Altera Corporation

Nima Safari

Richard Maiden

Volker Mauer

Shahin Gheitanchi

Benjamin Thomas Cope

A signal processing device includes a filter, configured to receive first data representing a signal for wireless transmission, modify the first data in a filter operation, and output second data as the modified first data; a peak detector, configured to detect third data representing a peak of the signal, wherein the third data are a subset of the first data; a signal canceller, configured to receive the third data and to generate fourth data representing a cancellation signal corresponding to the peak of the signal; and a peak modifier, configured to receive the second data and the fourth data, and to generate fifth data using the second data and the fourth data, wherein the fifth data represent the signal with a modified peak.

Joint channel filtering and crest factor reduction architecture

Techniques and mechanisms provide a technique for compression using an approximation of a mu-law algorithm.

Compression using mu-law approximation

Circuitry that efficiently implements loop functions in an integrated circuit is provided. The circuitry combines a feed-forward circuit with a feedback loop that includes a unit delay element in a feedback path. The feedback path may couple the output of a processing element to the input of the processing element. The processing element may implement a function that satisfies commutative, associative, and distributive properties. Combining the feedback loop with the feed-forward circuit may allow for register retiming in the feedback loop and for register pipelining with optional register retiming in the feed-forward circuit. The circuitry may thus trade off an increase in throughput and clock frequency for additional resources.

Methods and apparatus for implementing feedback loops

Integrated circuits with wireless communications circuitry having peak cancelation circuitry operable to perform crest factor reduction is provided. The peak cancelation circuitry may receive at least first and second carrier waveforms and may include at least a first canceling pulse generator (CPG), a second CPG, a first peak detector for performing peak detection on the first waveform, a second peak detector for performing peak detection on the second waveform, a third peak detector for performing peak detection on a combined waveform of the first and second waveforms, and a pulse allocator that receives clipping information from the three peak detectors and that controls the amount of peak cancelation that is being performed by the two CPGs. The allocator may determine whether the combined waveform contains any peaks. In response to determining that the combined waveform does not contain any peaks, the CPGs may be configured in bypass mode.

Multi-standard peak canceling circuitry

Integrated circuits are provided with wireless communications circuitry having digital predistortion (DPD) circuitry, peak canceling circuitry, a power amplifier, and signal conditioning circuitry for controlling the DPD and peak canceling circuitry. The peak canceling circuitry may receive transmit signals and may clip peaks in the transmit signals that exceed a magnitude threshold value. The DPD circuitry may compensate for non-linear characteristics of the power amplifier by outputting a predistorted version of the clipped transmit signals. The power amplifier may receive the predistorted signals and may perform amplification to generate amplified signals. The signal conditioning circuitry may identify power transfer characteristics of the power amplifier and DPD circuitry using the predistorted signals and the amplified signals. The signal conditioning circuitry may update the magnitude threshold value imposed by the peak canceling threshold based on the identified power transfer characteristics to mitigate out-of-band spectral regrowth in the predistorted signals.

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High Wycombe, United Kingdom

Nima Safari