Abstract:
Radio-frequency (RF) apparatus includes receiver analog circuitry that receives an RF signal and provides at least one digital signal to receiver digital circuitry that functions in cooperation with the receiver analog circuitry. The receiver analog circuitry and the receiver digital circuitry are partitioned so that interference effects between the receiver analog circuitry and the receiver digital circuitry tend to be reduced.
Abstract:
Components of a radio-frequency (RF) apparatus including transceiver circuitry and frequency modification circuitry of a crystal oscillator circuit that generates a reference signal with adjustable frequency may be partitioned in a variety of ways, for example, as one or more separate integrated circuits. The frequency modification circuitry may be implemented as part of a crystal oscillator circuit that includes digitally controlled crystal oscillator (“DCXO”) circuitry and a crystal. The frequency modification circuitry may include at least one variable capacitance device and may be employed to generate a reference signal with adjustable frequency. The adjustable reference signal may be provided to other components of the RF apparatus and/or the RF apparatus may be configured to provide the adjustable reference signal to baseband processor circuitry. Automatic frequency control (AFC) circuitry may be integrated with other components of RF circuitry and may generate frequency control signals for the frequency modification circuitry based on, for example, a signal received from a temperature sensor. Digital-to-analog converter (DAC) circuitry may be integrated with other components of RF circuitry to enable all-digital frequency control communications from baseband processor circuitry to RF circuitry.
Abstract:
A technique includes generating an analog voltage to control a frequency for an oscillator. The analog signal is converted into a digital signal, and the frequency is controlled in response to the digital signal.
Abstract:
A system and method are disclosed for dynamically selecting high-side injection or low-side injection of local oscillator mixing signals based upon an assessment of signal power within the input signal spectrum that could cause unwanted images in the processed signal. This image rejection assessment provides an advantageous basis upon which to make dynamic high-side versus low-side injection determinations.
Abstract:
A radio-frequency (RF) receiver includes a receiver analog circuitry and a receiver digital circuitry. The receiver analog circuitry resides within a first integrated circuit and the receiver digital circuitry resides within a second integrated circuit. The second integrated circuit couples to the first integrated circuit via a one-bit digital interface. The receiver analog circuitry receives an RF signal and processes the received RF signal to generate a digital signal. The receiver analog circuitry provides the digital signal to the receiver digital circuitry. The receiver digital circuitry includes a digital down-converter circuitry that mixes the digital signal with an intermediate frequency (IF) local oscillator (LO) signal to generate a digital down-converted signal. The receiver digital circuitry also includes a digital filter circuitry that filters the digital down-converted signal to generate a filtered digital signal.
Abstract:
A method and apparatus for enhancing signal quality within a wireless receiver are disclosed. An image of a desired signal is down-converted to a baseband signal by a digital down converter. The energy of the baseband signal is subsequently determined. If the energy of the baseband signal is equal to or greater than a predetermined threshold, then the IF is swapped for any incoming signals. If the energy of the baseband signal is less than the predetermined threshold, then the IF is maintained for any incoming signals.
Abstract:
A wireless communication device is disclosed wherein isolation buffers couple to respective active circuits or stages of the device to convey test information regarding such active circuits to a test data line from which status information may be collected. The communication device operates in two modes, namely a normal operational mode wherein the isolation buffers effectively short spurious emissions from the active circuits to a ground, and a test mode wherein the isolation buffers may convey test information from a selected active circuit to the test data line. The isolation buffers prevent spurious emissions from escaping the active circuits to which they are coupled and prevent spurious emissions from traveling from active circuit to active circuit over the test data line throughout the wireless device.
Abstract:
The digital interface between the baseband section and the RF transceiver section of a wireless communication device may cause undesired pulling to an impedance sensitive portion of the RF transceiver section. In one embodiment, an original interface signal that exhibits a duty cycle is modified by an interface control block in the baseband section. The resultant modified interface signal exhibits a duty cycle less than the duty cycle of the original interface signal. In this manner, when the modified interface signal is applied to the RF transceiver section, less pulling of the impedance sensitive portion occurs than if the original interface signal were applied directly to the RF transceiver section.
Abstract:
A voltage regulator configured to receive a supply voltage from a voltage supply and provide a regulated voltage to digital circuitry is provided. The voltage regulator comprises first circuitry configured to inhibit high frequency energy generated by the digital circuitry from transmitting into the voltage supply, second circuitry configured to inhibit low frequency energy generated by the digital circuitry from transmitting into the voltage supply, and third circuitry configured to maintain the regulated voltage at a substantially constant value in response to a current drawn by the digital circuitry.
Abstract:
Interchangeable high band low-noise-amplifiers (LNAs) and low band low-noise-amplifiers (LNAs) and related methods are disclosed that greatly enhance the efficiency of designing handsets for different combinations of frequency bands. The input signals to particular pins on a receiver or transceiver integrated circuit (IC) are swappable such that multiple frequency bands can be input to the same input pins thereby allowing for simplified system design. Efficient programmable techniques are also disclosed for controlling a swap mode within communication ICs. These interchangeable or band swappable input paths, for example, can be utilized to allow interchangeability between high band (PCS, DCS) and low band (GSM, E-GSM) inputs for cellular communications. In this way, for example, handset manufacturers can build a single printed circuit board (PCB) that can be utilized for cellular communications in the United States of America, where 850 MHz (GSM) and 1900 MHz (PCS) bands are utilized, and in Europe, wherein 900 MHz (E-GSM) and 1800 MHz (DCS) bands are utilized.