| 摘要 |
A transceiver includes a transmitter portion with an analog modulator that modulates data using frequency shift keyed (FSK) modulation techniques to increase efficiency, reduce power consumption, and reduce IC real estate in comparison to current digital FSK modulation circuits. The analog modulator comprises a loop that includes a pair of integrators and a pair of mixers. In at least one embodiment, the pair of mixers comprises switches that control a polarity of a modulated output signal that is produced to an up-conversion module for up-conversion to RF. The up-conversion module, then, when mixing the modulated output signal with a local oscillation signal, produces an output having one of two possible frequencies wherein the frequencies are a function of the polarity of the modulated output signal. In one embodiment of the invention, the analog modulator comprises differential circuitry, including a plurality of differential switches for cross-connecting input signals to one of a pair of inputs of an amplifier within each of a pair of integrators. Thus, the polarity of the modulated output signal is, at least in part, a function of whether a given signal is input to a positive or a negative terminal of the amplifier within the pair of integrators.
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