Signal lines (13) and (14) to be used for supplying a signal between an analog circuit and a digital circuit are provided in different regions from power-ground lines (11) and (12) to be used for supplying a power to the analog circuit and the digital circuit in such a manner that the signal lines (13) and (14) do not cross the power-ground lines (11) and (12). For example, the power-ground lines (11) and (12) are provided along an outer periphery of a semiconductor chip (10) and the analog circuit and the digital circuit are disposed on the inside of the power-ground lines (11) and (12), and the signal lines (13) and (14) are provided between the analog circuit and the digital circuit.
There are provided a BPF (15) for extracting an image frequency component from a modulating signal generated by modulating I and Q signals through a quadrature modulating portion (3), an energy detecting portion (16) for detecting an energy of the image frequency component, and an amplitude correcting portion (12) and a phase correcting portion (13) which correct an amplitude and a phase of the I signal to minimize the detected energy. By correcting the amplitude and the phase to minimize the energy of the image frequency component contained in the generated modulating signal without detecting amplitude and phase errors themselves of the I and Q signals, it is possible to accurately correct the amplitude and phase errors of the I and Q signals without an influence of a limit of precision in an error detection.
A first-stage amplifier of an AM receiving circuit is built into an IC 2 as a differential amplifying circuit 3. The differential amplifying circuit 3 is connected to one pad P1 of the IC 2. Then, a high pass filter is configured by connecting a resistor Ra between two input terminals of the differential amplifying circuit 3 and connecting a capacitor Ca between the resistor Ra and ground and in series with the resistor Ra and ground. Thus, the resistor Ra and capacitor Ca integrated into the IC 2 allows hum noise to be removed.
In a mixer circuit 6 connected in common to output sides of an LNA 2 for FM receiving and an LNA 4 for AM receiving, each of a radiofrequency signal output from the LNA 2 for FM receiving and a radiofrequency signal output from the LNA 4 for AM receiving is frequency-converted into an intermediate frequency signal of a lower intermediate frequency for AM broadcast waves. In this way, receiving of an FM broadcast is performed by a low IF system and receiving of an AM broadcast is performed by a single conversion system; the need for separately providing a mixer circuit, a local oscillation circuit and an IF filter for down-mixing of AM broadcast waves is eliminated.