Outdoor unit resonator correction
A system comprises a microwave backhaul outdoor unit having a first resonant circuit, phase error determination circuitry, and phase error compensation circuitry. The first resonant circuit is operable to generate a first signal characterized by a first amount of phase noise and a first amount of temperature stability. The phase error determination circuitry is operable to generate a phase error signal indicative of phase error between the first signal and a second signal, wherein the second signal is characterized by a second amount of phase noise that is greater than the first amount of phase noise, and the second signal is characterized by a second amount of temperature instability that is less than the first amount of temperature instability. The phase error compensation circuitry is operable to adjust the phase of a data signal based on the phase error signal, the adjustment resulting in a phase compensated signal.
1. A system comprising:
a local oscillator operable to generate a local oscillator signal comprising a phase distortion, wherein the local oscillator signal is characterized by a first phase noise and a first temperature instability; and
phase error compensation circuitry operable to:
determine a phase error of the local oscillator signal based on a reference signal, wherein the reference signal is characterized by a second phase noise that is greater than said first phase noise, and wherein the reference signal is characterized by a second temperature instability that is less than said first temperature instability; and
adapt the phase distortion of the local oscillator signal based on the determined phase error to generate a phase compensated signal.
2. The system of claim 1 , wherein the system comprises an interface operable to receive the reference signal from a microwave backhaul unit.
3. The system of claim 1 , wherein the system comprises a second local oscillator operable to generate the reference signal.
4. The system of claim 1 , wherein the local oscillator is a surface acoustic wave resonator.
5. The system of claim 1 , wherein the local oscillator is a bulk acoustic wave resonator.
6. The system of claim 1 , wherein the local oscillator is a crystal oscillator.
7. The system of claim 1 , wherein the system is operable to process a received signal according to the local oscillator signal.
8. The system of claim 1 , wherein the system is operable to process a signal for transmission according to the local oscillator signal.
9. The system of claim 1 , wherein the phase error compensation circuitry comprises:
a frequency synthesizer operable to generate a first signal based on the local oscillator signal;
frequency divider circuitry operable to divide the first signal by a determined ratio to generate a second signal; and
signal processing circuitry operable to generate the phase error based on a phase difference between the reference signal and the second signal.
10. The system of claim 9 , wherein the phase error compensation circuitry comprises a delta sigma modulator operable to control the determined ratio based on the phase error.
11. The system of claim 1 , wherein the phase error compensation circuitry comprises:
multiplier circuitry operable to multiply a frequency of the phase error signal by a determined ratio to generate a first signal;
frequency synthesizer circuitry operable to generate a second signal at a selected frequency; and
summer circuitry operable to sum the first signal and the second signal to generate a fifth signal.
12. The system of claim 11 , wherein the determined ratio is the ratio of the frequency of the local oscillator signal to the frequency of the reference signal.
13. The system of claim 1 , wherein phase error compensation circuitry comprises a phase locked loop.
14. The system of claim 1 , wherein the phase error compensation circuitry is operable to upconvert the phase compensated signal prior to a data transmission.
15. The system of claim 1 , wherein the phase compensated signal is transmitted over a coaxial cable.
16. The system of claim 1 , wherein the reference signal is a second phase compensated signal received from a microwave backhaul unit.
17. The system of claim 16 , wherein the system is communicatively coupled to the microwave backhaul unit via a coaxial cable.
18. The system of claim 1 , wherein the system comprises a frequency synthesizer operable to generate the reference signal based on the local oscillator signal.
19. The system of claim 1 , wherein a frequency synthesizer is operable to adjust a phase of the reference signal based on the phase error to generate a phase compensated reference signal.
20. The system of claim 19 , wherein the frequency synthesizer is operable to generate a microwave frequency local oscillator signal based on the phase compensated reference signal.