Patent ID: 6501735
Filing Date: 2002-12-31
Classification: H04B

Abstract:
A self-diagnostic method for detecting faults in a transceiver within a wireless receiving unit of a base transceiver station of the type having a down converter and a transceiver slave control board, an amplifier in the down converter for amplifying a received input signal, an automatic gain controller (AGC) for controlling a signal level from the amplified received input signal, an AGC detector for detecting an instantaneous intermediate frequency (IF) detection voltage value and for determining an instantaneous control voltage value generated by the AGC, a transceiver slave control board including an analog to digital converter for converting the instantaneous IF detection voltage value from the down converter and the AGC control voltage value into digital value, and an EEPROM for storing a look up table for converting the instantaneous AGC control voltage values into a received input signal levels, a predetermined first minimum and a predetermined maximum values of the received input signal levels, a predetermined second minimum and a predetermined second maximum values of the IF signal detection voltage values, and the instantaneous IF signal detection voltage value responsive to change of the received input signal, the said comprising the steps of:reading the predetermined first minimum value of the received input signal level and the predetermined first maximum value of a received input signal level stored in said EEPROM; reading the instantaneous control voltage value generated by the AGC; converting the instantaneous control voltage value into the received input signal level; comparing the converted received input signal level with the predetermined first minimum value of the received input signal level and the predetermined first minimum value of the received input signal level for determining that a fault exists in amplifier operation of the down converter when the converted received input signal level falls outside of the range between the predetermined first maximum value of the received input signal level and the predetermined first minimum value of the received input signal level; reading the predetermined second minimum value of the intermediate frequency (IF) detection voltage value and the predetermined second maximum value of the intermediate frequency (IF) detection voltage value when the converted received input signal stays between the predetermined first minimum value of the received input signal level and the predetermined first maximum value of the received input signal level; reading the instantaneous IF detection voltage value determined by the AGC detector; and, comparing the instantaneous IF detection voltage value with the predetermined second minimum value of the IF detection voltage value and the predetermined second maximum value of the IF detection voltage value and detecting faults in the AGC operation of the down converter when the instantaneous IF detection voltage value falls outside of the range between the predetermined second minimum of the IF detection voltage value and predetermined second maximum value of the IF detection voltage value.