US5239699A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Am-fm combined stereo receiver
Assignee: Motorola Solutions Inc
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Filing: 1991-02-06
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Granted: 1993-08-24
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Expires: 2011-02-06
Abstract
Abstract An improved AM-FM combined stereo receiver is provided having a single processor for removing, in the FM mode, arctangent distortion, and in the AM mode, to process the phase term from arctangent ##EQU1## to determine ##EQU2## Further, the radio includes a single discriminator circuit wherein, in the FM mode, the discriminator tank circuit is used to convert frequency deviation to baseband audio and, in the AM mode, the discriminator tank circuit is used as the frequency-determining element for the voltage controlled oscillator (VCO), the VCO being used to translate the intermediate frequency (IF) signal to baseband.
Inventors
- 👤 Lawrence M. Ecklund
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 14:10
CPC Classifications
H; H04; H04H; H04H20/00; H04H20/44; H04H20/46; H04H20/47; H04H20/49; H04B; H04B1/00; H04B1/06; H04B1/16; H04B1/1646
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
111 words
A radio having an FM mode and an AM mode and arranged for receiving FM-band stereo signals in the FM mode and AM-band stereo signals in the AM mode and having baseband detector means for providing in the FM mode a baseband FM signal, the baseband FM signal including arctangent distortion, and baseband detector means for providing in the AM mode a baseband AM stereo phase signal, the AM stereo phase signal including a phase term, the radio further having a single tangent function processor for removing the arctangent distortion in the FM mode and for processing the phase term from tan -1 ##EQU5## to provide ##EQU6## in the AM mode.
Claim 2
Dependent Claim
111 words
A radio having an FM mode and an AM mode and arranged for receiving FM-band stereo signals in the FM mode and AM-band stereo signals in the AM mode and having baseband detector means for providing in the FM mode a baseband FM signal, the baseband FM signal including arctangent distortion, and baseband detector means for providing in the AM mode a baseband AM stereo phase signal, the AM stereo phase signal including a phase term, the radio further having a single tangent function processor for removing the arctangent distortion in the FM mode and for processing the phase term from tan -1 ##EQU5## to provide ##EQU6## in the AM mode.
Claim 3
Dependent Claim
16 words
The radio of claim 1, further having switch means for controlling the mode of the radio.
Claim 4
Dependent Claim
27 words
The radio of claim 2, wherein the single tangent function processor has a first gain in the FM mode and a second gain in the AM mode.
Claim 5
Dependent Claim
43 words
The radio of claim 3, further including an FM discriminator circuit having an arctangent function, and wherein the single tangent function processor is further arranged so that the first gain is adjusted to compensate for the arctangent function of the FM discriminator circuit.
Claim 6
Dependent Claim
32 words
The radio of claim 4, wherein the single tangent function processor is further arranged so that the second gain is adjusted to compensate for the arctangent function in the received AM signal.
Claim 7
Dependent Claim
25 words
The radio of claim 5, wherein the single tangent function processor comprises a tangent function generator that is based on a precision piecewise linear construction.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-08-23 | 1997-02-22 | 1997-08-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-08-23 | 2001-02-22 | 2001-08-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-08-23 | 2005-02-22 | 2005-08-24 | $7700.00 | Window Closed / Lapsed |