We propose a binary amplitude shift keying (BASK) system of Giga-bit Modem without intermediate frequency process for the 60 GHz band. The proposed system consists of a high speed shutter of the transmitter and a repeater of the receiver. The shutter of the proposed system is introduced for pulse shaping to improve the intersymbol interference (ISI). The repeater consists of several stage converters. A converter is constructed with a low pass filter and a limiter. The repeater can improve the signal-to-noise ratio (SNR) and make the rectangular pulse train. The advantage of the proposed system is very simple without the intermediate frequency (IF) process.