Abstract: A method is described for producing coefficient leakage in an adaptive filter/equalizer without the need for using an adder/subtractor for each coefficient. Specifically, a method is provided for incrementally reducing the magnitude of one or more coefficients in an adaptive filter/equalizer solely through a defined manipulation of certain bits in that coefficient, such bit manipulation being carried out on a periodic basis. The period for such bit manipulation will generally track the frequency of adaptation iteration for such a filter/equalizer.

Abstract: A method of efficiently demodulating and isolating a signal within a fixed possibly wider band spectral region, having any of a wide range of baud rates. The signal is sampled at a fixed, first frequency which remains fixed no matter what the baud rate. Thus, the sample rate does not necessarily correspond to the desired baud rate. The sampled signal is then demodulated and low pass filtered to create baseband samples at the first frequency, which are then subject to user-specified arbitrary rate change in a continuously variable interpolator/decimator (continuously variable digital delay (CVDD) device), and decimated by a programmable power of 2, to produce samples at a second frequency. The second frequency is preferably determined to be a whole number multiple of the desired baud rate, e.g., twice the desired baud rate. The samples are equalized to produce output symbols at the target baud rate.

Abstract: In a digital receiver, an equalizing unit includes a power controller adapted to scale received components of a quadrature amplitude modulated signal based on a constellation size of the quadrature amplitude modulated signal. Alternatively, a method of scaling components of a quadrature amplitude modulated signal includes the steps of searching the quadrature amplitude modulated signal to determine a constellation size, and scaling the components of the quadrature amplitude modulated signal based on the constellation size.

Abstract: A method is described for eliminating the impact on an output of an adaptive equalizer due to the occurrence of "false" coefficients of such an equalizer. In particular, a method is provided for selecting a threshold as representing the smallest expected "ghost" value to be encountered by the filter/equalizer, and thereafter causing coefficients having values less than such threshold to be set to zero.

Abstract: A method is described for producing coefficient leakage in an adaptive filter/equalizer without the need for using an adder/subtractor for each coefficient. Specifically, a method is provided for incrementally reducing the magnitude of one or more coefficients in an adaptive filter/equalizer solely through a defined manipulation of certain bits in that coefficient, such bit manipulation being carried out on a periodic basis. The period for such bit manipulation will generally track the frequency of adaptation iteration for such a filter/equalizer.

Abstract: An apparatus and method of implementing an equalizer filter configuration including a plurality of memory blocks and a plurality of filter blocks. The respective pluralities of memory blocks and filter blocks are coupled so that the equalizer filter configuration has the capability to process input signal samples. The input signal samples include signal samples selected from the group consisting essentially of complex-valued signal samples and real-valued signal samples.

Abstract: An update block for an adaptive RAM-based equalizer filter configuration includes a multiplier, an adder, and a plurality of delay units. The multiplier, adder, and delay units are coupled in an manner so as to have the capability to perform full-rate equalizer filter coefficient adaptation. In accordance with another embodiment of the invention, a method of updating a coefficient signal for an adaptive RAM-based equalizer filter configuration is provided. The method selectively variably delays an error signal sample produced by the adaptive RAM-based equalizer filter configuration and an equalizer filter input signal sample and computes with selectively variably error signal sample and the selectively variably delayed equalizer filter input signal sample. Finally, the coefficient signal is updated by adding the product to the coefficient signal.

Abstract: A method and apparatus are described for application to an adaptive equalizer, or filter, whereby complex valued coefficients for such an equalizer may be updated with a significant reduction in complexity as compared to prior art methods. Specifically, the method of the invention causes a sum and a difference to be determined for a real-valued and an imaginary-valued component of an input signal sample to the equalizer. Those sum and difference terms are then applied according to the method of the invention to a determination of an update term for a coefficient under consideration. Because the method of the invention results in a material reduction in the number of addition/subtraction operations required for the coefficient update process, the hardware infrastructure needed to implement that process is considerably simplified.