Transparent multi-mode PAM interface
First Claim
1. A multi-mode PAM output driver for driving a sequence of symbols, the output driver comprising:
- an input interface configured to receive data to be output as the sequence of symbols;
an interface configured to receive a PAM mode signal specifying a PAM mode;
multiplexer circuitry configured to output the received data in an order determined by the PAM mode signal;
a clock circuit configured to generate an output clock having a clock rate determined by the PAM mode signal;
a driver circuit coupled to the clock circuit and to an output of the multiplexer circuit, the driver circuit configured to drive the sequence of symbols, the symbols driven in the order output by multiplexer circuit.
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Accused Products
Abstract
Provided are a method and apparatus for high-speed, multi-mode PAM symbol transmission. A multi-mode PAM output driver drives one or more symbols, the number of levels used in the PAM modulation of the one or more symbols depending on the state of a PAM mode signal. Additionally, the one or more symbols are driven at a symbol rate, the symbol rate selected in accordance with the PAM mode signal so that a data rate of the driven symbols in constant with respect to changes in the state of the PAM mode signal. Further provided are methods for determining the optimal number of PAM levels for symbol transmission and reception in a given physical environment.
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Citations
55 Claims
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1. A multi-mode PAM output driver for driving a sequence of symbols, the output driver comprising:
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an input interface configured to receive data to be output as the sequence of symbols;
an interface configured to receive a PAM mode signal specifying a PAM mode;
multiplexer circuitry configured to output the received data in an order determined by the PAM mode signal;
a clock circuit configured to generate an output clock having a clock rate determined by the PAM mode signal;
a driver circuit coupled to the clock circuit and to an output of the multiplexer circuit, the driver circuit configured to drive the sequence of symbols, the symbols driven in the order output by multiplexer circuit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A multi-mode PAM receiver for receiving a sequence of symbols, the receiver comprising:
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an interface configured to receive a PAM mode signal specifying a PAM mode;
a receive clock signal;
a receiver circuit configured to receive the sequence of symbols at a clock rate of the receive clock signal and to generate a corresponding data stream;
multiplexer circuitry configured to order data from the data stream in accordance with the PAM mode signal so as to produce a formatted data stream; and
an output interface coupled to an output of the multiplexer circuitry, the output interface configured to output data words from the formatted data stream at a rate determined, at least in part, by the PAM mode. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30)
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31. A multi-mode PAM transceiver comprising:
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a multi-mode PAM output driver, configured to output a first sequence of symbols and to receive a PAM mode signal specifying a PAM mode;
a multi-mode PAM receiver, configured to receive a second sequence of symbols and to receive the PAM mode signal;
wherein the first sequence of symbols includes an N-PAM symbol when the PAM mode is a first PAM mode;
wherein the first sequence of symbols includes an M-PAM symbol when the PAM mode is a second PAM mode;
wherein N is not equal to M. - View Dependent Claims (32, 33, 34, 35, 36, 37, 38, 39, 40, 41)
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42. A method of symbol transmission, comprising:
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configuring a multi-mode PAM output driver to operate in a specified PAM mode, the specified PAM mode selected from a plurality of predefined PAM modes;
using the multi-mode PAM output driver, outputting a sequence of symbols;
wherein the sequence of symbols includes an N-PAM symbol when the PAM mode is a first PAM mode;
wherein the sequence of symbols includes an M-PAM symbol when the PAM mode is a second PAM mode; and
wherein N is not equal to M. - View Dependent Claims (43, 44)
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45. A method of data transmission comprising:
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operating the multi-mode PAM output driver so as to drive a first sequence of symbols onto a channel at a first symbol rate, the sequence comprising a plurality of symbols, each symbol having a respective level of a predetermined first number of PAM levels;
receiving, at a multi-mode PAM receiver, the first sequence of symbols from the channel;
determining, based on a relationship between the sequence of driven symbols and the sequence of received symbols, a first symbol quality metric;
operating the multi-mode PAM output driver so as to drive a second sequence of symbols onto a channel at a second symbol rate, the sequence comprising a plurality of symbols, each symbol having a respective level of a predetermined second number of PAM levels; and
receiving, at a multi-mode PAM receiver, the second sequence of symbols from the channel;
wherein the predetermined first and second numbers of PAM levels are different. - View Dependent Claims (46, 47, 48, 49)
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50. A method of data transmission comprising:
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operating a multi-mode PAM output driver so as to drive a first sequence of symbols at a first symbol rate selected from a plurality of predetermined symbol rates, the sequence comprising a plurality of symbols, each symbol having a respective level of a first number of PAM levels, the first number of PAM levels selected from a plurality of available PAM levels;
receiving at a multi-mode PAM receiver the first sequence of symbols;
determining a first symbol quality metric corresponding to the first symbol rate and to the first number of PAM levels;
operating the multi-mode PAM driver so as to drive a second sequence of symbols at a second symbol rate selected from the plurality of predetermined symbol rates, the second sequence comprising a plurality of symbols, each symbol having a respective level of a second number of PAM levels, the second number of PAM levels selected from the plurality of available PAM levels;
receiving at the multi-mode PAM receiver the second sequence of symbols;
determining second symbol quality metric corresponding to the second symbol rate and to the second level of predetermined number of PAM levels;
based on the first and the second symbol quality metrics, choosing a mode of operation of the system, the mode of operation specified, at least, by a number of PAM levels. - View Dependent Claims (51, 52, 53, 54)
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55. A multi-mode PAM transceiver comprising:
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means for outputting a first sequence of symbols in accordance with a PAM mode signal specifying a PAM mode;
means for receiving a second sequence of symbols and for receiving the PAM mode signal;
wherein the first sequence of symbols includes an N-PAM symbol when the PAM mode is a first PAM mode;
wherein the first sequence of symbols includes an M-PAM symbol when the PAM mode is a second PAM mode;
wherein N is not equal to M.
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Specification