Sir Eric Ash obituary
The electrical engineer Eric Ash, who has died aged 93, made major contributions to controlling and manipulating electrical, optical and acoustic waves for signal processing and imaging applications. Already established as a leading figure in this field when he arrived at University College London in 1963, he undertook research that proved invaluable in televisions, mobile phones, satellite communications and imaging systems.
His particular interest lay in surface acoustic waves (SAW) - sound waves that travel on the surface of crystals, discovered by Lord Rayleigh in the 19th century. Compared to microwaves, which have similar frequencies, surface acoustic waves have very small wavelengths, and so practical devices using them can be made very compact.
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