Patent application number | Description | Published |
20090036069 | LO 2LO Upconverter For An In-Phase/Quadrature-Phase (I/Q) Modulator - An upconverter includes a switching architecture configured to receive an input signal, a first local oscillator (LO) signal, and a second local oscillator (2LO) signal that is at a frequency that is twice a frequency of the local oscillator (LO) signal, wherein the switching architecture is configured to switch the input signal on transitions of the second local oscillator (2LO) signal, and wherein the first local oscillator signal and the second local oscillator signal are combined to form combined LO 2LO switching signals. | 02-05-2009 |
20100194443 | dB-LINEAR VOLTAGE-TO-CURRENT CONVERTER - A dB-linear voltage-to-current (V/I) converter that is amenable to implementation in CMOS technology. In a representative embodiment, the dB-linear V/I converter has a voltage scaler, a current multiplier, and an exponential current converter serially connected to one another. The voltage scaler supplies an input current to the current multiplier based on an input voltage. The current multiplier multiplies the input current and a current proportional to absolute temperature and supplies the resulting current to the exponential current converter. The exponential current converter has a differential MOSFET pair operating in a sub-threshold mode and generating an output current that is proportional to a temperature-independent, exponential function of the input voltage. | 08-05-2010 |
20110151808 | System And Method For Power Control For A Surface Acoustic Wave (SAW) Filter-Less Transmitter - A power control system includes a transmitter having a plurality of gain-adjustable elements, a switchable attenuator located at an output of the transmitter, a gain-adjustable power amplifier coupled to the attenuator, and a power control element responsive to a power target signal, the power control element configured to calculate and apply a gain control signal to the plurality of gain-adjustable elements in the transmitter, to the switchable attenuator, and to the gain-adjustable power amplifier so that a signal to noise ratio (SNR) at the output of the transmitter remains substantially constant over a range of output power. | 06-23-2011 |
20110298503 | Dynamic voltage-controlled oscillator calibration and selection - A method and apparatus is disclosed for voltage-controlled oscillator selection in a multi-mode system having multiple voltage-controlled oscillators. Part of oscillator selection is a calibration operation that utilizes maximum and minimum capacitance limits for a voltage-controlled oscillator, which translates to a frequency range, to calculate overlap regions. Overlap regions comprise frequency ranges that overlap such that the overlap region may be generated by two voltage-controlled oscillators with adjacent frequency ranges. One voltage-controlled oscillator selection routine comprises a real time voltage-controlled oscillator calibration and selection routine that executes every time the system requests a new frequency. Another selection routine comprises a start-up routine that executes only at power up or periodically. Another selection routine comprises a successive voltage-controlled oscillator routine that executes every time a frequency is requested by comparing a requested frequency to different frequency thresholds without executing a calibration operation. | 12-08-2011 |
20120038418 | dB-LINEAR VOLTAGE-TO-CURRENT CONVERTER - A dB-linear voltage-to-current (V/I) converter that is amenable to implementation in CMOS technology. In a representative embodiment, the dB-linear V/I converter has a voltage scaler, a current multiplier, and an exponential current converter serially connected to one another. The voltage scaler supplies an input current to the current multiplier based on an input voltage. The current multiplier multiplies the input current and a current proportional to absolute temperature and supplies the resulting current to the exponential current converter. The exponential current converter has a differential MOSFET pair operating in a sub-threshold mode and generating an output current that is proportional to a temperature-independent, exponential function of the input voltage. | 02-16-2012 |
20120039401 | PROGRAMMABLE TRANSMIT CONTINUOUS-TIME FILTER - A programmable-current transmit continuous-time filter (TX-CTF) system can be included in a radio frequency (RF) transmitter. The input of the TX-CTF can receive a baseband transmission signal, and the output of the TX-CTF can be provided to an upconversion mixer for conversion to RF for transmission. The TX-CTF includes amplifier circuitry and passive circuitry that together define the filter parameters. The TX-CTF further includes programmable current circuitry that provides a programmable bias current to the amplifier circuitry. The TX-CTF system also includes control logic that receives one or more transmitter control signals and, in response, generates signals that control the bias current provided to the TX-CTF. | 02-16-2012 |
20120149316 | RADIO FREQUENCY POWER AMPLIFIER WITH LINEARIZING PREDISTORTER - A power amplifier circuit includes an amplifier MOSFET and a predistorter MOSFET. The predistorter MOSFET source and drain are connected together, and the predistorter MOSFET is connected between the gate of the amplifier MOSFET and a second bias voltage signal. This biasing of the predistorter MOSFET causes it to provide a nonlinear capacitance at the gate of the amplifier MOSFET. The combined non-linear capacitances of the amplifier MOSFET and predistorter MOSFET provide predistortion that promotes cancellation of the distortion or nonlinearity contributed by the amplifier MOSFET alone. | 06-14-2012 |
20120242379 | VARIABLE FREQUENCY CIRCUIT CONTROLLER - Apparatus and methods for distributing spurious tones through the frequency domain are disclosed. One such apparatus can include a dithering circuit configured to generate a sequence of numbers that exhibit statistical randomness and a variable frequency circuit configured to adjust a frequency of an output based on the sequence of numbers so as to spread energy of spurious tones in a frequency response of the output to lower a noise floor. In one example, spurious tones can be reduced in a negative voltage generator of a radio frequency (RF) attenuator. | 09-27-2012 |
20120280730 | APPARATUS AND METHODS FOR ADJUSTING VOLTAGE CONTROLLED OSCILLATOR GAIN - Apparatus and methods for adjusting a gain of an electronic oscillator, such as a voltage-controlled oscillator (VCO), are disclosed. In one aspect, an apparatus for compensating for VCO gain variations includes a charge pump controller. The charge pump controller can be configured to select a VCO gain model based on a comparison of a VCO gain indicator and a threshold value stored in a memory, obtain VCO gain model parameters from the memory corresponding to the selected VCO gain model, and compute a charge pump current control value using the VCO gain model parameters. The charge pump current control value can be used to compensate for VCO gain variations. | 11-08-2012 |
20130241612 | APPARATUS AND METHODS FOR ADJUSTING PHASE-LOCKED LOOP GAIN - Apparatus and methods for adjusting a gain of an electronic oscillator, such as a voltage-controlled oscillator (VCO), are disclosed. In one aspect, an apparatus for compensating for VCO gain variations includes a charge pump controller. The charge pump controller can be configured to select a VCO gain model based on a comparison of a VCO gain indicator and a threshold value stored in a memory, obtain VCO gain model parameters from the memory corresponding to the selected VCO gain model, and compute a charge pump current control value using the VCO gain model parameters. The charge pump current control value can be used to compensate for VCO gain variations. | 09-19-2013 |
20140235300 | PROGRAMMABLE TRANSMIT CONTINUOUS-TIME FILTER - A programmable-current transmit continuous-time filter (TX-CTF) system can be included in a radio frequency (RF) transmitter. The input of the TX-CTF can receive a baseband transmission signal, and the output of the TX-CTF can be provided to an upconversion mixer for conversion to RF for transmission. The TX-CTF includes amplifier circuitry and passive circuitry that together define the filter parameters. The TX-CTF further includes programmable current circuitry that provides a programmable bias current to the amplifier circuitry. The TX-CTF system also includes control logic that receives one or more transmitter control signals and, in response, generates signals that control the bias current provided to the TX-CTF. | 08-21-2014 |
20140333350 | VARIABLE FREQUENCY CIRCUIT CONTROLLER - Apparatus and methods for distributing spurious tones through the frequency domain are disclosed. One such apparatus can include a dithering circuit configured to generate a sequence of numbers that exhibit statistical randomness and a variable frequency circuit configured to adjust a frequency of an output based on the sequence of numbers so as to spread energy of spurious tones in a frequency response of the output to lower a noise floor. In one example, spurious tones can be reduced in a negative voltage generator of a radio frequency (RF) attenuator. | 11-13-2014 |
20150055737 | DITHER-LESS MULTI-STAGE NOISE SHAPING FRACTIONAL-N FREQUENCY SYNTHESIZER SYSTEMS AND METHODS - A fractional-N divider of a frequency synthesizer is driven by a dither-less and seed-less multi-stage noise shaping (MASH) modulator to alleviate fractional spurious tones introduced by the cyclic train of division ratios from delta-sigma modulators. The MASH modulator includes at least two cascaded dither-less delta-sigma modulators where each modulator includes a first feedback loop the generates the modulator feedback signal, a second feedback loop that disrupts fractional spurious tones and a third feedback loop that provides approximately zero static error. The MASH modulator further includes a combining circuit delays at least one code sequence from at least one of the delta-sigma modulators and that combines the code sequence generated by each of the delta-sigma modulators and at least one delayed code sequence. | 02-26-2015 |
20150055738 | DITHER-LESS ERROR FEEDBACK FRACTIONAL-N FREQUENCY SYNTHESIZER SYSTEMS AND METHODS - A fractional-N divider of a frequency synthesizer is driven by a dither-less error feedback modulator to alleviate fractional spurious tones introduced by the cyclic train of division ratios from delta-sigma modulators. A first feedback loop generates the feedback signal. A second feedback loop disrupts fractional spurious tones and a third feedback loop provides approximately zero static error. | 02-26-2015 |