| 摘要 |
The invention concerns the correction of transmissions on several subcarriers, in the case of a frequency variable carrier and, preferably, linearly variable. One of the subcarriers, generally the first (N1), is transmitted unmodulated and can therefore be used as reference to supply an estimation signal Cx(t) representing of its defects due to echo. The other subcarriers are corrected by means of the estimation signal taking into account the time difference in the passages (t1, t2, t3, t4, t5) by a common frequency value (Fi) of the subcarrier to be corrected and of the reference subcarrier; said correction is carried out in baseband, i.e. after eliminating the carrier. The invention is, in particular, useful for transmitting data with header (E) at fixed frequency followed by a frequency ramp serving as carrier for serveral subcarriers.
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