Circuit device, oscillator, electronic apparatus, and vehicle

Patent metadata

Field	Value
Publication number	US-2017194907-A1
Application number	US-201615385455-A
Country	US
Kind code	A1
Filing date	Dec 20, 2016
Priority date	Jan 6, 2016
Publication date	Jul 6, 2017
Grant date	—

Abstract

A circuit device includes an oscillation signal generation circuit that generates an oscillation signal having an oscillation frequency using a resonator, the oscillation frequency being a frequency set by using frequency control data, and a processor configured to perform a signal process on input frequency control data based on a phase comparison result between an input signal based on the oscillation signal and a reference signal. The processor is configured to estimate a true value for an observed value of the frequency control data based on the phase comparison result through a Karman filter process in a period before a hold-over state is detected, and generate aging-corrected frequency control data, in a case where the hold-over state is detected, by holding the true value at a timing corresponding to a timing of detecting the hold-over state, and by performing a calculation based on the true value.

First claim

What is claimed is:

1 . A circuit device comprising:
an oscillation signal generation circuit that generates an oscillation signal having an oscillation frequency using a resonator, the oscillation frequency being a frequency set by using frequency control data; and a processor configured to;
perform a signal process on input frequency control data based on a phase comparison result between an input signal based on the oscillation signal and a reference signal;
estimate a true value for an observed value of the frequency control data based on the phase comparison result through a Karman filter process in a period before a hold-over state due to the absence or abnormality of the reference signal is detected; and

generate aging-corrected frequency control data, in a case where the hold-over state is detected, by holding the true value at a timing corresponding to a timing of detecting the hold-over state, and by performing a calculation based on the true value.

2 . The circuit device according to claim 1 ,
wherein the processor is configured to generate the aging-corrected frequency control data by performing the calculation of adding a correction value to the true value.

3 . The circuit device according to claim 2 ,
wherein the processor is configured to obtain the aging-corrected frequency control data AC(k+1) at a time step k+1 according to AC(k+1)=AC(k)+D(k), where D(k) is the correction value at a time step k, and AC(k) is the aging-corrected frequency control data at the time step k.

4 . The circuit device according to claim 2 ,
wherein the processor is configured to perform the calculation of adding the correction value after a filter process to the true value.

5 . The circuit device according to claim 2 ,
wherein the processor is configured to obtain the correction value on the basis of an observation residual in the Karman filter process.

6 . The circuit device according to claim 1 , further comprising:
a storage that stores a system noise constant for setting system noise in the Karman filter process and an observation noise constant for setting observation noise in the Karman filter process.

7 . The circuit device according to claim 1 ,
wherein the processor is configured to determine whether or not the hold-over state has occurred, on the basis of a voltage of an input terminal to which a hold-over detection signal is input or hold-over detection information which is input via a digital interface.

8 . The circuit device according to claim 1 ,
wherein, in a case where the oscillation signal generation circuit is recovered from the hold-over state, the oscillation signal generation circuit generates the oscillation signal on the basis of the frequency control data based on the phase comparison result.

9 . An oscillator comprising:
the circuit device according to claim 1 ; and the resonator.

10 . An electronic apparatus comprising the circuit device according to claim 1 .

11 . A vehicle comprising the circuit device according to claim 6 .

Assignees

• Seiko Epson Corp

Inventors

• Yonezawa Takemi

Classifications

• H03B5/362 Primary

  the amplifier being a single transistor (H03B5/364 - H03B5/368 take precedence) · CPC title

• H03L7/18

  using a frequency divider or counter in the loop (H03L7/20, H03L7/22 take precedence) · CPC title

• H03L7/181

  a numerical count result being used for locking the loop, the counter counting during fixed time intervals {(H03L7/1806 takes precedence)} · CPC title

• H03B5/368

  the means being voltage variable capacitance diodes · CPC title

• H03L1/00

  Stabilisation of generator output against variations of physical values, e.g. power supply · CPC title