Radio frequency systems with tunable filter
Radio frequency (RF) systems with tunable filters are provided herein. In certain embodiments, an RF system includes a first RF processing circuit configured to process a first frequency band of a first communication standard and a second frequency band of a second communication standard. The first frequency band and the second frequency band are close in frequency and/or partially overlapping in frequency. The first RF processing circuit includes a tunable filter for changing the bandwidth of the first RF processing circuit to enhance the robustness of the first RF processing circuit to blocker or jammer signals of a third frequency band.
1. A mobile device comprising:
at least a first antenna; and
at least one front end circuit electrically coupled to the first antenna and including a first radio frequency processing circuit that processes a first frequency band with a bypass filter, the front end circuit further including a second processing circuit that processes a second frequency band with at least one blocker detector, at least one controller, and one or more tunable filters, the blocker detector generates a detection signal based on detecting a blocker signal, and the controller controls an amount of filtering of the one or more tunable filters based at least in part on the detection signal.
2. The mobile device of claim 1 wherein the blocker signal arises at least in part from antenna-to-antenna coupling between the first antenna and a second antenna.
3. The mobile device of claim 1 wherein the controller is a serial interface controller.
4. The mobile device of claim 1 wherein the controller controls the amount of filtering of the one or more tunable filters based at least in part on an amount of blocker signal detected by the blocker detector.
5. The mobile device of claim 1 wherein the blocker detector generates that detection signal based on the blocker signal in the first radio frequency processing circuit, and the controller controls the amount of filtering of the one or more tunable filters in the second radio frequency processing circuit based at least in part on the detection signal.
6. The mobile device of claim 1 wherein the front end circuit further includes a diplexer configured to couple the first radio frequency processing circuit and the second radio frequency processing circuit to the first antenna, the blocker signal arising from a finite isolation of the diplexer.
7. The mobile device of claim 1 wherein the blocker signal is output by an LNA.
8. The mobile device of claim 1 wherein the controller further controls the tunable filter based at least in part on system level information, band information, channel information, or radio network information.
9. The mobile device of claim 1 wherein the one or more tunable filters operate with a first bandwidth in a first mode and with a second bandwidth in a second mode and selection between the first and second modes is based at least in part on the detection signal.
10. A front end circuit comprising:
a first radio frequency processing circuit that processes a first frequency band with a bypass filter, the front end circuit further including a second processing circuit that processes a second frequency band with one or more tunable filters, at least one controller that controls the one or more tunable filters, and at least one blocker detector that generates a detection signal based on detecting a blocker signal, and the controller controls an amount of filtering of the one or more tunable filters based at least in part on the detection signal.
11. The front end circuit of claim 10 wherein the blocker signal arises at least in part from antenna-to-antenna coupling between a first antenna and a second antenna.
12. The front end circuit of claim 10 wherein the controller is a serial interface controller.
13. The front end circuit of claim 10 wherein the controller controls the amount of filtering of the one or more tunable filters based at least in part on an amount of blocker signal detected by the blocker detector.
14. The front end circuit of claim 10 wherein the blocker detector generates that detection signal based on the blocker signal in the first radio frequency processing circuit, and the controller controls the amount of filtering of the one or more tunable filters in the second radio frequency processing circuit based at least in part on the detection signal.
15. The front end circuit of claim 10 further including a diplexer configured to couple the first radio frequency processing circuit and the second radio frequency processing circuit to at least one antenna, the blocker signal arising from a finite isolation of the diplexer.
16. The front end circuit of claim 10 wherein the blocker signal is output by an LNA.
17. The front end circuit of claim 10 wherein the controller further controls the one or more tunable filters based at least in part on system level information, band information, channel information, or radio network information.
18. The front end circuit of claim 10 wherein the one or more tunable filters operate with a first bandwidth in a first mode and with a second bandwidth in a second mode and selection between the first and second modes is based at least in part on the detection signal.
19. The front end circuit of claim 10 further including a diplexer that couples the first processing circuit and the second processing circuit to at least one antenna and the blocker signal arises at least in part from a finite isolation of a diplexer.
20. The mobile device of claim 1 wherein the front end circuit further includes a diplexer that couples the first processing circuit and the second processing circuit to the at least one antenna and the blocker signal arises at least in part from a finite isolation of a diplexer.