Digital phase locked loop for different frequency bands
AssigneeSiemens Aktiengesellscaft
InventorsJens Peter Eilken, Harry Siebert
Life of this patent
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Abstract
For controlling frequency and phase of an output clock signal dependent on a reference signal, a digital phase locked loop comprises a ring oscillator connected to a switch-over unit for generating the output clock signal. The ring oscillator has a plurality of serially arranged delay units. A phase comparator for comparing the phase of the reference signal and of the output clock signal. At least one switchable frequency divider unit is provided between the phase comparator and the output clock signal. A control unit controls the ring oscillator frequency by cut-in or cut-outs of delay units with the assistance of the switchover unit.
Claims13
A transmission equipment, comprising:
- a digital phase locked loop for controlling frequency and phase of an output clock signal dependent on a reference signal;
- the digital phase locked loop comprising a ring oscillator connected to a switch-over unit for generating the output clock signal, said ring oscillator comprising a plurality of serially arranged delay units;
- a phase comparator for comparing a phase of the reference signal and of the output clock signal;
- at least one switchable frequency divider unit connected between an output of the switch-over unit and the phase comparator;
- and
- a control unit for controlling a frequency of the ring oscillator by regularly switching between outputs of neighboring delay units of the ring oscillator with assistance of the switch-over unit to alter a number of the delay units which are effective within the ring oscillator.
A digital phase locked loop for controlling frequency and phase of an output clock signal dependent on a reference signal comprising:
- a ring oscillator connected to a switch-over unit for generating the output clock signal, said ring oscillator comprising a plurality of delay units;
- a phase comparator for comparing a phase of the reference signal and of the output clock signal;
- at least one switchable frequency divider unit;
- and
- a control unit for controlling a frequency of the ring oscillator by regularly switching between outputs of neighboring delay units of the ring oscillator with assistance of the switch-over unit to alter a number of the delay units which are effective within the ring oscillator.
Dependencies are inferred from the claim text.