Abstract: A system and method for inverting automatic frequency control applied to a reference signal used to process an input signal is disclosed. When receiving an input communication signal, a receiver controls the frequency of the reference signal to compensate for frequency differences between a transmitter and a local oscillator in the receiver. The frequency control applied to the reference signal causes frequency variations in a resultant signal processed signal when the input signal is processed using the reference signal. The frequency of a second reference signal is controlled such that further processing of the resultant processed signal removes effects of the frequency control applied to the reference signal. The processing which applies frequency control to the reference signal is performed in real time while the inversion process is performed in a separate processing section.

Abstract: A soft limiter for a signal processor includes a variable-gain amplifier, and a threshold detector. The variable-gain amplifier includes a signal input for receiving an input signal, a signal output for providing an output signal representative of the input signal, and a gain control input for controlling a gain of the amplifier. The threshold detector is coupled to the gain control input, and includes a control input for receiving a control variable thereon. The threshold detector is configured to set the gain of the amplifier to a first gain value when the control variable exceeds a threshold value, and to set the gain to a second gain value different from the first gain value when the control variable is less than the threshold value.

Abstract: An automatic gain control (AGC) and DC estimation and correction technique for wireless communication devices is provided. An AGC signal, which controls a gain applied to a received signal by a gain stage to generate a scaled signal, is assigned one of a relatively small number of values in accordance with the amplitude of the scaled signal. An estimate of a DC offset in the scaled signal corresponding to each value of the AGC signal is stored in a memory. A DC estimation arrangement then reads the stored estimate associated with the particular value of the AGC signal from the memory and generates a current DC estimate based thereon. The current estimate is then used to correct the scaled signal for DC offset and to update the stored estimate.

Abstract: An automatic gain control (AGC) and DC estimation and correction technique for wireless communication devices is provided. An AGC signal, which controls a gain applied to a received signal by a gain stage to generate a scaled signal, is assigned one of a relatively small number of values in accordance with the amplitude of the scaled signal. An estimate of a DC offset in the scaled signal corresponding to each value of the AGC signal is stored in a memory. A DC estimation arrangement then reads the stored estimate associated with the particular value of the AGC signal from the memory and generates a current DC estimate based thereon. The current estimate is then used to correct the scaled signal for DC offset and to update the stored estimate.

Abstract: A system and method for inverting automatic frequency control applied to a reference signal used to process an input signal is disclosed. When receiving an input communication signal, a receiver controls the frequency of the reference signal to compensate for frequency differences between a transmitter and a local oscillator in the receiver. The frequency control applied to the reference signal causes frequency variations in a resultant signal processed signal when the input signal is processed using the reference signal. The frequency of a second reference signal is controlled such that further processing of the resultant processed signal removes effects of the frequency control applied to the reference signal. The processing which applies frequency control to the reference signal is performed in real time while the inversion process is performed in a separate processing section.

Abstract: A synchronization (sync) signal detector and associated method detect the occurrence of a known sync signal in a received signal. The known sync signal is generated and correlated with the received signal to generate a correlation waveform. A peak value of the correlation waveform, indicative of the occurrence of the sync signal in the received signal, is detected and used to determine a timing offset between the received signal and the sync signal. The sync signal is then shifted in time to compensate for the timing offset. Such shifting of the sync signal is simpler and requires substantially less processing time and resources compared to known sync signal detection schemes, in which a received signal or the sampling timing of a received signal is shifted to compensate for timing offset.

Abstract: A system and method for detecting a synchronization (sync) signal in a communication signal are disclosed. A received communication signal is stored in a memory and portions thereof are read from the memory and monitored to detect the sync signal. When a detected sync signal is determined to be invalid, previously read portions of the received communication signal, preferably beginning at a portion of the received signal immediately after a start of the detected sync signal, are again read and monitored to detect the sync signal. Such reading and monitoring of previously read portions of a received signal provide for recovery from so-called false triggering based on invalid sync signals.

Abstract: A soft limiter for a signal processor includes a variable-gain amplifier, and a threshold detector. The variable-gain amplifier includes a signal input for receiving an input signal, a signal output for providing an output signal representative of the input signal, and a gain control input for controlling a gain of the amplifier. The threshold detector is coupled to the gain control input, and includes a control input for receiving a control variable thereon. The threshold detector is configured to set the gain of the amplifier to a first gain value when the control variable exceeds a threshold value, and to set the gain to a second gain value different from the first gain value when the control variable is less than the threshold value.