digital radiosystem, digital radiovorrichtung and demodulator for quadraturkomponente

摘要

A digital radio device having a quadrature demodulator that does not suffer from substantial amplitude roll-off at the relevant operating range. Such a device is obtained by a phase shifting network in a quadrature branch of the demodulator having a series arrangement of a resistor and an capacitor coupled to an inductor coupled to ground. A junction between the series arrangement and the inductor forms the output of the quadrature branch. Alternative embodiments are provided. The demodulator avoids asymmetric digital signal distortion which can have deteriorating effects, in particular to GFSK-signals or pi/4-DQPSK signals, or the like, and further noise shift of data which is of particular importance in low [S/N]-systems such as paging systems.