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KR-102962775-B1 - Circuit and method for determining the ratio between two frequencies

KR102962775B1KR 102962775 B1KR102962775 B1KR 102962775B1KR-102962775-B1

Abstract

Determining the ratio between two frequencies can be a useful electronic building block in different electronic circuits with very diverse functionalities. The present invention comprises a circuit for determining the frequency ratio between a first input signal having a first frequency and a second input signal having a second frequency, wherein the circuit comprises: a controlled fractional frequency divider arranged to generate a divided signal having a divided frequency which is substantially divided by a control signal; a frequency phase detector arranged to generate a phase difference signal based on the frequency phase difference between the divided frequency of the divided signal and the second frequency of the second input signal; and a loop filter arranged to generate a control signal based on the phase difference signal; wherein a loop is formed by the controlled fractional frequency divider, the divided signal, the frequency phase detector, the phase difference signal, the loop filter, and the control signal; the loop filter filters the phase difference signal so as to prevent instability of the loop; and the control signal, preferably the magnitude of the control signal, represents the frequency ratio.

Inventors

  • 반 엘자커, 미힐
  • 반 데르 발크, 롭
  • 반 니유버그, 키스

Assignees

  • 세미블록스 비.브이.

Dates

Publication Date
20260512
Application Date
20200224
Priority Date
20190227

Claims (20)

  1. As a circuit (100, 101, 102) for determining the frequency ratio (107) between a first input signal (104) having a first frequency and a second input signal (135) having a second frequency, A controlled fractional frequency divider (110) arranged to generate a divided signal (115) having a divided frequency - said divided frequency is substantially equal to said first frequency divided by a control signal (107) -; A resonator (130) arranged to be excited by an excitation signal (129) having the above divided frequency and based on the above divided signal, and to generate the above second input signal; A frequency phase detector (150) arranged to generate a phase difference signal (155) based on the frequency phase difference between the divided frequency of the divided signal and the second frequency of the second input signal; and It includes a loop filter (160) arranged to generate the control signal based on the phase difference signal; A loop is formed by the above-mentioned controlled fractional frequency divider, the divided signal, the frequency phase detector, the phase difference signal, the loop filter, and the control signal; The loop filter filters the phase difference signal to prevent instability of the loop; and The above control signal represents the frequency ratio, and The above second frequency is a circuit (100, 101, 102) for determining the frequency ratio (107) between a first input signal (104) having a first frequency and a second input signal (135) having a second frequency, the resonance frequency of the resonator.
  2. In paragraph 1, A circuit (100, 101, 102) for determining a frequency ratio (107) between a first input signal (104) having a first frequency and a second input signal (135) having a second frequency, characterized in that the phase difference signal has a magnitude based on the frequency phase difference or the control signal has a magnitude representing the frequency ratio.
  3. As a circuit (100, 101, 102) for determining the frequency ratio (107) between a first input signal (104) having a first frequency and a second input signal (135) having a second frequency, A controlled fractional frequency divider (110) arranged to generate a divided signal (115) having a divided frequency - said divided frequency is substantially equal to said first frequency divided by a control signal (107) -; A resonator (130) arranged to be excited by an excitation signal (129) having the above divided frequency and based on the above divided signal, and to generate the above second input signal; A frequency phase detector (150) arranged to generate a phase difference signal (155) based on the frequency phase difference between the divided frequency of the divided signal and the second frequency of the second input signal; and It includes a loop filter (160) arranged to generate the control signal based on the phase difference signal; A loop is formed by the above-mentioned controlled fractional frequency divider, the divided signal, the frequency phase detector, the phase difference signal, the loop filter, and the control signal; The loop filter filters the phase difference signal to prevent instability of the loop; and The above control signal represents the frequency ratio, and The above loop filter is a circuit (100, 101, 102) for determining a frequency ratio (107) between a first input signal (104) having a first frequency and a second input signal (135) having a second frequency, the circuit being a low-pass filter having a cutoff frequency below the frequency noise introduced by the controllable fractional frequency divider.
  4. As a circuit (100, 101, 102) for determining the frequency ratio (107) between a first input signal (104) having a first frequency and a second input signal (135) having a second frequency, A controlled fractional frequency divider (110) arranged to generate a divided signal (115) having a divided frequency - said divided frequency is substantially equal to said first frequency divided by a control signal (107) -; A resonator (130) arranged to be excited by an excitation signal (129) having the above divided frequency and based on the above divided signal, and to generate the above second input signal; A frequency phase detector (150) arranged to generate a phase difference signal (155) based on the frequency phase difference between the divided frequency of the divided signal and the second frequency of the second input signal; and It includes a loop filter (160) arranged to generate the control signal based on the phase difference signal; A loop is formed by the above-mentioned controlled fractional frequency divider, the divided signal, the frequency phase detector, the phase difference signal, the loop filter, and the control signal; The loop filter filters the phase difference signal to prevent instability of the loop; and The above control signal represents the frequency ratio, and A circuit (100, 101, 102) for determining a frequency ratio (107) between a first input signal (104) having a first frequency and a second input signal (135) having a second frequency, wherein the digital second signal is supplied to the frequency phase detector.
  5. As a circuit (100, 101, 102) for determining the frequency ratio (107) between a first input signal (104) having a first frequency and a second input signal (135) having a second frequency, A controlled fractional frequency divider (110) arranged to generate a divided signal (115) having a divided frequency - said divided frequency is substantially equal to said first frequency divided by a control signal (107) -; A resonator (130) arranged to be excited by an excitation signal (129) having the above divided frequency and based on the above divided signal, and to generate the above second input signal; A frequency phase detector (150) arranged to generate a phase difference signal (155) based on the frequency phase difference between the divided frequency of the divided signal and the second frequency of the second input signal; and It includes a loop filter (160) arranged to generate the control signal based on the phase difference signal; A loop is formed by the above-mentioned controlled fractional frequency divider, the divided signal, the frequency phase detector, the phase difference signal, the loop filter, and the control signal; The loop filter filters the phase difference signal to prevent instability of the loop; and The above control signal represents the frequency ratio, and A circuit (100, 101, 102) for determining a frequency ratio (107) between a first input signal (104) having a first frequency and a second input signal (135) having a second frequency, wherein the frequency change rate of the first frequency and the second frequency is within the dynamic frequency tracking range of the loop.
  6. In paragraph 5, The above excitation signal is a circuit (100, 101, 102) for determining the frequency ratio (107) between a first input signal (104) having a first frequency and a second input signal (135) having a second frequency, which is shifted in phase with respect to the second input signal or substantially in phase with respect to the second input signal.
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  8. In paragraph 1, A circuit (100, 101, 102) for determining a frequency ratio (107) between a first input signal (104) having a first frequency and a second input signal (135) having a second frequency, wherein the resonator is a crystal resonator and the second frequency is the overtone resonance frequency of the crystal resonator.
  9. As a circuit (100, 101, 102) for determining the frequency ratio (107) between a first input signal (104) having a first frequency and a second input signal (135) having a second frequency, A controlled fractional frequency divider (110) arranged to generate a divided signal (115) having a divided frequency - said divided frequency is substantially equal to said first frequency divided by a control signal (107) -; A resonator (130) arranged to be excited by an excitation signal (129) having the above divided frequency and based on the above divided signal, and to generate the above second input signal; A frequency phase detector (150) arranged to generate a phase difference signal (155) based on the frequency phase difference between the divided frequency of the divided signal and the second frequency of the second input signal; and It includes a loop filter (160) arranged to generate the control signal based on the phase difference signal; A loop is formed by the above-mentioned controlled fractional frequency divider, the divided signal, the frequency phase detector, the phase difference signal, the loop filter, and the control signal; The loop filter filters the phase difference signal to prevent instability of the loop; and The above control signal represents the frequency ratio, and A circuit (100, 101, 102) for determining a frequency ratio (107) between a first input signal (104) having a first frequency and a second input signal (135) having a second frequency, comprising a digital-to-analog converter arranged to generate the excitation signal based on the divided signal.
  10. As a circuit (100, 101, 102) for determining the frequency ratio (107) between a first input signal (104) having a first frequency and a second input signal (135) having a second frequency, A controlled fractional frequency divider (110) arranged to generate a divided signal (115) having a divided frequency - said divided frequency is substantially equal to said first frequency divided by a control signal (107) -; A resonator (130) arranged to be excited by an excitation signal (129) having the above divided frequency and based on the above divided signal, and to generate the above second input signal; A frequency phase detector (150) arranged to generate a phase difference signal (155) based on the frequency phase difference between the divided frequency of the divided signal and the second frequency of the second input signal; and It includes a loop filter (160) arranged to generate the control signal based on the phase difference signal; A loop is formed by the above-mentioned controlled fractional frequency divider, the divided signal, the frequency phase detector, the phase difference signal, the loop filter, and the control signal; The loop filter filters the phase difference signal to prevent instability of the loop; and The above control signal represents the frequency ratio, and The above circuit is arranged to determine a second frequency ratio (108) between a third input signal (105) having a third frequency and a second input signal having a fourth frequency, and the circuit is: A second control fractional frequency divider (111) arranged to generate a second divided signal (116) having a second divided frequency, which is the third frequency that is substantially divided by the second control signal (108); An adder (120) arranged to generate an added signal (121) supplied to the resonator - the added signal is based on adding the divided signal and the second divided signal; A second frequency phase detector (151) arranged to generate a second phase difference signal (156) based on the second frequency phase difference between the second divided frequency of the second divided signal and the fourth frequency of the second input signal; and It includes a second loop filter (161) arranged to generate the second control signal based on the second phase difference signal; A second loop is formed by the second controlled fractional frequency divider, the second divided signal, the second frequency phase detector, the second phase difference signal, the second loop filter, and the second control signal; The second loop filter filters the second phase difference signal to prevent instability of the second loop; and The above second control signal is a circuit (100, 101, 102) for determining the frequency ratio (107) between a first input signal (104) having a first frequency and a second input signal (135) having a second frequency, which represents the second frequency ratio.
  11. In Paragraph 10, A circuit (100, 101, 102) for determining a frequency ratio (107) between a first input signal (104) having a first frequency and a second input signal (135) having a second frequency, characterized in that the second phase difference signal has a second magnitude based on the second frequency phase difference or the second control signal has a magnitude representing the second frequency ratio.
  12. In Article 10 or Article 11, A circuit (100, 101, 102) for determining a frequency ratio (107) between a first input signal (104) having a first frequency and a second input signal (135) having a second frequency, wherein the second frequency and the fourth frequency are different.
  13. In Article 10 or Article 11, The above second frequency is the resonance frequency of the above resonator, and The above resonator is a crystal resonator, and the above second frequency is the overtone resonance frequency of the crystal resonator, and The above-mentioned fourth frequency is a circuit (100, 101, 102) for determining the frequency ratio (107) between a first input signal (104) having a first frequency and a second input signal (135) having a second frequency, the fourth frequency being the harmonic frequency of the crystal resonator.
  14. In Article 10 or Article 11, The above third input signal is a circuit (100, 101, 102) for determining the frequency ratio (107) between the first input signal, which is the first input signal, a first input signal (104) having a first frequency, and a second input signal (135) having a second frequency.
  15. In Article 10 or Article 11, The above circuit is arranged to determine a third frequency ratio between a fourth input signal (106) having a fifth frequency and a second input signal having a sixth frequency, and the circuit is: A third control fractional frequency divider (112) arranged to generate a third divided signal (117) having a third divided frequency, which is the fifth frequency substantially divided by a third control signal; A third frequency phase detector (152) arranged to generate a third phase difference signal (157) based on the third frequency phase difference between the third divided frequency of the third divided signal and the sixth frequency of the second input signal; and It includes a third loop filter (162) arranged to generate the third control signal based on the third phase difference signal; The above added signal is also based on adding the above third divided signal; A third loop is formed by the third controlled fractional frequency divider, the third divided signal, the third frequency phase detector, the third phase difference signal, the third loop filter, and the third control signal; The third loop filter filters the third phase difference signal to prevent instability of the third loop; and The above third control signal is a circuit (100, 101, 102) for determining the frequency ratio (107) between a first input signal (104) having a first frequency and a second input signal (135) having a second frequency, which represents the above third frequency ratio.
  16. In paragraph 15, A circuit (100, 101, 102) for determining a frequency ratio (107) between a first input signal (104) having a first frequency and a second input signal (135) having a second frequency, characterized in that the third phase difference signal has a third magnitude based on the third frequency phase difference or the third control signal has a magnitude representing the third frequency ratio.
  17. In paragraph 15, The above second frequency and the above fourth frequency are different; The second frequency and the sixth frequency are different; or The above fourth frequency and the above sixth frequency are different. A circuit (100, 101, 102) for determining a frequency ratio (107) between a first input signal (104) having a first frequency and a second input signal (135) having a second frequency, characterized by at least one of the above.
  18. In paragraph 15, The above second frequency is the resonance frequency of the above resonator, and The above resonator is a crystal resonator, and the above second frequency is the overtone resonance frequency of the crystal resonator, and The above-mentioned sixth frequency is a circuit (100, 101, 102) for determining the frequency ratio (107) between a first input signal (104) having a first frequency and a second input signal (135) having a second frequency, the sixth frequency being the harmonic frequency of the crystal resonator.
  19. In paragraph 15, The above-mentioned fourth input signal is a circuit (100, 101, 102) for determining the frequency ratio (107) between the first input signal, which is the first input signal, a first input signal (104) having a first frequency, and a second input signal (135) having a second frequency.
  20. As a system for determining the temperature indication of a resonator, A circuit according to claim 10 or 11, comprising the resonator and providing the control signal and the second control signal; and It includes a control signal divider (220) arranged to generate a divided control signal based on the division of the control signal by the second control signal; The above divided control signal is a system for determining the temperature indication of a resonator, which is the temperature indication.

Description

Circuit and method for determining the ratio between two frequencies The present invention relates to the field of circuits and methods for determining the ratio between two frequencies. Determining the ratio between two frequencies can be a useful electronic building block in different electronic circuits with very diverse functionalities. A known circuit for determining the frequency ratio is known from WO 2013/066161 A1, specifically from FIG. 2. WO 2013/066161 A1 discloses an electronic oscillator circuit comprising: a first oscillator for supplying a first oscillation signal; a second oscillator for supplying a second oscillation signal; a first controller for transmitting a first control signal as a function of a phase difference between a first controller input and a second controller input of a first controller; a second controller for transmitting a second control signal as a function of a phase difference between a first controller input and a second controller input of a second controller; a resonator; and processing means for receiving a first oscillator signal and a second oscillator signal, having a first phase shift that depends on the difference between the frequency of a second excitation signal and a second resonance frequency, determining their mutual ratio, looking up a frequency compensation factor in a pre-stored table, and outputting a compensated oscillation signal. In Figure 2 of WO 2013/066161 A1, the divider setting of the feedback divider determines the ratio between the resonator frequency and the frequency output. A disadvantage of the circuit in Fig. 2 of WO 2013/066161 A1 is that the frequency output is the output rather than the input of the circuit. Furthermore, a disadvantage is that the circuit uses a controlled oscillator, which is a bulky component. Moreover, the controlled oscillator has the disadvantage of requiring a minimum frequency distance from other controlled oscillators to prevent crosstalk, which hinders miniaturization and integration. US 2013/0076415 A1 discloses one or more PLLs formed on an integrated circuit. Each PLL includes an interpolating divider configured as a digitally controlled oscillator that receives a reference clock signal and supplies an output signal divided according to a division ratio. A feedback divider is coupled to the output signal of the interpolating divider and supplies the divided output signal as a feedback signal. A phase detector receives the feedback signal and the clock signal that locks the PLL. The phase detector supplies a phase error corresponding to the difference between the clock signal and the feedback signal, and the division ratio is adjusted according to the phase error. A disadvantage is relatively high phase noise on the divided output signal. The objective of the present invention is to overcome one or more of the disadvantages mentioned above. According to a first aspect of the present invention, a circuit for determining a frequency ratio between a first input signal having a first frequency and a second input signal having a second frequency, wherein the circuit comprises: - A controlled fractional frequency divider arranged to generate a divided signal having a divided frequency, which is substantially divided by a control signal, such that the divided frequency is a first frequency; - A resonator arranged to be excited by an excitation signal based on a divided signal having a divided frequency and to generate a second input signal; - A frequency phase detector arranged to generate a phase difference signal based on the frequency phase difference between the divided frequency of the divided signal and the second frequency of the second input signal; and - Includes a loop filter arranged to generate a control signal based on a phase difference signal; A loop is formed by a controlled fractional frequency divider, a divided signal, a frequency phase detector, a phase difference signal, a loop filter, and a control signal; The loop filter filters the phase difference signal to prevent loop instability; and The control signal, preferably the magnitude of the control signal, represents the frequency ratio. The controlled frequency divider may be a digital controlled frequency divider. The controlled frequency divider may be a controlled multiple frequency divider or a controlled fractional frequency divider. The frequency phase detector may be a frequency mixer, an analog multiplier, a digital circuit, or a logic circuit configured as a phase detector. Alternatively, the frequency phase detector may be a digital mixer, such as an XOR port mixer. The first input signal may be any repeating signal and thus may have a frequency. The first input signal may be a block signal, such as a digital signal. Alternatively, the first input signal may be an analog signal, such as a triangular signal or a sine wave signal. The first input signal is typically a signal having low phase noise. The phase noise may be less than