Abstract: An analog/digital receiver comprises a noise detecting circuit for checking whether a noise component, output from an analog signal detecting means, is not less than a specified value, and an RSSI detecting circuit for checking whether received signal strength, output from the receiver, is not less than a specified value. A discriminating circuit is included for making a determination as to whether the received input is an analog modulation signal or a digital modulation signal according to the result of the determination made by the noise detecting circuit as well as by the RSSI detecting circuit. A select switch selects the output from either the digital signal detecting circuit or the analog signal detecting circuit.

Abstract: A method of suppressing generation of carrier leak in a transmitter and reducing deterioration of communication quality comprises the steps of outputting DC elements (I, Q) from a DSP gradually changing the voltage values, measuring a sum of the DC elements (.DELTA.I.sub.DC, .DELTA.Q.sub.DC) and DC elements (I, Q), storing the DC elements (I, Q), when the above sum is equal to a specified value (herein, 0 V), as DC elements -.DELTA.I.sub.DC, -.DELTA.Q.sub.DC for correction, and correcting the DC elements (I.sub.DC, Q.sub.DC) (DC elements obtained by amplifying DC elements for (I, Q) channels demodulated by a quadrature demodulator during transmission) using the DC elements (-.DELTA.I.sub.DC, -.DELTA.Q.sub.DC) for correction during transmission.