Frequency synthesizer
AssigneeMitsubishi Denki Kabushiki Kaisha
InventorsKenji Itoh, Akio Iida, Shuji Urasaki
Life of this patent
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Abstract
A frequency synthesizer, including a direct digital synthesizer (DDS) for providing wave amplitude data as a standard signal source, and a phase lock loop for comparing a branched synthesizer frequency with the standard signal source at a phase comparator. A frequency converter converts the output frequency of the DDS to a higher frequency and provides the resultant higher frequency to the phase comparator in the phase loop. A small loop dividing ratio is obtained by converting the low frequency of the DDS to a higher frequency. A spurious of the synthesizer output signal is reduced and provides a low power consumption apparatus.
Claims17
A frequency synthesizer, including a direct digital synthesizer (DDS) for providing wave amplitude data as a standard signal source, and a phase lock loop for comparing a branched synthesizer frequency with the standard signal source at a phase comparator, comprising:
- a frequency converter for converting the output frequency of the DDS to a higher frequency and for providing the resultant higher frequency to the phase comparator in the phase lock loop.
A frequency synthesizer, including a direct digital synthesizer (DDS) for providing wave amplitude data as a standard signal source, and a phase lock loop for comparing a mixed signal generated from a branched synthesizer frequency with the standard signal source at a phase comparator, comprising:
- a frequency converter for mixing the branched synthesizer frequency with a local oscillator frequency to generate a mixed lower frequency and for providing the resultant mixed lower frequency to the phase comparator in the phase loop.
A frequency synthesizer, including a phase lock loop for comparing a branched synthesizer frequency with a standard signal source comprised of a local oscillator at a phase comparator, comprising:
- a divider for providing a divided synthesizer frequency to the frequency converter in the phase lock loop;
- a frequency converter for mixing the frequency from the divider with an output frequency of DDS to generate a lower mixed frequency and for providing the resultant lower mixed frequency to the phase comparator in the phase loop.
Dependencies are inferred from the claim text.