Systems and methods for asynchronous re-modulation with adaptive I/Q adjustment
View Patent ↗Various embodiments provide for systems and methods for signal conversion of one modulated signal to another modulated signal using demodulation and then re-modulation. According to some embodiments, a signal receiving system may comprise an I/Q demodulator that demodulates a first modulated signal to an in-phase (“I”) signal and a quadrature (“Q”) signal, an I/Q signal adjustor that adaptively adjusts the Q signal to increase the signal-to-noise ratio (SNR) of a transitory signal that is based on a second modulated signal, and an I/Q modulator that modulates the I signal and the adjusted Q signal to the second modulated signal. To increase the SNR, the Q signal may be adjusted based on a calculated error determined for the transitory signal during demodulation by a demodulator downstream from the I/Q modulator.
1. A signal receiving system configured to convert a first modulated signal to a second modulated signal, the signal receiving system comprising:
an I/Q demodulator configured to demodulate the first modulated signal to an in-phase (“I”) signal and a quadrature (“Q”) signal based on a first oscillator signal, the first modulated signal being modulated based on a second oscillator signal that is asynchronous to the first oscillator signal;
an I/Q signal adjustor configured to adaptively adjust the I or Q signal to increase a signal-to-noise ratio (SNR) of a transitory signal that is based on the second modulated signal, the I or Q signal being adjusted based on a calculated error determined for the transitory signal; and
an I/Q modulator configured to modulate the second modulated signal based on the I signal and the Q signal as adjusted.
2. The signal receiving system of claim 1 , wherein adaptively adjusting the I or Q signal comprises adjusting a gain of the I or Q signal based on the calculated error.
3. The signal receiving system of claim 1 , wherein adaptively adjusting the I or Q signal comprises applying a correction to the I or Q signal.
4. The signal receiving system of claim 3 , wherein the I/Q signal adjustor comprises a multiplier configured to apply the correction to the I or Q signal.
5. The signal receiving system of claim 1 , wherein the first modulated signal is based on a radio frequency signal.
6. The signal receiving system of claim 1 , wherein the signal receiving system is an out-door unit (ODU).
7. The signal receiving system of claim 6 , wherein the ODU is configured to receive the calculated error from an in-door unit (IDU) as telemetry data.
8. A method for downconverting a first modulated signal to a second modulated signal, the method comprising:
demodulating the first modulated signal to an in-phase (“I”) signal and a quadrature (“Q”) signal based on a first oscillator signal, the first modulated signal being modulated based on a second oscillator signal that is asynchronous to the first oscillator signal;
adaptively adjusting the Q signal to increase a signal-to-noise ratio (SNR) for a transitory signal that is based on the second modulated signal, the Q signal being adjusted based on a calculated error for the transitory signal; and
modulating the second modulated signal based on the I signal and the Q signal as adjusted.
9. The method of claim 8 , wherein adaptively adjusting the I or Q signal comprises adjusting a gain of the I or Q signal based on the calculated error.
10. The method of claim 8 , wherein adaptively adjusting the I or Q signal comprises applying a correction to the I or Q signal based on the calculated error.
11. The method of claim 8 , wherein the correction is applied by a multiplier that applies the correction to the I or Q signal.
12. The method of claim 8 , further comprising receiving the calculated error from an in-door unit (IDU).
13. The method of claim 12 , wherein the calculated error is received from the IDU as telemetry data.
14. A signal receiving system configured to convert a first modulated signal to a second modulated signal, the signal receiving system comprising:
means for demodulating the first modulated signal to an in-phase (“I”) signal and a quadrature (“Q”) signal based on a first oscillator signal, the first modulated signal being modulated based on a second oscillator signal that is asynchronous to the first oscillator signal;
means for adaptively adjusting the Q signal to increase a signal-to-noise ratio (SNR) for a transitory signal that is based on the second modulated signal, the Q signal being adjusted based on a calculated error for the transitory signal; and
means for modulating the second modulated signal based on the I signal and the Q signal as adjusted.