Acquiring digital hi-fi know-how

Building on university research, Greek SMEs can now apply electronics circuitry for digital signal processing (DSP) to multimedia audio equipment thanks to funding from the European Commission’s IST programme.

Under the project name of HIPRO, the coordinating organisation Spectrum Electronics Company S.A learnt how to apply sophisticated DSP technology, a highly technical area involving complex mathematics as a result of the technology transfer of microelectronics know-how from project partner University of Athens.

The great advantage of such a numerical approach versus any analogue process is its reproducibility. Once a numerical procedure is settled, it becomes an ’easy task’ to duplicate without failure and thoroughly maintain the quality of the result. This explains why the DSP technology has found its place in many electronics applications such as radio, high definition television, high-end audio, etc.

In audio applications, the use of DSPs offers several advantages over analogue systems. Since general purpose DSP hardware can be programmed to perform many different functions, this approach offers extended flexibility and programmability. DSPs are also not affected by temperature and need no tuning.

The underlying aims

HIPRO’s aim was to acquire the technologies and tools in audio signal processing and advanced algorithms in Field Programmable Gate Arrays (FPGA) for audio control to build highly efficient digital audio amplifiers as a substitute to analogue-based hi-fi systems.

Digital amplifiers receive digital input and produce analogue waveforms driven to the loudspeakers using solely digital stages. The main concept is the direct conversion of input data from Pulse Code Modulation (PCM) – a digital way for transmitting analogue information – from a digital audio source, such as a CD/DVD player into a Pulse Width Modulation (PWM) waveform – a powerful technique for driving analogue circuits with digital outputs – and the replacement of the analogue amplification stage with a bridge of field-effect transistors (FETs) operating as switches, operating on this PWM format.

Digital amplifiers that switch from analogue to digital have numerous advantages compared to conventional amplifiers, as they dissipate less heat, are lighter and smaller, more powerful yet energy efficient, more reliable, and ultimately perform better providing superior sound quality.

Finding a market

As Spectrum Electronics’ main business is the development and marketing of high quality (electronic) loudspeakers in Greece, the acquisition of modern microelectronics technology provided the company with the capability to design and develop complex systems for audio processing in a cost effective way, allowing it to extend its business to a new market niche, i.e. home theatre equipment. The target customers are extremely demanding audiophiles seeking high quality music systems, usually delivered by expensive analogue hi-fi audio equipment.

However, although the latest consumer electronics sales figures released by the European Information Technology Observatory (EITO) indicate a 6 per cent growth rate in 2003, the 2002 static audio market share (tuners, amplifiers, receivers, loudspeakers, digital recorders etc.) fell 7.8 per cent compared with 2001 reaching €5,871.8 million according to data from the European Information and Communications Technology Industry Association (EICTA) from the EU-15 Member States.

As Anthony Tavoularis, project coordinator from Spectrum Electronics explains: “Unfortunately, the hi-fi market in Europe suffers a serious slow-down nowadays. The introduction of home cinema has considerably lowered the market standards for high quality sound. The market segment of high-end audio products is very small… That’s why we have decided to produce a lower cost, less featured audio amplifier (actually a DAC [Digital to Analogue Converter]) based on HIPRO’s results.”

The developed DAC has been already prototyped and presented in comparative tests in the local specialist press (audio and hi-fi magazines in Greece). “The results were very positive,” says Tavoularis. Further demonstrations to the local special audio press as well as participation in exhibitions will be pursued in the near future.

Contact:
Anthony Tavoularis
Spectrum Electronics Company S.A.
Electronics Dept.
1 Verikokkias Str.
GR-13671 Athens
Greece
Tel: +30-210-2405111
Email: sec@otenet.gr
Source: Based on information from HIPRO