US5220583A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Digital fm demodulator with a reduced sampling rate
Assignee: Motorola Solutions Inc
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Filing: 1988-10-03
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Granted: 1993-06-15
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Expires: 2008-10-03
Abstract
Abstract A method of recovering a frequency modulated signal wherein the frequency modulated information signal is sampled at a rate less than the Nyquist sampling rate, following which the under sampled signal can be demodulated to extract the original information signal.
Inventors
- 👤 James D. Solomon
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 17:23
CPC Classifications
H; H04; H04B; H04B1/00; H04B1/06; H04B1/10; H03; H03D; H03D3/00; H03D3/006; H03D2200/00; H03D2200/0041; H03D2200/005; H03D2200/0052; H03D2200/0054; H03D2200/0056; H03D2200/006
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
124 words
A method of recovering an information signal that has been frequency modulated at a peak frequency deviation f p on a radio frequency carrier and contained substantially within an allotted communication channel to provide a frequency modulated signal, said allotted communication channel having a predetermined bandwidth of approximately plus/minus f MAX , said method comprising the steps of: A) sampling said frequency modulated signal at a sample rate f S , wherein said sample rate f S is: i) less than 2f MAX ; but ii) greater than 2f D ; to provide a resultant sampled signal that includes aliased information; B) demodulating said resultant sampled signal to recover said information signal without degradation that is attributable to the sample rate f S .
Claim 2
Independent Claim
124 words
A method of recovering an information signal that has been frequency modulated at a peak frequency deviation f p on a radio frequency carrier and contained substantially within an allotted communication channel to provide a frequency modulated signal, said allotted communication channel having a predetermined bandwidth of approximately plus/minus f MAX , said method comprising the steps of: A) sampling said frequency modulated signal at a sample rate f S , wherein said sample rate f S is: i) less than 2f MAX ; but ii) greater than 2f D ; to provide a resultant sampled signal that includes aliased information; B) demodulating said resultant sampled signal to recover said information signal without degradation that is attributable to the sample rate f S .
Claim 3
Dependent Claim
56 words
The method of claim 1 wherein said modulated signal comprises an FM signal, wherein said allotted channel has associated therewith a peak frequency deviation f D and a maximum frequency f M , and wherein said sampling rate f S is also no less than two times the greater of f M and f D .
Claim 4
Dependent Claim
24 words
The method of claim 1 wherein f MAX is substantially equal to 25 kHz and f S is substantially equal to 11 1/9 kHz.
Claim 5
Dependent Claim
36 words
The method of claim 1 wherein said modulated signal is sampled at a first sampling rate higher than said sampling rate f S , and then further decimated down to said sampling rate f S .
Claim 6
Dependent Claim
14 words
The method of claim 1 wherein said modulated signal comprises an angle modulated signal.
Claim 7
Dependent Claim
13 words
The method of claim 1 wherein said modulated signal comprises an FM signal.
Claim 8
Independent Claim
126 words
A device for recovering an information signal that has been frequency modulated at a peak frequency deviation f D on a radio frequency carrier and contained substantially within an allotted communication channel to provide a modulated signal, said allotted communication channel having a predetermined bandwidth of approximately plus/minus f MAX , said device comprising: A) sampling means for sampling said frequency modulated signal at a sample rate f S , wherein said sampling rate f S is; i) less than 2f MAX ; but ii) greater than 2f D ; to provide a resultant sampled signal that includes aliased information; B) demodulating means for demodulating said resultant samples signal to recover said information signal without degradation that is attributable to the sample rate f S .
Claim 9
Independent Claim
126 words
A device for recovering an information signal that has been frequency modulated at a peak frequency deviation f D on a radio frequency carrier and contained substantially within an allotted communication channel to provide a modulated signal, said allotted communication channel having a predetermined bandwidth of approximately plus/minus f MAX , said device comprising: A) sampling means for sampling said frequency modulated signal at a sample rate f S , wherein said sampling rate f S is; i) less than 2f MAX ; but ii) greater than 2f D ; to provide a resultant sampled signal that includes aliased information; B) demodulating means for demodulating said resultant samples signal to recover said information signal without degradation that is attributable to the sample rate f S .
Claim 10
Dependent Claim
14 words
The device of claim 7 wherein said modulated signal comprises a frequency modulated signal.
Claim 11
Dependent Claim
134 words
A radio for use with an information signal that has been frequency modulated at a peak frequency deviation f D on a radio frequency carrier and contained substantially within an allotted communication channel to provide a modulated signal, said allotted communication channel having a predetermined bandwidth of approximately plus/minus f MAX , said radio comprising: A) receiving means for receiving said modulated signal; B) sampling means for sampling said modulated signal at a sample rate f S , wherein said sample rate f S is; i) less than 2f MAX ; but ii) greater than 2f D ; to provide a resultant sampled signal that includes aliased information; C) demodulating means or demodulating said resultant sampled signal to recover said information signal without degradation that is attributable to the sample rate f S .
Claim 12
Dependent Claim
134 words
A radio for use with an information signal that has been frequency modulated at a peak frequency deviation f D on a radio frequency carrier and contained substantially within an allotted communication channel to provide a modulated signal, said allotted communication channel having a predetermined bandwidth of approximately plus/minus f MAX , said radio comprising: A) receiving means for receiving said modulated signal; B) sampling means for sampling said modulated signal at a sample rate f S , wherein said sample rate f S is; i) less than 2f MAX ; but ii) greater than 2f D ; to provide a resultant sampled signal that includes aliased information; C) demodulating means or demodulating said resultant sampled signal to recover said information signal without degradation that is attributable to the sample rate f S .
Claim 13
Dependent Claim
14 words
The radio of claim 9 wherein said modulated signal comprises a frequency modulated signal.
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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) | 1996-06-14 | 1996-12-14 | 1997-06-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-06-14 | 2000-12-14 | 2001-06-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-06-14 | 2004-12-14 | 2005-06-15 | $7700.00 | Window Closed / Lapsed |