Oscillators having arbitrary frequencies and related systems and methods
Systems and methods for operating with oscillators configured to produce an oscillating signal having an arbitrary frequency are described. The frequency of the oscillating signal may be shifted to remove its arbitrary nature by application of multiple tuning signals or values to the oscillator. Alternatively, the arbitrary frequency may be accommodated by adjusting operation one or more components of a circuit receiving the oscillating signal.
1. A method of generating an oscillating signal having a target frequency from an oscillator having a mechanical resonator, the oscillator being coupled to a circuit to provide the oscillating signal to the circuit, the method comprising:
providing, from the oscillator to the circuit, at least one value indicative of a frequency of the oscillator and/or the mechanical resonator;
generating a first tuning signal having a first value, wherein the first tuning signal is generated in response to receiving the at least one value;
applying to the oscillator, from the circuit, the first tuning signal having the first value;
applying to the oscillator, from the circuit, an automatic frequency control (AFC) tuning signal having a second value different than the first value;
receiving, at the circuit, the oscillating signal from the oscillator; and
synthesizing, using a frequency synthesizer, a synthesized signal having a synthesized frequency different than a frequency of the oscillating signal.
2. The method of claim 1 , wherein the frequency synthesizer is a programmable frequency synthesizer having discrete frequency steps and wherein synthesizing the synthesized signal comprises setting the programmable frequency synthesizer to a setting indicated in a reference table, the reference table identifying settings to which to set the frequency synthesizer such that the synthesized signal has the target frequency for a given frequency of the oscillating signal.
3. The method of claim 2 , wherein the reference table is stored in memory coupled to the frequency synthesizer.
4. The method of claim 1 , wherein the first tuning signal adjusts the frequency of the oscillating signal by between 10 ppm and 500 ppm.
5. The method of claim 4 , wherein the first tuning signal adjusts the frequency of the oscillating signal by between 10 ppm and 100 ppm.
6. The method of claim 1 , wherein the first tuning signal adjusts the frequency of the oscillating signal by up to approximately 10,000 ppm.
7. The method of claim 1 , wherein providing, from the oscillator to the circuit, the at least one value indicative of the frequency of the oscillator and/or the mechanical resonator is performed by providing the at least one value on a wire distinct from a wire on which the oscillating signal is to be provided to the circuit.