Frequency agile duplex filter
Systems and methods are disclosed for an electronically adjustable signal filter system, which comprises, in some embodiments, a first filter coupled to an antenna coupling network and a second filter, a power amplifier coupled to the first filter, an antenna connected to an antenna coupling network, a pilot tone generator coupled to the first filter, and a first signal source connected to the power amplifier and first filter. In some embodiments, the power amplifier amplifies the first signal, the first filter places a notch into the first signal transmitted to the antenna coupling network, the antenna coupling network combines the first signal and a second signal received from the antenna and transmits a third signal to the second filter.
1. A method of signal processing, the method comprising:
performing frequency agile duplex filtering of an input signal at a wireless transceiver, wherein the frequency agile duplex filtering is accomplishing through a combination of (1) electronic feed forward vector cancellation, and (2) switched filter banks to enable operation of the wireless transceiver over multiple frequency bands without requiring a change in front end filter components.
2. The method of claim 1 , wherein the electronic feed forward vector cancellation suppresses receive band noise generated by a power amplifier of the wireless transceiver.
3. The method of claim 1 , wherein the electronic feed forward vector cancellation isolates a noise cancellation circuit of the wireless transceiver from transmit power.
4. The method of claim 1 , wherein the electronic feed forward vector cancellation is performed by a Frequency Agile Band Stop Filter (FABSF) of the wireless transceiver.
5. The method of claim 4 , the method further comprising:
receiving a signal from a pilot tone generator at the FABSF; and
using the signal received from the pilot tone generator at the FABSF to ensure that a FABSF frequency notch is aligned with a receive channel.
6. The method of claim 4 , wherein the switched filter banks comprise a switched circulator bank that receives an output signal from the FABSF and selects a circulator appropriate for a band of operation.
7. The method of claim 6 , wherein the switched filter banks further comprise a switch bank of transmit band reject filters that suppress transmit power leaking from the switched circulator bank.
8. The method of claim 1 , the method further comprising:
receiving the input signal at both a power amplifier (PA) and the FABSF, wherein the input signal to the PA is used to cancel a transmit signal at an input to the FABSF.
9. The method of claim 1 , the method further comprising:
receiving an output signal from the FABSF and a signal received from an antenna at the switched circulator bank such that a filtered output signal is generated by the wireless transceiver based upon the input signal and the signal received from the antenna.
10. A wireless transceiver for electronically adjustable signal filtering, the wireless transceiver configured to perform frequency agile duplex filtering of an input signal, wherein the frequency agile duplex filtering is accomplishing through a combination of (1) electronic feed forward vector cancellation, and (2) switched filter banks to enable operation of the wireless transceiver over multiple frequency bands without requiring a change in front end filter components.
11. The wireless transceiver of claim 10 , wherein the wireless transceiver comprises a power amplifier, and the electronic feed forward vector cancellation suppresses receive band noise generated by the power amplifier.
12. The wireless transceiver of claim 11 , wherein the electronic feed forward vector cancellation isolates a noise cancellation circuit of the wireless transceiver from transmit power.
13. The wireless transceiver of claim 10 , wherein the electronic feed forward vector cancellation is performed by a Frequency Agile Band Stop Filter (FABSF) of the wireless transceiver.
14. The wireless transceiver of claim 13 , wherein the wireless transceiver comprises a pilot tone generator, and the FABSF receives a signal from the pilot tone generator to ensure that a FABSF frequency notch is aligned with a receive channel.
15. The wireless transceiver of claim 13 , wherein the switched filter banks comprise a switched circulator bank that receive an output signal from the FABSF and selects an circulator appropriate for a band of operation.
16. The wireless transceiver of claim 15 , wherein the switched filter banks further comprise a switch bank of transmit band reject filters that suppress transmit power leaking from the switched circulator bank.
17. The wireless transceiver of claim 13 , wherein an input signal is passed to both a power amplifier (PA) and the FABSF, and the input signal to the PA is used to cancel a transmit signal at an input to the FABSF.
18. The wireless transceiver of claim 10 , the wireless transceiver further being configured to generate a filtered output signal that is based upon the input signal and a signal received from an antenna.