Systems and methods for asynchronous re-modulation with adaptive I/Q adjustment

Patent metadata

Field	Value
Publication number	US-9337965-B2
Application number	US-201514679987-A
Country	US
Kind code	B2
Filing date	Apr 6, 2015
Priority date	Sep 26, 2011
Publication date	May 10, 2016
Grant date	May 10, 2016

Abstract

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.

First claim

What is claimed is:

1. A signal receiving system comprising:
a first demodulator configured to use a local oscillator to demodulate a current first modulated signal into a current in-phase (I) signal and a current quadrature (Q) signal, the current first modulated signal being previously modulated using a transmitter oscillator that is not synchronized with the local oscillator;
an I/Q signal adjustor coupled to the first demodulator and configured to adaptively adjust at least one of the current in-phase signal or the current quadrature signal based on a current feedback signal to generate a current adjusted I/O signal;
a remodulator coupled to the I/Q signal adjustor and configured to remodulate the current adjusted I/Q signal to a current second modulated signal before transmission onto a cable; and
a telemetry receiver coupled to the I/O signal adjustor and configured to receive the current feedback signal from a telemetry transmitter and to provide the current feedback signal to the I/Q signal adjustor, the current feedback signal being based on error information measured in a previous I/Q signal that was generated from a previous second modulated signal.

2. The signal receiving system of claim 1 , further comprising a second demodulator configured to demodulate the previous second modulated signal to generate the previous I/Q signal.

3. The signal receiving system of claim 2 , further comprising a feedback system configured to generate the current feedback signal from the previous I/Q signal.

4. The signal receiving system of claim 1 , wherein the error information is determined based on a mean squared error (MSE).

5. The signal receiving system of claim 1 , wherein the signal receiving system is within an outdoor unit (ODU) of a heterodyne system.

6. The signal receiving system of claim 1 , wherein the I/Q adjustor is configured to adjust a gain of the current in-phase signal or the current quadrature signal based on the current feedback signal.

7. The signal receiving system of claim 1 , wherein the I/Q adjustor is configured to apply a correction to the current in-phase signal or the current quadrature signal based on the current feedback signal.

8. A method comprising:
using a local oscillator to demodulate a current first modulated signal into a current in-phase (I) signal and a current quadrature (Q) signal, the current first modulated signal being previously modulated using a transmitter oscillator that is not synchronized with the local oscillator;
adaptively adjusting at least one of the current in-phase signal or the current quadrature signal based on a current feedback signal to generate a current adjusted I/Q signal;
remodulating the current adjusted I/Q signal to a current second modulated signal before transmission onto a cable; and
receiving the current feedback signal, the current feedback signal being based on error information measured in a previous I/Q signal that was generated from a previous second modulated signal.

9. The method of claim 8 , further comprising demodulating the previous second modulated signal to generate the previous I/Q signal.

10. The method of claim 9 , further comprising generating the current feedback signal from the previous I/Q signal.

11. The method of claim 8 , further comprising determining the error information, the determining being based on a mean squared error (MSE).

12. The method of claim 8 , wherein the method is performed by an outdoor unit (ODU) of a heterodyne system.

13. The method of claim 8 , wherein the adaptively adjusting the at least one of the current in-phase signal or the current quadrature signal comprises adjusting a gain of the at least one of the current in-phase signal or the current quadrature signal based on the current feedback signal.

14. The method of claim 8 , wherein the adaptively adjusting the at least one of the current in-phase signal or the current quadrature signal comprises applying a correction to the at least one of the current in-phase signal or the current quadrature signal based on the current feedback signal.

Assignees

• Aviat Us Inc

Inventors

• Vann Emerick
• Chao Yen-Fang
• Qin Youming
• Matian Roland

Classifications

• H03D7/168

  using a feedback loop containing mixers or demodulators · CPC title

• H04B1/16 Primary

  Circuits · CPC title

• H04L1/208

  involving signal re-encoding · CPC title

• H04L1/203

  Details of error rate determination, e.g. BER, FER or WER · CPC title

• H04B1/0014

  using DSP [Digital Signal Processor] quadrature modulation and demodulation · CPC title