Abstract: An RF receiver (12) includes a channel estimator (52). The channel estimator (52) includes a channel estimation filter (82), error signal generator (84), and normalized Least-Mean-Square (NLMS) filter-definition generator 86. The filter (82), error generator (84) and NLMS filter-definition generator (86) function together as an adaptive estimator. An error signal (90) is formed with a received signal (48). The filter (82) filters an estimated transmit signal (74) constructed from lower confidence decision data (66) and higher confidence known preamble data (30?). An adaptive filter definition (94) is formed in a feedback, loop which minimizes correlation between the estimated transmit signal (74) and the error signal (90). A convergence signal (122) is modulated in synchronism with the changes between lower and higher confidence data in the estimated transmit signal (74).

Abstract: An RF receiver (12) includes a channel estimator (52). The channel estimator (52) includes a channel estimation filter (82), error signal generator (84), and normalized Least-Mean-Square (NLMS) filter-definition generator 36. The filter (82), error generator (84) and NLMS filter-definition generator (86) function together as an adaptive estimator. An error signal (90) is formed with a received signal (48). The filter (82) filters an estimated transmit signal (74) constructed from lower confidence decision data (66) and higher confidence known preamble data (30?). .An adaptive filter definition (94) is formed in a feedback, loop which minimizes correlation between the estimated transmit signal (74) and the error signal (90). A convergence signal (122) is modulated in synchronism with the changes between lower and higher confidence data in the estimated transmit signal (74).

Abstract: A signal calibrator (14) for a software-defined communications device (10) that enables device communications signals to be transmitted in a manner that maximally decouples the calibrator (14) from the device hardware (40), and that simplifies the design and reduces the cost of the communications device (10). The calibrator (14) includes a software modulator (16) for generating a nonstop stream of samples including zero valued samples and non-zero valued waveform bursts, and a software demodulator (18) connected to the software modulator (16) via a closed loop feedback path (20) that receives a nonstop stream of samples. The non-zero valued samples create radio emissions. The software demodulator (18) is for determining a timing error of the transmission sample and for transmitting a timing error correction value to the software modulator (16) via the closed loop feedback path (20).

Abstract: A radio is disclosed in which different waveforms may be utilized. The radio includes a memory (801) in which software (802, 805, 806) for specific waveforms is stored. The radio further includes one or more processors (807, 809, 811) which extract waveform specific software to process information for transmission or reception. All processing of the information between reception or reproduction of speech and transmission and reception of radio frequency signals, respectively, is performed in software.

Abstract: A method and system for reducing the sampling rate of a signal for use with high modulation index frequency modulated signals reduces the power consumption and processing requirements of the digital signal processing equipment which performs the demodulation. In a preferred embodiment, a high modulation index FM signal is divided into in-phase and quadrature phase components by a downconverter (FIG. 1, 10). These components are sampled by analog to digital converters (20, 21) and input to a delay element (40, 41). The resulting delayed and undelayed samples are conveyed to downsamplers (60-63) where the sampling rate is reduced. The undelayed in-phase and delayed quadrature phase components are multiplied together by a first multiplier (70) while the undelayed quadrature phase and delayed in-phase components are multiplied together by a second multiplier (71).