摘要:
A method and system for buffering a clock signal is provided. The method may include self-biasing a PMOS transistor of a buffer, utilized for amplifying an in-phase/quadrature phase signal, to produce a first bias voltage at the gate of a PMOS transistor, and biasing an NMOS transistor of the buffer via a controllable current source to produce a second bias voltage at the gate of the NMOS transistor. The gain of the buffer may be controlled by varying a controllable current source coupled to a second NMOS transistor configured as a diode. Two coupling capacitors may be utilized to remove a DC component of the signal. Multiple buffers may be coupled end-to-end to increase the overall drive capability, where the channel width of the transistors within the transistors may be doubled in each successive buffer.
摘要:
According to one disclosed embodiment, an on-chip resistor calibration circuit includes an RC oscillator having a test resistor and a precision capacitor as elements, a counter, and a reference clock. In one embodiment, an RC oscillator generates a waveform having a period dependent upon the resistance of the test resistor and the capacitance of the precision capacitor. In such an embodiment, a counter and a reference clock may be configured to measure the period of the waveform. Using a pre-determined capacitance of the precision capacitor, a resistance of the test resistor may be determined. In another embodiment, an RC oscillator generates first and second waveforms through use of an additional capacitor that can be switched in and out of the RC oscillator circuit. Using a pre-determined capacitance of the precision capacitor, an RC product of the test resistor and the additional capacitor may be determined.
摘要:
Aspects of a method and system for simultaneous signal transmission on multiple selected frequencies may include generating from a single baseband signal, a plurality of radio frequency transmission signals each at a different radio frequency, wherein the single baseband signal comprises an in-phase signal component and/or a quadrature signal component. The single baseband signal, to generate said plurality of radio frequency transmission signals, may be modulated in a single radio frequency transmission chain, the radio frequency transmission chain comprising intermediate frequency modulation and radio frequency modulation. The plurality of radio frequency transmission signals may be a radio frequency signal and a corresponding image frequency signal, based on the intermediate frequency modulation and the radio frequency modulation. The signals resulting from the intermediate frequency modulation and the radio frequency modulation may be filtered to preserve the radio frequency signal and the corresponding image frequency signal.
摘要:
Methods and systems for optimal frequency planning for an integrated communication system with multiple receivers may include adjusting a center frequency of a low IF signal to reduce interference by a second order interference signal. The center frequency may be adjusted to avoid high power portions of the second order interference signal. The interference level corresponding to a center frequency may be determined by, for example, a SNR of the low IF signal, or by determining a BER for the low IF signal. The center frequency of the low IF signal may be dynamically adjusted to keep second order interference level at an acceptable level. Adjusting the center frequency of the low IF signal may also comprise keeping the low IF signal from being blocked by a DC component of the second order interference signal.
摘要:
A system for processing signals is disclosed and may include a single chip having an integrated Bluetooth radio and an integrated FM radio. The single chip may include at least one processor that enables selecting from a range of FM channels, a particular frequency for one of the FM channels based on an intermediate frequency (IF). The particular frequency may be selected so that it is an integer multiple of a channel spacing between neighboring allocated FM channels within the range of FM channels, and may be offset by at most one-half the channel spacing. The at least one processor may enable determining a frequency error of the selected particular frequency for the one of the FM channels. The at least one processor may also enable determining, whether the particular frequency includes an on-frequency channel based on the determined frequency error.
摘要:
Methods and systems for wireless communication are disclosed and may include controlling one or more scans of a received signal detection frequency across a frequency range and storing a magnitude of the received signal at each frequency where the magnitude exceeds a threshold level. A type of one or more signals in the received signal may be determined based on a bandwidth of the signals. A Bluetooth page/inquiry scan may be initiated if the determined type is a page/inquiry signal, and scans may be continued if the determined type may not be a page/inquiry signal. The scans may be repeated on a periodic basis and may be controlled utilizing a voltage controlled oscillator. Each of the scans may include a plurality of discrete frequency steps or a continuous frequency ramp. The controlling may include a start frequency, an end frequency and a frequency step size for the scans.
摘要:
A method and system is provided for enabling communication, where a FM radio system including an integrated FM radio transmitter and FM radio receiver may use an in-band FM or out of band transmitter to communicate a dynamically generated list with alternate local FM channels to an in-band or out of band receiver of another FM radio device with a FM radio receiver. The generated list of local FM channels may be ranked according to the least neighboring channel interference and may be selected for tuning the FM radio device. The FM radio system and the FM radio device may both scan to generate a substantially matched list of local FM channels. In response to detecting a new signal of a transmitted channel by the FM radio system, the FM radio device may tune to the same channel using an open loop, closed loop or semi-open loop method.
摘要:
Aspects of a method and system for sharing low noise amplifier (LNA) circuitry in a single chip Bluetooth and wireless local area network (WLAN) system are disclosed. Aspects of the system may comprise a chip with integrated WLAN and Bluetooth radios. RF signals may be received via a single antenna coupled to a shared LNA integrated in chip. When WLAN signals are received they are communicated from the shared LNA to a subsequent amplification stage integrated within the WLAN radio. When Bluetooth signals are received they are communicated from the shared LNA to a subsequent amplification stage that comprises a transconductance amplifier integrated within the WLAN radio and an LNA load integrated within the Bluetooth radio. Gains in the LNAs, the transconductance amplifier, and/or the subsequent WLAN amplification stage may be dynamically adjusted. Outputs from the subsequent amplification stages may be communicated to mixers for further processing.
摘要:
A method for simplifying common mode feedback circuitry utilized in multi-stage operational amplifiers may comprise generating a first differential output signal by a first amplifying circuit in an amplifying stage and communicating the first differential output signal to a first output of the amplifying stage. A second amplifying circuit in the amplifying stage may generate a second differential output signal that may be communicated to a second output of the amplifying stage. The second differential output signal may be fed back to a first feedback circuit in the amplifying stage, and the first differential output signal may be fed back to a second feedback circuit in the amplifying stage. Additionally, the first and the second differential output signals may be fed back to the second feedback circuit and the first feedback circuit, respectively, in a first amplifying stage and/or any one or more of succeeding amplifying stages.
摘要:
A complex filter such as the channel select filter in a radio transceiver is implemented using a transconductance/C topology to benefit from the ability to tune such filters and thereby stabilize the output transfer function of the filter over variations in temperature, power supply voltage and process. The topology is based on an active R/C biquadratic topology to achieve the additional benefit of independently controlled stages. The problem created by the R in the output impedance is can be overcome by separately tuning the R value along with the transconductance/C ratio, by implementing the R as a transconductance amplifier having common mode feedback, or by implementing the transconductance amplifiers of the topology using Nauta transconductors, and unbalancing the common mode circuit of the Nauta transconductor to achieve a differential resistance that can be used to implement the R in the output impedance.