Emission control for receiver operating over UTP cables in automotive environment

Patent metadata

Field	Value
Publication number	US-10644906-B2
Application number	US-201816054973-A
Country	US
Kind code	B2
Filing date	Aug 3, 2018
Priority date	Aug 3, 2018
Publication date	May 5, 2020
Grant date	May 5, 2020

Abstract

A transceiver system includes a transmitter circuit having a line driver with a programmable signal level to generate a transmit signal for transmission in an automotive environment over an unshielded-twisted pair (UTP) cable. The transceiver system further includes a physical layer (PHY) receiver. The PHY receiver includes a high-pass filter (HPF), an adaptive feed-forward equalizer (FFE) block and a noise aware adaptation block. The HPF rejects transient noise of a received signal, and the FFE block receives a digital signal and adaptively filters out narrowband continuous wave (CW) noise using an adaptation signal. The digital signal is based on the received signal, and the noise aware adaptation block receives an error signal and generates the adaptation signal. The error signal is generated based on an equalized signal of the FFE block and an estimated signal. The combined transmit and receive circuitry allow lowering emission while rejecting strong receiver automotive noises.

First claim

What is claimed is:

1. A transceiver system comprising:
a transmitter circuit including a line driver configurable to generate a transmit signal for transmission in an automotive environment over an unshielded-twisted pair (UTP) cable; and
a physical layer (PHY) receiver, wherein the PHY receiver comprises:
a high-pass filter (HPF) configured to reject transient noise of a received signal;
a noise aware adaptation block configured to receive an error signal and to generate an adaptation signal;
an error shaping block configured to shape the error signal to generate a shaped error signal; and
an adaptive feed-forward equalizer (FFE) block configured to receive a digital signal and to adaptively filter out narrowband continuous wave (CW) noise using the adaptation signal, the digital signal being based on the received signal,
wherein the error signal is generated based on an equalized signal of the FFE block and an estimated signal.

2. The transceiver system of claim 1 , wherein the PHY receiver further comprises a decision feedback equalizer (DFE) block configured to receive the shaped error signal, the estimated signal and the adaptation signal and to generate a feedback signal.

3. The transceiver system of claim 2 , wherein the PHY receiver further comprises a slicer block configured to provide the estimated signal based a first signal resulting from subtraction of the feedback signal from the equalized signal.

4. The transceiver system of claim 2 , wherein the PHY receiver further comprises a first subtraction block configured to generate a first signal based on subtraction of the feedback signal from the equalized signal.

5. The transceiver system of claim 4 , wherein the PHY receiver further comprises a second subtraction block configured to generate the error signal by subtracting the estimated signal from the first signal.

6. The transceiver system of claim 5 , wherein the PHY receiver further comprises a high-resolution analog-to-digital converter (ADC) configured to convert the received signal to the digital signal, and wherein the high-resolution ADC comprises an ADC with an effective number of bits (ENOB) of more than 8 bits.

7. The transceiver system of claim 6 , wherein the FFE block comprises a multi-tab FFE configured to receive the digital signal, the shaped error signal, and the feedback signal and to generate the equalized signal based on the digital signal, the shaped error signal, and the feedback signal.

8. The transceiver system of claim 1 , wherein the transmitter circuit further comprises a transmit-level control circuit configured to generate a control signal to adjust a transmit level of the line driver.

9. The transceiver system of claim 8 , wherein the transmit-level control circuit comprises a plurality of control register, and wherein the control signal is generated based on content of the plurality of control registers including a number of transmit-level choices lower than a default transmit level of the line driver.

10. A receiver circuit comprising:
an automatic gain control (AGC) circuit configured to generate a digital signal and a channel information signal based on a received signal over an unshielded-twisted pair (UTP) cable;
a digital-signal processing (DSP) block configured to generate an estimated signal and an error signal based on the digital signal; and
a transmit-level control circuit configured to generate a control signal for dynamically adjusting a transmit level of a transmitter circuit for transmitting over the UTP cable,
wherein the transmit-level control circuit is configured to generate the control signal based on the error signal and the channel information signal.

11. The receiver circuit of claim 10 , wherein receiver comprises a 1000BASE-T1 physical layer (PHY) receiver, and wherein the transmit-level control circuit is configured to generate the control signal to adapt for dynamically adjusting the transmit level of the transmitter circuit to be compatible with the 1000BASE-T1 PHY receiver.

12. The receiver circuit of claim 11 , further comprising a high-pass filter (HPF), a programmable gain amplifier (PGA) circuit and a high-resolution analog-to-digital converter (ADC), wherein the high-resolution ADC comprises an ADC with an effective number of bits (ENOB) of more than 8 bits.

13. The receiver circuit of claim 12 , wherein the HPF is configured to filter out a transient noise of a received signal, and the PGA is configured to amplify a filtered signal output of the HPF by a gain controlled by an AGC feedback signal.

14. The receiver circuit of claim 10 , wherein the DSP block comprises a feed-forward equalizer (FFE), a slicer, a decision feedback equalizer (DFE), a first subtractor and a second subtractor.

15. The receiver circuit of claim 14 , wherein the FFE is configured to receive an output signal of the AGC circuit and to generate an equalized signal, and wherein the slicer is coupled to the first subtractor that is configured to subtract a feedback signal from the equalized signal and to generate a first signal.

16. The receiver circuit of claim 15 , wherein the slicer is configured to generate the estimated signal based on the first signal, wherein the second subtractor is configured to subtract the estimated signal from the first signal and to generate the error signal.

17. The receiver circuit of claim 15 , wherein the DFE is configured to receive the estimated signal and to generate the feedback signal.

18. A method comprising:
receiving a signal over an unshielded-twisted pair (UTP) cable;
generating, by an automatic gain control (AGC) circuit, a digital signal and a channel information signal based on the received signal;
generating, by a digital signal processing (DSP) block, an estimated signal and an error signal based on the digital signal; and
generating, by a transmit-level control circuit, a control signal for dynamically adjusting a transmit level of a transmitter circuit for transmitting over the UTP cable based on the error signal and the channel information signal.

19. The method of claim 18 , wherein the DSP block comprises a feed-forward equalizer (FFE), a slicer, a decision feedback equalizer (DFE), a first subtractor and a second subtractor, and wherein the FFE is configured to receive an output signal of the AGC circuit and to generate an equalized signal.

20. The method of claim 18 , wherein the slicer is coupled to the first subtractor that is configured to subtract a feedback signal from the equalized signal and to generate a first signal.

Assignees

• Avago Technologies General Ip
• Avago Tech Int Sales Pte Lid

Inventors

• Chini Ahmad
• Wang Peiqing
• Tazebay Mehmet Vakif

Classifications

• H04B3/54 Primary

  Systems for transmission via power distribution lines · CPC title

• H04B3/02

  Details · CPC title

• H04B1/40

  Circuits · CPC title

• H03H2021/0092

  Equalization, i.e. inverse modeling · CPC title

• H03H21/0027

  filtering in the frequency domain · CPC title