Matsushita Mobile Communications Development Corporation of U.s.a.

Matsushita Mobile Communication Development Corporation of USA

Stephen J Pratt

A system and method for using a dual band transceiver to transmit and receive in a first and second band, while reducing the frequency sources. By reducing the number of frequency sources needed to operate a dual band transceiver and using common transmitter and receiver Intermediate Frequencies, the invention also reduces the number of filters and other components needed for its operation. The oscillating signals from these two frequency sources are scaled, combined, mixed, and filtered, such that only two primary frequency sources are needed to operate the front-end and back-end of both the transmitter and receiver of this dual band transceiver.

Multi-band tranceivers with reduced frequency sources for digital transmissions

A circuit for increasing the precision of an N-bit digital-to-analog converter. The N-bit digital-to-analog converter includes a digital signal input and an analog signal output. The analog signal output connects to the analog signal input of a translating circuit. The translating circuit includes an analog signal output and a bias enable input. The N-bit digital-to-analog converter receives an N-bit digital signal and converts it into a first analog output signal having 2 possible values over a first voltage range. When the enable input is in an enabled state, the translating circuit translates the first analog output signal into a second analog voltage having 2 possible values over a second voltage range, the second voltage range having a smaller maximum value than maximum value of the first voltage range. When the enable input is in a disabled state, the translating circuit translates the first analog output signal into the second analog voltage having 2 possible values over a third voltage range, the third voltage range having a larger minimum value than the minimum value of the first voltage range. As a result, the full precision range of the N-bit digital-to-analog converter is applied to two voltage ranges within the original voltage range of the N-bit digital-to-analog converter. Thus, the precision of the N-bit digital-to-analog converter is increased.

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Cumming, GA, United States of America

Stephen J Pratt