摘要:
A dynamically matched mixer system (200) for use in a direct conversion radio frequency (RF) receiver includes a frequency generator (201, 203, 205) that includes plurality of dividers (407) for providing differential local oscillator reference sources (FLO+ and FLO−) and mitigation frequency reference sources (F1 and F2) from reference oscillator (205). A mixer (209) mixes the differential local oscillator reference sources (FLO+ and FLO−) and the mitigation frequency reference sources (F1 and F2) while dynamic matching units (211, 213) are used for receiving the mitigation frequency reference sources and matching switching parameters of differential input signals (IRF+ and IRF−) and differential baseband output signals (IBB+ and IBB−). The frequencies of the mitigation frequency reference sources (F1 and F2) are selected so as to establish a non-integer relationship to the reference oscillator (201) for mitigating the occurrence of interference with FLO+ and FLO−.
摘要翻译:用于直接转换射频(RF)接收机的动态匹配混频器系统(200)包括频率发生器(201,203,205),其包括多个分频器(407),用于提供差分本地振荡器参考源(F and and> LO LO LO LO LO LO LO LO)和缓解频率参考源(F 1和F 2) 单元(211,213)用于接收缓解频率参考源和差分输入信号(I + RF +和I + RF - )的匹配切换参数和差分基带输出信号 (I BB +和/或BB - )。 选择缓解频率参考源(F 1和F 2)的频率以便建立与参考振荡器(201)的非整数关系,以便减轻与F LO和/ F SUB>。
摘要:
A method and apparatus for processing a radio frequency (RF) signal is provided. The method includes generating a periodic square wave local oscillator (LO) signal of a first phase, a periodic square wave LO signal of a second phase, and a chopping signal. The method further includes coding the periodic square wave LO signal of the first phase and the periodic square wave LO signal of the second phase synchronously with the chopping signal to generate a first set of synchronized signals (116, 118) and a second set of synchronized signals (120, 122), respectively. A phase difference between the first phase and the second phase is a predefined value. The RF signal is processed with the first set of synchronized signals (116, 118) and the second set of synchronized signals (120, 122) to obtain an in-phase intermediate frequency (IF) signal (132) and a quadrature-phase IF signal (142), respectively.
摘要:
A method and apparatus for processing a radio frequency (RF) signal is provided. The method includes generating a periodic square wave local oscillator (LO) signal of a first phase, a periodic square wave LO signal of a second phase, and a chopping signal. The method further includes coding the periodic square wave LO signal of the first phase and the periodic square wave LO signal of the second phase synchronously with the chopping signal to generate a first set of synchronized signals (116, 118) and a second set of synchronized signals (120, 122), respectively. A phase difference between the first phase and the second phase is a predefined value. The RF signal is processed with the first set of synchronized signals (116, 118) and the second set of synchronized signals (120, 122) to obtain an in-phase intermediate frequency (IF) signal (132) and a quadrature-phase IF signal (142), respectively.
摘要:
A method of detecting an on-channel signal and synchronizing signal detection with correcting for DC offset errors in a direct conversion receiver is presented. A received signal is digitized, and a state machine operates to detect the presence of an on-channel signal. If the signal is not detected, a mixed mode training sequence is initiated in which the DC offset errors in both an analog and digital received signal path are corrected. While training, processing of the digitized samples by a digital signal processor and a host controller is suspended (while they are put into battery save mode) and the gain provided to subsequently received signals is minimized. The DC offset correction circuitry is bypassed and put into battery save mode at predetermined periods when DC offset correction is not performed.
摘要:
An automatic gain control (AGC) method and circuit (10) within a receiver uses a digital state machine (26) to implement the AGC function. independent from interaction with a host processor (36) and for multiple modulation protocols without duplicating circuitry. Modulation protocol and parameters for any of various gain responses are stored in a register (29). Multiple states, each corresponding to a predetermined range of RF input signal strength, are stored in the register. Each state contains parameters that determine a gain control signal for controlling a variable gain amplifier (16). The states are independent and may be selectively disabled to create asymmetric responses. Within any state, an adaptable number of iterations may be set to implement a different update rate or step size after a predetermined number of closed loop gain change iterations has not resulted in a transition to a state that represents a desired output gain.
摘要:
A receiver for a wireless communication device provides a dual path receiver receiving first and second protocol-agnostic, uncorrelated receive signals simultaneously. The dual path receiver generating first and second offset IF signals from the simultaneously received first and second protocol-agnostic, uncorrelated receive signals. The receiver utilizes at least one converter for converting the first and second offset IF signals into at least one serial synchronous interface (SSI) signal representing the spectrum at IF. At least one processor receives the at least one SSI signal and applies parallel processing paths to demodulate the at least one SSI signal into separate baseband signals. The processor provides interference detection of, and level control for, the first and second offset IF signals.
摘要:
An apparatus and method for demodulating an FM RF signal is presented. An Adaptive Differentiate Cross Multiply (ADCM) system in which the energy estimate of the desired on-channel RF is generated using adaptive filtering. The adaptive filter includes low pass filtering of the instantaneous energy estimate. The bandwidth of the LPF is adjusted in real time based on the received signal strength energy estimate, the periodicity of any changes in the energy estimate, AGC setting for the receiver, and/or the type of sub-audible signaling applied to the RF signal if known. After the bandwidth is set, the optimum filtered energy estimate is applied to the system to demodulate the received information free from distortion artifacts associated with IQ imbalance. A normalized signal in the ADCM system is clipped by a limiter whose clipping threshold is equal to a maximum gain of differentiators in the ADCM system.
摘要:
A method for minimizing undesired signal coupling from digital interface between peripherals is presented. The method includes transmitting over the interface first and second signals having a parameter ζk set by a dynamic sequencer respectively to a first and second value α1 and α2, receiving the first and second signal and generating a first and second interference metric respectively for the first and second signal. The first and second interference metrics are correlated to generate a final parameter value αf, and a transmitter is then configured to transmit a third signal over the interface with the final parameter value αf.
摘要:
An apparatus and method for receiving and processing multiple independent, uncorrelated RF signals is presented. The apparatus includes a Hybrid-Direct Conversion Receiver incorporating front end branches, protocol-specific digital processing branches, an interference detector, a correlator, and an offset control for controlling oscillator sources. The front end branches each contain a preselector that filters received signals and a mixer that down converts the received signal to an IF offset from a reference frequency by a unique offset. The bandwidth of an IF processor is partitioned into sub-channels corresponding to the different offsets and is wider than the combination of the sub-channels. The interference detector and correlator determine whether a particular desired signal is degraded by interference signals and select a new sub-channel. This information is provided to the offset control, which adjusts a LO source coupled to the corresponding down mixer accordingly.
摘要:
A frequency generation unit (FGU) in a communication device includes a voltage controlled oscillator (VCO), an adjustable filter having a capacitive element for wideband operation, a current source with variable gain, and chirp generation control circuitry (CGC) that is used to generate location signals. The FGU receives, from a reference device, at least one location signal control parameter that defines linear frequency slope characteristics for a location signal. The CGC configures, based on the at least one location signal control parameter, the gain and a polarity of the current source to generate a first current during a first time period for charging the capacitive element to generate a control signal that is coupled to the VCO to generate a first part of the location signal having the defined linear frequency slope characteristics, wherein the first part of the location signal is transmitted using a transceiver of the communication device.