Multi-frequency signal source
View Patent ↗A multi-frequency signal source and a method for providing a multi-frequency signal source with phase-lock capability are provided. The multi-frequency signal source includes a plurality of single-section filters each configured to provide oscillation of a signal at a different frequency. The multi-frequency signal source further includes a phase lock component providing a reference signal to control the oscillation at each of the frequencies.
1. A multi-frequency signal source comprising:
a plurality of selectable single-section filters each configured to provide oscillation of a signal at a different frequency; and
a phase lock component providing a reference signal to control the oscillation at each of the frequencies, wherein each of the plurality of single-section filters forms part of a discrete feedback loop for controlling the oscillation at the different frequencies.
2. A multi-frequency signal source in accordance with claim 1 further comprising a wideband amplifier connected to an output of the plurality of filters.
3. A multi-frequency signal source in accordance with claim 1 further comprising an analog phase shift controller connected to an output of the phase lock component to provide phase locking at each of the different frequencies.
4. A multi-frequency signal source in accordance with claim 1 wherein the plurality of filters are configured as a selectable bank of filters.
5. A multi-frequency signal source in accordance with claim 1 wherein a line length providing a fixed phase shift for each of the filters provides oscillation at each of the filters.
6. A multi-frequency signal source in accordance with claim 1 further comprising a phase shift component and an amplifier, which together with the plurality of filters form a voltage controlled oscillator.
7. A multi-frequency signal source in accordance with claim 1 wherein a frequency shift between each of the filters is about equal.
8. A multi-frequency signal source in accordance with claim 1 wherein a frequency shift between each of the filters is variable.
9. A multi-frequency signal source in accordance with claim 1 further comprising a digital phase shift controller for receiving a frequency control input and connected to the plurality of filters to provide additional frequency control at each of the different frequencies.
10. A multi-frequency signal source in accordance with claim 1 further comprising a phase lock component for receiving a reference signal and wherein the phase lock component providing a multiple of the reference signal to control the oscillation at each of the frequencies.
11. A multi-frequency signal source in accordance with claim 1 further comprising a sampling phase detector configured to receive a feedback signal from at least one of the plurality of filters for controlling signal oscillation.
12. A system for providing a multi-frequency signal source, said system comprising:
a first feedback loop for determining a phase difference between an output signal and a reference signal; and
a second feedback loop for controlling oscillation of the output signal at a plurality of frequencies, the second feedback loop receiving signals from a plurality of filters, each filter corresponding to a different one of the plurality of frequencies.
13. A system in accordance with claim 12 further comprising a sampling phase detector and in combination with the first feedback loop forming a phase-locked loop configuration.
14. A system in accordance with claim 12 further comprising an analog phase shift controller and an amplifier, which in combination with the plurality of filters forming a voltage controlled oscillator.
15. A system in accordance with claim 14 further comprising a digital phase shift controller in combination with the analog phase shift controller, which together controls the frequency of the output signal.
16. A method for providing a multi-frequency signal source, said method comprising:
configuring a plurality of selectable filters to provide a voltage controlled oscillator at a plurality of frequencies, wherein the voltage controlled oscillator includes a phase shift component and an amplifier; and
providing a phase lock signal based on a reference signal to control the oscillation at each of the plurality of frequencies.
17. A method in accordance with claim 16 further comprising providing phase correction at each of the plurality of frequencies using a sampling phase detector receiving feedback signals from the voltage controlled oscillator.
18. A method in accordance with claim 16 further comprising configuring an analog phase shift controller to control the oscillation frequency at each of the plurality of frequencies.
19. A method in accordance with claim 18 further comprising configuring a digital phase shift controller to control the oscillation frequency at each of the plurality of frequencies.