Method and apparatus for synthesizing signals with phase continuous and phase coherent transitions
AssigneeKeysight Technologies, Inc.
InventorsMichael S. Foster, Stephen T. Sparks
Life of this patent
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Abstract
A direct digital synthesizer (DDS) includes a phase increment calculator that determines a phase increment for a selected frequency; a phase accumulator that accumulates the phase increment over time and provides an accumulated phase value; a converter that converts the accumulated phase value to an analog signal at the selected frequency; and a phase preset calculator that determines a phase preset value for the selected frequency. The phase accumulator resets the accumulated phase value to the phase preset value at a transition to the selected frequency in a phase coherent mode.
Claims19
A direct digital synthesizer (DDS) comprising:
- a phase increment calculator configured to determine a phase increment for a selected frequency;
- a phase accumulator configured to accumulate the phase increment over time and provide an accumulated phase value;
- a converter configured to convert the accumulated phase value to an analog signal having the selected frequency;
- and
- a phase preset calculator configured to determine a phase preset value for the selected frequency and output the phase preset value to the phase accumulator,
- the phase accumulator further configured to output the accumulated phase value in a phase continuous mode and preset the accumulated phase value to the phase preset value at a transition to the selected frequency in a phase coherent mode.
A method of digitally synthesizing an analog signal, the method comprising:
- determining a phase increment for a selected frequency;
- accumulating the phase increment over time in a phase accumulator to provide an accumulated phase value in a phase continuous mode;
- converting the accumulated phase value to an analog signal having the selected frequency;
- determining a phase preset value for the selected frequency;
- and
- presetting the accumulated phase value of the phase accumulator to the phase preset value at a transition to the selected frequency in a phase coherent mode.
A non-transitory computer readable medium that stores a program executable by a computer for digitally synthesizing an analog signal, the non-transitory computer readable medium comprising:
- a phase increment code segment for determining a phase increment for a selected frequency;
- a phase accumulation code segment for accumulating the phase increment over time and providing an accumulated phase value in a phase continuous mode;
- a conversion code segment for converting the accumulated phase value to an amplitude value representing a signal having the selected frequency;
- a phase preset code segment for determining a phase preset value for the selected frequency;
- and
- an accumulation preset code segment for presetting the accumulated phase value to the phase preset value at a transition to the selected frequency in a phase coherent mode.
Dependencies are inferred from the claim text.