US5952895A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Direct digital synthesis of precise, stable angle modulated RF signal
Assignee: Panasonic Holdings Corp
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Filing: 1998-02-23
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Granted: 1999-09-14
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Expires: 2018-02-23
Abstract
Abstract The present invention, generally speaking, provides an RF modulator that allows precise, stable phase shifts to be obtained. The modulator uses a PLL structure including an auxiliary feedforward path used to inject a baseband modulation signal into the PLL at a point past a loop filter of the PLL. A phase demodulator recovers phase information from the output signal of the PLL. The recovered phase information is compared to the phase information of the baseband modulation signal. A resulting error signal is used to control injection of the baseband modulation signal into the PLL, to automatically achieve the correct "dosage." A precise, adaptive, phase-stable modulator results. The adaptation of the modulator compensates for variability of the VCO and other components of the PLL.
Inventors
- 👤 Earl W. McCune, Jr.
- 👤 Wendell Sander
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 05:59
CPC Classifications
H; H03; H03C; H03C3/00; H03C3/02; H03C3/09; H03C3/0908; H03C3/0958; H03C3/0966; H03C3/08; H03C3/0916; H03C3/0925; H03C3/0941; H03C3/095; H03C5/00; H03B; H03B28/00; H03C2200/00; H03C2200/0037; H03C2200/005; H03C2200/0079
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
80 words
An RF modulator comprising: a phase lock loop including a loop filter and receiving as an input signal a baseband modulation signal and producing as an output signal a modulated RF signal; circuitry for producing an injection modulation signal; circuitry for injecting the injection modulation signal into the phase lock loop at a point past the loop filter; and control circuitry, coupled to the circuitry for injecting the injection modulation signal, for controlling the amplitude of the injection modulation signal.
Claim 2
Dependent Claim
80 words
An RF modulator comprising: a phase lock loop including a loop filter and receiving as an input signal a baseband modulation signal and producing as an output signal a modulated RF signal; circuitry for producing an injection modulation signal; circuitry for injecting the injection modulation signal into the phase lock loop at a point past the loop filter; and control circuitry, coupled to the circuitry for injecting the injection modulation signal, for controlling the amplitude of the injection modulation signal.
Claim 3
Dependent Claim
15 words
The apparatus of claim 1, wherein said circuitry for injecting comprises an adaptive gain amplifier.
Claim 4
Dependent Claim
13 words
The apparatus of claim 2, wherein said control circuitry includes a phase demodulator.
Claim 5
Dependent Claim
11 words
The apparatus of claim 3, wherein said phase demodulator is digital.
Claim 6
Dependent Claim
14 words
The apparatus of claim 4, wherein said control circuitry further comprises a comparison circuit.
Claim 7
Dependent Claim
29 words
The apparatus of claim 5, wherein the comparison circuit compares the baseband modulation signal to a phase information signal recovered by the phase demodulator and produces an error signal.
Claim 8
Dependent Claim
20 words
The apparatus of claim 6, wherein said error signal is used to set the gain of the adaptive gain amplifier.
Claim 9
Dependent Claim
33 words
The apparatus of claim 1, further comprising a direct digital synthesis circuit for receiving the baseband modulation signal, producing a corresponding modulated signal, and applying the modulated signal to the phase lock loop.
Claim 10
Dependent Claim
17 words
The apparatus of claim 8, wherein the direct digital synthesis circuit includes a number controlled modulated oscillator.
Claim 11
Dependent Claim
16 words
The apparatus of claim 1, wherein said phase lock loop includes a divide by N counter.
Claim 12
Dependent Claim
13 words
The apparatus of claim 1, wherein said phase lock loop includes a downconverter.
Claim 13
Dependent Claim
21 words
The apparatus of claim 1, further comprising a amplitude modulation stage coupled to the output signal of the phase lock loop.
Claim 14
Independent Claim
91 words
A method of producing precise, stable phase shifts in a modulated RF signal, comprising the steps of: using a baseband modulation signal, producing a modulated signal; applying the modulated signal as a reference signal to a phase lock loop; and automatically deriving an adaptive gain factor and applying the adaptive gain factor to the baseband modulation signal to produce an injection signal and injecting the injection signal into the phase lock loop; wherein the injection signal compensates for the phase lock loop partially removing modulation introduced by the baseband modulation signal.
Claim 15
Independent Claim
91 words
A method of producing precise, stable phase shifts in a modulated RF signal, comprising the steps of: using a baseband modulation signal, producing a modulated signal; applying the modulated signal as a reference signal to a phase lock loop; and automatically deriving an adaptive gain factor and applying the adaptive gain factor to the baseband modulation signal to produce an injection signal and injecting the injection signal into the phase lock loop; wherein the injection signal compensates for the phase lock loop partially removing modulation introduced by the baseband modulation signal.
Claim 16
Dependent Claim
49 words
The method of claim 13, wherein automatically deriving an adaptive gain factor comprises: recovering phase information from an output signal of the phase lock loop; comparing the phase information to the baseband modulation signal and producing an error signal, the adaptive gain factor being derived from the error 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) | 2002-09-13 | 2003-03-15 | 2003-09-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-09-13 | 2007-03-15 | 2007-09-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-09-13 | 2011-03-15 | 2011-09-14 | $7700.00 | Window Closed / Lapsed |