Timing reproducing device and demodulator

• US 6,683,493 B1
• Filed: 08/23/2001
• Issued: 01/27/2004
• Est. Priority Date: 02/04/2000
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Fujimora, Akinori, Okubo, Seiji, Kojima, Toshiharu
• Primary Examiner(s): KINKEAD, ARNOLD M
• Application Number:
  US09/926,069
• Time in Patent Office: 887 Days
• Field of Search: 329/304, 375/324, 375/326, 375/327, 375/376
• US Class Current: 329/304
• CPC Class Codes: H04L 27/22 Demodulator circuits; Receiver circuits
• CPC Class Codes: H04L 7/04 Speed or phase control by synchronisation signals H04L7/0075 takes precedence
• CPC Class Codes: H04L 7/046 using a dotting sequence

Abstract

In-phase and orthogonal components of a base band signal having a preamble symbol are squared to obtain squared in-phase orthogonal components. Amount of correlation is obtained between the squared in-phase component and a ½ symbol frequency component output from a VCO or an oscillator, and amount of correlation is obtained between the squared orthogonal component and the ½ symbol frequency component. Finally, a phase control signal for carrying out a phase control is generated by using the obtained amount of correlations.

Claims

1. A timing regenerating device comprising:

an in-phase component square calculation unit that receives a base band signal having a preamble symbol, calculates square of an in-phase component of the base band signal and outputs the squared in-phase component;

an in-phase multiplier that multiplies a sign bit (±

1) of the in-phase component of the base band signal to the squared in-phase component and outputs the result as signed squared in-phase component;

an orthogonal component square calculation unit that receives the base band signal, calculates square of an orthogonal component of the base band signal and outputs the squared orthogonal component;

an orthogonal multiplier that multiplies a sign bit (±

1) of the orthogonal component of the base band signal to the squared orthogonal component and outputs the result as a signed squared orthogonal component;

a squared-preamble in-phase correlation calculating unit that calculates a correlation value between the signed squared in-phase component and a ½

symbol frequency component, and outputs the correlation value as an in-phase correlation signal;

a squared-preamble orthogonal correlation calculating unit that calculates a correlation value between the signed squared orthogonal component and the ½

symbol frequency component, and outputs the correlation value as an orthogonal correlation signal;

a vector combination selecting unit that compares the magnitudes of the in-phase and orthogonal correlation signals, matches the direction of a vector obtained from the in-phase or orthogonal correlation signals whichever is smaller to the direction of a vector obtained from the in-phase or orthogonal correlation signals whichever is larger, combines these signals, and outputs a correlation signal after the combination as a combined correlation signal; and

a timing phase difference calculating unit that outputs a phase control signal based on a vector angle shown by the combined correlation signal.

2. A timing regenerating device according to claim 1, further comprising:

a VCO that outputs a regeneration symbol clock, a regeneration sample clock, and the ½

symbol frequency component, based on the phase control signal, wherein

the base band signal to be input into the in-phase component square calculation unit and the orthogonal component square calculation unit is a signal that has been sampled based on the regeneration sample clock,

said squared-preamble in-phase correlation calculating unit calculates the correlation value using the ½

symbol frequency component output from said VCO, and

said squared-preamble orthogonal correlation calculating unit calculates the correlation value using the ½

symbol frequency component output from said VCO.

3. A timing regenerating device according to claim 2, further comprising:

a phase detecting unit that detects advancement/delay of a timing phase using the base band signal sampled based on the regeneration sample clock, and outputs detected signals as phase detection signals; and

a phase detection signal averaging unit that calculates an average of the phase detection signals, and outputs the average as a phase advance/delay signal, wherein

said VCO outputs the regeneration symbol clock, the regeneration sample clock, and the ½

symbol frequency component, based on the phase control signal and the phase advance/delay signal.

4. A timing regenerating device according to claim 1, further comprising:

an oscillator that outputs an asynchronous sample clock and the ½

symbol frequency component, wherein

the base band signal to be input into said in-phase component square calculation unit and said orthogonal component square calculation unit is a signal that has been sampled based on the asynchronous sample clock,

said squared-preamble in-phase correlation calculating unit calculates the correlation value using the ½

symbol frequency component output from said oscillator, and

said squared-preamble orthogonal correlation calculating unit calculates the correlation value using the ½

symbol frequency component output from said oscillator.

5. A timing regenerating device according to claim 1, wherein said timing phase difference calculating unit calculates a timing phase difference from a square root of the in-phase component and the vector angle of a square root of the orthogonal component of the combined correlation signal.

6. A timing regenerating device according to claim 1, further comprising:

a clip detecting unit configured to receive digitally sampled in-phase and quadrature components of the base band signal having a preamble symbol, and either converts both the in-phase and orthogonal components of the base band signal into “

0”

when at least one value of the in-phase and orthogonal components of the base band signal is outside a predetermined range or outputs the received, digitally sampled in-phase and quadrature components of the base band signal without alteration when all values of the in-phase and orthogonal components of the base band signal are within the predetermined range, wherein

the base band signal to be input into said in-phase component square calculation unit and into said orthogonal component square calculation unit is the base band signal output of said clip detecting unit.

7. A timing regenerating device comprising:

an in-phase component square calculation unit that receives a base band signal having a preamble symbol, calculates square of an in-phase component of the base band signal and outputs the squared in-phase component;

an in-phase multiplier that multiplies a sign bit (±

1) of the in-phase component of the base band signal to the squared in-phase component and outputs the result as signed squared in-phase component;

an orthogonal component square calculation unit that receives the base band signal, calculates square of an orthogonal component of the base band signal and outputs the squared orthogonal component;

an orthogonal multiplier that multiplies a sign bit (±

1) of the orthogonal component of the base band signal to the squared orthogonal component and outputs the result as a signed squared orthogonal component;

a squared-preamble in-phase correlation calculating unit that calculates a correlation value between the signed squared in-phase component and a ½

symbol frequency component, and outputs the correlation value as an in-phase correlation signal;

a squared-preamble orthogonal correlation calculating unit that calculates a correlation value between the signed squared orthogonal component and the ½

symbol frequency component, and outputs the correlation value as an orthogonal correlation signal;

a vector combination selecting unit that compares the magnitudes of the in-phase and orthogonal correlation signals, matches the direction of a vector obtained from the in-phase or orthogonal correlation signals whichever is smaller to the direction of a vector obtained from the in-phase or orthogonal correlation signals whichever is larger, combines these signals, and outputs a correlation signal after the combination as a combined correlation signal; and

a preamble detecting/timing phase difference calculating unit that calculates a vector angle and a vector length of the combined correlation signal, decides that the preamble symbol has been detected when the vector length is larger than a predetermined threshold value, calculates a timing phase difference using a vector angle shown by the combined correlation signal at that time, and outputs a phase control signal.

8. A timing regenerating device according to claim 7, further comprising:

a VCO that outputs a regeneration symbol clock, a regeneration sample clock, and the ½

symbol frequency component, based on the phase control signal, wherein

the base band signal to be input into the in-phase component square calculation unit and the orthogonal component square calculation unit is a signal that has been sampled based on the regeneration sample clock,

said squared-preamble in-phase correlation calculating unit calculates the correlation value using the ½

symbol frequency component output from said VCO, and

said squared-preamble orthogonal correlation calculating unit calculates correlation value using the ½

symbol frequency component output from said VCO.

9. A timing regenerating device according to claim 8, further comprising:

a phase detecting unit that detects advancement/delay of a timing phase using the base band signal sampled based on the regeneration sample clock, and outputs detected signals as phase detection signals; and

a phase detection signal averaging unit that calculates an average of the phase detection signals, and outputs the average as a phase advance/delay signal, wherein

said VCO outputs the regeneration symbol clock, the regeneration sample clock, and the ½

symbol frequency component, based on the phase control signal and the phase advance/delay signal.

10. A timing regenerating device according to claim 7, further comprising:

an oscillator that outputs an asynchronous sample clock and the ½

symbol frequency component, wherein

the base band signal to be input into said in-phase component square calculation unit and said orthogonal component square calculation unit is a signal that has been sampled based on the asynchronous sample clock,

said squared-preamble in-phase correlation calculating unit calculates the correlation value using the ½

symbol frequency component output from said oscillator, and

said squared-preamble orthogonal correlation calculating unit calculates the correlation value using the ½

symbol frequency component output from said oscillator.

11. A timing regenerating device according to claim 7, wherein said preamble detecting/timing phase difference calculating unit calculates a timing phase difference from a vector angle shown by a value obtained by multiplying a sign {±

1} of the in-phase component to a square root of an absolute value of an in-phase component of a combined correlation signal and a value obtained by multiplying a sign {±

1} of the orthogonal component to a square root of an absolute value of an orthogonal component of the combined correlation signal.

12. A timing regenerating device according to claim 7, further comprising:

a clip detecting unit configured to receive digitally sampled in-phase and quadrature components of the base band signal having a preamble symbol, and either converts both the in-phase and orthogonal components of the base band signal into “

0”

when at least one value of the in-phase and orthogonal components of the base band signal is outside a predetermined range or outputs the received, digitally sampled in-phase and quadrature comnponents of the base band signal without alteration when all values of the in-phase and orthogonal components of the base band signal are within the predetermined range, wherein

the base band signal to be input into said in-phase component square calculation unit and into said orthogonal component square calculation unit is the base band signal output of said clip detecting unit.

13. A timing regenerating device comprising:

an in-phase component square calculation unit that receives a base band signal having a preamble symbol, calculates square of an in-phase component of the base band signal and outputs the squared in-phase component;

an in-phase multiplier that multiplies a sign bit (±

1) of the in-phase component of the base band signal to the squared in-phase component and outputs the result as signed squared in-phase component;

an orthogonal component square calculation unit that receives the base band signal, calculates square of an orthogonal component of the base band signal and outputs the squared orthogonal component;

an orthogonal multiplier that multiplies a sign bit (±

1) of the orthogonal component of the base band signal to the squared orthogonal component and outputs the result as a signed squared orthogonal component;

an adder that adds the signed squared in-phase and orthogonal components to generate a squared addition signal, and outputs the squared addition signal;

a subtracter that subtracts the signed squared in-phase component from the signed squared orthogonal component or vice versa to generate a squared subtraction signal, and outputs the squared subtraction signal;

a squared-addition signal component correlation calculating unit that calculates a correlation value between the squared addition signal and a ½

symbol frequency component, and outputs this correlation value as an addition correlation signal;

a squared-subtraction signal component correlation calculating unit that calculates a correlation value between the squared subtraction signal and the ½

symbol frequency component, and outputs this correlation value as a subtraction correlation signal;

a vector selecting unit that compares the magnitudes of the addition and subtraction correlation signals, selects the addition correlation signal or the subtraction correlation signal whichever is larger, and outputs this signal as a selected correlation signal; and

a timing phase difference calculating unit that outputs a phase control signal based on a vector angle shown by the selected correlation signal.

14. A timing regenerating device according to claim 13, further comprising:

a VCO that outputs a regeneration symbol clock, a regeneration sample clock, and the ½

symbol frequency component, based on the phase control signal, wherein

the base band signal to be input into the in-phase component square calculation unit and the orthogonal component square calculation unit is a signal that has been sampled based on the regeneration sample clock,

said squared-addition signal component correlation calculating unit calculates the correlation value using the ½

symbol frequency component output from said VCO, and

said squared-subtraction signal component correlation calculating unit calculates the correlation value using the ½

symbol frequency component output from said VCO.

15. A timing regenerating device according to claim 14, further comprising:

a phase detecting unit that detects advancement/delay of a timing phase using the base band signal sampled based on the regeneration sample clock, and outputs detected signals as phase detection signals; and

a phase detection signal averaging unit that calculates an average of the phase detection signals, and outputs the average as a phase advance/delay signal, wherein

said VCO outputs the regeneration symbol clock, the regeneration sample clock, and the ½

symbol frequency component, based on the phase control signal and the phase advance/delay signal.

16. A timing regenerating device according to claim 13, further comprising:

an oscillator that outputs an asynchronous sample clock and the ½

symbol frequency component, wherein

the base band signal to be input into said in-phase component square calculation unit and said orthogonal component square calculation unit is a signal that has been sampled based on the asynchronous sample clock,

said squared-addition signal component correlation calculating unit calculates correlation value using the ½

symbol frequency component output from said oscillator, and

said squared-subtraction signal component correlation calculating unit calculates correlation value using the ½

symbol frequency component output from said oscillator.

17. A timing regenerating device according to claim 13, wherein said adder adds the signed squared in-phase and orthogonal components to obtain a result as a squared addition signal, and the subtracter subtracts the signed squared in-phase component from the signed squared orthogonal component or vice versa, and obtains a result as a squared subtraction signal.

18. A timing regenerating device according to claim 13, wherein said adder adds the signed squared in-phase and orthogonal components and, multiplies a sign {±

1} of this sum to a square root of an absolute value of the sum, thereby to obtain a squared addition signal, and the subtracter subtracts the signed squared in-phase component from the signed squared orthogonal component or vice versa, and multiplies a sign {±

1} of this difference to a square root of an absolute value of the difference, thereby to obtain a squared subtraction signal.

19. A timing regenerating device according to claim 13, further comprising:

a clip detecting unit configured to receive digitally sampled in-phase and quadrature components of the base band signal having the preamble symbol, and either converts both the in-phase and orthogonal components of the base band signal into “

0”

when at least one value of the in-phase and orthogonal components of the base band signal is outside a predetermined range or outputs the received, digitally sampled in-phase and quadrature components of the base band signal without alteration when all values of the in-phase and orthogonal components of the base band signal are within the predetermined range, wherein

the base band signal to be input into said in-phase component square calculation unit and into said orthogonal component square calculation unit is the base band signal output of said clip detecting unit.

20. A timing regenerating device comprising:

an in-phase component square calculation unit that receives a base band signal having a preamble symbol, calculates square of an in-phase component of the base band signal and outputs the squared in-phase component;

an in-phase multiplier that multiplies a sign bit (±

1) of the in-phase component of the base band signal to the squared in-phase component and outputs the result as signed squared in-phase component;

an orthogonal component square calculation unit that receives the base band signal, calculates square of an orthogonal component of the base band signal and outputs the squared orthogonal component;

an orthogonal multiplier that multiplies a sign bit (±

1) of the orthogonal component of the base band signal to the squared orthogonal component and outputs the result as a signed squared orthogonal component;

an adder that adds the signed squared in-phase and orthogonal components and generates a squared addition signal, and outputs the squared addition signal;

a subtracter that subtracts the signed squared in-phase component from the signed squared orthogonal component or vice versa and generates a squared subtraction signal, and outputs the squared subtraction signal;

a squared-addition signal component correlation calculating unit that calculates a correlation value between the squared addition signal and a ½

symbol frequency component, and outputs this correlation value as an addition correlation signal;

a squared-subtraction signal component correlation calculating unit that calculates a correlation value between the squared subtraction signal and the ½

symbol frequency component, and outputs this correlation value as a subtraction correlation signal;

a vector selecting unit that compares the magnitude of the addition correlation signal with the magnitude of the subtraction correlation signal, selects the addition correlation signal or the subtraction correlation signal whichever is larger, and outputs this signal as a selected correlation signal; and

a preamble detecting/timing phase difference calculating unit that calculates a vector angle and a vector length of the selected correlation signal, decides that the preamble symbol has been detected when the vector length is larger than a predetermined threshold value, calculates a timing phase difference using a vector angle shown by the selected correlation signal at that time, and outputs a phase control signal.

21. A timing regenerating device according to claim 20, further comprising:

a VCO that outputs a regeneration symbol clock, a regeneration sample clock, and the ½

symbol frequency component, based on the phase control signal, wherein

the base band signal to be input into said in-phase component square calculation unit and said orthogonal component square calculation unit is a signal that has been sampled based on the regeneration sample clock,

said squared-addition signal component correlation calculating unit calculates the correlation value using the ½

symbol frequency component output from said VCO, and

said squared-subtraction signal component correlation calculating unit calculates the correlation value using the ½

symbol frequency component output from said VCO.

22. A timing regenerating device according to claim 21, further comprising:

a phase detecting unit that detects advancement/delay of a timing phase using the base band signal sampled based on the regeneration sample clock, and outputs detected signals as phase detection signals; and

a phase detection signal averaging unit that calculates an average of the phase detection signals, and outputs the average as a phase advance/delay signal, wherein

said VCO outputs the regeneration symbol clock, the regeneration sample clock, and the ½

symbol frequency component, based on both the phase control signal and the phase advance/delay signal.

23. A timing regenerating device according to claim 20, further comprising:

an oscillator that outputs an asynchronous sample clock and the ½

symbol frequency component, wherein

the base band signal to be input into said in-phase component square calculation unit and said orthogonal component square calculation unit is a signal that has been sampled based on the asynchronous sample clock,

said squared-addition signal component correlation calculating unit calculates the correlation value using the ½

symbol frequency component output from said oscillator, and

said squared-subtraction signal component correlation calculating unit calculates the correlation value using the ½

symbol frequency component output from said oscillator.

24. A timing regenerating device according to claim 20, wherein said adder adds the signed squared in-phase and orthogonal components to obtain the squared addition signal, and the subtracter subtracts the signed squared in-phase component from the signed squared orthogonal component or vice versa to obtain the squared subtraction signal.

25. A timing regenerating device according to claim 20, wherein said adder adds the signed squared in-phase and orthogonal components, multiplies a sign {±

1} of this sum to a square root of an absolute value of the sum, thereby to obtain the squared addition signal, and

the subtracter subtracts the signed squared in-phase component from the signed squared orthogonal component or vice versa, multiplies a sign {±

1} of this difference to a square root of an absolute value of the difference, thereby to obtain the squared subtraction signal.

26. A timing regenerating device according to claim 20, further comprising:

a clip detecting unit configured to receive digitally sampled in-phase and quadrature components of the base band signal having the preamble symbol, and either converts both the in-phase and orthogonal components of the base band signal into “

0”

when at least one value of the in-phase and orthogonal components of the base band signal is outside a predetermined range or outputs the received, digitally sampled in-phase and quadrature components of the base band signal without alterations when all values of the in-phase and orthogonal components of the base band signal are within the predetermined range, wherein

the base band signal to be input into said in-phase component square calculation unit and into said orthogonal component square calculation unit is the base band signal output of said clip detecting unit.

27. A timing regenerating device comprising:

an in-phase component square calculation unit that receives a base band signal having a preamble symbol, calculates square of an in-phase component of the base band signal and outputs the squared in-phase component;

an in-phase multiplier that multiplies a sign bit (±

1) of the in-phase component of the base band signal to the squared in-phase component and outputs the result as signed squared in-phase component;

an orthogonal component square calculation unit that receives the base band signal, calculates square of an orthogonal component of the base band signal and outputs the squared orthogonal component;

an orthogonal multiplier that multiplies a sign bit (±

1) of the orthogonal component of the base band signal to the squared orthogonal component and outputs the result as a signed squared orthogonal component;

an adder that adds the signed squared in-phase and orthogonal components to obtain a squared addition signal, and outputs the squared addition signal;

a subtracter that subtracts the signed squared in-phase component from the signed squared orthogonal component or vice versa to obtain a squared subtraction signal, and outputs the squared subtraction signal;

a squared-addition signal component correlation calculating unit that calculates a correlation value between the squared addition signal and a ½

symbol frequency component, and outputs this correlation value as an addition correlation signal;

a squared-subtraction signal component correlation calculating unit that calculates a correlation value between the squared subtraction signal and the ½

symbol frequency component, and outputs this correlation value as a subtraction correlation signal;

a vector selecting unit that compares the magnitudes of the addition and subtraction correlation signals, selects the addition correlation signal or the subtraction correlation signal whichever is larger, and outputs this signal as a selected correlation signal;

a weighting unit that gives a weight corresponding to a vector length shown by the selected correlation signal to the selected correlation signal, and outputs the weighted correlation signal;

an averaging unit that doubles the weighted correlation, calculates an average of the signals, and outputs this average as a weighted average correlation signal; and

a timing phase difference calculating unit that outputs a phase control signal based on a vector angle shown by the weighted average correlation signal.

28. A timing regenerating device according to claim 27, further comprising:

a VCO that outputs a regeneration symbol clock, a regeneration sample clock, and the ½

symbol frequency component, based on the phase control signal, wherein

the base band signal to be input into said in-phase component square calculation unit and said orthogonal component square calculation unit is a signal that has been sampled based on the regeneration sample clock,

said squared-addition signal component correlation calculating unit calculates the correlation value using the ½

symbol frequency component output from said VCO, and

said squared-subtraction signal component correlation calculating unit calculates correlation value using the ½

symbol frequency component output from said VCO.

29. A timing regenerating device according to claim 27, further comprising:

an oscillator that outputs an asynchronous sample clock and the ½

symbol frequency component, wherein

the base band signal to be input into said in-phase component square calculation unit and said orthogonal component square calculation unit is a signal that has been sampled by the asynchronous sample clock,

said squared-addition signal component correlation calculating unit calculates the correlation value using the ½

symbol frequency component output from said oscillator, and

said squared-subtraction signal component correlation calculating unit calculates the correlation value using the ½

symbol frequency component output from said oscillator.

30. A timing regenerating device according to claim 27, wherein said adder adds the signed squared in-phase and orthogonal components to obtain the squared addition signal, and the subtracter subtracts the signed squared in-phase component from the signed squared orthogonal component or vice versa to obtain the squared subtraction signal.

31. A timing regenerating device according to claim 27, wherein said adder adds the signed squared in-phase and orthogonal components and, multiplies a sign {±

1} of this sum to a square root of an absolute value of the sum, thereby to obtain the squared addition signal, and the subtracter subtracts the signed squared in-phase component from the signed squared orthogonal component or vice versa, and multiplies a sign {±

1} of this difference to a square root of an absolute value of the difference, thereby to obtain the squared subtraction signal.

32. A timing regenerating device according to claim 27, wherein

when the in-phase component of a weighted correlation signal is negative, said averaging unit inverts the signs of the in-phase and orthogonal components of the weighted correlation signal respectively, and generates a correlation signal with the inverted signs as a first correlation signal,

when the in-phase component of the weighted correlation signal is positive, said averaging unit generates this weighted correlation signal as a first correlation signal,

when the orthogonal component of the weighted correlation signal is negative, said averaging unit inverts the signs of the in-phase and orthogonal components of the weighted correlation signal respectively, and generates a correlation signal with the inverted signs as a second correlation signal,

when the orthogonal component of the weighted correlation signal is positive, said averaging unit generates this weighted correlation signal as a second correlation signal, and

said averaging unit calculates averages of the first and second correlation signals respectively, and when the vector length of the averaged first correlation signal is larger than the vector length of the averaged second correlation signal, said averaging unit outputs the averaged first correlation signal as the weighted average correlation signal, and when the vector length of the averaged second correlation signal is larger than the vector length of the averaged first correlation signal, said averaging unit outputs the averaged second correlation signal as the weighted average correlation signal.

33. A timing regenerating device according to claim 27, further comprising:

a clip detecting unit configured to receive digitally sampled in-phase and quadrature components of the base band signal having the preamble symbol, and either converts both the in-phase and orthogonal components of the base band signal into “

0”

when at least one value of the in-phase and orthogonal components of the base band signal is outside a predetermined range or outputs the received, digitally sampled in-phase and quadrature comnponents of the base band signal straight when at least one value of the in-phase and orthogonal components of the base band signal are within the predetermined range, wherein

the base band signal input into said in-phase component square calculation unit and into said orthogonal component square calculation unit is the base band signal output of said clip detecting unit.

34. A demodulator comprising:

an antenna that receives a radio signal;

a frequency converting unit that converts the frequency of the received radio signal into the frequency of a base band signal;

an A/D converting unit that converts the base band signal into a digital base band signal based on a sampling at two times a symbol rate using a regeneration sample clock;

a timing regenerating device including;

an in-phase component square calculation unit that receives a base band signal having a preamble symbol, calculates square of an in-phase component of the base band signal and outputs the squared in-phase component;

an in-phase multiplier that multiplies a sign bit (±

1) of the in-phase component of the base band signal to the squared in-phase component and outputs the result as signed squared in-phase component;

an orthogonal component square calculation unit that receives the base band signal, calculates square of an orthogonal component of the base band signal and outputs the squared orthogonal component;

an orthogonal multiplier that multiplies a sign bit (±

1) of the orthogonal component of the base band signal to the squared orthogonal component and outputs the result as a signed squared orthogonal component;

a squared-preamble in-phase correlation calculating unit that calculates a correlation value between the signed squared in-phase component and a ½

symbol frequency component, and outputs the correlation value as an in-phase correlation signal;

a squared-preamble orthogonal correlation calculating unit that calculates a correlation value between the signed squared orthogonal component and the ½

symbol frequency component, and outputs the correlation value as an orthogonal correlation signal;

a vector combination selecting unit that compares the magnitudes of the in-phase and orthogonal correlation signals, matches the direction of a vector obtained from the in-phase or orthogonal correlation signals whichever is smaller to the direction of a vector obtained from the in-phase or orthogonal correlation signals whichever is larger, combines these signals, and outputs a correlation signal after the combination as a combined correlation signal;

a timing phase difference calculating unit that outputs a phase control signal from a vector angle shown by the combined correlation signal;

a VCO that outputs a regeneration symbol clock, a regeneration sample clock, and the ½

symbol frequency component, based on the phase control signal, wherein

the base band signal to be input into the in-phase component square calculation unit and the orthogonal component square calculation unit is a signal that has been sampled based on the regeneration sample clock,

said squared-preamble in-phase correlation calculating unit calculates the correlation value using the ½

symbol frequency component output from said VCO, and

said squared-preamble orthogonal correlation calculating unit calculates the correlation value using the ½

symbol frequency component output from said VCO;

a phase detecting unit that detects advancement/delay of a timing phase using the base band signal sampled based on the regeneration sample clock, and outputs detected signals as phase detection signals;

a phase detection signal averaging unit that calculates an average of the phase detection signals, and outputs the average as a phase advance/delay signal, wherein

said VCO outputs the regeneration symbol clock, the regeneration sample clock, and the ½

symbol frequency component, based on the phase control signal and the phase advance/delay signal; and

a data deciding unit that extracts Nyquist point data from the digital base band signal using the regeneration symbol clock, decides the extracted Nyquist point data, and outputs the data as demodulated data.

35. A demodulator comprising:

an antenna that receives a radio signal;

a frequency converting unit that converts the frequency of the received radio signal into the frequency of a base band signal;

an A/D converting unit that converts the base band signal into a digital base band signal based on a sampling at two times a symbol rate using a regeneration sample clock;

a timing regenerating device including;

an in-phase component square calculation unit that receives a base band signal having a preamble symbol, calculates square of an in-phase component of the base band signal and outputs the squared in-phase component;

an in-phase multiplier that multiplies a sign bit (±

1) of the in-phase component of the base band signal to the squared in-phase component and outputs the result as signed squared in-phase component;

an orthogonal component square calculation unit that receives the base band signal, calculates square of an orthogonal component of the base band signal and outputs the squared orthogonal component;

an orthogonal multiplier that multiplies a sign bit (±

1) of the orthogonal component of the base band signal to the squared orthogonal component and outputs the result as a signed squared orthogonal component;

a squared-preamble in-phase correlation calculating unit that calculates a correlation value between the signed squared in-phase component and a ½

symbol frequency component, and outputs the correlation value as an in-phase correlation signal;

a squared-preamble orthogonal correlation calculating unit that calculates a correlation value between the signed squared orthogonal component and the ½

symbol frequency component, and outputs the correlation value as an orthogonal correlation signal;

a vector combination selecting unit that compares the magnitudes of the in-phase and orthogonal correlation signals, matches the direction of a vector obtained from the in-phase or orthogonal correlation signals whichever is smaller to the direction of a vector obtained from the in-phase or orthogonal correlation signals whichever is larger, combines these signals, and outputs a correlation signal after the combination as a combined correlation signal;

a timing phase difference calculating unit that outputs a phase control signal from a vector angle shown by the combined correlation signal;

an oscillator that outputs an asynchronous sample clock and the ½

symbol frequency component, wherein

the base band signal to be input into said in-phase component square calculation unit and said orthogonal component square calculation unit is a signal that has been sampled based on the asynchronous sample clock,

said squared-preamble in-phase correlation calculating unit calculates the correlation value using the ½

symbol frequency component output from said oscillator,

said squared-preamble orthogonal correlation calculating unit calculates the correlation value using the ½

symbol frequency component output from said oscillator; and

a data deciding unit that extracts Nyquist point data from the digital base band signal using the regeneration symbol clock, decides the extracted Nyquist point data, and outputs the data as demodulated data.

36. A demodulator comprising:

an antenna that receives a radio signal;

a frequency converting unit that converts the frequency of the received radio signal into the frequency of a base band signal;

an A/D converting unit that converts the base band signal into a digital base band signal based on a sampling at two times a symbol rate using a regeneration sample clock;

a timing regenerating device including;

an in-phase component square calculation unit that receives a base band signal having a preamble symbol, calculates square of an in-phase component of the base band signal and outputs the squared in-phase component;

an in-phase multiplier that multiplies a sign bit (±

1) of the in-phase component of the base band signal to the squared in-phase component and outputs the result as signed squared in-phase component;

an orthogonal component square calculation unit that receives the base band signal, calculates square of an orthogonal component of the base band signal and outputs the squared orthogonal component;

an orthogonal multiplier that multiplies a sign bit (±

1) of the orthogonal component of the base band signal to the squared orthogonal component and outputs the result as a signed squared orthogonal component;

a squared-preamble in-phase correlation calculating unit that calculates a correlation value between the signed squared in-phase component and a ½

symbol frequency component, and outputs the correlation value as an in-phase correlation signal;

a squared-preamble orthogonal correlation calculating unit that calculates a correlation value between the signed squared orthogonal component and the ½

symbol frequency component, and outputs the correlation value as an orthogonal correlation signal;

a vector combination selecting unit that compares the magnitudes of the in-phase and orthogonal correlation signals, matches the direction of a vector obtained from the in-phase or orthogonal correlation signals whichever is smaller to the direction of a vector obtained from the in-phase or orthogonal correlation signals whichever is larger, combines these signals, and outputs a correlation signal after the combination as a combined correlation signal;

a preamble detecting/timing phase difference calculating unit that calculates a vector angle and a vector length of the combined correlation signal, decides that the preamble symbol has been detected when the vector length is larger than a predetermined threshold value, calculates a timing phase difference using a vector angle shown by the combined correlation signal at that time, and outputs a phase control signal;

an oscillator that outputs an asynchronous sample clock and the ½

symbol frequency component, wherein

the base band signal to be input into said in-phase component square calculation unit and said orthogonal component square calculation unit is a signal that has been sampled based on the asynchronous sample clock,

said squared-preamble in-phase correlation calculating unit calculates the correlation value using the ½

symbol frequency component output from said oscillator,

said squared-preamble orthogonal correlation calculating unit calculates the correlation value using the ½

symbol frequency component output from said oscillator; and

a data deciding unit that extracts Nyquist point data from the digital base band signal using the regeneration symbol clock, decides the extracted Nyquist point data, and outputs the data as demodulated data.

37. A demodulator comprising:

an antenna that receives a radio signal;

a frequency converting unit that converts the frequency of the received radio signal into the frequency of a base band signal;

an A/D converting unit that converts the base band signal into a digital base band signal based on a sampling at two times a symbol rate using a regeneration sample clock;

a timing regenerating device including;

an in-phase component square calculation unit that receives a base band signal having a preamble symbol, calculates square of an in-phase component of the base band signal and outputs the squared in-phase component;

an in-phase multiplier that multiplies a sign bit (±

1) of the in-phase component of the base band signal to the squared in-phase component and outputs the result as signed squared in-phase component;

an orthogonal component square calculation unit that receives the base band signal, calculates square of an orthogonal component of the base band signal and outputs the squared orthogonal component;

an orthogonal multiplier that multiplies a sign bit (±

1) of the orthogonal component of the base band signal to the squared orthogonal component and outputs the result as a signed squared orthogonal component;

a squared-preamble in-phase correlation calculating unit that calculates a correlation value between the signed squared in-phase component and a ½

symbol frequency component, and outputs the correlation value as an in-phase correlation signal;

a squared-preamble orthogonal correlation calculating unit that calculates a correlation value between the signed squared orthogonal component and the ½

symbol frequency component, and outputs the correlation value as an orthogonal correlation signal;

a vector combination selecting unit that compares the magnitudes of the in-phase and orthogonal correlation signals, matches the direction of a vector obtained from the in-phase or orthogonal correlation signals whichever is smaller to the direction of a vector obtained from the in-phase or orthogonal correlation signals whichever is larger, combines these signals, and outputs a correlation signal after the combination as a combined correlation signal;

a preamble detecting/timing phase difference calculating unit that calculates a vector angle and a vector length of the combined correlation signal, decides that the preamble symbol has been detected when the vector length is larger than a predetermined threshold value, calculates a timing phase difference using a vector angle shown by the combined correlation signal at that time, and outputs a phase control signal;

wherein said preamble detecting/timing phase difference calculating unit calculates a timing phase difference from a vector angle shown by a value obtained by multiplying a sign {±

1} of the in-phase component to a square root of an absolute value of an in-phase component of a combined correlation signal and a value obtained by multiplying a sign {±

1} of the orthogonal component to a square root of an absolute value of an orthogonal component of the combined correlation signal; and

a data deciding unit that extracts Nyquist point data from the digital base band signal using the regeneration symbol clock, decides the extracted Nyquist point data, and outputs the data as demodulated data.

38. A demodulator comprising:

an antenna that receives a radio signal;

a frequency converting unit that converts the frequency of the received radio signal into the frequency of a base band signal;

an A/D converting unit that converts the base band signal into a digital base band signal based on a sampling at two times a symbol rate using a regeneration sample clock;

a timing regenerating device including;

an in-phase component square calculation unit that receives a base band signal having a preamble symbol, calculates square of an in-phase component of the base band signal and outputs the squared in-phase component;

an in-phase multiplier that multiplies a sign bit (±

1) of the in-phase component of the base band signal to the squared in-phase component and outputs the result as signed squared in-phase component;

an orthogonal component square calculation unit that receives the base band signal, calculates square of an orthogonal component of the base band signal and outputs the squared orthogonal component;

an orthogonal multiplier that multiplies a sign bit (±

1) of the orthogonal component of the base band signal to the squared orthogonal component and outputs the result as a signed squared orthogonal component;

an adder that adds the signed squared in-phase and orthogonal components to generate a squared addition signal, and outputs the squared addition signal;

a subtracter that subtracts the signed squared in-phase component from the signed squared orthogonal component or vice versa to generate a squared subtraction signal, and outputs the squared subtraction signal;

a squared-addition signal component correlation calculating unit that calculates a correlation value between the squared addition signal and a ½

symbol frequency component, and outputs this correlation value as an addition correlation signal;

a squared-subtraction signal component correlation calculating unit that calculates a correlation value between the squared subtraction signal and the ½

symbol frequency component, and outputs this correlation value as a subtraction correlation signal;

a vector selecting unit that compares the magnitudes of the addition and subtraction correlation signals, selects the addition correlation signal or the subtraction correlation signal whichever is larger, and outputs this signal as a selected correlation signal;

a timing phase difference calculating unit that outputs a phase control signal from a vector angle shown by the selected correlation signal;

a VCO that outputs a regeneration symbol clock, a regeneration sample clock, and the ½

symbol frequency component, based on the phase control signal, wherein

the base band signal to be input into the in-phase component square calculation unit and the orthogonal component square calculation unit is a signal that has been sampled based on the regeneration sample clock,

said squared-addition signal component correlation calculating unit calculates the correlation value using the ½

symbol frequency component output from said VCO,

said squared-subtraction signal component correlation calculating unit calculates the correlation value using the ½

symbol frequency component output from said VCO; and

a data deciding unit that extracts Nyquist point data from the digital base band signal using the regeneration symbol clock, decides the extracted Nyquist point data, and outputs the data as demodulated data.

39. A demodulator comprising:

an antenna that receives a radio signal;

a frequency converting unit that converts the frequency of the received radio signal into the frequency of a base band signal;

an A/D converting unit that converts the base band signal into a digital base band signal based on a sampling at two times a symbol rate using an asynchronous sample clock;

a timing regenerating device including;

an in-phase component square calculation unit that receives a base band signal having a preamble symbol, calculates square of an in-phase component of the base band signal and outputs the squared in-phase component;

an in-phase multiplier that multiplies a sign bit (±

1) of the in-phase component of the base band signal to the squared in-phase component and outputs the result as signed squared in-phase component;

an orthogonal component square calculation unit that receives the base band signal, calculates square of an orthogonal component of the base band signal and outputs the squared orthogonal component;

an orthogonal multiplier that multiplies a sign bit (±

1) of the orthogonal component of the base band signal to the squared orthogonal component and outputs the result as a signed squared orthogonal component;

a squared-preamble in-phase correlation calculating unit that calculates a correlation value between the signed squared in-phase component and a ½

symbol frequency component, and outputs the correlation value as an in-phase correlation signal;

a squared-preamble orthogonal correlation calculating unit that calculates a correlation value between the signed squared orthogonal component and the ½

symbol frequency component, and outputs the correlation value as an orthogonal correlation signal;

a vector combination selecting unit that compares the magnitudes of the in-phase and orthogonal correlation signals, matches the direction of a vector obtained from the in-phase or orthogonal correlation signals whichever is smaller to the direction of a vector obtained from the in-phase or orthogonal correlation signals whichever is larger, combines these signals, and outputs a correlation signal after the combination as a combined correlation signal;

a timing phase difference calculating unit that outputs a phase control signal from a vector angle shown by the combined correlation signal;

wherein said timing phase difference calculating unit calculates a timing phase difference from a square root of the in-phase component and the vector angle of a square root of the orthogonal component of the combined correlation signal;

a data interpolating unit that interpolates the digital base band signal that has been sampled by the asynchronous sample clock, and outputs the interpolated data as an interpolated base band signal; and

a data deciding unit that extracts a Nyquist point of the interpolated base band signal based on a phase control signal, decides data at the extracted Nyquist point, and outputs the data as demodulated data.

40. A demodulator comprising:

an antenna that receives a radio signal;

a frequency converting unit that converts the frequency of the received radio signal into the frequency of a base band signal;

an A/D converting unit that converts the base band signal into a digital base band signal based on a sampling at two times a symbol rate using the asynchronous sample clock;

a timing regenerating device including;

an in-phase component square calculation unit that receives a base band signal having a preamble symbol, calculates square of an in-phase component of the base band signal and outputs the squared in-phase component;

an in-phase multiplier that multiplies a sign bit (±

1) of the in-phase component of the base band signal to the squared in-phase component and outputs the result as signed squared in-phase component;

an orthogonal component square calculation unit that receives the base band signal, calculates square of an orthogonal component of the base band signal and outputs the squared orthogonal component;

an orthogonal multiplier that multiplies a sign bit (±

1) of the orthogonal component of the base band signal to the squared orthogonal component and outputs the result as a signed squared orthogonal component;

a squared-preamble in-phase correlation calculating unit that calculates a correlation value between the signed squared in-phase component and a ½

symbol frequency component, and outputs the correlation value as an in-phase correlation signal;

a squared-preamble orthogonal correlation calculating unit that calculates a correlation value between the signed squared orthogonal component and the ½

symbol frequency component, and outputs the correlation value as an orthogonal correlation signal;

a vector combination selecting unit that compares the magnitudes of the in-phase and orthogonal correlation signals, matches the direction of a vector obtained from the in-phase or orthogonal correlation signals whichever is smaller to the direction of a vector obtained from the in-phase or orthogonal correlation signals whichever is larger, combines these signals, and outputs a correlation signal after the combination as a combined correlation signal;

a preamble detecting/timing phase difference calculating unit that calculates a vector angle and a vector length of the combined correlation signal, decides that the preamble symbol has been detected when the vector length is larger than a predetermined threshold value, calculates a timing phase difference using a vector angle shown by the combined correlation signal at that time, and outputs a phase control signal;

a clip detecting unit that receives the base band signal having a preamble symbol, converts both the in-phase and orthogonal components of the base band signal into “

0”

when at least one value of the in-phase and orthogonal components of the base band signal is outside a predetermined range, and outputs the base band signal straight when at least one value of the in-phase and orthogonal components of the base band signal is within the predetermined range, wherein

the base band signal to be input into said in-phase component square calculation unit and said orthogonal component square calculation unit is the base band signal output from said clip detecting unit;

a data interpolating unit that interpolates the digital base band signal that has been sampled by the asynchronous sample clock, and outputs the interpolated data as an interpolated base band signal; and

a data deciding unit that extracts a Nyquist point of the interpolated base band signal based on a phase control signal, decides data at the extracted Nyquist point, and outputs the data as demodulated data.

41. A demodulator comprising:

an antenna that receives a radio signal;

a frequency converting unit that converts the frequency of the received radio signal into the frequency of a base band signal;

an A/D converting unit that converts the base band signal into a digital base band signal based on a sampling at two times a symbol rate using an asynchronous sample clock;

a timing regenerating device including;

an in-phase component square calculation unit that receives a base band signal having a preamble symbol, calculates square of an in-phase component of the base band signal and outputs the squared in-phase component;

an in-phase multiplier that multiplies a sign bit (±

1) of the in-phase component of the base band signal to the squared in-phase component and outputs the result as signed squared in-phase component;

an orthogonal component square calculation unit that receives the base band signal, calculates square of an orthogonal component of the base band signal and outputs the squared orthogonal component;

an orthogonal multiplier that multiplies a sign bit (±

1) of the orthogonal component of the base band signal to the squared orthogonal component and outputs the result as a signed squared orthogonal component;

an adder that adds the signed squared in-phase and orthogonal components to generate a squared addition signal, and outputs the squared addition signal;

a subtracter that subtracts the signed squared in-phase component from the signed squared orthogonal component or vice versa to generate a squared subtraction signal, and outputs the squared subtraction signal;

a squared-addition signal component correlation calculating unit that calculates a correlation value between the squared addition signal and a ½

symbol frequency component, and outputs this correlation value as an addition correlation signal;

a squared-subtraction signal component correlation calculating unit that calculates a correlation value between the squared subtraction signal and the ½

symbol frequency component, and outputs this correlation value as a subtraction correlation signal;

a vector selecting unit that compares the magnitudes of the addition and subtraction correlation signals, selects the addition correlation signal or the subtraction correlation signal whichever is larger, and outputs this signal as a selected correlation signal;

a timing phase difference calculating unit that outputs a phase control signal from a vector angle shown by the selected correlation signal;

a VCO that outputs a regeneration symbol clock, a regeneration sample clock, and the ½

symbol frequency component, based on the phase control signal, wherein

the base band signal to be input into the in-phase component square calculation unit and the orthogonal component square calculation unit is a signal that has been sampled based on the regeneration sample clock,

said squared-addition signal component correlation calculating unit calculates the correlation value using the ½

symbol frequency component output from said VCO,

said squared-subtraction signal component correlation calculating unit calculates the correlation value using the ½

symbol frequency component output from said VCO;

a phase detecting unit that detects advancement/delay of a timing phase using the base band signal sampled based on the regeneration sample clock, and outputs detected signals as phase detection signals;

a phase detection signal averaging unit that calculates an average of the phase detection signals, and outputs the average as a phase advance/delay signal, wherein

said VCO outputs the regeneration symbol clock, the regeneration sample clock, and the ½

symbol frequency component, based on the phase control signal and the phase advance/delay signal;

a data interpolating unit that interpolates the digital base band signal that has been sampled by the asynchronous sample clock, and outputs the interpolated data as an interpolated base band signal; and

a data deciding unit that extracts a Nyquist point of the interpolated base band signal based on a phase control signal, decides data at the extracted Nyquist point, and outputs the data as demodulated data.