- on Audio and sound generation
- Published in issue 9/1983 on page 46
personal FM - miniature high quality FM receiver
personal FM elektor september 1983 Manufacturers are always interested in miniaturising receiver circuits and they keep pushing the limits further and further. In a normal receiver set-up extreme integration is to be avoided especially as regards tuning coils, ceramic filters, band filters, and trimmers. Coils especially are a problem. Certainly they could be replaced by gyrator circuits, but because of their complexity these also have certain disadvantages at high frequencies, such as low Q factor, limited dynamic range and fairly high current con- sumption. So Philips set out to develop a receiver that was less sensitive to the various problems posed by IC technology itself. And they succeeded with an 18 pin chip that needs only an oscillator and a few small capacitors to form an FM receiver. Everything else is internal, from the aerial input right through to the IF filters and demodulator! The break through came when they decided to aban- don accepted practice and chose to use ...