Antenna bandwidth limitation

Transfer frequency characteristics

The parasitic capcitance of the transmit coil and the receive coil have a large influence on the frequency response of the hearing loop.

We will investigate these influences and, if necessary, take measures to reduce tem.

The figure below shows the transfer with an instantaneous transadmittance transmitter amplifier and an integrating voltage receiver amplifier.

The two resonsnce peaks are cause by the self resonance of the transmit coil and the receive coil.

Alhough these peaks occur outside the frequency range of interest they increase the systems sensitivity for 'out-of-band' interference.

We will reduce these resonances by inserting damping resistors in parallel with the coils.