Systems and methods for cancellation of cross-coupled noise
View Patent ↗Systems and methods for canceling cross-coupled satellite signals in a LNB IC include receiving a first satellite signal at a first pin of the LNB IC and adjusting the first satellite signal by applying a first adaptive filter to the first satellite signal signal, the first adaptive filter having first filter coefficients; combining the adjusted first satellite signal with a second satellite signal received at a second pin of the LNB IC to generate a first combined satellite signal; measuring the total output power of the combined satellite signal; changing the filter coefficients of the first adaptive filter; remeasuring the total output power of the first combined satellite signal after the changing of the first filter coefficients to determine whether the total power of the first combined satellite signal has decreased.
1. A method for canceling cross-coupled satellite signals in a low noise amplifier and block down converter integrated circuit (LNB IC), the method comprising:
receiving a first satellite signal at a first pin of the LNB IC and adjusting the first satellite signal by applying a first adaptive filter to the first satellite signal, the first adaptive filter having first filter coefficients;
combining the adjusted first satellite signal with a second satellite signal
received at a second pin of the LNB IC to generate a first combined satellite signal;
measuring the total output power of the first combined satellite signal; changing the first filter coefficients of the first adaptive filter;
remeasuring the total output power of the first combined satellite signal after the changing of the first filter coefficients to determine whether the total output power of the first combined satellite signal has decreased.
2. The method of claim 1 , further comprising delaying the second received satellite signal prior to combining it with the adjusted first satellite signal.
3. The method of claim , further comprising repeating the operations of changing the first filter coefficients and remeasuring the total output power of the first combined satellite signal after the change until the measured total output power reaches a minimum value.
4. The method of claim 1 , further comprising repeating the operations of changing the first filter coefficients and remeasuring the total output power of the first combined satellite signal after the change.
5. The method of claim 1 , further comprising minimizing the total output power of the first combined satellite signal by repeating the operations of changing the first filter coefficients and remeasuring the total output power of the first combined satellite signal until a minimum power level is reached.
6. The method of claim 1 , wherein the first adaptive filter applied is a least mean square filter.
7. The method of claim 1 , further comprising repeating the canceling for additional pairs of satellite signals.
8. The method of claim 1 , further comprising repeating the canceling for a remaining number of p pairs of satellite signals, where p comprises a number of possible pairings of satellite signals in the LNB.
9. The method of claim 1 , further comprising repeating the canceling for a remaining number of pairs p of satellite signals, where p is given by n!/2(n−2), where n is the number of satellite signals under consideration.
10. The method of claim 7 , further comprising
adjusting the second satellite signal by applying a second adaptive filter to the second satellite signal, the second adaptive filter having second filter coefficients;
combining the adjusted second satellite signal with the first satellite signal received at the first pin of the LNB IC to form a second combined signal;
measuring the total output power of the second combined satellite signal;
changing the filter coefficients of the second adaptive filter;
remeasuring the total output power of the second combined satellite signal after the changing of the second filter coefficients to determine whether the total output power of the second combined satellite signal has decreased.
11. A low noise amplifier and block down converter integrated circuit (IC), comprising:
a plurality of input pins each configured to receive a satellite signal;
a plurality of delay modules, each delay module having an input coupled to a corresponding input pin and an output to output a delayed satellite signal;
a plurality of adaptive filter modules, each adaptive filter module having an input coupled to a corresponding input pin;
a plurality of signal combiners, each signal combiner having inputs coupled to an output of a corresponding delay module and an output of a corresponding adaptive filter module, and each signal combiner configured to output a combined satellite signal; and
a filter coefficient computation module, comprising computer executable program code embodied on a non-transitory medium and configured to cause the filter coefficient computation module to perform the operations of:
measuring the total output power of the combined satellite signal from a first one of the plurality of signal combiners;
changing the filter coefficients of the adaptive filter corresponding to the first one of the plurality of signal combiners;
remeasuring the total output power of the combined satellite signal from the first one of the plurality of signal combiners after the operation of changing the filter coefficients to determine whether the total output power of the combined satellite signal from the first one of the plurality of signal combiners has decreased.
12. The LNB IC of claim 11 , wherein the computer executable program code is further configured to delay the second received satellite signal prior to combining it with the adjusted first satellite signal.
13. The LNB IC of claim 12 , wherein the computer executable program code is further configured to cause the filter coefficient computation module to repeat the operations of changing the filter coefficients and remeasuring the total output power of the combined satellite signal after the change.
14. The LNB IC of claim 11 , wherein the computer executable program code is further configured to cause the filter coefficient computation module to minimize the total output power of the combined satellite signal by repeating the operations of changing the filter coefficients and remeasuring the total output power of the combined satellite signal until a minimum power level is reached.
15. The LNB IC of claim 11 , wherein the first adaptive filter applied is a least mean square filter.
16. The LNB IC of claim 11 , wherein the computer executable program code is further configured to cause the filter coefficient computation module to repeat the measuring the total output power, changing the filter coefficients, and remeasuring the total output power operations for additional pairs of satellite signals.
17. The LNB IC of claim 11 , wherein the computer executable program code is further configured to cause the filter coefficient computation module to repeat the measuring the total output power, changing the filter coefficients, and remeasuring the total output power operations for a remaining number of pairs p of satellite signals, where p comprises a number of possible pairings of satellite signals in the low noise amplifier and block down converter (LNB).
18. The LNB IC of claim 11 , wherein the computer executable program code is further configured to cause the filter coefficient computation module to repeat the measuring the total output power, changing the filter coefficients, and remeasuring the total output power operations for a remaining number of pairs of p pairs of satellite signals, where p is given by n!/2(n−2), where n is the number of satellite signals under consideration.