Method and system for transmit upsampling via IFFT

摘要

A technique for eliminating from or reducing the complexity of an upsampler/interpolator of a transmit system. In general, the technique involves configuring an IFFT to perform both the conversion of a modulated signal from frequency to time domain, and at least a portion of the upsampling from the first sampling rate towards the sampling rate of a DAC. In one embodiment, the IFFT is configured to have a bandwidth substantially equal to the sampling rate of a DAC. In this embodiment, the upsampler/interpolator may be totally eliminated. In another embodiment, the IFFT is configured to have a bandwidth that is greater than the first sampling rate of the modulated signal, and lower than the sampling rate of the DAC. In this embodiment, a simpler upsampler/interpolator may be employed to perform the remaining upsampling from the IFFT bandwidth to the sampling rate of the DAC.

主权项

1. An apparatus for transmitting a radio frequency (RF) signal, comprising:
a frequency-domain modulator adapted to generate a frequency-domain modulated signal with a first sampling rate; an inverse fast Fourier Transform (IFFT) module adapted to convert the frequency-domain modulated signal to a time-domain modulated signal at a second sampling rate that is greater than the first sampling rate, wherein the second sampling rate is chosen toward a desired sampling rate for a transmitted signal; and a digital-to-analog converter (DAC) adapted to convert the time-domain modulated signal from a digital domain to an analog time-domain modulated signal at a third sampling rate, wherein the third sampling rate is substantially the same as the second sampling rate if the second sampling rate is substantially the same as the desired sampling rate for the transmitted signal, or the third sampling rate is greater than the second sampling rate if the second sampling rate is lower than the desired sampling rate for a transmitted signal, such that to achieve the desired sampling rate for the transmitted signal, and the RF signal is based on the analog time-domain modulated signal.