| Patent application number | Description | Published |
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| 20080287087 | Merged high pass filtering and down-converting mixer circuit - According to one exemplary embodiment, a mixer circuit comprises first and second switching branches driven by a local oscillator and an input radio frequency (RF) signal. The mixer circuit further comprises at least one capacitor coupled between the first and second switching branches for high-pass filtering of a down-converted output signal of the mixer circuit. In one embodiment, each switching branch comprises a respective mixer transistor, for example, a field effect transistor (FET). In one embodiment, the mixer circuit includes an inductor to reduce or eliminate the effects of parasitic capacitors at a resonance frequency selected to approximately match a desired RF signal frequency. In one embodiment, an inductor at resonance with parasitic capacitors produces a band pass filter for an input RF signal. | 11-20-2008 |
| 20080299935 | IC with saw-less RF front-end - An IC includes an RF front end, a down conversion module, an up conversion module, and a local oscillation generating module. The RF front end includes a receive section, a transmit section, and an interference reduction module. The receive section receives an inbound RF signal within a receive frequency band and the transmit section transmits an outbound RF signal within a transmit frequency band. The interference reduction module is coupled to at least one of the receive section and the transmit section and facilitates at least one of: attenuating energy of the outbound RF signal within the receive frequency band based on a transmit local oscillation or a receive local oscillation; and attenuating energy of the inbound RF signal within the transmit frequency band based on the transmit local oscillation or the receive local oscillation. | 12-04-2008 |
| 20080317165 | Systems and methods of calibrating a transmitter - In one embodiment the present invention includes a method of calibrating the frequency response of a transmitter comprising generating a plurality of calibration tones across a frequency range, coupling the plurality of calibration tones to an input of said transmitter, detecting the plurality of calibration tones at an output in said transmitter, and in accordance therewith, generating a plurality of calibration values, receiving digital data to be transmitted, the digital data comprising a plurality of frequency components in said frequency range, and calibrating said frequency components of said digital data using the calibration values. | 12-25-2008 |
| 20090002065 | Buffer circuit for reducing differential-mode phase noise and quadrature phase error - According to one exemplary embodiment, a buffer circuit for reducing differential-mode phase noise and quadrature phase error comprises first and second switching branches driven by an in-phase (I) signal, third and fourth switching branches driven by a quadrature-phase (Q) signal, the first and second switching branches and third and fourth switching branches being coupled to a common bias current source to reduce the differential-mode phase noise and quadrature phase error at an output of the buffer circuit. In one embodiment, the switching branches may be loaded by first, second, third, and fourth resonators formed, for example, by L-C circuits tuned to a local oscillator frequency. In one embodiment, the buffer circuit may comprise switching branches formed by FETs, and be used in conjunction with a local oscillator and mixer circuits to down-convert a radio frequency (RF) signal, in a receiving system, for example. | 01-01-2009 |
| 20090010317 | Nullification of transmitter noise at receive signal frequency - According to one exemplary embodiment, a transceiver for nullification of a noise component in a transmitter comprises a noise nullification module loading a selected node in the transmitter. The noise nullification module comprises a mixer that receives inputs from the selected node and a local oscillator, where the mixer is also coupled to a filter such that the noise nullification module presents a low impedance at an approximate frequency of a noise component so as to nullify the noise component. In one embodiment, the noise nullification module results in band-pass filtering of an approximate receive signal frequency so as to nullify a noise component at the receive frequency. In another embodiment, the noise nullification module results in notch filtering of an approximate transmit signal frequency so as to nullify a noise component at a receive signal frequency. | 01-08-2009 |
| 20090017770 | Noise cancellation system for transceivers - According to one exemplary embodiment, a transceiver providing noise cancellation has a transmitter and a receiver, and comprises a noise cancellation system receiving input from the transmitter. The noise cancellation system generates a noise cancellation signal injected into the receiver such that the noise cancellation signal has an amplitude substantially matching an amplitude of a noise signal in the receiver, and a phase substantially opposite to a phase of the noise signal in the receiver. In one exemplary embodiment, a noise cancellation system comprises a forward injection circuit including a scaling and rotation block, and first and second phase shift and attenuation controllers providing feedback from outputs of the receiver. In one exemplary embodiment, the scaling and rotation block includes first, second, third, and fourth amplifiers to receive a down-converted noise signal and provide a noise cancellation signal. | 01-15-2009 |
| 20090036087 | Highly Linear and Very Low-Noise Down-Conversion Mixer for Extracting Weak Signals in the Presence of Very Strong Unwanted Signals - A highly linear and very low-noise down-conversion mixer for extracting weak signals in the presence of very strong unwanted signals is disclosed. Aspects of an embodiment may include a source follower circuit in a transmitter front end of a mobile terminal. The source follower circuit may receive RF signals prior to the RF signals being amplified by a power amplifier for transmission. The RF signals may comprise in-phase and quadrature components. The source follower circuit may generate output RF voltage signals, and communicate the output RF voltage signals to a switching circuit via a coupling capacitor. The switching circuit may down-convert the communicated output RF voltage signals to generate differential baseband signals. The capacitance of the coupling capacitor may be changed to change gain and/or linearity of the differential baseband signals. Each of the differential baseband signals may be low-pass filtered to attenuate higher frequencies. | 02-05-2009 |
| 20100303172 | METHODS AND TECHNIQUES FOR 3G CELLULAR TRANSMITTERS - A transmitter operates in different modulation modes to support both GSM/EDGE and WCDMA cellular telephony applications. The transmitter modulates an outgoing signal to produce a complex modulated signal in a first modulation mode and a constant or variable envelope modulated signal in a second modulation mode. A local oscillation generator and mixer operate to up-convert the complex modulated signal to produce a modulated RF signal in the first modulation mode and to up-convert the phase component of the constant or variable envelope modulated signal to an RF phase signal and mix the RF phase signal with the envelope component thereof to produce the modulated RF signal in the second modulation mode. | 12-02-2010 |
| 20110032922 | Highly Linear and Very Low-Noise Down-Conversion Mixer for Extracting Weak Signals in the Presence of Very Strong Unwanted Signals - A method and system for wireless communication is provided and may include mitigating blocker signals in transmitted RF signals in a wireless device including a transmitter front end. The mitigation may include up-converting a baseband signal, mixing the up-converted baseband signal with a feedback signal, and amplifying the mixed up-converted baseband signal and the feedback signal to generate an output signal. The feedback signal may be generated by down-converting the output signal, low-pass filtering the down-converted output signal, and up-converting the filtered down-converted signal for the summing. The blocker signals may correspond to receive frequencies for the wireless device and may be converted to DC via the down-converting. The wireless devices may operate in accordance with at least a CDMA standard. The mixed up-converted baseband signal and the feedback signal may be amplified utilizing a source follower amplifier, where the gain and/or linearity may be configured by varying coupling capacitors. | 02-10-2011 |
