摘要:
A first periodic voltage waveform (20) is downconverted into a second periodic voltage waveform (35, 36). A plurality of temporally distinct samples (SA1, SA2, . . . ) respectively indicative of areas under corresponding fractional cycles of the first voltage waveform are obtained. The samples are obtained in response to a control signal indicative of a code used to produce the first voltage waveform, and the samples are combined to produce the second voltage waveform.
摘要:
A mixer 1100 with a plurality of signal paths typically requires separate clock generating hardware for each signal path. However, the redundancy of having multiple clock generating hardware significantly increases power consumption and integrated circuit area when the mixer 1100 is integrated into silicon. A method and apparatus 1125 containing a circuit for generating a set of clock signals that can be shared by the different signal paths is presented. Advantage is taken of the significant capacitance difference between different sampling capacitors in the mixer and the superposition property.
摘要:
Methods and apparatus to perform radio frequency (RF) analog-to-digital conversion are described. According to one example, a receiver includes an amplifier to amplify received analog RF signals and a mixer-free circuit for converting the received analog RF signals to digital signals.
摘要:
A mixer 1100 with a plurality of signal paths typically requires separate clock generating hardware for each signal path. However, the redundancy of having multiple clock generating hardware significantly increases power consumption and integrated circuit area when the mixer 1100 is integrated into silicon. A method and apparatus 1125 containing a circuit for generating a set of clock signals that can be shared by the different signal paths is presented. Advantage is taken of the significant capacitance difference between different sampling capacitors in the mixer and the superposition property.
摘要:
A technique of improving antialiasing and adjacent channel interference filtering uses cascaded passive IIR filter stages combined with direct sampling and mixing. The methodology and related architecture allows for increased passive IIR filtering without necessitating use of amplifier stages.
摘要:
A sigma-delta analog-to-digital converter-offers advantages such as noise shaping and high frequency operation. However, a sampling circuit needed to provide a highly oversampled discrete-time sample stream with low noise characteristics is difficult to design and implement. The present invention provides a sigma-delta mixer 300 with such a sampling circuit 310. The present invention discloses a sampling circuit using switched capacitors 307, 308, and 309 with low noise characteristics and at the same time is capable of providing a highly oversampled discrete-time sample stream.
摘要:
The application of a non-zero voltage offset to rotating capacitors 1111 and 1112 permit the use of a single positive voltage supply. However, the precharging of the rotating capacitors 1111 and 1112 is power inefficient. A power efficient and low-noise precharging operation is realized through the sharing of the charge on a feedback capacitor 1075 and 1080 that is significantly larger than the rotating capacitors 1111. Once a precharging operation is complete, the charge on the feedback capacitor 1075 and 1080 is refreshed from its residual charge level (rather than zero charge level) to a desired charge level.
摘要:
A novel apparatus for and a method of noise and spurious tones suppression in a digital RF processor (DRP). The invention is well suited for use in highly integrated system on a chip (SoC) radio solutions that incorporate a very large amount of digital logic circuitry. The noise suppression scheme eliminates the noise caused by various on chip interference sources transmitted through electromagnetic, power, ground and substrate paths. The noise suppression scheme permits an all digital PLL (ADPLL) to operate in such a way to avoid generating the spurs that would normally be generated from the injection pulling effect of interfering sources on the chip. The frequency reference clock is retimed to be synchronous to the RF oscillator clock and used to drive the entire digital logic circuitry of the DRP. This ensures that the different clock edges throughout the system will not exhibit mutual drift. A method of improving the resolution quality of a time to digital converter within the ADPLL is also taught. The method dithers the reference clock by passing it through a delay circuit that is controlled by a sigma-delta modulator. The dithered reference clock reduces the affect on the phase noise at the output of the ADPLL due to ill-behaved quantization of the TDC timing estimation.
摘要:
A system and method for amplifier gain measurement and compensation. A method for compensating a signal gain of an amplifier circuit includes determining a desired gain for the amplifier circuit, determining an operating temperature of the amplifier circuit, adjusting a set of signal gains based on the operating temperature to produce a set of adjusted signal gains, determining a desired gain setting based on the desired gain and the set of signal gains, and providing the desired gain setting to the amplifier circuit.
摘要:
A radio receiver 2000 with a sampling mixer 1100 for creating a discrete-time sample stream by directly sampling an RF current with history and rotating capacitors 1111 and 1112, wherein the accumulated charge on the rotating capacitors is read-out to produce a sample. The mixer provides immunity to noise glitches by predicting the occurrence of the glitch (or detecting a significant difference between observed and predicted samples) and creating corrected samples for the corrupted samples. These corrected samples can be created with special circuitry 1933 (digital) or in the mixer 1100 (analog).