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US5486789A
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Apparatus and method for providing a baseband digital error signal in an adaptive predistorter
Assignee: Google Technology Holdings LLC
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Filing: 1995-02-28
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Granted: 1996-01-23
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Expires: 2015-02-28
Abstract
Abstract The present invention provides an apparatus (200) and method (500) for providing a baseband digital error signal in an adaptive predistorter. A carrier cancellation circuit (202) provides a difference (212) between a first signal (208) based on an amplifier output and second signal (210) based on a data input. A quadrature demodulator (204) provides a baseband analog error signal (214) based on the difference (212). An analog-to-digital converter (206) provides the baseband digital error signal (216) based on the baseband analog error signal (214).
Inventors
- 👤 Robert L. Palandech
- 👤 Wayne H. Bradley
- 👤 George F. Opas
- 👤 James E. Mitzlaff
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 22:37
CPC Classifications
H; H03; H03F; H03F1/00; H03F1/32; H03F1/3241; H03F1/3258; H03F1/3247; H03F2200/00; H03F2200/57; H03F2201/00; H03F2201/32; H03F2201/3233
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
117 words
An apparatus for providing a baseband digital error signal for an adaptive predistorter, wherein the adaptive predistorter comprises a first signal based on an amplifier output and a second signal based on a data input, the apparatus comprising: a) a carrier cancellation circuit, operably coupled to receive the first signal and the second signal, for deriving a high frequency analog error signal as a difference between the first signal and the second signal; b) a quadrature demodulator, operably coupled to the carrier cancellation circuit, for deriving a baseband analog error signal by demodulating the high frequency analog error signal; and c) an analog-to-digital converter, operably coupled to the quadrature demodulator, for deriving the baseband digital error signal.
Claim 2
Independent Claim
117 words
An apparatus for providing a baseband digital error signal for an adaptive predistorter, wherein the adaptive predistorter comprises a first signal based on an amplifier output and a second signal based on a data input, the apparatus comprising: a) a carrier cancellation circuit, operably coupled to receive the first signal and the second signal, for deriving a high frequency analog error signal as a difference between the first signal and the second signal; b) a quadrature demodulator, operably coupled to the carrier cancellation circuit, for deriving a baseband analog error signal by demodulating the high frequency analog error signal; and c) an analog-to-digital converter, operably coupled to the quadrature demodulator, for deriving the baseband digital error signal.
Claim 3
Dependent Claim
125 words
The apparatus of claim 1, wherein the apparatus further comprises: d) a memory updater, operably coupled to the analog-to-digital converter and to receive the data input, for updating a plurality of scaling factors; e) a random access memory, operably coupled to the memory updater, for storage of the scaling factors; f) a memory-lookup encoder, operably coupled to receive the data input, for determining a scaling factor to be accessed from the random access memory; g) a multiplier, operably coupled to the storage unit and data input, for multiplying the data input by the scaling factor determined by the encoder to provide a scaled input; and h) a radio frequency amplifier, operably coupled to the multiplier, for amplifying the scaled input to provide the amplifier output.
Claim 4
Dependent Claim
29 words
The apparatus of claim 1 wherein the carrier cancellation circuit further comprises a filter operably coupled to receive and filter the second signal to produce a filtered second signal.
Claim 5
Dependent Claim
29 words
The apparatus of claim 3 wherein the filter comprises one of an electronically adjustable analog filter, an adjustable tap surface acoustic wave (SAW) filter and a programmable digital device.
Claim 6
Dependent Claim
32 words
The apparatus of claim 4 further comprising a filter control element having an input coupled to receive at least one voltage signal and an output coupled to an input of the filter.
Claim 7
Dependent Claim
23 words
The apparatus of claim 5 wherein the at least one voltage signal comprises an average amplitude of the high frequency analog error signal.
Claim 8
Dependent Claim
21 words
The apparatus of claim 5 wherein the at least one voltage signal comprises an average amplitude of the filtered second signal.
Claim 9
Independent Claim
87 words
A method for providing a baseband digital error signal for an adaptive predistorter, wherein the adaptive predistorter comprises a first signal based on an amplifier output and a second signal based on a data input, the method comprising: a) deriving a high frequency analog error signal as a difference between the first signal and the second signal; b) deriving a baseband analog error signal by demodulating the high frequency analog error signal; and c) deriving the baseband digital error signal by using an analog to digital conversion.
Claim 10
Independent Claim
87 words
A method for providing a baseband digital error signal for an adaptive predistorter, wherein the adaptive predistorter comprises a first signal based on an amplifier output and a second signal based on a data input, the method comprising: a) deriving a high frequency analog error signal as a difference between the first signal and the second signal; b) deriving a baseband analog error signal by demodulating the high frequency analog error signal; and c) deriving the baseband digital error signal by using an analog to digital conversion.
Claim 11
Dependent Claim
62 words
The method of claim 8, wherein the method further comprises: d) updating a plurality of scaling factors; e) storing the plurality of scaling factors; f) determining a scaling factor of the plurality of scaling factors to access; g) multiplying the data input by the scaling factor to provide a scaled input; and h) amplifying the scaled input to provide the amplifier output.
Claim 12
Dependent Claim
14 words
The method of claim 8 further comprising the step of filtering the second 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) | 1999-01-22 | 1999-07-24 | 2000-01-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-01-22 | 2003-07-24 | 2004-01-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-01-22 | 2007-07-24 | 2008-01-23 | $7700.00 | Window Closed / Lapsed |