Methods and systems for communicating data and control information over a serial link
A communication system includes a digital data processor that produces a digital data sample and one or more control bits. A serialized transmit interface combines the digital data sample and the control bit(s) into one or more data packets and sends the data packet(s) over a signal line. A serialized receive interface receives the transmitted data packet(s) from the signal line and produces a reconstructed digital data sample and the control bit(s) from the transmitted data packet(s). A control circuit coupled to the serialized receive interface produces a control signal from the control bit(s). The communication system may include a converter circuit, which produces an RF input signal by performing a digital-to-analog conversion of the reconstructed digital data sample, and by upconverting the resulting analog data sample signal to RF. A power amplifier amplifies the RF input signal and modifies operation of a sub-circuit based on the control signal.
1. A communication system comprising:
a digital data processor configured to produce a digital data sample and one or more control bits;
a serialized transmit interface coupled to the digital data processor and to a first end of a signal line, wherein the serialized transmit interface is configured to
combine the digital data sample and the one or more control bits into one or more data packets, and
send the one or more data packets over the signal line as one or more transmitted data packets;
a serialized receive interface coupled a second end of the signal line, wherein the serialized receive interface is configured to
receive the one or more transmitted data packets from the signal line,
produce a reconstructed digital data sample from the one or more transmitted data packets, and
produce the one or more control bits from the one or more transmitted data packets; and
a control circuit coupled to the serialized receive interface, and configured to produce a control signal from the one or more control bits provided by the serialized receive interface.
2. The communication system of claim 1 , wherein the serialized transmit interface and the serialized receive interface implement a JESD204 serial link communications protocol.
3. The communication system of claim 1 , wherein the serialized transmit interface is configured to combine the digital data sample and the one or more control bits into one or more data packets by combining at least one bit of the digital data sample and at least one control bit of the one or more control bits into a data packet of the one or more data packets.
4. The communication system of claim 1 , wherein the serialized transmit interface is configured to send the one or more data packets over the signal line as one or more transmitted data packets by:
encoding the one or more data packets to produce one or more encoded symbols; and
sending the one or more data packets over the serial link within the one or more encoded symbols.
5. The communication system of claim 4 , wherein the serialized receive interface is configured to receive the one or more transmitted data packets from the signal line by:
decoding the one or more encoded symbols.
6. The communication system of claim 1 , further comprising:
a converter circuit configured to produce a radio frequency (RF) input signal by performing a digital-to-analog conversion of the reconstructed digital data sample to produce an analog data sample signal, and upconverting the analog data sample signal to RF; and
a power amplifier that includes a sub-circuit that is controllable based on the control signal produced by the control circuit, wherein the power amplifier is configured to amplify the RF input signal, and to modify operation of the sub-circuit based on the control signal.
7. The communication system of claim 6 , wherein the control circuit comprises a buffer with a programmable delay that is configured to synchronize, in the power amplifier, amplification of the RF input signal with modification of the operation of the sub-circuit based on the control signal.
8. The communication system of claim 7 , wherein the control circuit is configured to produce the control signal from the one or more control bits in the form of an analog control signal.
9. The communication system of claim 8 , wherein the sub-circuit of the power amplifier includes a switch, and the power amplifier is configured to modify operation of the sub-circuit by altering a state of the switch based on the analog control signal.
10. The communications system of claim 9 , wherein the power amplifier is a Doherty power amplifier with a carrier amplifier path and a peaking amplifier path, and wherein the switch is connected to the peaking amplifier path in a shunt configuration.
11. The communication system of claim 6 , wherein the control circuit is configured to produce the control signal from the one or more control bits in the form of a digital control signal.
12. The communication system of claim 11 , wherein the sub-circuit of the power amplifier includes a digitally controlled circuit, and the power amplifier is configured to modify operation of the sub-circuit by altering operation of the digitally controlled circuit based on the digital control signal.
13. The communications system of claim 12 , wherein:
the power amplifier is a Doherty power amplifier with a carrier amplifier path and a peaking amplifier path,
the Doherty power amplifier includes a power splitter configured to divide the RF input signal into a carrier RF signal and a peaking RF signal,
the digitally controlled circuit comprises one or more variable phase shifters coupled to either or both of the carrier amplifier path and the peaking amplifier path, and
the power amplifier is configured to modify operation of the digitally controlled circuit by changing one or more phase shifts applied by the one or more variable phase shifters to either or both of the carrier RF signal and the peaking RF signal.
14. The communication system of claim 6 , wherein the converter circuit comprises:
a digital-to-analog converter configured to performing the digital-to-analog conversion to produce the analog signal; and
an upconverter configured to upconvert the analog signal to RF.
15. A method performed by a communication system, the method comprising:
producing, by a digital data processor, a digital data sample and one or more control bits;
combining, by a serialized transmit interface, the digital data sample and the one or more control bits into one or more data packets;
sending, by the serialized transmit interface, the one or more data packets over a signal line as one or more transmitted data packets;
receiving, by a serialized receive interface, the one or more transmitted data packets from the signal line;
producing, by the serialized receive interface, a reconstructed digital data sample from the one or more transmitted data packets;
producing, by the serialized receive interface, the one or more control bits from the one or more transmitted data packets; and
producing, by a control circuit, a control signal from the one or more control bits produced by the serialized receive interface.
16. The method of claim 15 , wherein the serialized transmit interface and the serialized receive interface implement a JESD204 serial link communications protocol.
17. The method of claim 15 , wherein:
sending, by the serialized transmit interface, the one or more data packets over the signal line as one or more transmitted data packets includes encoding the one or more data packets to produce one or more encoded symbols, and sending the one or more data packets over the serial link within the one or more encoded symbols; and
receiving, by the serialized receive interface, the one or more transmitted data packets from the signal line includes decoding the one or more encoded symbols.
18. The method of claim 15 , further comprising:
producing, by a converter circuit, a radio frequency (RF) input signal by performing a digital-to-analog conversion of the reconstructed digital data sample to produce an analog data sample signal, and upconverting the analog data sample signal to RF;
amplifying the RF input signal, by a power amplifier that includes a sub-circuit that is controllable based on the control signal produced by the control circuit; and
modifying operation of the sub-circuit, by the power amplifier, based on the control signal.
19. The method of claim 18 , wherein producing the control signal by the control circuit includes delaying production of the control signal by a programmable delay that is configured to synchronize, in the power amplifier, amplifying the RF signal with modifying the operation of the sub-circuit based on the control signal.
20. The method of claim 18 , wherein:
producing the control signal comprises producing an analog control signal;
the sub-circuit of the power amplifier includes a switch; and
modifying operation of the sub-circuit comprises altering a state of the switch based on the analog control signal.
21. The method of claim 18 , wherein:
producing the control signal comprises producing a digital control signal;
the sub-circuit of the power amplifier includes a digitally controlled circuit; and
modifying operation of the sub-circuit comprises altering operation of the digitally controlled circuit based on the digital control signal.
22. The method of claim 18 , wherein the power amplifier is a Doherty power amplifier, and wherein modifying operation of the sub-circuit based on the control signal comprises modifying operation of the Doherty power amplifier.