Multichannel receiver for simultaneously receiving a plurality of different channel signals

Abstract

A multichannel receiver for effectively receiving multichannel signals at the same time without any restrictions in the symbol timing and channel interval of modulated signals. A quadrature detector of the multichannel receiver includes first and second multipliers. The first multiplier multiplies a received signal by a real number axis signal generated from a quadrature carrier oscillator. The second multiplier multiplies a received signal by an imaginary number axis signal. The quadrature detector converts a carrier of a center signal of odd signals into a DC component of zero frequency, and converts the center signal into a complex baseband signal, and at the same time converts carrier signals other than the center carrier signal into a complex IF signal symmetrical to the DC component of zero frequency. ADCs (Analog-to-Digital Converters) convert the complex IF signals into complex IF digital signals. The complex IF digital signals are applied to a first group of complex mixers and a second group of complex mixers at the same time. The complex mixers correspond to individual channels, and their local signal frequencies have a complex conjugate relation to each other. The complex mixers perform frequency conversion on their reception signals, and thus generate complex baseband signals.