29-10-2010, 03:44 PM
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DSP chip design
INTRODUCTION
An SDR device allows users to change transmitter and receiver characteristics
such as modulation type, wideband and narrowband operations, radiated power, and
air interfaces by making software changes without any hardware alternation.
Traditional LMR devices are based on specialized hardware such as transistors and
integrated circuits. In more modern LMR radios, digital signal processor (DSP) chips
are used for analog- to-digital and digital-to-analog conversion of the radio
transmissions. A DSP chip is a real-time digital signal processor that can alter its
functionality by executing different software algorithms.
Recent advances in DSP chip design and fabrication will allow for more
advanced DSP chips able to support multiple functions. This is due to continuous
improvement in manufacturing techniques for creating chip components at extremely
small sizes (fractions of a micron), therefore producing DSP chips with more built-in
functionality. SDR devices will take advantage of these advanced DSP chips to have
multiple functionalities such as supporting multiple access technologies (e.g., operate
on different radio technologies). SDR devices are envisioned to interoperate with
existing and evolving LMR systems by switching modes and also are capable of
operating in multiple public safety frequency bands.