# US 8,787,430 B2 · Low complexity high-speed communications transceiver

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- Number: US 8,787,430 B2
- Document ID: US8787430B2
- Status: Granted
- Kind: B2
- Application number: 12/558,781
- Filed: 2009-09-14
- Published: 2010-01-07
- Granted: 2014-07-22
- Earliest claimed: 2001-07-11
- Assignees: Entropic Communications, Inc.
- Applicants: Sreen Raghavan; Thulasinath G. Manickam; Peter J. Sallaway
- Inventors: Sreen Raghavan; Thulasinath G. Manickam; Peter J. Sallaway
- Web page: https://patentgrep.com/patent/US8787430B2

## CPC

- H04L 27/2601: {Multicarrier modulation systems}
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)

## Abstract

A communication system is disclosed that allows high data-rate transmission of data between components. N-bit parallel data is transmitted in K-frequency separated channels on the transmission medium so as to fully take advantage of the overall bandwidth of the transmission medium. As a result, a very high data-rate transmission can be accomplished with low data-bit transmission on individual channels. A transmitter system and a receiver system are described for the communication system.

## Claims

### Claim 1

A transmission system, comprising:
a plurality of receivers, each of the plurality of receivers receiving signals from one of a plurality of transmission bands, at least one of the plurality of receivers comprising:
a down-converter that converts an input signal from the one of the plurality of transmission bands to a base band, the down-converter creating an in-phase signal and a quadrature signal, the in-phase signal being the input signal multiplied by a cosine function at the frequency of the one of the plurality of transmission bands and the quadrature signal being the input signal multiplied by a sine function at the frequency of the one of the plurality of transmission bands;
a filter coupled to receive signals from the down-converter, the filter substantially filtering out signals not in the base band and including an in-phase filter filtering the in-phase signal and a quadrature filter filtering the quadrature signal;
an analog-to-digital converter coupled to receive signals from the filter and generate digitized signals;
an equalizer coupled to receive the digitized signals; and
a trellis decoder coupled to receive signals from the equalizer and generate recreated data, the recreated data being substantially the same data transmitted by a corresponding transmitter, and
an offset block coupled between the down-converter and the filter, the offset block offsetting the in-phase signal and the quadrature signal such that signals output from the analog-to-digital converter averages zero.

### Claim 2

A transmission system, comprising:
a plurality of receivers, each of the plurality of receivers receiving signals from one of a plurality of transmission bands, at least one of the plurality of receivers comprising:
a down-converter that converts an input signal from the one of the plurality of transmission bands to a base band, the down-converter creating an in-phase signal and a quadrature signal, the in-phase signal being the input signal multiplied by a cosine function at the frequency of the one of the plurality of transmission bands and the quadrature signal being the input signal multiplied by a sine function at the frequency of the one of the plurality of transmission bands;
a filter coupled to receive the in-phase and the quadrature signals from the down-converter, the filter substantially filtering out signals not in the base band and including an in-phase filter filtering the in-phase signal and a quadrature filter filtering the quadrature signal;
an analog-to-digital converter coupled to receive signals from the filter and generate digitized signals;
an amplifier coupled between the filter and the analog-to-digital converter, the amplifier amplifying an in-phase filtered signal from the in-phase filter and a quadrature filter signal from the quadrature filter such that the analog-to-digital converter is filled;
an equalizer coupled to receive the digitized signals; and
a trellis decoder coupled to receive signals from the equalizer and generate recreated data, the recreated data being substantially the same data transmitted by a corresponding transmitter,
wherein an in-phase gain of the amplifier and a quadrature gain of the amplifier are adaptively chosen in an automatic gain controller.

### Claim 3 (depends on 2)

The system of claim 2, wherein the automatic gain controller sets the in-phase gain and the quadrature gain based on the digitized signals from the analog to digital converters.

### Claim 4 (depends on 3)

The system of claim 3, wherein the in-phase gain and the quadrature gain are equal.

### Claim 5

A transmission system, comprising:
a plurality of receivers, each of the plurality of receivers receiving signals from one of a plurality of transmission bands, at least one of the plurality of receivers comprising:
a down-converter that converts an input signal from the one of the plurality of transmission bands to a base band, the down-converter creating an in-phase signal and a quadrature signal, the in-phase signal being the input signal multiplied by a cosine function at the frequency of the one of the plurality of transmission bands and the quadrature signal being the input signal multiplied by a sine function at the frequency of the one of the plurality of transmission bands;
a filter coupled to receive signals from the down-converter, the filter substantially filtering out signals not in the base band and including an in-phase filter filtering the in-phase signal and a quadrature filter filtering the quadrature signal;
an analog-to-digital converter coupled to receive signals from the filter and generate digitized signals, the analog-to-digital converter including a first analog-to-digital converter coupled to receive signals from the in-phase filter and a second analog-to-digital converter coupled to receive signals from the quadrature filter;
an equalizer coupled to receive the digitized signals;
a correction circuit coupled between the analog-to-digital converter and the equalizer, the correction circuit including an adjustment to correct phases between the in-phase signal and the quadrature signal; and
a trellis decoder coupled to receive signals from the equalizer and generate recreated data, the recreated data being substantially the same data transmitted by a corresponding transmitter,
wherein a small portion of one of the in-phase signal and the quadrature signal are added to the opposite one of the in-phase signal and the quadrature signal.

### Claim 6 (depends on 5)

The system of claim 5, wherein a second portion of the opposite one of the in-phase signal and the quadrature signal is added to the opposite one of the in-phase signal and the quadrature signal.

### Claim 7 (depends on 6)

The system of claim 6, wherein the small portion and the second portion are adaptively chosen.

### Claim 8 (depends on 7)

The system of claim 7, wherein the small portion is a function of in-phase and quadrature output signals from the correction circuit.

### Claim 9 (depends on 7)

The system of claim 7, wherein the second portion is a function of the ratio between in-phase and quadrature signals from the correction circuit.

### Claim 10 (depends on 5)

The system of claim 5, wherein a phase rotator circuit is coupled between the analog-to-digital converter and the equalizer.

### Claim 11 (depends on 10)

The system of claim 10, wherein a parameter of the phase rotator circuit is adaptively chosen.

### Claim 12

A transmission system, comprising:
a plurality of receivers, each of the plurality of receivers receiving signals from one of a plurality of transmission bands, at least one of the plurality of receivers comprising:
a down-converter that converts an input signal from the one of the plurality of transmission bands to a base band, the down-converter creating an in-phase signal and a quadrature signal, the in-phase signal being the input signal multiplied by a cosine function at the frequency of the one of the plurality of transmission bands and the quadrature signal being the input signal multiplied by a sine function at the frequency of the one of the plurality of transmission bands;
a filter coupled to receive signals from the down-converter, the filter substantially filtering out signals not in the base band;
an analog-to-digital converter coupled to receive signals from the filter and generate digitized signals;
an equalizer coupled to receive the digitized signals;
a trellis decoder coupled to receive signals from the equalizer and generate recreated data, the recreated data being substantially the same data transmitted by a corresponding transmitter;
an amplifier coupled between the equalizer and the trellis decoder; and
a quadrature correction coupled between the amplifier and the trellis decoder.

### Claim 13 (depends on 12)

The system of claim 12, wherein an offset circuit is coupled between the quadrature correction and the trellis decoder.

### Claim 14 (depends on 13)

The system of claim 13, wherein a parameter of the offset circuit is adaptively chosen.

### Claim 15 (depends on 12)

The system of claim 12, wherein an in-phase gain and a quadrature gain of the amplifier are adaptively chosen from error signals calculated from sliced values.

### Claim 16 (depends on 15)

The system of claim 15, wherein the sliced values are determined from input signals to the trellis decoder.

### Claim 17 (depends on 12)

The system of claim 12, wherein a parameter of the quadrature correction is adaptively chosen.

### Claim 18

A transmission system comprising:
a plurality of receivers, each of the plurality of receivers receiving signals from one of a plurality of transmission bands, at least one of the plurality of receivers comprising:
a down-converter that converts an input signal from the one of the plurality of transmission bands to a base band, the down-converter creating an in-phase signal and a quadrature signal, the in-phase signal being the input signal multiplied by a cosine function at the frequency of the one of the plurality of transmission bands and the quadrature signal being the input signal multiplied by a sine function at the frequency of the one of the plurality of transmission bands;
a filter coupled to receive signals from the down-converter, the filter substantially filtering out signals not in the base band;
an analog-to-digital converter coupled to receive signals from the filter and generate digitized signals;
an equalizer coupled to receive the digitized signals, wherein the equalizer is a complex equalizer executing a transfer function, the transfer function having parameters Ckx(j) and Cky(j), where j is an integer; and
a trellis decoder coupled to receive signals from the equalizer and generate recreated data, the recreated data being substantially the same data transmitted by a corresponding transmitter.

### Claim 19 (depends on 18)

The system of claim 18, wherein the center parameters Ckx(0) and Cky(0) are fixed.

### Claim 20 (depends on 19)

The system of claim 19, wherein Ckx(0) is one and Cky(0) is zero.

### Claim 21 (depends on 19)

The system of claim 19, wherein the parameters Ckx(−1) and Cky(−1), are fixed.

### Claim 22 (depends on 21)

The system of claim 21, wherein the parameter Ckx(−1) is about −0.3125.

### Claim 23 (depends on 21)

The system of claim 21, wherein the parameter Cky(−1) is about −0.015625.