IP99: U.K. design house tunes in to digital-radio library

IP99: U.K. design house tunes in to digital-radio library
By Rick Boyd-Merritt, EE Times
March 24, 1999 (5:23 p.m. EST)
URL: http://www.eetimes.com/story/OEG19990324S0030

SANTA CLARA, Calif. — A U.K. design house has rolled out a functional library for building Digital Audio Broadcast (DAB) receivers. Using those libraries, Ensigma Ltd. (Chepstow, England) is developing its own receiver chip that it expects to field by the end of the year for Europe's emerging market for digital-radio receivers.

Ensigma's library is the result of work with Hitachi Ltd. on a version of that company's SH-DSP chip, dubbed SH-DAB, that is currently used in at least two consumer car and home digital radio receivers from JVC and others that have recently hit the market in Europe. "After a long development cycle OEMs are finally at the point where they will be able to watch the uptake of these products by the public," said Adrian Anderson, technical director of Ensigma.

At a presentation at the IP99 conference here, Anderson detailed the DAB library which Ensigma is now making available for a negotiated fee. The library is derived from the company's work on the Hitachi SH7490, which was tested in field trials last summer.

The library includes a number of hardware functions, such as a fast Fourier transform, DQPSK modulation, Viterbi decoder for forward error correction, and an SRAM or SDRAM shared-memory controller. The hardware is defined using the Visual HDL from Summit and is available in VHDL or Verilog for synthesis.

The library also includes a variety of software-based functions, including an MPEG-2 audio decoder which requires an estimated 10 Mips from a 16-bit DSP. Other software functions include signal acquisition and tracking, the extraction of identity codes from a DAB transmitter and a packet-data decoder. The software functions are expressed in C.

Anderson said the software was written so as to make it readily portable to any 16-bit DSP architecture. "There are so many different DSPs in use in this space, we didn't know which to target," he said.

The DAB standard, ratified by ETSI in 1995, is now being u sed by as many as 280 broadcast services in more than 30 countries, Anderson said. Beyond home and car digital radios, Ensigma expects DAB receivers to appear in a variety of car navigation and mobile communications products.

As in the arena of digital cellular phones, Europe has a lead over the United States in having a single standard established for services. So far, the U.S market has only engaged in field trials of various approaches to digital broadcast radio. However, unlike the cell-phone area, Europe is still struggling to deliver DAB receivers at consumer price points.