DSP – Digital Signal Processing is a specialized digital signal processor (DSP) — a dedicated chip designed for processing digitized signals in real time. DSPs are specialized processors based on the Harvard architecture and provide a stream of high-speed, intensive computations.
Differences between DSP and other types of microprocessors
High-speed arithmetic
A DSP processor must be capable of performing in a single cycle multiplication, multiply–accumulate operations, cyclic shift, as well as standard arithmetic and logical operations.
Extended dynamic range for multiply/accumulate operations.
The operation of summing a sequence of values is fundamental for algorithms implemented on DSPs. Overflow protection is essential to avoid data loss.
Dual operand fetch per cycle.
For most DSP operations, two operands are required. Therefore, to achieve maximum performance, the processor must be able to fetch two operands simultaneously, which also necessitates a flexible addressing system.
Hardware-implemented circular buffers (internal and external).
A wide range of algorithms implemented on DSPs require the use of circular buffers. Hardware support for circular pointer wrap-around or modular addressing reduces unproductive CPU time and simplifies algorithm implementation.
Loop and branch organization without performance loss.
DSP algorithms often include many repetitive operations that can be implemented as loops. The ability to execute program sequences in a loop without performance degradation distinguishes DSPs from other processors. Similarly, conditional branching must not introduce delays during digital signal processing.
In radio communications, digital processing is most often applied to signals received from the air, in order to ensure higher reception quality and eliminate interference accompanying the correspondent’s transmission. This applies to any mode of communication, including digital. A DSP processor provides, at the software level, transmitter frequency response boost of 6 dB per octave with corresponding receiver path pre-correction, deviation level control, microphone sensitivity adjustment, and receiver bandwidth setting. These parameters directly influence speech intelligibility.
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