A filter circuit includes a first stage comprising a first infinite impulse response (IIR) filter; a third stage comprising a third IIR filter; and a second stage interposed between the first stage and the third stage, the second stage comprising a second IIR filter, where an output terminal of the first IIR filter is coupled to an input terminal of the second IIR filter, and an output terminal of the second IIR filter is coupled to an input terminal of the third IIR filter, where the second stage of the filter circuit is configured to operate in an acquisition mode when a transient is detected in an input signal to the first IIR filter, where during the acquisition mode, the second stage of the filter circuit is bypassed.

Embodiments of the present invention provide a digital signal processing apparatus, including an interpolator, an interpolating convolver, or the like, for providing a plurality of output samples or output values in parallel, such as P output samples provided by P Farrow cores, based on a set of input samples or input values, such as 2P+M−2 samples. The digital signal processing apparatus includes a sample distribution logic or structure configured to provide a plurality of subsets of the set of input samples to a plurality of processing cores, such as interpolation cores (e.g., Farrow cores) that perform processing operations associated with different time shifts, for example with respect to a reference time (e.g., a time associated with the input samples). The sample distribution logic includes a hierarchical tree structure having a plurality of hierarchical levels of splitting nodes.

Embodiments of the present invention provide a digital signal processing apparatus including a combiner logic and a plurality of processing cores. Input samples of the digital signal processing apparatus are provided to the plurality of processing cores. Sets of output samples of the processing cores are provided to the combiner logic as input samples, and the sets of samples are provided to the combiner nodes c of the highest hierarchical level (h=0). A digital signal processing apparatus or a parallel decimating digital convolver may be used as a building block of a signal processor application-specific integrated circuit (ASIC) and/or part of other instruments for generating output samples. Furthermore, applications of the digital signal processing apparatus described herein can be addressed on a parallel DSP, in a response time of real-time or near to real-time, for flexible (or almost arbitrary high) sample rates.

A filter circuit includes a first stage comprising a first infinite impulse response (IIR) filter; a third stage comprising a third IIR filter; and a second stage interposed between the first stage and the third stage, the second stage comprising a second IIR filter, where an output terminal of the first IIR filter is coupled to an input terminal of the second IIR filter, and an output terminal of the second IIR filter is coupled to an input terminal of the third IIR filter, where the second stage of the filter circuit is configured to operate in an acquisition mode when a transient is detected in an input signal to the first IIR filter, where during the acquisition mode, the second stage of the filter circuit is bypassed.

Efficient and low-latency cueing means for initiating and updating a process of signal detection and separation in a wideband receiver. The method uses an array of IIR filters that feed an inverted state tree. The inverted state tree provides the directions for separating, detecting, and tracking multiple simultaneous signals that are being received. These signals could be either radar or communications signals and are of widely differing frequencies, bandwidths, and other characteristics. The directions are sent by the cueing system to a set of tunable tracking filters and continuously updated so that the set of tracking filters produce noise-reduced, separated signals on their outputs representing the various simultaneous incoming signals.