Communication apparatus

Patent metadata

Field	Value
Publication number	US-10938507-B2
Application number	US-202016874784-A
Country	US
Kind code	B2
Filing date	May 15, 2020
Priority date	May 29, 2019
Publication date	Mar 2, 2021
Grant date	Mar 2, 2021

Abstract

In a communication apparatus, a specific bit is detected from a communication data decoded in a low-speed state of a communication speed. The specific bit is a bit having undergone an inverse change in a logical value. A signal waveform of the communication signal is acquired, which is recorded in a memory and corresponds to the specific bit. Then, a sampling point of the communication signal in a high-speed state of the communication signal is calculated based on (i) the acquired signal waveform and (ii) a logical value of the specific bit.

First claim

What is claimed is:

1. A communication apparatus in a communication system in which
(i) the communication apparatus is configured to receive a communication data transmitted from each of a plurality of transmission nodes to a transmission path common to the plurality of transmission nodes, the communication data having a frame structure in which an arbitration area is provided before a data area,
(ii) each of the plurality of transmission nodes switches a communication speed between a low speed state in the arbitration area and a high speed state in the data area, and
(iii) in response to the plurality of transmission nodes each starting transmitting the communication data in the arbitration area, a transmission node among the plurality of transmission nodes acquires a transmission right in the arbitration area and the transmission node acquiring the transmission right continues transmitting the communication data,
the communication apparatus comprising:
a reception unit configured
to sample a communication signal flowing through the transmission path at a predetermined sampling point and
to decode a logical value of each bit of the communication data;
a waveform record unit configured to record a signal waveform of the communication signal; and
a calculation unit configured
to detect a specific bit from the communication data decoded by the reception unit in the low speed state of the communication speed, the specific bit being a bit having undergone an inverse change in the logical value,
to acquire the signal waveform of the communication signal, which is recorded in the waveform record unit and corresponds to the specific bit, and
to calculate the sampling point for each bit of the communication signal in the high speed state of the communication speed based on (i) the acquired signal waveform and (ii) the logical value of the specific bit,
wherein the reception unit is configured, in the high speed state of the communication speed,
to sample the communication signal at the calculated sampling point calculated by the calculation unit and
to decode the logical value of each bit of the communication data.

2. The communication apparatus according to claim 1 , wherein
the waveform record unit is configured
to detect a receiving period that is a period, in which the reception unit receives the specific bit in the arbitration area, based on the communication data decoded in the low speed state of the communication speed by the reception unit, and
to record the signal waveform of the communication signal in the receiving period.

3. The communication apparatus according to claim 2 , wherein
the waveform record unit is configured
to detect, in the arbitration area, the receiving period based on the communication data decoded in the low speed state of the communication speed by the reception unit, and
to record the signal waveform of the communication signal in the receiving period,

wherein the receiving period appears after an arbitration period, which is needed for the transmission node acquiring the transmission right to acquire the transmission right within the arbitration area.

4. The communication apparatus according to claim 1 , wherein
the calculation unit is configured
to compare the logical value of the signal waveform that changes within a period of the specific bit with the logical value of the specific bit detected by the reception unit, and
to determine the sampling point of the communication signal in the high speed state of the communication speed to be a point at which the logical value of the signal waveform matches the logical value of the specific bit.

5. The communication apparatus according to claim 4 , wherein
the calculation unit is configured to determine the sampling point from a plurality of periods in each of which the logical value of the signal waveform matches the logical value of the specific bit.

6. The communication apparatus according to claim 1 , wherein:
the waveform record unit is configured
to specify, based on the communication data decoded in the low speed state of the communication speed by the reception unit, a transmission node having transmitted the communication data, and
to record the signal waveform of the communication signal with respect to the specified transmission node having transmitted the communication data; and

the calculation unit is configured
to specify, based on the communication data decoded in the low speed state of the communication speed by the reception unit, the specified transmission node having transmitted the communication data,
to acquire the signal waveform of the specific bit that has been transmitted from the specified transmission node having transmitted the communication data, the acquired signal waveform being recorded in the waveform record unit, and
to calculate the sampling point for each bit of the communication signal transmitted in the high speed state from the specified transmission node having transmitted the communication data based on the acquired signal waveform and the logical value of the specific bit decoded by the reception unit.

7. The communication apparatus according to claim 6 , wherein
with respect to the specified transmission node having transmitted the communication data,
the waveform record unit is configured
to acquire the signal waveform of the communication signal when the reception unit is receiving the specific bit as a plurality of signal waveforms corresponding to the logical values with respect to respective unit times, the unit time being shorter than a time of one bit in the high speed state of the communication speed, and
to generate and record, based on the acquired plurality of signal waveforms, the signal waveform that is to be used by the calculation unit to calculate the sampling point.

8. The communication apparatus according to claim 7 , wherein
with respect to the specified transmission node having transmitted the communication data,
each time acquiring the signal waveform of the communication signal when the reception unit receives the specific bit,
the waveform record unit is configured
to compare the acquired signal waveform with the signal waveform already recorded as the signal waveform that is to be used by the calculation unit to calculate the sampling point,

wherein, in response to that there is the logical value that does not match in both the acquired signal waveform and the already recorded signal waveform,
the waveform record unit is configured
to determine the logical value not matching to be different from the logical value of the specific bit decoded by the reception unit and
to update the already recorded signal waveform.

9. A communication apparatus in a communication system in which
(i) the communication apparatus is configured to receive a communication data transmitted from each of a plurality of transmission nodes to a transmission path common to the plurality of transmission nodes, the communication data having a frame structure in which an arbitration area is provided before a data area,
(ii) each of the plurality of transmission nodes switches a communication speed between a low speed state in the arbitration area and a high speed state in the data area, and
(iii) in response to the plurality of transmission nodes each starting transmitting the communication data in the arbitration area, a transmission node among the plurality of transmission nodes acquires a transmission right in the arbitration area and the transmission node acquiring the transmission right continues transmitting the communication data,
the communication apparatus comprising:
a computer including one or more processors configured
to sample a communicat

Assignees

• Denso Corp

Inventors

• Kashima Hideki

Classifications

• H04L1/0002

  by adapting the transmission rate · CPC title

• H04L1/0023 Primary

  characterised by the signalling · CPC title

• H04L1/0046

  Code rate detection or code type detection (H04L1/0038 takes precedence; detection of the data rate H04L25/0262; for packet format H04L1/0091) · CPC title

• H04L27/2602 Primary

  Signal structure · CPC title