1989-11-13
Abstract
Abstract A method of and an apparatus for cancelling second harmonics in electrical signals resulting from nonlinear devices within electrical networks. The signal applied to the network includes not only the fundamental frequency of interest, but also a component at a frequency equal to the third harmonic of that fundamental frequency. If a nonlinear device is included in the network, energy at new frequencies is generated including components at the frequency of the second harmonic of the fundamental frequency of interest. These second harmonic components are adjusted to cancel each other so that the output has no component at that second harmonic frequency. This cancellation is usable in a broad range of applications including, for example, acoustic couplers utilized in data transmission over telephone networks in which the telephone microphone is nonlinear, causing second harmonics of the transmitted signal which if uncancelled would interfere with received signals during full-duplex operation.
Inventors
- 👤 Reuven Meidan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 10:48
CPC Classifications
H; H04; H04L; H04L27/00; H04L27/10
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
71 words
A method of cancelling the second harmonic component of a fundamental frequency signal resulting from application of the fundamental frequency signal to a nonlinear device comprising adding to the fundamental frequency signal prior to application to the nonlinear device a component having a frequency equal to the third harmonic of the fundamental frequency signal and adjusting the magnitude and phase of the added component to substantially eliminate the second harmonic component.
Claim 2
Independent Claim
71 words
A method of cancelling the second harmonic component of a fundamental frequency signal resulting from application of the fundamental frequency signal to a nonlinear device comprising adding to the fundamental frequency signal prior to application to the nonlinear device a component having a frequency equal to the third harmonic of the fundamental frequency signal and adjusting the magnitude and phase of the added component to substantially eliminate the second harmonic component.
Claim 3
Dependent Claim
34 words
A method as claimed in claim 1 in which the added component magnitude is adjusted to a value substantially one-half the magnitude of the fundamental frequency signal prior to application to the nonlinear device.
Claim 4
Dependent Claim
28 words
A method as claimed in claim 2 in which the added component phase is adjusted to bring the added component substantially into phase with the fundamental frequency signal.
Claim 5
Independent Claim
126 words
A method of obtaining in response to an input fundamental frequency signal applied to a nonlinear circuit device an output signal including a component at the frequency of the input fundamental frequency signal and lacking components at the frequency of the second harmonic of the input fundamental frequency signal, said method comprising applying to the nonlinear circuit device a composite input signal including a first portion consisting of the input fundamental frequency signal and including a second portion consisting of a signal at a frequency equal to the third harmonic of the input fundamental frequency signal, and adjusting the magnitude and phase of the second portion to substantially eliminate from the output signal components at the frequency of the second harmonic of the fundamental frequency signal.
Claim 6
Independent Claim
126 words
A method of obtaining in response to an input fundamental frequency signal applied to a nonlinear circuit device an output signal including a component at the frequency of the input fundamental frequency signal and lacking components at the frequency of the second harmonic of the input fundamental frequency signal, said method comprising applying to the nonlinear circuit device a composite input signal including a first portion consisting of the input fundamental frequency signal and including a second portion consisting of a signal at a frequency equal to the third harmonic of the input fundamental frequency signal, and adjusting the magnitude and phase of the second portion to substantially eliminate from the output signal components at the frequency of the second harmonic of the fundamental frequency signal.
Claim 7
Dependent Claim
70 words
A method as claimed in claim 4 in which the composite input signal is generated by generating a first signal at a frequency equal to the third harmonic of the fundamental frequency signal, applying the first signal to a frequency divider to generate the first portion, applying the first signal to a magnitude and phase controller to generate the second portion, and summing the first portion and the second portion.
Claim 8
Dependent Claim
104 words
Apparatus for cancelling the second harmonic component of a fundamental frequency signal resulting from application of the fundamental frequency signal to a nonlinear device comprising a first signal source for providing a fundamental frequency signal; a second signal source for providing a second signal with a frequency equal to the third harmonic of the fundamental frequency signal, the second signal source including means for adjusting the magnitude and phase of the second signal relative to the first; means for summing the fundamental frequency signal and the second signal; and means for applying the summed fundamental frequency signal and second signal to a nonlinear device.
Claim 9
Dependent Claim
104 words
Apparatus for cancelling the second harmonic component of a fundamental frequency signal resulting from application of the fundamental frequency signal to a nonlinear device comprising a first signal source for providing a fundamental frequency signal; a second signal source for providing a second signal with a frequency equal to the third harmonic of the fundamental frequency signal, the second signal source including means for adjusting the magnitude and phase of the second signal relative to the first; means for summing the fundamental frequency signal and the second signal; and means for applying the summed fundamental frequency signal and second signal to a nonlinear device.
Claim 10
Dependent Claim
71 words
Apparatus as claimed in claim 6: a. further comprising an oscillator for providing an oscillator signal at a frequency equal to the third harmonic of the fundamental frequency signal; and b. in which the first signal source comprises a frequency divider connected to the oscillator for generating the fundamental frequency signal and the second signal source comprises an amplitude and phase controller connected to the oscillator for generating the second signal.
Claim 11
Dependent Claim
204 words
An electroacoustic coupler comprising: an oscillator adapted for connection to a source of digital signals, said oscillator providing in response to a digital signal of a first type a first oscillator output of a first frequency, said oscillator providing in response to a digital signal of a second type a second oscillator output of a second frequency; a frequency divider connected to the oscillator for dividing the frequency of signals applied thereto by three to provide a first fundamental frequency signal in response to the first oscillator output and a second fundamental frequency signal in response to the second oscillator output; amplitude and phase control means connected to the oscillator for providing an amplitude-and-phase controlled signal; summing means connected to the frequency divider and to the amplitude-and-phase control means, for providing the combined output from the frequency divider and the amplitude-and-phase control means; a loudspeaker connected to the summing means for providing acoustic signals in response to the combined output from the summing means; a microphone for providing electrical signals in response to acoustic signals applied thereto; and signal receiver means connected to said microphone and adapted for connection to digital-signal-utilizing device for providing digital signals in response to electrical signals from the microphone.
Claim 12
Dependent Claim
204 words
An electroacoustic coupler comprising: an oscillator adapted for connection to a source of digital signals, said oscillator providing in response to a digital signal of a first type a first oscillator output of a first frequency, said oscillator providing in response to a digital signal of a second type a second oscillator output of a second frequency; a frequency divider connected to the oscillator for dividing the frequency of signals applied thereto by three to provide a first fundamental frequency signal in response to the first oscillator output and a second fundamental frequency signal in response to the second oscillator output; amplitude and phase control means connected to the oscillator for providing an amplitude-and-phase controlled signal; summing means connected to the frequency divider and to the amplitude-and-phase control means, for providing the combined output from the frequency divider and the amplitude-and-phase control means; a loudspeaker connected to the summing means for providing acoustic signals in response to the combined output from the summing means; a microphone for providing electrical signals in response to acoustic signals applied thereto; and signal receiver means connected to said microphone and adapted for connection to digital-signal-utilizing device for providing digital signals in response to electrical signals from the microphone.
Claim 13
Dependent Claim
93 words
In an electroacoustic coupler including means for providing a first fundamental frequency signal in response to a first digital signal of a first type and a second fundamental frequency signal in response to a digital signal of a second type, the improvement comprising means for providing with the first fundamental frequency signal a first component having a frequency equal to the third harmonic of the first fundamental frequency signal and with the second fundamental frequency signal a second component having a frequency equal to the third harmonic of the second fundamental frequency signal.
Claim 14
Dependent Claim
93 words
In an electroacoustic coupler including means for providing a first fundamental frequency signal in response to a first digital signal of a first type and a second fundamental frequency signal in response to a digital signal of a second type, the improvement comprising means for providing with the first fundamental frequency signal a first component having a frequency equal to the third harmonic of the first fundamental frequency signal and with the second fundamental frequency signal a second component having a frequency equal to the third harmonic of the second fundamental frequency signal.
References Cited (Backward Citations)
US2795650A
Cited
US3535456A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-11-29 | 1975-05-31 | 1975-11-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-11-29 | 1979-05-31 | 1979-11-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-11-29 | 1983-05-31 | 1983-11-30 | $7700.00 | Window Closed / Lapsed |