Automatic gain control circuit and method thereof and demodulation apparatus using the same

• US 20040037378A1
• Filed: 08/04/2003
• Published: 02/26/2004
• Est. Priority Date: 06/25/2001
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Morohashi, Hideo, Usui, Takashi, Sato, Hideaki, Wakamatsu, Masataka, Komori, Kenji, Saijo, Kazuyuki, Fujimura, Kazuhiro, Tanabe, Shinichi
• Granted Patent: US 7,397,872 B2
• Time in Patent Office: Days
• US Class Current: 375/345
• CPC Class Codes: H03G 3/3052 in bandpass amplifiers (H.F. or I.F.) or in frequency-changers used in a (super)heterodyne receiver H03G3/32, H03G3/34 take precedence
• CPC Class Codes: H03G 3/3078 Circuits generating control signals for digitally modulated signals
• CPC Class Codes: H04L 27/2647 Arrangements specific to the receiver only equalisation H04L27/01

Abstract

An automatic gain control circuit able to perform high speed and correct level acquisition, able to prevent occurrence of error, and able to prevent a crash of the system, a method of same, and a demodulation apparatus, provided with an amplification gain controller 211 for outputting a gain control signal to an automatic gain control amplifier 201 so as to amplify the reception signal with the maximum value when receiving a burst detection starting use trigger signal, calculating a second gain based on a reception signal power value detected at a reception signal power monitor 202 when receiving a first burst synchronization detection signal from the burst detector, outputting the gain control signal to the automatic gain control amplifier 201 so as to amplify the reception signal with the second gain, receiving the digital reception signal amplified with the second gain and integrating the same to find the reception signal power value, calculating a third gain based on the found reception signal power value when receiving the second burst synchronization detection signal by the burst detector, and outputting the gain control signal to the automatic gain control amplifier 201 so as to amplify the reception signal with the third gain.

Claims

1. An automatic gain control circuit for control of an amplification gain of a reception signal comprised of a data signal to the header part of which is added a burst portion including at least a preamble signal, comprising:

an automatic gain control amplifier for amplifying an input reception signal level by a gain in accordance with a gain control signal;

a reception signal power monitor for detecting a power of the reception signal;

a delay unit for delaying the output of the automatic gain control amplifier by a predetermined time;

a burst detector for burst detection based on a correlation operation between the output signal of the automatic gain control amplifier and the output signal of the delay unit and outputting a burst synchronization detection signal; and

an amplification gain controller for outputting the gain control signal to the automatic gain control amplifier so as to amplify the reception signal with a first gain set in advance when receiving a trigger signal indicating the start of the burst detection, calculating a second gain based on a detected reception signal power value when the reception signal power is detected at the reception signal power monitor, outputting the gain control signal to the automatic gain control amplifier so as to amplify the reception signal with the second gain, finding the reception signal power value upon receipt of the output signal of the automatic gain control amplifier amplified with the second gain, calculating a third gain based on the found reception signal power value when receiving the burst synchronization detection signal from the burst detector, and outputting the gain control signal to the automatic gain control amplifier so as to amplify the reception signal with the third gain.

2. An automatic gain control circuit as set forth in claim 1, wherein the amplification gain controller fixes the gain of the automatic gain control amplifier at the third gain until the start of the next burst detection after setting the third gain.

3. An automatic gain control circuit as set forth in claim 1, wherein:

the burst signal includes a reference signal subsequent to the preamble signal;

the circuit further comprises a timing controller for detecting the reference signal upon receipt of the correlation operation result of the burst detector and outputting the second burst synchronization detection signal to the amplification gain controller; and

the amplification gain controller shifts to a waiting mode of the trigger signal when receiving the second burst synchronization detection signal and fixes the gain of the automatic gain control amplifier at the third gain until the input of the next trigger signal.

4. An automatic gain control circuit as set forth in claim 1, wherein the reception signal power monitor is reset for every start of burst detection and detects the reception signal power after reset.

5. An automatic gain control circuit as set forth in claim 1, wherein the reception signal power monitor detects the peak value of the reception signal.

6. An automatic gain control circuit as set forth in claim 4, wherein the reception signal power monitor detects the peak value of the reception signal.

7. An automatic gain control circuit as set forth in claim 1, wherein:

a reference signal is inserted in the data signal section following the burst portion of the reception signal, and

the amplification gain controller finely adjusts the value of the third gain during the reference signal section.

8. An automatic gain control circuit as set forth in claim 7, wherein the amplification gain controller finds the reception signal power value in the reference signal section and finely adjusts the value of the third gain based on the reception signal power value in the previous reference signal section.

9. An automatic gain control circuit for control of an amplification gain of a reception signal comprised of a data signal to the header part of which is added a burst portion including at least a preamble signal and having the preamble signal divided into two stages of a front half section and a rear half section, comprising:

an automatic gain control amplifier for amplifying an input reception signal level with a gain in accordance with a gain control signal;

a reception signal power monitor for detecting a power of the reception signal;

a delay unit for delaying the output of the automatic gain control amplifier by a predetermined time;

a burst detector for burst detection based on a correlation operation between the output signal of the automatic gain control amplifier and the output signal of the delay unit, outputting a first burst synchronization detection signal when detecting the front half section of the preamble signal, and outputting a second burst synchronization detection signal when detecting the rear half section; and

an amplification gain controller for outputting the gain control signal to the automatic gain control amplifier so as to amplify the reception signal with a first gain set in advance when receiving a trigger signal indicating the start of the burst detection, calculating a second gain based on a reception signal power value detected at the reception signal power monitor when receiving the first burst synchronization detection signal by the burst detector, outputting the gain control signal to the automatic gain control amplifier so as to amplify the reception signal with the second gain, finding the reception signal power value upon receipt of the output signal of the automatic gain control amplifier amplified with the second gain, calculating a third gain based on the found reception signal pwer value when receiving the second burst synchronization detection signal by the burst detector, and outputting the gain control signal to the automatic gain control amplifier so as to amplify the reception signal with the third gain.

10. An automatic gain control circuit as set forth in claim 9, wherein the amplification gain controller fixes the gain of the automatic gain control amplifier at the third gain until the start of the next burst detection after setting the third gain.

11. An automatic gain control circuit as set forth in claim 9, wherein:

the burst signal includes a reference signal subsequent to the preamble signal;

the circuit further comprises a timing controller for detecting the reference signal upon receipt of the correlation operation result of the burst detector and outputting the third burst synchronization detection signal to the amplification gain controller; and

the amplification gain controller shifts to a waiting mode of the trigger signal when receiving the third burst synchronization detection signal and fixes the gain of the automatic gain control amplifier at the third gain until the input of the next trigger signal.

12. An automatic gain control circuit as set forth in claim 9, wherein the reception signal power monitor is reset for every start of burst detection and detects the reception signal power after reset.

13. An automatic gain control circuit as set forth in claim 9, wherein the reception signal power monitor detects the peak value of the reception signal.

14. An automatic gain control circuit as set forth in claim 12, wherein the reception signal power monitor detects the peak value of the reception signal.

15. An automatic gain control circuit as set forth in claim 9, wherein:

a reference signal is inserted in the data signal section following the burst portion of the reception signal, and

the amplification gain controller finely adjusts the value of the third gain during the reference signal section.

16. An automatic gain control circuit as set forth in claim 15, wherein the amplification gain controller finds the reception signal power value in the reference signal section and finely adjusts the value of the third gain based on the reception signal power value in the previous reference signal section.

17. An automatic gain control circuit for control of an amplification gain of a reception signal comprised of a data signal to the header part of which is added a burst portion including at least a preamble signal, comprising:

an automatic gain control amplifier for amplifying an input reception signal level with a gain in accordance with a gain control signal;

an analog-to-digital converter for converting an output signal of the automatic gain control amplifier from an analog signal to a digital signal;

a reception signal power monitor for detecting a power of the reception signal;

a delay unit for delaying the output of the automatic gain control amplifier by a predetermined time;

a burst detector for burst detection based on a correlation operation between a digital output signal of the analog-to-digital converter and an output signal of the delay unit and outputting a burst synchronization detection signal; and

an amplification gain controller for outputting the gain control signal to the automatic gain control amplifier so as to amplify a reception signal with a first gain set in advance when receiving a trigger signal indicating the start of the burst detection, calculating a second gain based on at least the detected reception signal power value when the reception signal power is detected at the reception signal power monitor, outputting the gain control signal to the automatic gain control amplifier so as to amplify the reception signal with the second gain, receiving the digital output signal of the analog-to-digital converter amplified with the second gain and integrating the same to find the reception signal power value, calculating a third gain based on the found reception signal power value when receiving a burst synchronization detection signal from the burst detector, and outputting the gain control signal to the automatic gain control amplifier so as to amplify the reception signal with the third gain.

18. An automatic gain control circuit as set forth in claim 17, wherein the amplification gain controller adds the second gain to the reception signal power value from the reception signal power monitor and performs calculations based on a reference signal power value not distorting the analog-to-digital converter.

19. An automatic gain control circuit as set forth in claim 17, wherein the amplification gain controller adds the third gain to the found reception signal power value and performs calculations based on a reference signal power value obtained by optimizing the reception signal power after gain control.

20. An automatic gain control circuit as set forth in claim 17, wherein the amplification gain controller adds the second gain to the reception signal power value from the reception signal power monitor and performs calculations based on a first reference signal power value not distorting the analog-to-digital converter, adds the third gain to the found reception signal power value, and performs calculations based on a second reference signal power value obtained by optimizing the reception signal power after gain control.

21. An automatic gain control circuit as set forth in claim 17, wherein the amplification gain controller fixes the gain of the automatic gain control amplifier at the third gain until the start of the next burst detection after setting the third gain.

22. An automatic gain control circuit as set forth in claim 17, wherein:

the burst signal includes a reference signal following the preamble signal;

the circuit further comprises a timing controller for detecting the reference signal upon receipt of the correlation operation result of the burst detector and outputting the second burst synchronization detection signal to the amplification gain controller; and

the amplification gain controller shifts to a waiting mode of the trigger signal when receiving the second burst synchronization detection signal and fixes the gain of the automatic gain control amplifier at the third gain until the input of the next trigger signal.

23. An automatic gain control circuit as set forth in claim 17, wherein the reception signal power monitor is reset for every start of burst detection and detects the reception signal power after reset.

24. An automatic gain control circuit as set forth in claim 17, wherein the reception signal power monitor detects a peak value of the reception signal.

25. An automatic gain control circuit as set forth in claim 23, wherein the reception signal power monitor detects a peak value of the reception signal.

26. An automatic gain control circuit as set forth in claim 17, wherein

a reference signal is inserted in the data signal section following the burst portion of the reception signal, and

the amplification gain controller finely adjusts the value of the third gain during the reference signal section.

27. An automatic gain control circuit as set forth in claim 26, wherein the amplification gain controller finds the reception signal power value in the reference signal section and finely adjusts the value of the third gain based on the reception signal power value in the previous reference signal section.

28. An automatic gain control circuit for control of an amplification gain of a reception signal comprised of a data signal to the header part of which is added a burst portion including at least a preamble signal and having the preamble signal divided into two stages of a front half section and a rear half section, comprising:

an automatic gain control amplifier for amplifying an input reception signal level with a gain in accordance with a gain control signal;

an analog-to-digital converter for converting an output signal of the automatic gain control amplifier from an analog signal to a digital signal;

a reception signal power monitor for detecting a power of the reception signal;

a delay unit for delaying an output of the automatic gain control amplifier by a predetermined time;

a burst detector for burst detection based on a correlation operation between a digital output signal of the analog-to-digital converter and an output signal of the delay unit, outputting a first burst synchronization detection signal when detecting the front half section of the preamble signal, and outputting a second burst synchronization detection signal when detecting the rear half section; and

an amplification gain controller for outputting the gain control signal to the automatic gain control amplifier so as to amplify a reception signal with a first gain set in advance when receiving a trigger signal indicating the start of the burst detection, calculating a second gain based on the reception signal power value detected at the reception signal power monitor when receiving the first burst synchronization detection signal from the burst detector, outputting the gain control signal to the automatic gain control amplifier so as to amplify the reception signal with the second gain, receiving the digital output signal of the analog-to-digital converter amplified by the second gain and integrating the same to find the reception signal power value, calculating the third gain based on the found reception signal power value when receiving the second burst synchronization detection signal by the burst detector, and outputting the gain control signal to the automatic gain control amplifier so as to amplify the reception signal by the third gain.

29. An automatic gain control circuit as set forth in claim 28, wherein the amplification gain controller adds the second gain to the reception signal power value from the reception signal power monitor and performs calculations based on a reference signal power value not distorting the analog-to-digital converter.

30. An automatic gain control circuit as set forth in claim 28, wherein the amplification gain controller adds the third gain to the found reception signal power value and performs calculations based on a reference signal power value obtained by optimizing the reception signal power after gain control.

31. An automatic gain control circuit as set forth in claim 28, wherein the amplification gain controller adds the second gain to the reception signal power value from the reception signal power monitor and performs calculations based on a first reference signal power value not distorting the analog-to-digital converter, adds the third gain to the found reception signal power value, and performs calculations based on a second reference signal power value obtained by optimizing the reception signal power after gain control.

32. An automatic gain control circuit as set forth in claim 28, wherein the amplification gain controller fixes the gain of the automatic gain control amplifier at the third gain until the start of the next burst detection after setting the third gain.

33. An automatic gain control circuit as set forth in claim 28, wherein:

the burst signal includes a reference signal following the preamble signal;

the circuit further comprises a timing controller for detecting the reference signal upon receipt of the correlation operation result of the burst detector and outputting the third synchronization detection signal to the amplification gain controller; and

the amplification gain controller shifts to a waiting mode of the trigger signal when receiving the third burst synchronization detection signal and fixes the gain of the automatic gain control amplifier at the third gain until the input of the next trigger signal.

34. An automatic gain control circuit as set forth in claim 28, wherein the reception signal power monitor is reset for every start of burst detection and detects the reception signal power after reset.

35. An automatic gain control circuit as set forth in claim 28, wherein the reception signal power monitor detects a peak value of the reception signal.

36. An automatic gain control circuit as set forth in claim 34, wherein the reception signal power monitor detects a peak value of the reception signal.

37. An automatic gain control circuit as set forth in claim 28, wherein

a reference signal is inserted in the data signal section following the burst portion of the reception signal, and

the amplification gain controller finely adjusts the value of the third gain during the reference signal section.

38. An automatic gain control circuit as set forth in claim 37, wherein the amplification gain controller finds the reception signal power value in the reference signal section and finely adjusts the value of the third gain based on the-reception signal power value in the previous reference signal section.

39. An automatic gain control method for control of an amplification gain of a reception signal comprised of a data signal to the header part of which is added a burst portion including at least a preamble signal, comprising the steps of:

setting the amplification gain so as to amplify the reception signal with a first gain set in advance when starting the burst detection,

amplifying the reception signal with the first gain when the burst detection is started and detecting a power of the reception signal in parallel to this,

calculating a second gain based on the detected reception signal power value and setting the amplification gain so as to amplify the reception signal with the second gain,

finding the power value of the reception signal amplified with the second gain,

performing burst detection based on a correlation operation between the reception signal amplified with the second gain and the delay signal of the reception signal, and

calculating a third gain based on the reception signal power value amplified with the found second gain when the burst is detected and setting the amplification gain so as to amplify the reception signal with the third gain.

40. An automatic gain control method as set forth in claim 39, further comprising, after setting the third gain, fixing the amplification gain to the third gain until the start of the next burst detection.

41. An automatic gain control method as set forth in claim 40, wherein:

the burst signal includes a reference signal following the preamble signal and

further comprising detecting the reference signal upon receipt of the correlation operation result at the time of the burst detection,

shifting to a waiting mode of a burst detection start instruction when the reference signal is detected, and

fixing the amplification gain at the third gain until receiving the next burst detection start instruction.

42. An automatic gain control method as set forth in claim 40, wherein:

a reference signal is inserted in the data signal section following the burst portion of the reception signal, and

further comprising finely adjusting the third gain during the reference signal section.

43. An automatic gain control method as set forth in claim 42, further comprising finding the reception signal power value in the reference signal section and finely adjusting the value of the third gain based on the reception signal power value in the previous reference signal section.

44. An automatic gain control method for control of an amplification gain of a reception signal comprised of a data signal to the header part of which is added a burst portion including at least a preamble signal and having the preamble signal divided into two stages of a front half section and a rear half section, comprising the steps of:

setting the amplification gain so as to amplify the reception signal with a first gain set in advance when starting the burst detection,

amplifying the reception signal with the first gain when the burst detection is started and detecting a power of the reception signal in parallel to this,

performing burst detection of the front half section of the preamble signal based on a correlation operation between the reception signal amplified with the first gain and the delay signal of the reception signal,

calculating a second gain based on the detected reception signal power value when a burst in the front half section is detected and setting the amplification gain so as to amplify the reception signal with the second gain,

finding the power value of the reception signal amplified with the second gain,

performing burst detection of the rear half section of the preamble signal based on a correlation operation between the reception signal amplified with the second gain and the delay signal of the reception signal, and

calculating a third gain based on the reception signal power value amplified with the found second gain when a burst in the rear half section is detected and setting the amplification gain so as to amplify the reception signal with the third gain.

45. An automatic gain control method as set forth in claim 44, further comprising, after setting the third gain, fixing the amplification gain to the third gain until the start of the next burst detection.

46. An automatic gain control method as set forth in claim 44, wherein:

the burst signal includes a reference signal following the preamble signal and

further comprising detecting the reference signal upon receipt of the correlation operation result at the time of the burst detection,

shifting to a waiting mode of a burst detection start instruction when the reference signal is detected, and

fixing the amplification gain at the third gain until receiving the next burst detection start instruction.

47. An automatic gain control method as set forth in claim 44, wherein:

a reference signal is inserted in the data signal section following the burst portion of the reception signal, and

further comprising finely adjusting the third gain during the reference signal section.

48. An automatic gain control method as set forth in claim 47, further comprising finding the reception signal power value in the reference signal section and finely adjusting the value of the third gain based on the reception signal power value in the previous reference signal section.

49. A demodulation apparatus for control of an amplification gain of a reception signal comprised of a data signal to the header part of which is added a burst portion including at least a preamble signal and demodulating the reception signal after amplification, including:

an automatic gain control circuit having an automatic gain control amplifier for amplifying an input reception signal level with a gain in accordance with a gain control signal;

a reception signal power monitor for detecting a power of the reception signal;

a delay unit for delaying an output of the automatic gain control amplifier by a predetermined time;

a burst detector for burst detection based on a correlation operation between an output signal of the automatic gain control amplifier and an output signal of the delay unit and outputting a burst synchronization detection signal; and

an amplification gain controller for outputting the gain control signal to the automatic gain control amplifier so as to amplify the reception signal with a first gain set in advance when receiving a trigger signal indicating the start of the burst detection, calculating a second gain based on a detected reception signal power value when the reception signal power is detected at the reception signal power monitor, outputting the gain control signal to the automatic gain control amplifier so as to amplify the reception signal with the second gain, finding the reception signal power value upon receipt of the output signal of the automatic gain control amplifier amplified with the second gain, calculating a third gain based on the found reception signal power value when receiving a burst synchronization detection signal from the burst detector, and outputting the gain control signal to the automatic gain control amplifier so as to amplify the reception signal with the third gain.

50. A demodulation apparatus as set forth in claim 49, wherein the reception signal is modulated based on an orthogonal frequency division multiplexed modulation method.

51. A demodulation apparatus for control of an amplification gain of a reception signal comprised of a data signal to the header part of which is added a burst portion including at least a preamble signal and having the preamble signal divided into two stages of a front half section and a rear half section and demodulating the reception signal after amplification, including:

an automatic gain control circuit having an automatic gain control amplifier for amplifying the input reception signal level with a gain in accordance with a gain control signal;

a reception signal power monitor for detecting a power of the reception signal;

a delay unit for delaying an output of the automatic gain control amplifier by a predetermined time;

a burst detector for burst detection based on a correlation operation between an output signal of the automatic gain control amplifier and an output signal of the delay unit, outputting a first burst synchronization detection signal when detecting the front half section of the preamble signal, and outputting a second burst synchronization detection signal when detecting the rear half section; and

an amplification gain controller for outputting the gain control signal to the automatic gain control amplifier so as to amplify the reception signal with a first gain set in advance when receiving a trigger signal indicating the start of the burst detection, calculating a second gain based on the reception signal power value detected at the reception signal power monitor when receiving the first burst synchronization detection signal from the burst detector, outputting the gain control signal to the automatic gain control amplifier so as to amplify the reception signal with the second gain, finding the reception signal power value upon receipt of the output signal of the automatic gain control amplifier amplified with the second gain, calculating a third gain based on the found reception signal power value when receiving the second burst synchronization detection signal by the burst detector, and outputting the gain control signal to the automatic gain control amplifier so as to amplify the reception signal with the third gain.

52. A demodulation apparatus as set forth in claim 51, wherein the reception signal is modulated based on an orthogonal frequency division multiplexed modulation method.

53. A demodulation apparatus for control of an amplification gain of a reception signal comprised of a data signal to the header part of which is added a burst portion including at least a preamble signal and demodulating the reception signal after amplification, including:

an automatic gain control circuit having an automatic gain control amplifier for amplifying an input reception signal level with a gain in accordance with a gain control signal;

an analog-to-digital converter for converting an output signal of the automatic gain control amplifier from an analog signal to a digital signal;

a reception signal power monitor for detecting a power of the reception signal;

a delay unit for delaying the output of the automatic gain control amplifier by a predetermined time;

a burst detector for burst detection based on a correlation operation between a digital output signal of the analog-to-digital converter and an output signal of the delay unit and outputting a burst synchronization detection signal; and

an amplification gain controller for outputting the gain control signal to the automatic gain control amplifier so as to amplify the reception signal with a first gain set in advance when receiving the trigger signal indicating the start of the burst detection, calculating a second gain based on at least the detected reception signal power value when the reception signal power is detected at the reception signal power monitor, outputting the gain control signal to the automatic gain control amplifier so as to amplify the reception signal with the second gain, receiving the digital output signal of the analog-to-digital converter amplified with the second gain and integrating the same to find the reception signal power value, calculating a third gain based on the found reception signal power value when receiving the burst synchronization detection signal from the burst detector, and outputting the gain control signal to the automatic gain control amplifier so as to amplify the reception signal with the third gain.

54. A demodulation apparatus as set forth in claim 53, wherein the reception signal is modulated based on an orthogonal frequency division multiplexed modulation method.

55. A demodulation apparatus for control of an amplification gain of a reception signal comprised of a data signal to the header part of which is added a burst portion including at least a preamble signal and having the preamble signal divided into two stages of a front half section and a rear half section and demodulating the reception signal after amplification, including:

an automatic gain control circuit having an automatic gain control amplifier for amplifying an input reception signal level with a gain in accordance with a gain control signal;

an analog-to-digital converter for converting the output signal of the automatic gain control amplifier from an analog signal to a digital signal;

a reception signal power monitor for detecting a power of the reception signal;

a delay unit for delaying the output of the automatic-gain control amplifier by a predetermined time;

a burst detector for burst detection based on a correlation operation between a digital output signal of the analog-to-digital converter and an output signal of the delay unit, outputting a first burst synchronization detection signal when detecting the front half section of the preamble signal, and outputting a second burst synchronization detection signal when detecting the rear half section; and

an amplification gain controller for outputting the gain control signal to the automatic gain control amplifier so as to amplify the reception signal with a first gain set in advance when receiving a trigger signal indicating the start of the burst detection, calculating a second gain based on the reception signal power value detected at the reception signal power monitor when receiving the first burst synchronization detection signal from the burst detector, outputting the gain control signal to the automatic gain control amplifier so as to amplify the reception signal with the second gain, receiving the digital output signal of the analog-to-digital converter amplified with the second gain and integrating the same to find the reception signal power value, calculating a third gain based on the found reception signal power value when receiving the second burst synchronization detection signal from the burst detector, and outputting the gain control signal to the automatic gain control amplifier so as to amplify the reception signal with the third gain.

56. A demodulation apparatus as set forth in claim 55, wherein the reception signal is modulated based on an orthogonal frequency division multiplexed modulation method.