Et System with Adjustment for Noise

1. An envelope tracking transceiver comprising: a power amplifier to receive an input signal and generate an amplified output signal, the power amplifier receiving a supply voltage providing power to the power amplifier; a lookup circuit to generate a power supply control signal based on an estimated amplitude of the input signal and a feedback signal indicating a compression level for operating the power amplifier; a power supply to provide the supply voltage to the power amplifier based on the power supply control signal; a receiver to receive a receive signal and to generate a noise margin signal representative of a noise margin of the receive signal; and a configuration circuit to generate the feedback signal based on the noise margin signal and generate a filter control signal to increase filtering of the power supply control signal responsive to the noise margin signal indicating a decrease in the noise margin and to decrease filtering of the power supply control signal responsive to the noise margin signal indicating an increase in the noise margin.

2. The envelope tracking transceiver of claim 1 wherein the noise margin signal is based on a receive signal strength indicator indicating a strength of the receive signal at the receiver.

3. The envelope tracking transceiver of claim 1 wherein the noise margin signal is based on a public safety indicator indicating that the receiver is communicating with a public safety network having specific noise specifications.

4. The envelope tracking transceiver of claim 1 wherein the noise margin signal is based on an error rate of the receive signal.

5. The envelope tracking transceiver of claim 1 wherein the configuration circuit is further configured to generate a bias control signal to adjust a bias of the power amplifier to increase a noise susceptibility of the power amplifier responsive to the noise margin signal indicating an increase in the noise margin and to adjust the bias of the power amplifier to decrease the noise susceptibility of the power amplifier response to the noise margin signal indicating a decrease in the noise margin.

6. The envelope tracking transceiver of claim 1 wherein the configuration circuit is further configured to generate a control signal that causes the power supply to hold the supply voltage constant during one or more transmit periods responsive to the noise margin signal indicating a decrease in the noise margin.

7. The envelope tracking transceiver of claim 1 wherein the configuration circuit is configured to generate the feedback signal to increase the compression level responsive to the noise margin increasing and to decrease the compression level responsive to the noise margin decreasing.

8. An envelope tracking transceiver comprising: a power amplifier to receive an input signal and generate an amplified output signal, the power amplifier receiving a supply voltage providing power to the power amplifier; a lookup circuit to generate a power supply control signal based on an estimated amplitude of the input signal; a power supply to provide the supply voltage to the power amplifier based on the power supply control signal; a receiver to receive a receive signal and to generate a noise margin signal representative of a noise margin of the receive signal; and a configuration circuit to generate one or more control signals to control parameters of at least one of the power amplifier, the lookup circuit, and the power supply based on the noise margin signal, the one or more control signals including a filter control signal to control the power supply to increase filtering of the power supply control signal responsive to the noise margin signal indicating a decrease in the noise margin and to decrease filtering of the power supply control signal responsive to the noise margin signal indicating an increase in the noise margin.

9. The envelope tracking transceiver of claim 8 wherein the one or more control signals control the parameters to increase power efficiency of the power amplifier responsive to the noise margin increasing, and wherein the one or more control signals control the parameters to reduce noise in the amplified output signal responsive to the noise margin decreasing.

10. The envelope tracking transceiver of claim 8 wherein the noise margin signal is based on a receive signal strength indicator indicating a strength of the receive signal at the receiver.

11. The envelope tracking transceiver of claim 8 wherein the noise margin signal is based on a public safety indicator indicating that the receiver is communicating with a public safety network having specific noise specifications.

12. The envelope tracking transceiver of claim 8 wherein the noise margin signal is based on an error rate of the receive signal.

13. The envelope tracking transceiver of claim 8 wherein the configuration circuit is further configured to generate a bias control signal to increase a noise susceptibility of the power amplifier responsive to the noise margin signal indicating an increase in the noise margin and to adjust the bias of the power amplifier to decrease the noise susceptibility of the power amplifier response to the noise margin signal indicating a decrease in the noise margin.

14. An envelope tracking transceiver comprising: a power amplifier to receive an input signal and generate an amplified output signal, the power amplifier receiving a supply voltage providing power to the power amplifier; a lookup circuit to generate a power supply control signal based on an estimated amplitude of the input signal and a feedback signal indicating an amount of voltage headroom for operating the power amplifier; a power supply to provide the supply voltage to the power amplifier based on the power supply control signal; and a feedback receiver to generate a noise measure in the amplified output signal and to generate the feedback signal responsive to the noise measure, the feedback signal decreasing the amount of voltage headroom responsive to the noise measure falling below a threshold and increasing the amount of voltage headroom responsive to the noise measure exceeding the threshold.

15. The envelope tracking transceiver of claim 14 wherein the feedback receiver is configured to determine the noise measure based on the input signal and a signal representative of the amplified output signal.

16. The envelope tracking transceiver of claim 15 wherein the feedback receiver is further configured to downsample the signal representative of the amplified output signal and perform a comparison between the downsampled signal and the input signal.

17. The envelope tracking transceiver of claim 14 wherein the noise measure represents an adjacent channel power.

18. The envelope tracking transceiver of claim 14 further comprising a duplex filter coupled between an output of the power amplifier and at least one antenna.

19. The envelope tracking transceiver of claim 14 further comprising a coupler coupled between an output of the power amplifier and at least one antenna, the coupler configured to generate a coupled signal.

20. The envelope tracking transceiver of claim 19 wherein the feedback receiver generates the noise measure based on the input signal and the coupled signal.