Direct digital synthesizer-based injection locked oscillator
First Claim
1. A method of tuning an analog oscillator to cause the analog oscillator to generate an oscillator output signal substantially free from spectral impurities, the analog oscillator including a direct digital synthesizer and an analog oscillator circuit, the method comprising the steps of:
- tuning the analog oscillator circuit to cause the analog oscillator circuit to generate an analog signal at a frequency f1, the analog oscillator circuit having a predetermined locking bandwidth over which the analog oscillator circuit can be injection locked to a desired frequency within the locking bandwidth;
tuning the direct digital synthesizer to cause the direct digital synthesizer to generate a digitally synthesized signal at a frequency f0, the frequency f0 being within the locking bandwidth of the analog oscillator circuit; and
injection locking the frequency of the analog signal to the frequency of the digitally synthesized signal, the analog oscillator circuit being responsive to the digitally synthesized signal so that the frequency f1 of the analog signal equals N times the frequency f0 of the digitally synthesized signal, where N is an integer greater than 0, the analog oscillator being responsive to the analog signal injection locked at the frequency f0 so that the oscillator output signal corresponds in frequency to the analog signal.
3 Assignments
0 Petitions
Accused Products
Abstract
A direct digitally synthesizer-based, injection locked oscillator includes a direct digital synthesizer for generating a digitally synthesized signal at frequency f0, an analog oscillator circuit for generating an analog signal at frequency f1 and a filter coupled to the direct digital synthesizer for filtering the digitally synthesized signal to provide a signal at frequency Nf0. N may be an integer from 1 to 10. Also included is a coupler to couple the filtered, digitally synthesized signal into the analog oscillator to lock the frequency of the analog output signal to the frequency of the digitally synthesized signal such that the frequency f1 is equal to the frequency Nf0. The coupler also electrically couples the analog signal from the analog oscillator circuit to a second filter to filter the analog signal. An amplifier electrically coupled to the second filter amplifies the filtered signal to provide an analog oscillator output signal. The direct digital synthesizer may be used to high-order, sub-harmonically injection lock the analog oscillator circuit thereby providing an output signal reflecting a frequency up-conversion in order to broaden the frequency range of the synthesized analog output signal beyond that of the direct digital synthesizer.
14 Citations
22 Claims
-
1. A method of tuning an analog oscillator to cause the analog oscillator to generate an oscillator output signal substantially free from spectral impurities, the analog oscillator including a direct digital synthesizer and an analog oscillator circuit, the method comprising the steps of:
-
tuning the analog oscillator circuit to cause the analog oscillator circuit to generate an analog signal at a frequency f1, the analog oscillator circuit having a predetermined locking bandwidth over which the analog oscillator circuit can be injection locked to a desired frequency within the locking bandwidth; tuning the direct digital synthesizer to cause the direct digital synthesizer to generate a digitally synthesized signal at a frequency f0, the frequency f0 being within the locking bandwidth of the analog oscillator circuit; and injection locking the frequency of the analog signal to the frequency of the digitally synthesized signal, the analog oscillator circuit being responsive to the digitally synthesized signal so that the frequency f1 of the analog signal equals N times the frequency f0 of the digitally synthesized signal, where N is an integer greater than 0, the analog oscillator being responsive to the analog signal injection locked at the frequency f0 so that the oscillator output signal corresponds in frequency to the analog signal. - View Dependent Claims (2, 3)
-
-
4. A method of tuning an analog oscillator to cause the analog oscillator to generate a frequency up-converted oscillator output signal substantially free from spectral impurities, the analog oscillator including a direct digital synthesizer and an analog oscillator circuit, the method comprising the steps of:
-
tuning the analog oscillator circuit to cause the analog oscillator circuit to generate an analog signal at a frequency f1, the analog oscillator circuit having a predetermined locking bandwidth over which the analog oscillator circuit can be injection locked to a desired frequency within the locking bandwidth; tuning the direct digital synthesizer to cause the direct digital synthesizer to generate a digitally synthesized signal at a frequency f0 ; generating a harmonic signal which is at a harmonic frequency of the digitally synthesized signal, the frequency of the harmonic signal being within the locking bandwidth of the analog oscillator circuit; and injection locking the frequency of the analog signal to the frequency of the harmonic signal, the analog oscillator circuit being responsive to the harmonic signal so that the frequency f1 of the analog signal equals N times the frequency f0 of the harmonic signal, where N is a positive non-zero integer, the analog oscillator being responsive to the analog signal injection locked at the frequency of the harmonic signal so that the oscillator output signal corresponds in frequency to the analog signal. - View Dependent Claims (5, 6, 7)
-
-
8. A direct digital synthesizer-based, injection locked oscillator for generating an oscillator output signal that is substantially free from spectral impurities, comprising:
-
an analog oscillator circuit for generating an analog signal at a frequency f1, the analog oscillator circuit having a predetermined locking bandwidth over which the analog oscillator circuit can be injection locked to a desired frequency within the locking bandwidth; and a direct digital synthesizer for generating a digitally synthesized signal at a frequency f0, the frequency f0 being within the locking bandwidth of the analog oscillator circuit, the analog oscillator circuit being injection locked to the digitally synthesized signal so that the frequency f1 of the analog signal equals N times the frequency f0 of the digitally synthesized signal, where N is a positive non-zero integer, the analog oscillator being responsive to the analog signal injection locked at frequency f0 so that the oscillator output signal corresponds in frequency to the analog signal. - View Dependent Claims (9, 10, 11, 12, 13, 14)
-
-
15. A direct digital synthesizer-based, injection locked oscillator for generating an oscillator output signal that is substantially free from spectral impurities, comprising:
-
an analog oscillator circuit for generating an analog signal at a frequency f1, the analog oscillator circuit having a predetermined locking bandwidth over which the analog oscillator circuit can be injection locked to a desired frequency within the locking bandwidth; a direct digital synthesizer for generating a digitally synthesized signal at a frequency f0 ; and means for generating a harmonic signal which is at a harmonic frequency of the digitally synthesized signal, the frequency of the harmonic signal being within the locking bandwidth of the analog oscillator circuit; wherein the frequency of the analog signal is injection locked to the frequency of the harmonic signal, the analog oscillator circuit being injection locked to the harmonic signal so that the frequency f1 of the analog signal equals N times the frequency f0 of the harmonic signal, where N is a positive non-zero integer, the analog oscillator being responsive to the analog signal injection locked at the frequency of the harmonic signal so that the oscillator output signal corresponds in frequency to the analog signal. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22)
-
Specification