Frequency synthesizer operating according to the principle of fractional frequency synthesis

A frequency synthesizer operating according to fractional frequency synthesis, comprising:

• a phase-controlled oscillator and a phase detector that controls the oscillator;
• a loop filter arranged in a control line between the phase detector and the oscillator;
• a reference frequency source;
• a frequency divider arranged between the reference frequency source and a first input of the phase detector, the frequency divider having a division factor N where N is a whole number;
• an adjustment device that operates with multiple integration, a whole-number division ratio of the frequency divider being controlled by the adjustment device such that a fractional division ratio corresponding to a desired fractional rational division ratio is simulated;
• the phase detector having a second input connected to an output of the oscillator via a mixer, wherein a difference is formed of an output frequency of the oscillator and a reference frequency of the reference frequency source;
• the frequency divider having a division factor N where N is a whole number
• the output frequency is equal to the reference frequency multiplied by the term, 1+(1/N), where N is in the range of whole numbers 4 to 16.

A frequency synthesizer operating according to fractional frequency synthesis, comprising:

• a phase-controlled oscillator and a phase detector that controls the oscillator;
• a loop filter arranged in a control line between the phase detector and the oscillator;
• a reference frequency source;
• a frequency divider arranged between the reference frequency source and a first input of the phase detector, the frequency divider being adjustable to whole-number division ratios and having a minimum division factor of less than 5;
• an adjustment device that operates with multiple integration, a whole-number division ratio of the frequency divider being controlled by the adjustment device such that a fractional division ratio corresponding to a desired fractional rational division ratio is simulated;
• the phase detector having a second input connected to an output of the oscillator via a mixer, wherein a difference is formed of an output frequency of the oscillator and a reference frequency of the reference frequency source.