| 摘要 |
Methods and apparatuses for reducing noise in frequency to digital converters (FDCs). An FDC apparatus includes a first FDC, a second FDC and a combiner. The first and second FDCs are configured to independently sample an input signal according to a sample clock to generate first and second digital signals, each representing the instantaneous frequency of the input signal. The combiner is configured to form a resultant digital signal from the first and second digital signals. The first and second FDCs are designed and combined in the noise-canceling FDC apparatus so that the first and second signals they generate have correlated noise profiles in a frequency range of interest. When combined by the combiner to form the resultant digital signal, the resultant digital signal has a signal power to noise power ratio greater than the signal power to noise power ratios characterizing the first and second digital signals of the individual first and second FDCs.
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