the present invention provides an improved single chip radio receiver which has less external components than do previous similar receivers . with the present invention the integrated circuit which includes the radio receiver also has an on - chip adaptive filter . the radio receiver is designed for use in a radio pager which is only active for a very short time slot during a relative long repeat cycle . thus the adaptive filter only need remain stable for a short period after its coefficients are adjusted to the desired values . the radio receiver includes an external filter which has the same frequency response as desired from the adaptive filter . immediately prior to activating the radio receiver , the circuit is activated to adjust the parameters of the adaptive filter so that the adaptive filter matches the external filter . the radio receiver is then activated using both filters in series thereby producing the desired radio reception . the adaptive filter quickly changes characteristics ; however , since the radio receiver is only active for a short period of time , operation of the system is not affected .