Multi-mode adaptive filter
View Patent ↗A multi-mode device, capable of channel equalization and packet collision detection, includes a first switch, which is capable of receiving a transmit signal and a receive signal and outputting a filter input, which is multiplied by a first filter tap to generate a first product. The device also includes a delay unit for receiving the filter input and generating a delayed filter input, wherein the delayed filter input is multiplied by a second filter tap to generate a second product; an adder for adding the first product with the second product and generating a filter output; a decision block, which receives the filter output and generates a decision output; and a second switch capable of receiving the decision output, a training sequence and the receive signal and outputting a second switch output. The device generates an error signal using the filter output and the second switch output.
1. A device comprising:
a first switch for receiving a transmit signal and a receive signal and outputting a filter input, wherein said filter input is multiplied by a first filter tap to generate a first product;
a delay unit for receiving said filter input and generating a delayed filter input, wherein said delayed filter input is multiplied by a second filter tap to generate a second product;
an adder for adding said first product with said second product and generating a filter output;
a decision block receiving said filter output and generating a decision output; and
a second switch for receiving said decision output, a training sequence and said receive signal and outputting a second switch output;
wherein an error signal is generated using said filter output and said second switch output.
2. The device of claim 1 , wherein said filter input is said receive signal and said second switch output is said training sequence or said decision output.
3. The device of claim 2 , wherein said training sequence is a preamble.
4. The device of claim 1 , wherein said filter input is said transmit signal and said second switch output is said receive signal.
5. The device of claim 4 , wherein said error signal is used to generate a peak error and an error energy.
6. The device of claim 5 , wherein a packet collision is declared if said peak error is higher than a peak error threshold or said error energy is higher than an error energy threshold.
7. The device of claim 4 , wherein a packet collision is declared if said peak error is higher than a peak error threshold and said error energy is higher than an error energy threshold.
8. The device of claim 1 , wherein said transmit signal is delayed.
9. A method of detecting a packet collision, said method comprising the steps of:
setting a first switch to output a transmit signal;
filtering said transmit signal to generate a filter output;
setting a second switch to out put a receive signal;
generating an error signal using said filter output and said receive signal;
measuring a peak error using said error signal;
comparing said peak error with a peak error threshold;
measuring an error energy using said error signal;
comparing said error energy with an error energy threshold; and
declaring said packet collision if said peak error is higher than said peak error threshold or if said error energy is higher than said error energy threshold.
10. The method of claim 9 , wherein said declaring step declares said packet collision if said peak error is higher than said peak error threshold and if said error energy is higher than said error energy threshold.
11. The method of claim 9 further comprising the step of delaying said transmit signal.
12. The method of claim 9 , wherein said first switch is for receiving said receive signal and said transmit signal.
13. The method of claim 9 , wherein said second switch is for receiving a training sequence, a decision output and said receive signal.