A 1.9 GHz-band GaAs direct-quadrature modulator IC with a phase shifter

A 1.9-GHz-band direct-quadrature modulator IC has been developed for digital cordless telephone use. In the 1.9-GHz high-frequency band, both carrier and image rejections as low as -40 dBc have been obtained with low-power dissipation of 110 mW, corresponding to phase error below 1.1 degrees . A newly developed circuit configuration, which combines a quadrature phase shifter with drivers, make this excellent spectrum efficiency and low-power dissipation possible. This modulator IC is expected to contribute to the realization of enhanced digital mobile communication systems such as digital and cordless digital cellular telephones.<
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