Patent US6088581A successfully refreshed from Google Patents.
US6088581A
Expired / Lapsed
US
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Method and apparatus for reducing amplitude modulated interference in a receiver
Assignee: Zarbana Digital Fund LLC
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Filing: 1998-03-27
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Granted: 2000-07-11
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Expires: 2018-03-27
Abstract
Abstract A direct conversion receiver (DCR)(10) comprises amplitude modulated interference (AMI) nulling circuitry (32) for achieving enhanced cancellation of AMI. The AMI nulling circuitry (32) includes a first signal processor (42) and a second signal processor (44) for processing first and second differential output signals, respectively, from a mixer (24a). The first signal processor (42) includes an adjustable transfer function that is controlled by a controller (50). The controller (50) adjusts the transfer function of the first signal processor (42) to equalize the magnitudes of AMI components in the first and second differential output signals. The first and second differential output signals are then combined in a manner which cancels the equalized AMI components.
Inventors
- 👤 Robert Henry Bickley
- 👤 Michael Newton Pickett
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 14:18
CPC Classifications
H; H03; H03D; H03D3/00; H03D3/001; H03D3/002; H04; H04B; H04B1/00; H04B1/06; H04B1/10; H04B1/12; H04B1/16; H04B1/30
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
196 words
A receiver for processing a received amplitude modulated interference signal in a communications system, comprising: a mixer for performing a frequency conversion on the received signal, said mixer having a first port for inputting the received signal, a second port for inputting a local oscillator signal, and a third port for outputting an intermediate frequency (IF) signal, wherein said IF signal includes first and second differential signal components; a first signal processor for processing said first differential signal component according to a first transfer function; a second signal processor for processing said second differential signal component according to a second transfer function, wherein said first transfer function is adjustable with respect to said second transfer function; a signal combination unit for combining said first differential signal component and said second differential signal component, after processing in said first and second signal processors, in a manner that suppresses a common mode signal component; said signal combination unit includes a difference amplifier to minimize distortion of said first and second transfer functions; and a buffer amplifier located between said mixer and said signal combination unit, said buffer amplifier including a bipolar junction transistor in a common base configuration.
Claim 2
Dependent Claim
196 words
A receiver for processing a received amplitude modulated interference signal in a communications system, comprising: a mixer for performing a frequency conversion on the received signal, said mixer having a first port for inputting the received signal, a second port for inputting a local oscillator signal, and a third port for outputting an intermediate frequency (IF) signal, wherein said IF signal includes first and second differential signal components; a first signal processor for processing said first differential signal component according to a first transfer function; a second signal processor for processing said second differential signal component according to a second transfer function, wherein said first transfer function is adjustable with respect to said second transfer function; a signal combination unit for combining said first differential signal component and said second differential signal component, after processing in said first and second signal processors, in a manner that suppresses a common mode signal component; said signal combination unit includes a difference amplifier to minimize distortion of said first and second transfer functions; and a buffer amplifier located between said mixer and said signal combination unit, said buffer amplifier including a bipolar junction transistor in a common base configuration.
Claim 3
Dependent Claim
16 words
The receiver, as claimed in claim 1, wherein: said first signal processor includes variable gain means.
Claim 4
Dependent Claim
16 words
The receiver, as claimed in claim 1, wherein: said first signal processor includes variable phase means.
Claim 5
Dependent Claim
17 words
The receiver, as claimed in claim 1, further comprising: a controller for adjusting said first transfer function.
Claim 6
Dependent Claim
21 words
The receiver, as claimed in claim 4, wherein: said controller adjusts said first transfer function based on current receiver operating parameters.
Claim 7
Dependent Claim
31 words
The receiver, as claimed in claim 4, wherein: said current receiver operating parameters include one or more of the following: current operating frequency, current receiver temperature, and current IF filter bandwidth.
Claim 8
Dependent Claim
28 words
The receiver, as claimed in claim 4, further comprising: a memory, coupled to said controller, for storing transfer function adjustment values for delivery to said first signal processor.
Claim 9
Dependent Claim
25 words
The receiver, as claimed in claim 7, wherein: each of said transfer function adjustment values is associated with a particular combination of operating parameter values.
Claim 10
Dependent Claim
25 words
The receiver, as claimed in claim 7, wherein: said controller includes means for interpolating between transfer function adjustment values based on current operating parameter values.
Claim 11
Dependent Claim
22 words
The receiver, as claimed in claim 7, further comprising: self-calibration means for determining transfer function adjustment values for storage in said memory.
Claim 12
Dependent Claim
29 words
The receiver, as claimed in claim 10, wherein: said self-calibration means includes a test signal generator for generating an amplitude modulated (AM) test signal for input into said receiver.
Claim 13
Dependent Claim
26 words
The receiver, as claimed in claim 11, wherein: said AM test signal has a carrier frequency that is offset from a tuned frequency of the receiver.
Claim 14
Dependent Claim
31 words
The receiver, as claimed in claim 11, wherein: said test signal generator includes a baseband signal generator for creating a baseband signal that is used to modulate an RF carrier signal.
Claim 15
Dependent Claim
25 words
The receiver, as claimed in claim 13, wherein: said self-calibration means includes means for determining a receiver output level resulting from said AM test signal.
Claim 16
Dependent Claim
29 words
The receiver, as claimed in claim 14, wherein: said means for determining a receiver output level includes a synchronous detector that receives a signal from said baseband signal generator.
Claim 17
Dependent Claim
45 words
The receiver, as claimed in claim 14, wherein: said self-calibration means includes means for varying a transfer function adjustment value applied to said first signal processor while monitoring said receiver output level to determine a transfer function adjustment value that achieves a lowest output level.
Claim 18
Dependent Claim
31 words
The receiver, as claimed in claim 11, wherein: said self-calibration means includes a calibration switch for switching an input of said receiver between an antenna port and said test signal generator.
Claim 19
Independent Claim
174 words
An apparatus for use in a receiver having a mixer for performing a frequency conversion on a received amplitude modulated interference signal, said mixer having an output port for outputting an intermediate frequency (IF) signal, wherein said IF signal includes first and second differential signals, said apparatus comprising: a first signal processor for processing said first differential signal according to a first transfer function; a second signal processor for processing said second differential signal according to a second transfer function, wherein said first transfer function is adjustable with respect to said second transfer function; a signal combination unit for combining said first differential signal component and said second differential signal component, after processing in said first and second signal processors, in a manner that cancels a common mode signal component; said signal combination unit includes a difference amplifier to minimize distortion of said first and second transfer functions; and a buffer amplifier located between said mixer and said signal combination unit, said buffer amplifier including a bipolar junction transistor in a common base configuration.
Claim 20
Independent Claim
174 words
An apparatus for use in a receiver having a mixer for performing a frequency conversion on a received amplitude modulated interference signal, said mixer having an output port for outputting an intermediate frequency (IF) signal, wherein said IF signal includes first and second differential signals, said apparatus comprising: a first signal processor for processing said first differential signal according to a first transfer function; a second signal processor for processing said second differential signal according to a second transfer function, wherein said first transfer function is adjustable with respect to said second transfer function; a signal combination unit for combining said first differential signal component and said second differential signal component, after processing in said first and second signal processors, in a manner that cancels a common mode signal component; said signal combination unit includes a difference amplifier to minimize distortion of said first and second transfer functions; and a buffer amplifier located between said mixer and said signal combination unit, said buffer amplifier including a bipolar junction transistor in a common base configuration.
Claim 21
Dependent Claim
151 words
In a receiver having a mixer for performing a frequency conversion on a received signal, a method for improving cancellation of amplitude modulated interference in said received signal, said method comprising: receiving a signal from a channel; applying said signal to an input of the mixer, said mixer outputting an IF signal having first and second differential signal components; first processing said first differential signal component according to a first transfer function; second processing said second differential signal component according to a second transfer function; determining at least one operating parameter value for said receiver; changing said first transfer function based on said at least one operating parameter value; combining said first differential signal component and said second differential signal component after said steps of first processing and second processing; and said step of combining includes determining a difference between said first differential signal component and said second differential signal component.
Claim 22
Dependent Claim
151 words
In a receiver having a mixer for performing a frequency conversion on a received signal, a method for improving cancellation of amplitude modulated interference in said received signal, said method comprising: receiving a signal from a channel; applying said signal to an input of the mixer, said mixer outputting an IF signal having first and second differential signal components; first processing said first differential signal component according to a first transfer function; second processing said second differential signal component according to a second transfer function; determining at least one operating parameter value for said receiver; changing said first transfer function based on said at least one operating parameter value; combining said first differential signal component and said second differential signal component after said steps of first processing and second processing; and said step of combining includes determining a difference between said first differential signal component and said second differential signal component.
Claim 23
Dependent Claim
25 words
The method, as claimed in claim 19, wherein: said step of changing includes adjusting said first transfer function with respect to said second transfer function.
Claim 24
Dependent Claim
34 words
The method, as claimed in claim 19, wherein: said step of first processing includes amplifying said first differential signal component by a gain factor; and said step of changing includes adjusting said gain factor.
Claim 25
Dependent Claim
22 words
The method, as claimed in claim 19, wherein: said step of changing includes adjusting an insertion phase of said first transfer function.
Claim 26
Dependent Claim
33 words
The method, as claimed in claim 19, wherein: said step of determining includes finding current values for at least one of the following parameters: local oscillator (LO) frequency, operating temperature, and IF bandwidth.
References Cited (Backward Citations)
US4031469A
Cited
US5095536A
Cited
US5101509A
Cited
US5678219A
Cited
US5822687A
Cited
US5548840A
Cited
US5483696A
Cited
US5555451A
Cited
US5613233A
Cited
US5579347A
Cited
US5826182A
Cited
US5638401A
Cited
US5608331A
Cited
US5701600A
Cited
US5953643A
Cited
US5881376A
Cited
US5740520A
Cited
US5862466A
Cited
US5963600A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2003-07-11 | 2004-01-10 | 2004-07-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-07-11 | 2008-01-10 | 2008-07-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-07-11 | 2012-01-10 | 2012-07-11 | $7700.00 | Window Closed / Lapsed |