Method and device for generating a system clock

• US 20040228431A1
• Filed: 02/13/2004
• Published: 11/18/2004
• Est. Priority Date: 02/14/2003
• Status: Abandoned Application

• Current Assignee: Infineon Technologies AG
• Original Assignee: Infineon Technologies AG
• Inventors: Kramer, Ronalf, Honken, Stefan
• Application Number:
  US10/778,609
• Publication Number:
  US 20040228431A1
• Time in Patent Office: Days
• US Class Current: 375/376
• CPC Class Codes: G06F 1/08 Clock generators with changeable or programmable clock frequency
• CPC Class Codes: H03L 7/0991 the oscillator being a digital oscillator, e.g. composed of a fixed oscillator followed by a variable frequency divider H03L7/0995 takes precedence; fixed oscillators with means for selecting among various phases H03L7/0814

Abstract

A method and a device are presented for generating a system clock (OC) of a transmitting and/or receiving device with the aid of a system oscillator (1, 2). At least one control signal (PS, FS, JS, IS) is thereby evaluated by an evaluation unit (12) and the system oscillator (1, 11) is actuated as a function of this control signal (PS, FS, JS, IS) in order to change its frequency. This makes it possible for problems which arise due to an excessive frequency tolerance of an oscillating quartz element (1) to be eliminated or avoided by preventive means.

Claims

1-35. -35. (canceled)

36. A communications device comprising:

an oscillator with a controllable output frequency;

a phase locked loop operably connected to receive the controllable output frequency of the oscillator, the phase locked loop generating a clock output based upon the controllable output frequency and generating at least one condition signal output indicative of a condition within the phase locked loop; and

an evaluation unit operably connected to the phase locked loop to receive the at least one condition signal and operably connected to the oscillator to control the output frequency of the oscillator based upon the at least one condition signal.

37. The device of claim 36, wherein the at least one condition signal comprises a signal used within the phase locked loop.

38. The device of claim 37, wherein the phase locked loop comprises:

a phase detector operable to detect a phase difference between a first and a second signal and to generate a signal indicative of a detected phase difference between the first and the second signal, and wherein the at least one condition signal comprises the signal indicative of a detected phase difference.

39. The device of claim 38, wherein the first signal comprises a signal received by the communications device from another communications device and wherein the second signal comprises the controllable output frequency of the oscillator.

40. The device of claim 37, wherein the phase locked loop comprises a filter operable to generate a correction signal based upon a phase difference between a first and a second signal, and wherein the at least one condition signal comprises the correction signal.

41. The device of claim 37 wherein the phase locked loop comprises an adder operable to change a correction signal generated based upon a phase difference between a first and a second signal, and wherein the at least one condition signal comprises the changed correction signal.

42. The device of claim 36, wherein the phase locked loop comprises a filter having an integral portion and operable to generate a correction signal based upon a phase difference between a first and a second signal, and wherein the at least one condition signal comprises a signal indicative of the integral portion of the filter.

43. The device of claim 36, wherein the device further comprises:

a digital signal processor having at least one algorithm used to detect a signal, the processor operable to generate at least one signal indicative of the efficacy of the at least one algorithm, and wherein the evaluation unit is further operably connected to the processor to receive the at least one efficacy signal, the evaluation unit operable to control the output frequency of the oscillator based upon the at least one efficacy signal.

44. The device of claim 43, wherein the at least one efficacy signal is indicative of the algorithm'"'"'s run-up behavior.

45. The device of claim 43, wherein the at least one efficacy signal is indicative of the received signal strength of a received signal.

46. The device of claim 43, wherein the phase locked loop comprises:

a phase detector operable to detect a phase difference between a first and a second signal and to generate a phase difference signal indicative of the detected phase difference between the first and the second signal;

a filter having an integral portion, operably connected to the phase detector to receive the phase difference signal and operable to generate a signal indicative of the integral portion and to generate a correction signal based upon the phase difference signal; and

an adder operably connected to the filter to receive the correction signal and operable to generate a changed correction signal based upon the correction signal, and wherein the at least one condition signal comprises;

the phase difference signal;

the correction signal;

the changed correction signal; and

the signal indicative of the integral portion of the filter.

47. The device of claim 36, wherein the device comprises a variable capacitance provided by at least one capacitor operably connected to the oscillator and the evaluation unit, and wherein the evaluation unit controls the output frequency of the oscillator by controlling the variable capacitance.

48. A communications device comprising:

an oscillator with an output frequency;

a variable capacitance comprising at least one capacitor configured to be operably connected to the oscillator such that when the capacitance operably connected to the oscillator changes the output frequency of the oscillator; and

an evaluation unit operably configured to evaluate a signal indicative of at least one condition within the communications device, and operably connected to the variable capacitance to control variation of the capacitance based upon the at least one condition within the communications device.

49. The device of claim 48, wherein the at least one capacitor comprises:

a plurality if capacitors, each of the plurality of capacitors configured such that when each of the plurality of capacitors is not operably connected to the oscillator, each of the plurality of capacitors can be switched into operable connection with the oscillator to increase capacitance and such that when each of the plurality of capacitors is operably connected to the oscillator, each of the plurality of capacitors can be switched out of operable connection with the oscillator to decrease capacitance.

50. The device of claim 48, further comprising:

a phase locked loop operably connected to receive the output frequency of the oscillator, the phase locked loop generating a clock output based upon the output frequency and generating at least one condition signal indicative of a condition within the phase locked loop, and wherein the signal indicative of at least one condition within the communications device evaluated by the evaluation unit comprises the at least one condition signal indicative of a condition within the phase locked loop.

51. The device of claim 50, wherein the at least one condition signal comprises a signal used within the phase locked loop.

52. The device of claim 51, wherein the phase locked loop comprises:

a phase detector operable to detect a phase difference between a first and a second signal and to generate a signal indicative of the detected phase difference between the first and the second signal, and wherein the at least one condition signal used within the phase locked loop comprises the signal indicative of a detected phase difference.

53. The device of claim 51, wherein the phase locked loop comprises a filter operable to generate a correction signal based upon a phase difference between a first and a second signal, and wherein the at least one condition signal is the correction signal.

54. The device of claim 48, wherein the device further comprises:

a digital signal processor having at least one algorithm used to detect a signal, the processor operable to generate at least one signal indicative of the efficacy of the at least one algorithm, and wherein the evaluation unit is further operably connected to the processor to receive the at least one efficacy signal, the evaluation unit operable to control the output frequency of the oscillator based upon the at least one efficacy signal.

55. The device of claim 54, wherein the at least one efficacy signal is indicative of the processor run-up behavior.

56. The device of claim 54, wherein the at least one efficacy signal is indicative of the received signal strength of a received signal.

57. The device of claim 48 wherein the device comprises:

a chip, and wherein the variable capacitance comprises;

a plurality of capacitors within the chip, and wherein the evaluation unit is operably configured to switch each of the plurality of capacitors into and out of operable connection with the oscillator.

58. A method of generating a clock signal in a communications device having an oscillator, a phase locked loop, a digital signal processor and an evaluation unit, comprising the steps of:

generating with the oscillator a generated output frequency;

generating with the phase locked loop a first clock using the first generated output frequency;

generating a control signal based upon the condition of at least one part within the device, wherein the part is selected from the group consisting of phase locked loop parts and the digital signal processor;

evaluating with the evaluation unit the control signal against a predetermined control signal value; and

controlling the oscillator to change the output frequency generated by the oscillator based upon the evaluation.

59. The method of claim 58, wherein the step of generating comprises the step of generating a control signal based upon the efficacy of the run-up behavior of the digital signal processor.

60. The method of claim 58, wherein the step of generating a control signal comprises the step of:

generating a signal indicative of a condition within the phase locked loop, and wherein the step of evaluating comprises the step of;

evaluating with the evaluation unit the signal indicative of a condition against a predetermined signal value.

61. The method of claim 60, wherein the step of generating the first clock comprises the step of:

detecting a phase difference between a first and a second signal, and wherein the step of generating a signal indicative of a condition comprises the step of;

generating a signal indicative of the detected phase difference.

62. The method of claim 60, wherein the step of generating the first clock comprises the step of:

generating a correction signal based upon a phase difference between a first and a second signal, and wherein the step of generating a signal indicative of a condition comprises the step of;

generating the correction signal.

63. The method of claim 60, wherein the phase locked loop comprises a filter with an integral portion and wherein the step of generating a signal indicative of a condition within the phase locked loop comprises the step of:

generating a signal indicative of the integral portion of the filter within the phase locked loop.

64. The method of claim 60, wherein the digital signal processor comprises at least one algorithm used to detect a signal, the method further comprising the steps of:

generating a signal indicative of the efficacy of the at least one algorithm;

evaluating with the evaluation unit the efficacy signal; and

controlling the oscillator to change the frequency generated by the oscillator based upon the evaluation.

65. The method of claim 64, wherein the efficacy signal is indicative of the processor run-up behavior, and wherein the evaluating step further comprises the step of:

evaluating the run-up signal, and wherein the controlling step comprises the step of;

controlling the oscillator to change the frequency generated by the oscillator based upon the evaluation.

66. The method of claim 64, wherein the at least one efficacy signal is indicative of the received signal strength of a received signal, and wherein the step of evaluation further comprises the step of:

evaluating the signal indicative of the received signal strength, and wherein the controlling step comprises the step of;

controlling the oscillator to change the frequency generated by the oscillator based upon the evaluation.

67. The method of claim 60, wherein the device comprises a variable capacitance provided by at least one capacitor operably connected to the oscillator and the evaluation unit, and wherein the step of controlling comprises the step of:

controlling the variable capacitance to change the frequency generated by the oscillator.

68. The method of claim 67, wherein the step of controlling comprises at least one of the steps of:

switching a capacitor into operable connection with the oscillator; and

switching a capacitor out of operable connection with the oscillator.

69. A method of controlling the frequency of an oscillator within a communications device having a plurality of switchable capacitors providing a variable capacitance affecting the frequency of the oscillator, and a digital signal processor using at least one algorithm to process a signal detected by the communications device, the method comprising the steps of:

outputting with the oscillator an output frequency;

modifying the operation of the processor based upon the at least one algorithm;

generating an efficacy signal indicative of the efficacy of the algorithm in modifying the operation of the processor; and

evaluating the efficacy signal, the method further comprising at least one of the steps of;

switching in capacitors to increase the capacitance; and

switching out capacitors to decrease the capacitance