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US6018647A Expired / Lapsed US ⏱️ 0.0 years remaining

Diversity reception system

Assignee: IP MOBILENET LLC
•
Filing: 1997-11-10
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Granted: 2000-01-25
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Expires: 2017-11-10
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Abstract

Abstract A diversity reception system for use in narrow-band radio frequency communication systems includes a plurality of receivers that each generate a detected signal from a received radio frequency signal. The diversity reception system switches between receivers to output a high quality audio signal. The system selects a receiver having the highest quality reception at any given time by using a detected signal having the highest relative signal-to-noise ratio when the detected signals have less than a preselected threshold signal-to-noise ratio and a detected signal having the highest relative signal strength when one or more of the receivers is generating a detected signal having a signal-to-noise ratio at or above the preselected threshold signal-to-noise ratio.

Inventors

  • 👤 Shane Michael Fitzgerald

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-06 12:18
CPC Classifications
H; H04; H04B; H04B7/00; H04B7/02; H04B7/04; H04B7/08; H04B7/0802; H04B7/0817; H04B7/082

Claims Analysis

Total Claims: 23
Claim 1
Independent Claim 137 words
A diversity reception system for signal reception, comprising: a plurality of receivers, each receiver generating a detected signal from a received radio frequency signal; and a receiver selector coupled to each of the plurality of receivers to select a receiver and output the detected signal of the selected receiver, said receive selector including an audio selector for selecting the receiver from the plurality of receivers generating the detected signal having the highest relative signal-to-noise ratio when the detected signal from each of the receivers has a signal-to-noise ratio below a selected threshold signal-to-noise ratio corresponding to the maximum achievable signal-to-noise ratio, and for selecting the receiver from the plurality of receivers generating the detected signal having the highest relative signal strength when the detected signal from each of the receivers has a signal-to-noise ratio at the threshold.
Claim 2
Dependent Claim 137 words
A diversity reception system for signal reception, comprising: a plurality of receivers, each receiver generating a detected signal from a received radio frequency signal; and a receiver selector coupled to each of the plurality of receivers to select a receiver and output the detected signal of the selected receiver, said receive selector including an audio selector for selecting the receiver from the plurality of receivers generating the detected signal having the highest relative signal-to-noise ratio when the detected signal from each of the receivers has a signal-to-noise ratio below a selected threshold signal-to-noise ratio corresponding to the maximum achievable signal-to-noise ratio, and for selecting the receiver from the plurality of receivers generating the detected signal having the highest relative signal strength when the detected signal from each of the receivers has a signal-to-noise ratio at the threshold.
Claim 3
Dependent Claim 55 words
The diversity reception system of claim 1 wherein each receiver comprises a signal strength indicator for generating a received strength signal indicative of the signal strength of the received radio frequency signal, and wherein said receiver selector includes a comparator for selecting one of said plurality of receivers based on the generated received strength signal.
Claim 4
Dependent Claim 90 words
The diversity reception system of claim 2 further comprising a plurality of diversity reception controllers, each diversity reception controller individually coupled to a signal strength indicator of one of the plurality of receivers for receiving the received strength signal and equalizing the received strength signal from the signal strength indicator in relation to equalized signals from other diversity reception controllers, each diversity reception controller outputting the equalized signal, the equalized signals coupled to the comparator of the receiver selector to select the receiver having the highest relative quality detected signal.
Claim 5
Dependent Claim 41 words
The diversity reception system of claim 3 wherein each diversity reception controller comprises an adjustable signal strength processor for tuning the received strength signal to output an equalized signal having a specified signal level corresponding to a selected input signal level.
Claim 6
Dependent Claim 32 words
The diversity reception system of claim 4 wherein each diversity reception controller further comprises a low pass filter for filtering high frequency components of received strength signals from the signal strength indicator.
Claim 7
Dependent Claim 54 words
The diversity reception system of claim 1 further comprising a detected signal input stage for each of the plurality of receivers and receiving the detected signal from a receiver to equalize the amplitude of the detected signals to compensate for variations in receiver output levels and for filtering DC bias from the detected signals.
Claim 8
Dependent Claim 142 words
The diversity reception system of claim 3 wherein each receiver selector comprises: the comparator receives the equalized signals from the plurality of diversity reception controllers and determines the receiver having the highest relative detected signal quality according to the comparison, selecting the receiver generating the highest relative detected signal quality, and generating a receiver selection signal for indicating the selected receiver; a signal strength selector responsive to the receiver selection signal and the equalized signals from the plurality of diversity reception controllers for selecting and outputting a selected equalized signal, the selected equalized signal defined as the equalized signal output from the diversity reception controller coupled to the selected receiver; and a detected signal selector responsive to the receiver selection signal and the detected signals from the plurality of receivers for selecting and outputting a selected detected signal, from the selected receiver.
Claim 9
Dependent Claim 28 words
The diversity reception system of claim 1 wherein each receiver of the plurality of receivers further comprises a low noise amplifier for amplifying the received radio frequency signal.
Claim 10
Dependent Claim 34 words
The diversity reception system of claim 8 further comprising a gain reducing circuit for disabling the low noise amplifier in a receiver when an equalized signal from the receiver reaches a preselected threshold level.
Claim 11
Dependent Claim 31 words
The diversity reception system of claim 1 further comprising a plurality of antennas, each antenna individually coupled to one of the plurality of receivers for receiving a transmitted radio frequency signal.
Claim 12
Dependent Claim 21 words
The diversity reception system of claim 10 wherein each receiver further comprises a detector for detecting a received radio frequency signal.
Claim 13
Dependent Claim 38 words
The diversity reception system of claim 1 further comprising an output filter coupled to the receiver selector for filtering high speed transients induced by high-speed switching and for outputting a diversity reception audio output from the selected receiver.
Claim 14
Dependent Claim 34 words
The diversity reception system of claim 12 further comprising a frequency-shift keying data slicer coupled to said output filter and responsive to the diversity reception audio output for generating a diversity reception data output.
Claim 15
Dependent Claim 236 words
A diversity reception system for high quality signal reception, comprising: a plurality of reception branches, each reception branch comprising: an antenna for receiving a transmitted radio frequency signal; a receiver individually coupled to the antenna for generating a detected signal from the received radio frequency signal, the receiver including a signal strength indicator for generating a received strength signal indicative of the signal strength of the received radio frequency signal; a diversity reception controller coupled to the signal strength indicator of the receiver and receiving the received strength signal, the diversity reception controller equalizing the received strength signal in relation to equalized signals in the other reception branches of the diversity reception system, and outputting the equalized signal; and a receiver selector coupled to the receiver and the diversity reception controller of each of the plurality of reception branches and outputting the detected signal of a selected receiver, said receiver selector including an audio selector for selecting the receiver from the plurality of receivers generating the detected signal having the highest relative signal-to-noise ratio when the detected signal from each of the receivers has a signal-to-noise ratio below a selected threshold signal-to-noise ratio corresponding to the maximum achievable signal-to-noise ratio, and for selecting the receiver from the plurality of receivers generating the detected signal having the highest relative signal strength when the detected signal from each of the receivers has a signal-to-noise ratio at the threshold.
Claim 16
Dependent Claim 236 words
A diversity reception system for high quality signal reception, comprising: a plurality of reception branches, each reception branch comprising: an antenna for receiving a transmitted radio frequency signal; a receiver individually coupled to the antenna for generating a detected signal from the received radio frequency signal, the receiver including a signal strength indicator for generating a received strength signal indicative of the signal strength of the received radio frequency signal; a diversity reception controller coupled to the signal strength indicator of the receiver and receiving the received strength signal, the diversity reception controller equalizing the received strength signal in relation to equalized signals in the other reception branches of the diversity reception system, and outputting the equalized signal; and a receiver selector coupled to the receiver and the diversity reception controller of each of the plurality of reception branches and outputting the detected signal of a selected receiver, said receiver selector including an audio selector for selecting the receiver from the plurality of receivers generating the detected signal having the highest relative signal-to-noise ratio when the detected signal from each of the receivers has a signal-to-noise ratio below a selected threshold signal-to-noise ratio corresponding to the maximum achievable signal-to-noise ratio, and for selecting the receiver from the plurality of receivers generating the detected signal having the highest relative signal strength when the detected signal from each of the receivers has a signal-to-noise ratio at the threshold.
Claim 17
Dependent Claim 65 words
The diversity reception system of claim 14 wherein the diversity reception controller in each of the plurality of reception branches further comprises: a low pass filter for filtering high frequency components of the received strength signal; and an adjustable signal strength processor for tuning the diversity reception controller to output an equalized signal having a specified signal level corresponding to a selected input signal level.
Claim 18
Dependent Claim 43 words
The diversity reception system of claim 14 wherein each reception branch further comprises a detected signal input stage for equalizing the amplitude of the detected signals to compensate for variations in receiver output levels and for filtering DC bias from the detected signals.
Claim 19
Dependent Claim 43 words
The diversity reception system of claim 14 wherein the receiver in each reception branch further comprises: a low noise amplifier for amplifying a received radio frequency signal; and a detector coupled to the low noise amplifier for detecting a received radio frequency signal.
Claim 20
Dependent Claim 44 words
The diversity reception system of claim 17 further comprising a gain reducing circuit coupled to the receiver selector for disabling the low noise amplifier in the receiver in each reception branch when the equalized signal of the selected receiver reaches a preselected threshold level.
Claim 21
Independent Claim 216 words
A method for improving radio frequency signal reception in a communication system having a plurality of receivers, comprising the steps of: receiving a transmitted radio frequency signal at each of a plurality of receivers; detecting the radio frequency signal received by each receiver to generate a detected signal for each receiver; generating a plurality of equalized signals, each equalized signal corresponding to the detected signal for an individual receiver, wherein the generation of an equalized signal corresponding to an individual receiver comprises the steps of: generating a received strength signal related to the strength of the radio frequency signal received by the receiver; adjusting the amplitude of a received strength signal below a level required to produce a selected threshold signal-to-noise ratio corresponding to the maximum achievable signal-to-noise ratio to compensate for inaccuracies in the received strength signal and to provide correlation between the received strength signal and a signal-to-noise ratio of the detected signal; and calibrating the amplitude of the received strength signal to indicate the strength of the received signal with reference to a received strength signal above the level required to produce the preselected threshold signal-to-noise ratio; comparing the equalized signals for each of the plurality of receivers; and selecting the active receiver having the highest amplitude among the plurality of equalized signals.
Claim 22
Independent Claim 216 words
A method for improving radio frequency signal reception in a communication system having a plurality of receivers, comprising the steps of: receiving a transmitted radio frequency signal at each of a plurality of receivers; detecting the radio frequency signal received by each receiver to generate a detected signal for each receiver; generating a plurality of equalized signals, each equalized signal corresponding to the detected signal for an individual receiver, wherein the generation of an equalized signal corresponding to an individual receiver comprises the steps of: generating a received strength signal related to the strength of the radio frequency signal received by the receiver; adjusting the amplitude of a received strength signal below a level required to produce a selected threshold signal-to-noise ratio corresponding to the maximum achievable signal-to-noise ratio to compensate for inaccuracies in the received strength signal and to provide correlation between the received strength signal and a signal-to-noise ratio of the detected signal; and calibrating the amplitude of the received strength signal to indicate the strength of the received signal with reference to a received strength signal above the level required to produce the preselected threshold signal-to-noise ratio; comparing the equalized signals for each of the plurality of receivers; and selecting the active receiver having the highest amplitude among the plurality of equalized signals.
Claim 23
Dependent Claim 38 words
The method of claim 19 further comprising the steps of: adjusting the amplitude of the detected signals to compensate for variations in receiver output levels; and filtering the detected signals to remove DC bias from the detected signals.

References Cited (Backward Citations)

US4155041A Cited
US4246655A Cited
US4756023A Cited
US5065411A Cited
US5710795A Cited
US5621770A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 2003-01-24 2003-07-26 2004-01-25 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 2007-01-24 2007-07-26 2008-01-25 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2011-01-24 2011-07-26 2012-01-25 $7700.00 Window Closed / Lapsed

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