Frequency shift circuit and communication device

A communication device that receives a signal having two frequency bands using a single analog circuit and then separates it into respective signals using a digital circuit, the communication device comprising:

• an A/D converter that converts an analog signal output from the analog circuit to a digital signal;
• two frequency shift circuits that respectively perform frequency shifting on the A/D converted signal per signal having frequency bands to be separated;
• and
• two digital filters for the respective frequency shift circuits to extract the signal having the frequency bands to be separated from the frequency-shifted signal;
• wherein
• each of the frequency shift circuits includes
• a plurality of tables each of which stores complex data,
• a complex multiplication circuit that complex-multiplies the complex data stored in the plurality of tables and inputted to the complex multiplication circuit based on address information,
• a deletion circuit that generates a rotor corresponding to a phase rotation amount which is based on a result of the complex-multiplication, and
• a calculation circuit that calculates the address information for each of the plurality of tables such that exp(2πjθ) is obtained as the result of complex multiplication based on rotation angle information θ.