The company Teltronic in Biberist, Switzerland, has been successfully developing radio remote controls for several years. The aim of this thesis is to improve the receiver of such a switch. The Teltronic receiver is designed for a two-level FSK signal with a carrier frequency of 434 MHz and a deviation of 7.5 kHz. In this receiver the signal is mixed down to a second intermediate frequency as usual, at which point it is then demodulated through an FM-Discriminator.

After careful scrutiny it was shown that the aim of improving the receiver should not be underestimated. The product with a sensitivity of -118.5 dBm is already very good as it is.

Yet two approaches were found with which to increase the sensitivity by another 5 to 8 dBm. The first approach is a purely software-based solution in which all hardware can be retained. Using coding with an additional halving of the data rate an increase in sensitivity of 5.5 dB can theoretically be achieved. In practice an improvement of 5 db was shown.

The second approach is a complete redesign using digital signal processing. In this method a two-level FSK is applied as usual, which is filtered directly on the intermediate frequency with a narrowband digital filter. Thus a minimum of noise is recorded and the sensitivity is improved by 8 dB.