Abstract: A symbol independent automatic frequency controller (100) includes a symbol correlator (110) for receiving a complex digital signal generated within a selective call receiver wherein the symbol correlator provides a real signal (114), an imaginary signal (116), and a magnitude signal (112), a discriminator (140) coupled to the symbol correlator for receiving and processing the real signal and the imaginary signal to provide a frequency error signal, a low pass filter (120) and comparison element (130) for filtering the magnitude signal and comparing the magnitude signal to a predetermined lock threshold signal that controls the bandwidth of the symbol correlator in the event the magnitude signal exceeds the lock threshold signal, and a feedback loop providing the imaginary signal (116) to an accumulator (170) and back to the symbol correlator wherein the accumulator provides the symbol correlator with an apriori-symbol phase feedback (172).

Abstract: A symbol independent automatic frequency controller (100) includes a symbol correlator (110) for receiving a complex digital signal generated within a selective call receiver wherein the symbol correlator provides a real signal (114), an imaginary signal (116), and a magnitude signal (112), a discriminator (140) coupled to the symbol correlator for receiving and processing the real signal and the imaginary signal to provide a frequency error signal, a low pass filter (120) and comparison element (130) for filtering the magnitude signal and comparing the magnitude signal to a predetermined lock threshold signal that controls the bandwidth of the symbol correlator in the event the magnitude signal exceeds the lock threshold signal, and a feedback loop providing the imaginary signal (116) to an accumulator (170) and back to the symbol correlator wherein the accumulator provides the symbol correlator with an apriori-symbol phase feedback (172).

Abstract: A symbol independent automatic frequency controller (100) includes a symbol correlator (110) for receiving a complex digital signal generated within a selective call receiver wherein the symbol correlator provides a real signal (114), an imaginary signal (116), and a magnitude signal (112), a discriminator (140) coupled to the symbol correlator for receiving and processing the real signal and the imaginary signal to provide a frequency error signal, a low pass filter (120) and comparison element (130) for filtering the magnitude signal and comparing the magnitude signal to a predetermined lock threshold signal that controls the bandwidth of the symbol correlator in the event the magnitude signal exceeds the lock threshold signal, and a feedback loop providing the imaginary signal (116) to an accumulator (170) and back to the symbol correlator wherein the accumulator provides the symbol correlator with an apriori-symbol phase feedback (172).

Abstract: A full serial implementation of a M-level correlation based demodulator (100) includes a two's complement, pass-through, zero-out complex conjugate multiplier element (102), a boxcar filter (104) coupled to the multiplier element, a complex magnitude approximater element (106) coupled to the boxcar filter and a maximum value and index holding element (108). The multiplier element reuses common products along an M-level of cross-correlation to reduce multiplication functions at a rate 2 times M faster than a sampling rate at an input of the demodulator.

Abstract: A system for accurately measuring frequency response (phase and gain) in either a wireless or in a wired mode of operation is described. When used in either mode, a multiplexing method is employed which allows the use of a narrow channel bandwidth, with a simultaneous improvement in overall accuracy. Cancellation of all linear and time invariant errors, including those of the analog to digital conversion process, is thus accomplished. As a result, the system error only depends on the differential nonlinearity of the channel.