Patents by Inventor Edward A. Keehr
Edward A. Keehr has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Publication number: 20220173801Abstract: An adjustable payload for small geostationary communication satellites is disclosed. In an example, a communication satellite includes a payload system having a software defined payload that is configured to provide communication services. The software defined payload includes a processor for providing at least one of gain control per transponder and carrier/sub-channel, channelization, channel routing, signal conditioning or equalization, spectrum analysis, interference detection, regenerative or modem processing, bandwidth flexibility, digital beamforming, digital pre-distortion or power amplifier linearization, for at least one user slice for a plurality of user terminals and at least one gateway slice for a gateway station. The software defined payload also includes an input side and an output side for each slice. Each input side includes an input filter and an analog-to-digital converter and each output side includes an output filter and a digital-to-analog converter.Type: ApplicationFiled: February 21, 2022Publication date: June 2, 2022Inventors: John Gedmark, Steven Joseph, Ryan McLinko, Braedon Salz, Edward Keehr, Karl Clausing, Siamak Ebadi
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Patent number: 10972150Abstract: An RFID interrogator transceiver with various improvements is proposed. A digital interface element implemented in a field-programmable gate array permits the use of a low-cost, low pin count microcontroller unit to control various integrated circuits within the transceiver both with the complexity afforded by the microcontroller unit and with the speed afforded by the field-programmable gate array. A transmit waveform generation architecture which can store opcodes in a segmented random access memory permits both leisurely loading of information over a digital interface from a low-cost microcontroller unit and fast playback over a wireless interface during low-latency RFID exchanges. Finally, a dual digital second-order resonator infinite-impulse-response filter permits a more hardware efficient channel bandpass filter solution than a finite-impulse-response filter and can be easily adjusted to accommodate RFID backscatter link frequencies and frequency tolerances.Type: GrantFiled: December 4, 2018Date of Patent: April 6, 2021Assignee: SUPERLATIVE SEMICONDUCTOR, LLCInventor: Edward A. Keehr
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Publication number: 20200177272Abstract: An adjustable payload for small geostationary communication satellites is disclosed. In an example, a communication satellite includes a payload system having a software defined payload that is configured to provide communication services. The software defined payload includes a processor for providing at least one of gain control per transponder and carrier/sub-channel, channelization, channel routing, signal conditioning or equalization, spectrum analysis, interference detection, regenerative or modem processing, bandwidth flexibility, digital beamforming, digital pre-distortion or power amplifier linearization, for at least one user slice for a plurality of user terminals and at least one gateway slice for a gateway station. The software defined payload also includes an input side and an output side for each slice. Each input side includes an input filter and an analog-to-digital converter and each output side includes an output filter and a digital-to-analog converter.Type: ApplicationFiled: November 29, 2019Publication date: June 4, 2020Inventors: John Gedmark, Steven Joseph, Ryan McLinko, Braedon Salz, Ali Younis, Edward Keehr, Karl Clausing, Siamak Ebadi
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Publication number: 20190173528Abstract: An RFID interrogator transceiver with various improvements is proposed. A digital interface element implemented in a field-programmable gate array permits the use of a low-cost, low pin count microcontroller unit to control various integrated circuits within the transceiver both with the complexity afforded by the microcontroller unit and with the speed afforded by the field-programmable gate array. A transmit waveform generation architecture which can store opcodes in a segmented random access memory permits both leisurely loading of information over a digital interface from a low-cost microcontroller unit and fast playback over a wireless interface during low-latency RFID exchanges. Finally, a dual digital second-order resonator infinite-impulse-response filter permits a more hardware efficient channel bandpass filter solution than a finite-impulse-response filter and can be easily adjusted to accommodate RFID backscatter link frequencies and frequency tolerances.Type: ApplicationFiled: December 4, 2018Publication date: June 6, 2019Inventor: Edward A. Keehr
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Patent number: 10187120Abstract: A tunable microwave network and its application in a radio transceiver transmit signal cancellation network is described. The tunable microwave network realizes a large set of reflection coefficients over a predefined area in the complex reflection coefficient plane for the purpose of reflecting a variable cancellation signal which, when properly configured, results in the substantial attenuation of transmit reflection and transmit leakage signal at the radio transceiver receiver input. A relevant building block of the proposed tunable microwave network is a shunt tunable capacitive element coupled to another shunt tunable capacitive element through a phase shifting element with phase shift greater than 30 degrees divided by a quantity substantially similar to the total number of said tunable capacitive elements and less than 60 degrees at a predefined frequency.Type: GrantFiled: February 20, 2018Date of Patent: January 22, 2019Assignee: SUPERLATIVE SEMICONDUCTOR, LLCInventor: Edward A. Keehr
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Patent number: 9900060Abstract: A tunable microwave network and its application in a radio transceiver transmit signal cancellation network is described. The tunable microwave network realizes a large set of reflection coefficients over a predefined area in the complex reflection coefficient plane for the purpose of reflecting a variable cancellation signal which, when properly configured, results in the substantial attenuation of transmit reflection and transmit leakage signal at the radio transceiver receiver input. A relevant building block of the proposed tunable microwave network is a shunt tunable capacitive element coupled to another shunt tunable capacitive element through a phase shifting element with phase shift greater than 30 degrees divided by a quantity substantially similar to the total number of said tunable capacitive elements and less than 60 degrees at a predefined frequency.Type: GrantFiled: May 12, 2016Date of Patent: February 20, 2018Assignee: Superlative Semiconductor, LLCInventor: Edward A. Keehr
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Patent number: 8971834Abstract: Third-order intermodulation products (IM3) are attenuated in RF receivers by providing a typical main signal path and a parallel auxiliary signal path in which the IM3 products are accentuated, and the output from the main signal path is adaptively filtered to attenuate the IM3 products. In one embodiment, a multirate filter bank (MRFB) with asymmetric analysis and synthesis sections is used to detect and isolate the IM3 products. In another embodiment an analog nonlinear term generator is placed at the front of the auxiliary signal path. The analog nonlinear term generator takes advantage of the nonlinearities of a differential MOSFET circuit and a multiplier to extract the IM3 products in the RF input signal. The outputs of the main signal path and the auxiliary signal path are inputs to a complex least mean squares filter to attenuate the IM3 products in the resulting signal.Type: GrantFiled: November 23, 2010Date of Patent: March 3, 2015Assignee: California Institute of TechnologyInventors: Edward Keehr, Seyed Ali Hajimiri
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Patent number: 8290449Abstract: A feedforward error-compensated receiver for minimizing undesired odd-order nonlinear distortion products. The receiver includes a first receiver path configured to receive an input signal. The first receiver path outputs a signal including at least one baseband (BB) frequency. At least one second receiver path is configured to receive the input signal and to provide a second receiver path output signal. The second receiver path includes at least one odd-order nonlinear distortion reference generator. The at least one odd-order nonlinear distortion reference generator and the mixer are configured to generate a synthetic odd-order nonlinear distortion signal. A combining element is configured to receive the output signal from the first path and the output signal from the second receiver path output and to combine the signals such that the odd-order nonlinear distortion signals are substantially attenuated at an output of the combining element.Type: GrantFiled: September 18, 2008Date of Patent: October 16, 2012Assignee: California Institute of TechnologyInventors: Edward Keehr, Seyed Ali Hajimiri
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Patent number: 8233871Abstract: An incompressible receiver for minimizing undesired higher-order nonlinear distortion products includes a first receiver path configured to receive an input signal having at least one non-baseband frequency. A second receiver path is also configured to receive the input signal. The second receiver path includes at least one odd-order nonlinear distortion reference component and at least one even-order nonlinear distortion reference component. The distortion reference components are configured to be in an “on” state or in an “off” state. A combining element is configured to combine input signals from the first and second receiver paths such that the higher-order nonlinear distortion signals are substantially attenuated at an output of the combining element. An incompressible receiver that has an odd-order nonlinear distortion reference generator including a cubic term and at least one additional term of order greater than 3 and an incompressible receiver front end amplifier (IRFEA) are also described.Type: GrantFiled: June 16, 2010Date of Patent: July 31, 2012Assignee: California Institute of TechnologyInventors: Edward Keehr, Seyed Ali Hajimiri
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Patent number: 8150356Abstract: A polynomial nonlinear term generator is configured to receive an RF signal. An analog cubic term generator generates an analog cubic term signal and an analog square term generator generates an analog square term signal, both derived from the RF signal. A cubic term mixer assembly mixes a local oscillator (LO) signal with the cubic term signal to generate a synthetic IM3 signal. A square term ADC provides a digital square term signal and a cubic term ADC provides a digital cubic term signal. At least one digital multiplier has a first multiplier input terminal configured to receive a selected one of the digital square term signal and the digital cubic term signal, and a second multiplier input terminal configured to receive the digital square term signal. The multiplier provides as output a digital IMn product where n is greater than 3. A corresponding method is also described.Type: GrantFiled: January 13, 2010Date of Patent: April 3, 2012Assignee: California Institute of TechnologyInventors: Edward Keehr, Seyed Ali Hajimiri
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Patent number: 8077878Abstract: An integrated circuit within a cellular telephone has a wake mode and a sleep mode. In the wake mode, a voltage regulator supplies a regulated voltage onto a MIC BIAS terminal. This voltage biases a microphone of a headset/microphone accessory that is coupled to the cellular telephone. If the user presses a switch on the accessory, then a large current is drawn out of the MIC BIAS terminal. This switch press condition is detected by an ADC within the integrated circuit. In the sleep mode, the regulator and ADC are disabled to conserve power. A novel switch detect circuit supplies a current out of the MIC BIAS terminal at an unregulated voltage. If the user presses the switch, then the current supplied from the MIC BIAS terminal increases. This switch press condition is detected over temperature, voltage and process conditions by a special inverter in the switch detect circuit.Type: GrantFiled: July 26, 2006Date of Patent: December 13, 2011Assignee: QUALCOMM IncorporatedInventor: Edward A. Keehr
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Publication number: 20110110473Abstract: Third-order intermodulation products (IM3) are attenuated in RF receivers by providing a typical main signal path and a parallel auxiliary signal path in which the IM3 products are accentuated, and the output from the main signal path is adaptively filtered to attenuate the IM3 products. In one embodiment, a multirate filter bank (MRFB) with asymmetric analysis and synthesis sections is used to detect and isolate the IM3 products. In another embodiment an analog nonlinear term generator is placed at the front of the auxiliary signal path. The analog nonlinear term generator takes advantage of the nonlinearities of a differential MOSFET circuit and a multiplier to extract the IM3 products in the RF input signal. The outputs of the main signal path and the auxiliary signal path are inputs to a complex least mean squares filter to attenuate the IM3 products in the resulting signal.Type: ApplicationFiled: November 23, 2010Publication date: May 12, 2011Inventors: Edward Keehr, Seyed Ali Hajimiri
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Patent number: 7894788Abstract: Third-order intermodulation products (IM3) are attenuated in RF receivers by providing a typical main signal path and a parallel auxiliary signal path in which the IM3 products are accentuated, and the output from the main signal path is adaptively filtered to attenuate the IM3 products. In one embodiment, a multirate filter bank (MRFB) with asymmetric analysis and synthesis sections is used to detect and isolate the IM3 products. In another embodiment an analog nonlinear term generator is placed at the front of the auxiliary signal path. The analog nonlinear term generator takes advantage of the nonlinearities of a differential MOSFET circuit and a multiplier to extract the IM3 products in the RF input signal. The outputs of the main signal path and the auxiliary signal path are inputs to a complex least mean squares filter to attenuate the IM3 products in the resulting signal.Type: GrantFiled: May 21, 2007Date of Patent: February 22, 2011Assignee: California Institute of TechnologyInventors: Edward Keehr, Seyed Ali Hajimiri
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Publication number: 20100316172Abstract: An incompressible receiver for minimizing undesired higher-order nonlinear distortion products includes a first receiver path configured to receive an input signal having at least one non-baseband frequency. A second receiver path is also configured to receive the input signal. The second receiver path includes at least one odd-order nonlinear distortion reference component and at least one even-order nonlinear distortion reference component. The distortion reference components are configured to be in an “on” state or in an “off” state. A combining element is configured to combine input signals from the first and second receiver paths such that the higher-order nonlinear distortion signals are substantially attenuated at an output of the combining element. An incompressible receiver that has an odd-order nonlinear distortion reference generator including a cubic term and at least one additional term of order greater than 3 and an incompressible receiver front end amplifier (IRFEA) are also described.Type: ApplicationFiled: June 16, 2010Publication date: December 16, 2010Applicant: California Institute of TechnologyInventors: Edward Keehr, Seyed Ali Hajimiri
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Publication number: 20100176981Abstract: A polynomial nonlinear term generator is configured to receive an RF signal. An analog cubic term generator generates an analog cubic term signal and an analog square term generator generates an analog square term signal, both derived from the RF signal. A cubic term mixer assembly mixes a local oscillator (LO) signal with the cubic term signal to generate a synthetic IM3 signal. A square term ADC provides a digital square term signal and a cubic term ADC provides a digital cubic term signal. At least one digital multiplier has a first multiplier input terminal configured to receive a selected one of the digital square term signal and the digital cubic term signal, and a second multiplier input terminal configured to receive the digital square term signal. The multiplier provides as output a digital IMn product where n is greater than 3. A corresponding method is also described.Type: ApplicationFiled: January 13, 2010Publication date: July 15, 2010Applicant: California Institute of TechnologyInventors: Edward Keehr, Seyed Ali Hajimiri
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Publication number: 20090075612Abstract: A feedforward error-compensated receiver for minimizing undesired odd-order nonlinear distortion products. The receiver includes a first receiver path configured to receive an input signal. The first receiver path outputs a signal including at least one baseband (BB) frequency. At least one second receiver path is configured to receive the input signal and to provide a second receiver path output signal. The second receiver path includes at least one odd-order nonlinear distortion reference generator. The at least one odd-order nonlinear distortion reference generator and the mixer are configured to generate a synthetic odd-order nonlinear distortion signal. A combining element is configured to receive the output signal from the first path and the output signal from the second receiver path output and to combine the signals such that the odd-order nonlinear distortion signals are substantially attenuated at an output of the combining element.Type: ApplicationFiled: September 18, 2008Publication date: March 19, 2009Applicant: California Institute of Technology.Inventors: Edward Keehr, Seyed Ali Hajimiri
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Publication number: 20090075610Abstract: Third-order intermodulation products (IM3) are attenuated in RF receivers by providing a typical main signal path and a parallel auxiliary signal path in which the IM3 products are accentuated, and the output from the main signal path is adaptively filtered to attenuate the IM3 products. In one embodiment, a multirate filter bank (MRFB) with asymmetric analysis and synthesis sections is used to detect and isolate the IM3 products. In another embodiment an analog nonlinear term generator is placed at the front of the auxiliary signal path. The analog nonlinear term generator takes advantage of the nonlinearities of a differential MOSFET circuit and a multiplier to extract the IM3 products in the RF input signal. The outputs of the main signal path and the auxiliary signal path are inputs to a complex least mean squares filter to attenuate the IM3 products in the resulting signal.Type: ApplicationFiled: May 21, 2007Publication date: March 19, 2009Applicant: California Institute of TechnologyInventors: Edward Keehr, Seyed Ali Hajimiri
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Publication number: 20080044004Abstract: An integrated circuit within a cellular telephone has a wake mode and a sleep mode. In the wake mode, a voltage regulator supplies a regulated voltage onto a MIC BIAS terminal. This voltage biases a microphone of a headset/microphone accessory that is coupled to the cellular telephone. If the user presses a switch on the accessory, then a large current is drawn out of the MIC BIAS terminal. This switch press condition is detected by an ADC within the integrated circuit. In the sleep mode, the regulator and ADC are disabled to conserve power. A novel switch detect circuit supplies a current out of the MIC BIAS terminal at an unregulated voltage. If the user presses the switch, then the current supplied from the MIC BIAS terminal increases. This switch press condition is detected over temperature, voltage and process conditions by a special inverter in the switch detect circuit.Type: ApplicationFiled: July 26, 2006Publication date: February 21, 2008Inventor: Edward A. Keehr
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Patent number: 6956515Abstract: A digital to analog converter augmented with Direct Charge Transfer (DCT) techniques. A digital to analog converter augmented with DCT and CDS techniques. A digital to analog converter augmented with Postfilter Droop Compensation.Type: GrantFiled: June 17, 2003Date of Patent: October 18, 2005Assignee: QUALCOMM, IncorporatedInventors: Edward A. Keehr, Sean Wang, Seyfollah Bazarjani
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Publication number: 20040070528Abstract: A digital to analog converter augmented with Direct Charge Transfer (DCT) techniques. A digital to analog converter augmented with DCT and CDS techniques. A digital to analog converter augmented with Postfilter Droop Compensation.Type: ApplicationFiled: June 17, 2003Publication date: April 15, 2004Inventors: Edward A. Keehr, Sean Wang, Seyfollah Bazarjani