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US5930299A
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Digital modulator with compensation and method therefor
Assignee: Google Technology Holdings LLC
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Filing: 1996-08-08
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Granted: 1999-07-27
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Expires: 2016-08-08
Abstract
Abstract In a digital modulator with compensation, a digital bit stream from a microphone (705), a speech coder (706), and a channel encoder (707) is sent to an encoder (720) which translates the bits into I/Q digital pulses with phase shift keying. A symbol correlater (730) notes when predetermined target phase symbol sequences, which contribute to a high peak-to-average power ratio, enter the encoder. If a target symbol sequence is encountered, the correlater directs compensation amplifiers or compensation filters (734, 737) of the I/Q signals. Next, I/Q pulse shaping filters (764, 765) filter the I/Q pulses according to communication system specifications. The filtered I/Q signals are then sent to a quadrature modulator (790) for RF modulation. Compensation of target symbol sequences reduces the negative impact they have on peak-to-average power ratio and increases the efficiency of the power amplifier (795) which extends the battery life of a communication device (700).
Inventors
- 👤 Louis Jay Vannatta
- 👤 William P. Alberth, Jr.
- 👤 Terrie L. Frane
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 21:14
CPC Classifications
H; H04; H04L; H04L27/00; H04L27/18; H04L27/20; H04L27/2032; H04L27/2053; H04L27/206; H04L27/2067; H04L27/2071
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
85 words
A digital modulator with compensation comprising: an encoder for translating an input signal into an encoded signal; a symbol correlater, coupled to the encoder, for identifying a predetermined target symbol sequence in the input signal and producing a selection signal; a compensation circuit, coupled to the symbol correlater, for filtering a portion of the encoded signal as directed by the selection signal to create a composite signal; a pulse shaping filter coupled to the compensation circuit; and a modulator coupled to the pulse shaping filter.
Claim 2
Dependent Claim
85 words
A digital modulator with compensation comprising: an encoder for translating an input signal into an encoded signal; a symbol correlater, coupled to the encoder, for identifying a predetermined target symbol sequence in the input signal and producing a selection signal; a compensation circuit, coupled to the symbol correlater, for filtering a portion of the encoded signal as directed by the selection signal to create a composite signal; a pulse shaping filter coupled to the compensation circuit; and a modulator coupled to the pulse shaping filter.
Claim 3
Dependent Claim
23 words
A digital modulator with compensation according to claim 1 wherein the compensation circuit adjusts an amplitude of a portion of the encoded signal.
Claim 4
Dependent Claim
23 words
A digital modulator with compensation according to claim 1 wherein the compensation circuit adjusts a phase of a portion of the encoded signal.
Claim 5
Dependent Claim
17 words
A digital modulator with compensation according to claim 1 wherein the compensation circuit comprises: a lowpass filter.
Claim 6
Dependent Claim
24 words
A digital modulator with compensation according to claim 1 wherein the compensation circuit and the pulse shaping filter are implemented using a single filter.
Claim 7
Dependent Claim
19 words
A digital modulator with compensation according to claim 5 wherein the single filter is a finite-duration impulse response filter.
Claim 8
Dependent Claim
73 words
A digital modulator with compensation according to claim 6 wherein the finite-duration impulse response filter comprises: a storage element for storing the encoded signal; a memory element, coupled to the storage element, for storing values representing an uncompensated filter coefficient multiplied by an encoded signal magnitude and a compensated filter coefficient multiplied by an encoded signal magnitude; and a summing element, coupled to the memory element, for summing values from the memory element.
Claim 9
Dependent Claim
17 words
A digital modulator with compensation according to claim 7 wherein the storage element is a shift register.
Claim 10
Dependent Claim
17 words
A digital modulator with compensation according to claim 7 wherein the memory element is a read-only memory.
Claim 11
Dependent Claim
20 words
A digital modulator with compensation according to claim 7 wherein the summing element is an arithmetic logic unit and accumulator.
Claim 12
Dependent Claim
101 words
A radiotelephone comprising: a microphone for receiving an input signal; an encoder, coupled to the microphone, for translating the input signal into an encoded signal; a symbol correlater, coupled to the encoder, for identifying a predetermined target symbol sequence in the input signal and producing a selection signal; a compensation circuit, coupled to the symbol correlater, for filtering a portion of the encoded signal as directed by the selection signal to create a composite signal; a pulse shaping filter coupled to the compensation circuit; a modulator coupled to the pulse shaping filter; and a power amplifier coupled to the quadrature modulator.
Claim 13
Dependent Claim
101 words
A radiotelephone comprising: a microphone for receiving an input signal; an encoder, coupled to the microphone, for translating the input signal into an encoded signal; a symbol correlater, coupled to the encoder, for identifying a predetermined target symbol sequence in the input signal and producing a selection signal; a compensation circuit, coupled to the symbol correlater, for filtering a portion of the encoded signal as directed by the selection signal to create a composite signal; a pulse shaping filter coupled to the compensation circuit; a modulator coupled to the pulse shaping filter; and a power amplifier coupled to the quadrature modulator.
Claim 14
Dependent Claim
14 words
A radiotelephone according to claim 11 wherein the compensation circuit comprises: an allpass filter.
Claim 15
Dependent Claim
14 words
A radiotelephone according to claim 11 wherein the compensation circuit comprises: a lowpass filter.
Claim 16
Dependent Claim
21 words
A radiotelephone according to claim 11 wherein the compensation circuit and the pulse shaping filter are implemented using a single filter.
Claim 17
Independent Claim
57 words
A method for modulating a composite signal comprising the steps of: translating an input signal into an encoded signal; identifying a predetermined target symbol sequence in the input signal and creating a selection signal; filtering a portion of the encoded signal as directed by the selection signal to create a composite signal; and modulating the composite signal.
Claim 18
Independent Claim
57 words
A method for modulating a composite signal comprising the steps of: translating an input signal into an encoded signal; identifying a predetermined target symbol sequence in the input signal and creating a selection signal; filtering a portion of the encoded signal as directed by the selection signal to create a composite signal; and modulating the composite signal.
Claim 19
Dependent Claim
27 words
A method for modulating a composite signal according to claim 15 wherein the step of filtering comprises: adjusting an amplitude of a portion of the encoded signal.
Claim 20
Dependent Claim
27 words
A method for modulating a composite signal according to claim 15 wherein the step of filtering comprises: adjusting a phase of a portion of the encoded signal.
Claim 21
Dependent Claim
25 words
A method for modulating a composite signal according to claim 15 wherein the step of filtering comprises: lowpass filtering a portion of the encoded 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) | 2002-07-26 | 2003-01-25 | 2003-07-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-07-26 | 2007-01-25 | 2007-07-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-07-26 | 2011-01-25 | 2011-07-27 | $7700.00 | Window Closed / Lapsed |