Devices and methods of measuring gain of a voltage-controlled oscillator

• US 9,784,770 B2
• Filed: 05/27/2014
• Issued: 10/10/2017
• Est. Priority Date: 05/27/2014
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Yu, Shih-An, Lin, Yu-Hong, Liu, Sen-You, Liao, Fang-Ren
• Primary Examiner(s): Chang, Joseph
• Application Number:
  US14/287,569
• Publication Number:
  US 20150346244A1
• Time in Patent Office: 1,232 Days
• Field of Search: 331 17, 331 44
• CPC Class Codes: G01R 19/0023 Measuring currents or voltages from sources with high internal resistance by means of measuring circuits with high input impedance, e.g. OP-amplifiers electrostatic instruments G01R5/28; measuring electrostatic potential G01R15/165; measuring electrostatic fields G01R29/12; amplifiers per se H03F
• CPC Class Codes: G01R 19/10 Measuring sum, difference or ratio
• CPC Class Codes: G01R 23/02 Arrangements for measuring frequency, e.g. pulse repetition rate; Arrangements for measuring period of current or voltage
• CPC Class Codes: G01R 27/28 Measuring attenuation, gain, phase shift or derived characteristics of electric four pole networks, i.e. two-port networks; Measuring transient response in line transmission systems H04B3/46
• CPC Class Codes: H03L 7/099 concerning mainly the controlled oscillator of the loop
• CPC Class Codes: H03L 7/183 a time difference being used for locking the loop, the counter counting between fixed numbers or the frequency divider dividing by a fixed number H03L7/1806 takes precedence

Abstract

A voltage-controlled oscillator gain measurement system includes a voltage-controlled oscillator, a voltage detector, and a processor. The voltage-controlled oscillator, which is configured in a phase-locked loop circuit, generates an output signal with an output frequency according to a control signal. The control signal is generated according to the output signal divided by a scaling number. The voltage detector is configured to measure a voltage difference of the control signal. The processor adjusts the scaling number to generate an output frequency difference of the output signal, and obtains a reciprocal gain of the voltage-controlled oscillator by dividing the voltage difference by the output frequency difference.

Claims

1. A voltage-controlled oscillator gain measurement system, comprising:

a voltage-controlled oscillator, configured in a phase-locked loop circuit, generating an output signal with an output frequency according to a control signal, wherein the control signal is generated according to the output signal divided by a scaling number;

a voltage detector that is a differential analog-to-digital converter, configured to measure a voltage difference of the control signal; and

a processor adjusting the scaling number to generate an output frequency difference of the output signal, and obtaining a reciprocal gain of the voltage-controlled oscillator by dividing the voltage difference by the output frequency difference.

2. The voltage-controlled oscillator gain measurement system of claim 1, wherein the phase-locked loop circuit further comprises:

a frequency divider, coupled to the processor, generating a feedback signal with a feedback frequency according to the output signal, wherein the feedback frequency equals the output frequency divided by the scaling number.

3. The voltage-controlled oscillator gain measurement system of claim 2, wherein the phase-locked loop circuit further comprises:

a phase detector, coupled to the frequency divider, generating an up/down signal by comparing a reference signal and the feedback signal;

a charge pump, coupled to the phase detector, receiving the up/down signal to generate a current signal; and

a filter, coupled to the charge pump, receiving the current signal to generate the control signal.

4. The voltage-controlled oscillator gain measurement system of claim 1, further comprising:

a switch, switched by the processor, coupling the control signal to a first node of the voltage detector to measure a first voltage and coupling the control signal to a second node of the voltage detector to measure a second voltage, wherein the voltage difference is the difference between the first voltage and the second voltage.

5. A method of measuring a gain of a voltage-controlled oscillator configured in a phase-locked loop circuit, comprising:

adjusting a scaling number to generate an output signal with a frequency of an output frequency plus an output frequency difference;

measuring a first voltage of a control signal;

adjusting the scaling number to generate the output signal with a frequency of the output frequency;

measuring a second voltage of the control signal; and

dividing a voltage difference that is measured by a differential analog-to-digital converter between the first voltage and the second voltage by the output frequency difference to obtain the reciprocal of the gain of the voltage-controlled oscillator, wherein the control signal is generated according to the output signal divided by the scaling number, wherein the output signal is generated according to the control signal.

6. The method of claim 5, further comprising:

controlling, by a processor, a frequency divider of the phase-locked loop circuit to adjust the scaling number.

7. The method of claim 6, wherein the control signal is generated by a phase detector, a charge pump, and a filter, wherein an up/down signal is generated by the phase detector comparing a reference signal and a feedback signal, a current signal is generated by the charge pump according to the up/down signal, and the control signal is generated according to the current signal by the filter, and wherein the frequency divider generates the feedback signal by dividing the output signal by the scaling number.

8. The method of claim 5, further comprising:

coupling, by a switch switched by a processor, the control signal to a first node of a voltage detector to measure the first voltage; and

coupling, by the switch switched by the processor, the control signal to a second node of the voltage detector to measure the second voltage.