| 摘要 |
A frequency synthesizer is described. In particular, the frequency synthesizer includes a modulator circuit for producing a signal of modulated frequency. The frequency synthesizer includes an accumulator for summing a plurality of errors in the modulator circuit. An error sum value is generated. More particularly, the accumulator increases the rate of sign change of the plurality of errors. An error signal modulator is coupled to the accumulator and modulates an index that is associated with a current error based on the error sum value. The index that is modulated is used for selecting a feedback loop divider count value used for dividing a frequency of the signal. As a result, the error noise around a target signal shows an increased sign change of error, which moves the error noise to higher frequencies. This improves EMI performance.
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