Abstract: A plurality of reception branches receive digital modulated signals and convert received digital modulated signals into intermediate frequency signals having frequency differences having a predetermined relationship with a modulation baseband signal. An adder adds the intermediate frequency signals converted by the plurality of reception branches. A delayed and differential detection section delays and differentially detects a sum signal from the adder. A post detection filter filters a delayed and differentially detected signal from the delayed and differential detection section at a bandwidth higher than a Nyquist frequency of the received digital modulated signals, thereby outputting demodulated signals of the received digital modulated signals.

Abstract: In a transmitting section, a modulator modulates a first carrier with data o be transmitted, thereby producing a modulated output f.sub.m, a local oscillator generates a local oscillating signal to be used as a second carrier f.sub.LO, a mixer mixes the modulated output and the local oscillating signal, thereby generating waves of different frequencies. These waves include an upper side band wave f.sub.LO +f.sub.m and a lower side band wave f.sub.LO -f.sub.m. A transmitting antenna radiates electromagnetic waves into the air, which includes the waves of different frequencies generated by the mixer. In a receiving section, a receiving antenna receives the electromagnetic waves, a diversity section extracts at least one of the upper side band and lower side band waves f.sub.LO +f.sub.m, f.sub.LO -f.sub.

Abstract: According to this invention, a modulator modulates a carrier serving as a fundamental wave with data to be transmitted, thereby to generate a modulated output including at least the fundamental wave and double wave thereof. A transmitting antenna radiates electromagnetic waves into the air, and the electromagnetic waves include the fundamental wave and the double wave included in the modulated output generated by the modulator. A receiving antenna receives the electromagnetic waves including the fundamental wave and the double wave radiated from the transmitting antenna. A diversity section generates an output having a diversity effect on the basis of the fundamental wave and the double wave included in the electromagnetic waves received by the receiving antenna. A demodulator demodulates the output having the diversity effect and generated by the diversity section, thereby to output data corresponding to the data to be transmitted.