The receiving circuit of a mobile telephone apparatus normally includes a so-called equalizer which is operative to compensate for irregularities or deficiencies in the radio medium when transmitting radio signals from a base station.  An equalizer is primarily used in receiving circuits for the purpose of reducing bit errors that occur in the incoming radio signal as a result of multipath propagation in the radio medium.  This is described, for instance, in WO 88/05981, which relates to a TDMA-system which includes so-called adaptive equalization.  The setting of the equalizer incorporated in the radio receiver is contingent on synchronizing words that are sent simultaneously with the data words transmitted from the radio transmitter in time multiplex.  With the aid of these synchronizing words, the equalizer can be set so as to equalize the dispersion properties of the medium upon receipt of the data words.  Radio receivers which include equalizers are primarily used for high symbol rate (&gt;100 kbit/s) the bit sensitivity of which due to multipath propagation is greater than the bit sensitivity of slower symbol rate.