Data receiving apparatus and data receiving method

1. A data receiving apparatus, comprising:

a measuring section configured to measure a first pulse width of a first pulse, a second pulse width of a second pulse, and a third pulse width of a third pulse, during each of the first pulse, the second pulse, and the third pulse, a first signal level of a reception signal is continuous, wherein the first pulse, the second pulse, and the third pulse are sequentially and continuously received by putting a portion of a second signal level different from the first signal level between the first and second pulse and the second and third pulse;

a first comparing section configured to perform a first determination based on a measured value of the first pulse width and a measured value of the second pulse width, wherein the first determination is that the first pulse indicates a start of the reception signal and the second pulse indicates a synchronization signal;

a second comparing section configured to perform a second determination based on the measured value of the second pulse width and a measured value of the third pulse width, wherein the second determination is that the second pulse and the third pulse indicate the synchronization signal;

a control section configured to determine the second pulse as a head of the synchronization signal, based on the first determination of said first comparing section and the second determination of said second comparing section;

a third comparing section; and

a mean calculating section,

wherein said third measuring section measures a fourth pulse width of a fourth pulse having the first signal level which is continued from the third pulse by interposing a portion of the second signal level,

wherein said third comparing section determines that the second pulse and the fourth pulse are the synchronization signal, based on the measured value of the second pulse width and a measured value of the fourth pulse width, and

wherein said mean calculating section calculates a mean value of the second pulse width, the third pulse width and the fourth pulse width.

2. The data receiving apparatus according to claim 1 , wherein said first comparing section performs the first determination based on a ratio of the measured value of said first pulse width and the measured value of said second pulse width.

3. The data receiving apparatus according to claim 2 , wherein the first determination comprises determining that a ratio of the measured value of the third pulse width to the measured value of the second pulse width is equal to or more than 11.

4. The data receiving apparatus according to claim 1 , wherein said second comparing section performs the second determination based on a difference between the measured value of said second pulse width and the measured value of the third pulse width.

5. The data receiving apparatus according to claim 1 , further comprising a baud rate calculation section configured to calculate a baud rate based on the second pulse width.

6. The data receiving apparatus according to claim 1 , further comprising a baud rate calculating section configured to calculate a baud rate based on the mean value.

7. A data receiving method, comprising:

measuring a first pulse width of a first pulse, a second pulse width of a second pulse, and a third pulse width of a third pulse, during each of the first pulse, the second pulse, and the third pulse, a first signal level of a reception signal being continuous, wherein the first pulse, the second pulse, and the third pulse are sequentially and continuously received by putting a portion of a second signal level different from the first signal level between the first and second pulses and the second and third pulses;

performing a first determination that the first pulse indicates a start of the reception signal and the second pulse indicates a synchronization signal, based on a measured value of the first pulse width and a measured value of the second pulse width;

performing a second determination that the second pulse and the third pulse indicate the synchronization signal, based on the measured value of the second pulse width and a measured value of the third pulse width;

determining the second pulse as a head of the synchronization signal, based on the first and second determinations; and

measuring a fourth pulse width of a fourth pulse having the first signal level which is continued from the third pulse by interposing a portion of the second signal level,

wherein said data receiving method further comprises:

determining that the second pulse and the fourth pulse are the synchronization signal, based on the measured value of the second pulse width and a measured value of the fourth pulse width; and

calculating a mean value of the second pulse width, the third pulse width and the fourth pulse width.

8. The data receiving method according to claim 7 , wherein said performing a first determination comprises performing the first determination based on a ratio of the measured value of the first pulse width and the measured value of the second pulse width.

9. The data receiving method according to claim 7 , wherein said performing a second determination comprises performing the second determination based on an error between the measured value of the second pulse width and the measured value of the third pulse width.

10. The data receiving method according to claim 7 , further comprising calculating a baud rate based on the second pulse width.

11. The data receiving method according to claim 7 , further comprising calculating a baud rate based on the mean value.

12. A tangible, non-transitory computer-readable storage medium in which a computer-executable program code is stored for a data receiving method, said method comprising:

measuring a first pulse width of a first pulse, a second pulse width of a second pulse, and a third pulse width of a third pulse, during each of the first pulse, the second pulse, and the third pulse, a first signal level of a reception signal being continuous, wherein the first pulse, the second pulse, and the third pulse are sequentially and continuously received by putting a portion of a second signal level different from the first signal level between the first and second pulses and the second and third pulses;

performing a first determination that the first pulse indicates a start of the reception signal and the second pulse indicates a synchronization signal, based on a measured value of the first pulse width and a measured value of the second pulse width;

performing a second determination that the second pulse and the third pulse indicate the synchronization signal, based on the measured value of the second pulse width and a measured value of the third pulse width; and

determining the second pulse as a head of the synchronization signal, based on the first and second determinations

wherein said measuring comprises measuring a fourth pulse width of a fourth pulse having the first signal level which is continued from the third pulse by interposing a portion of the second signal level,

wherein said data receiving method further comprises:

determining that the second pulse and the fourth pulse are the synchronization signal, based on the measured value of the second pulse width and a measured value of the fourth pulse width; and

calculating a mean value of the second pulse width, the third pulse width and the fourth pulse width.

13. The tangible, non-transitory computer-readable storage medium according to claim 12 , wherein said performing a first determination comprises performing the first determination based on a ratio of the measured value of the first pulse width and the measured value of the second pulse width.

14. The tangible, non-transitory computer-readable storage medium according to claim 12 , wherein said performing a second determination comprises performing the second determination based on an error between the measured value of the second pulse width and the measured value of the third pulse width.

15. The tangible, non-transitory computer-readable storage medium according to claim 12 , further comprising calculating a baud rate based on the second pulse width.

16. The tangible, non-transitory computer-readable storage medium according to claim 12 , further comprising calculating a baud rate based on the mean value.

17. A data receiving apparatus, comprising:

a measuring section configured to measure a first pulse width of a first pulse, a second pulse width of a second pulse, and a third pulse width of a third pulse, during each of the first pulse, the second pulse, and the third pulse, a first signal level of a reception signal is continuous, wherein the first pulse, the second pulse, and the third pulse are sequentially and continuously received by putting a portion of a second signal level different from the first signal level between the first and second pulse and the second and third pulse;

a first comparing section configured to perform a first determination based on a measured value of the first pulse width and a measured value of the second pulse width, wherein the first determination is that the first pulse indicates a start of the reception signal and the second pulse indicates a synchronization signal;

a second comparing section configured to perform a second determination based on the measured value of the second pulse width and a measured value of the third pulse width, wherein the second determination is that the second pulse and the third pulse indicate the synchronization signal;

a control section configured to determine the second pulse as a head of the synchronization signal, based on the first determination of said first comparing section and the second determination of said second comparing section,

wherein said first comparing section performs the first determination based on a ratio of the measured value of said first pulse width and the measured value of said second pulse width

wherein the first determination comprises determining that a ratio of the measured value of the third pulse width to the measured value of the second pulse width is equal to or more than 11,

wherein said second comparing section performs the second determination based on a difference between the measured value of said second pulse width and the measured value of the third pulse width, and

wherein said difference between the measured value of said second pulse width and the measured value of the third pulse width is within one twentieth of a period of time required to transfer one bit in a synch field.