Abstract: Large interfering signals (interferers) with spectra near a desired signal can cause distortion in a wireless receiver due to a non-linear signal path. It is typically a performance advantage to attenuate these interferers earlier in the signal path, rather than later in the signal path, because these interferers can cause saturation of amplifying stages. In certain situations, the frequency offset of an interfering signal, with respect to the desired signal, can be on the order of 10 megahertz (MHz), whereas the center frequencies can be on the order of several gigahertz (GHz). Thus, a filter with “baseband” precision would be needed at radio frequency to notch out the interferer, which is relatively difficult to do. Disclosed is a technique to estimate the relative strength and center frequency of the interferer and to place the center frequency of a notch filter adaptively and precisely at the interferer location.

Abstract: A method and apparatus are provided for reducing, and preferably substantially eliminating, data-pattern autocorrelations found in digital communication systems. The method employed is referred to as Data Subset Selection (DSS) and is implemented in the form of DSS engine. Autocorrelations in the data-pattern can cause many digital adaptive systems to converge to an incorrect solution. For example, the LMS method, which is often used in adaptive filtering applications, can converge to an incorrect set of filter coefficients in the presence of data-pattern autocorrelations. Digital timing recovery methods are also susceptible. Other impairments that result from data-pattern autocorrelations include increased convergence time and increased steady-state chatter.

Abstract: A phase detector customized for Clock Synthesis Unit (CSU) is disclosed. The phase detector improves jitter performance by providing minimal activity on VCO control lines and pushing ripple frequency to one octave higher, while maintaining wide linear characteristic. Moreover, it provides a frequency-scalable circuit that unlike a conventional phase-and-frequency detector (PFD), does not rely on asynchronous elements.

Abstract: A phase detector customized for Clock Synthesis Unit (CSU) is disclosed. The phase detector improves jitter performance by providing minimal activity on VCO control lines and pushing ripple frequency to one octave higher, while maintaining wide linear characteristic. Moreover, it provides a frequency-scalable circuit that unlike a conventional phase-and-frequency detector (PFD), does not rely on asynchronous elements.