Digital transmitter with data stream transformation circuitry

• US 20060280259A1
• Filed: 08/25/2005
• Published: 12/14/2006
• Est. Priority Date: 06/10/2005
• Status: Active Grant

• Current Assignee: Rambus Inc., Board of Trustees of the Leland Stanford Junior University (Stanford University)
• Original Assignee: Rambus Inc.
• Inventors: Stojanovic, Vladimir Marko, Alon, Elad, Amirkhany, Amir
• Granted Patent: US 7,711,063 B2
• Time in Patent Office: Days
• US Class Current: 375/295
• CPC Class Codes: H04L 1/0033 arrangements specific to the transmitter

Abstract

A transmitter with data stream transformation circuitry is described. The transmitter has a first driver and a second driver. Each driver has an output for a respective analog signal. A summation circuit combines respective analog signals from the first driver and the second driver. A data selection circuit processes at least two data streams. Each data stream corresponds to a time sequence of digital data symbols. The data selection circuit selectively couples at least one of the data streams to at least one of the drivers during each time interval of a sequence of time intervals, thereby applying a linear transformation to the data streams. A finite state machine controls the data selection circuit during each time interval of the sequence of time intervals.

Claims

1. A transmitter, comprising:

a first driver and a second driver, each driver having an output for a respective analog signal;

a summation circuit for combining respective analog signals from the first driver and the second driver;

a data selection circuit to process at least two data streams, each data stream corresponding to a time sequence of digital data symbols, wherein the data selection circuit selectively couples at least one of the data streams to at least one of the drivers during each time interval of a sequence of time intervals, thereby applying a linear transformation to the data streams; and

a finite state machine to control the data selection circuit during each time interval of the sequence of time intervals in accordance with a programmable code word.

2. A transmitter, comprising:

a first driver and a second driver, each driver having an output for a respective analog signal;

a summation circuit for combining respective analog signals from at least the two drivers;

a data selection circuit to process at least two data streams, each data stream corresponding to a time sequence of digital data symbols and at least one data stream includes, during each of a sequence of time intervals, a current digital data symbol and at least one prior digital data symbol, the data selection circuit selectively coupling at least one of the data streams to at least one of the drivers during each time interval during the sequence of time intervals, thereby applying a linear transformation to the data streams, wherein the linear transformation includes combining the current digital data symbol and at least the one prior digital data symbol of at least the one data stream; and

a finite state machine to control the data selection circuit during each time interval of the sequence of time intervals in accordance with a respective code word in a set of code words.

3. The transmitter of claim 2, wherein combining the current digital data symbol and at least the one prior digital data symbol of at least the one data stream accomplishes equalization.

4. The transmitter of claim 2, wherein the selective coupling is varied during a plurality of time intervals in accordance with a sequence of code words in the set of code words.

5. The transmitter of claim 2, further comprising a memory, wherein the memory stores the set of code words.

6. The transmitter of claim 2, further comprising a control logic, wherein the control logic provides the respective code word to the finite state machine and the respective code word is programmable.

7. The transmitter of claim 2, further comprising an interface coupled to the finite state machine, wherein the interface is configured to receive the respective code word.

8. The transmitter of claim 2, wherein a sum of respective gains of the first driver and the second driver substantially corresponds to a maximum output signal power from the summation circuit.

9. The transmitter of claim 2, wherein at least the two data streams are selectively coupled to the first driver and the second driver during each time interval.

10. The transmitter of claim 2, further comprising a digital delay circuit for delaying at least the two data streams, wherein the digital delay circuit includes at least a first digital delay, and wherein at least the one prior digital data symbol is provided by an output from the digital delay circuit.

11. The transmitter of claim 2, further comprising a phase rotation circuit for processing at least the two data streams, wherein the phase rotation circuit modifies a respective phase of at least the two data streams and the linear transformation includes an inverse discrete Fourier transform.

12. The transmitter of claim 2, wherein at least the two data streams correspond to respective sub-channels in a multi-tone system.

13. The transmitter of claim 2, wherein the respective code word is selected in accordance with at least a characteristic of a communications channel coupled to the transmitter.

14. The transmitter of claim 2, wherein the respective code word is selected in accordance with at least a characteristic of a communications channel and at least one receiver device coupled to the transmitter.

15. A computer readable medium containing data representing a circuit that includes:

a transmitter, comprising;

a first driver and a second driver, each driver having an output for a respective analog signal;

a summation circuit for combining respective analog signals from at least the first driver and the second driver;

a data selection circuit to process at least two data streams, each data stream corresponding to a time sequence of digital data symbols and at least one data stream includes, during each of a sequence of time intervals, a current digital data symbol and at least one prior digital data symbol, the data selection circuit selectively coupling at least one of the data streams to at least one of the drivers during each time interval during the sequence of time intervals, thereby applying a linear transformation to the data streams, wherein the linear transformation includes combining the current digital data symbol and at least the one prior digital data symbol of at least the one data stream; and

a finite state machine to control the data selection circuit during each time interval of the sequence of time intervals in accordance with a respective code word in a set of code words.

16. A transmitter mechanism, comprising:

a first driver means and a second driver means, each driver means having an output for a respective analog signal;

a summation means for combining respective analog signals from the first driver means and the second driver means;

a data selection means for processing at least two data streams, each data stream corresponding to a time sequence of digital data symbols and at least one data stream includes, during each of a sequence of time intervals, a current digital data symbol and at least one prior digital data symbol, the data selection means selectively coupling at least one of the data streams to at least one of the driver means during each time interval during the sequence of time intervals, thereby applying a linear transformation to the data streams, wherein the linear transformation includes combining the current digital data symbol and at least the one prior digital data symbol of at least the one data stream; and

a finite state machine means to control the data selection means during each time interval of the sequence of time intervals in accordance with a respective code word in a set of code words.

17. A method of transmitting data, comprising:

receiving at least two data streams, each data stream corresponding to a time sequence of digital data symbols and at least one data stream including, during each of a sequence of time intervals, a current digital data symbol and at least one prior digital data symbol;

selectively coupling at least one of the data streams to a first driver and a second driver during each time interval during the sequence of time intervals, thereby applying a linear transformation to the data streams, wherein the linear transformation includes combining the current digital data symbol and at least the one prior digital data symbol of at least the one data stream and the selectively coupling is in accordance with a respective code word in a set of code words and an output from a finite state machine;

converting digital data symbols to analog signals in the first driver and the second driver; and

combining respective analog output signals from the first driver and the second driver.

18. The method of claim 17, wherein the selective coupling is varied during a plurality of time intervals in accordance with a sequence of code words in the set of code words.

19. The method of claim 17, further comprising programming the respective code word.

20. The method of claim 17, further comprising receiving the respective code word using an external interface.

21. The method of claim 17, wherein a sum of respective gains of the first driver and the second driver substantially corresponds to a maximum output signal power.

22. The method of claim 17, wherein at least the two data streams are selectively coupled to the first driver and the second driver during each time interval.

23. The method of claim 17, further comprising phase rotating a respective phase of at least the two data streams, wherein the linear transformation includes an inverse discrete Fourier transform.

24. The method of claim 17, further comprising selecting the respective code word in accordance with at least a characteristic of a communications channel.

25. The method of claim 17, further comprising selecting the respective code word in accordance with at least a characteristic of a communications channel and at least one receiver device.

26. The method of claim 17, wherein combining the current digital data symbol and at least the one prior digital data symbol of at least the one data stream accomplishes equalization.