JPH0936732A - Frequency adjustment method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the automation by adjusting the frequency to an object frequency automatically in a short time. SOLUTION: An adjustment device 12 provided in an oscillator 11 is driven to adjust an oscillating frequency oscillated from the oscillator to an object frequency in the frequency adjustment method. In this frequency adjustment method, the beat system is used to mix a signal in the oscillating frequency from the oscillator with a signal of a reference frequency from a reference frequency signal oscillator 21 to generate a beat signal and a motor 17 is controlled to drive an adjustment device 12 by a microcomputer 15 and a motor control and drive section 16 so that the frequency or period of the beat signal is equal to the offset frequency or its period.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a frequency adjusting method for driving a regulator such as a trimmer capacitor or a coil core in a high-precision oscillator such as a crystal oscillator to match a target frequency.

[0002]

2. Related Background Art In an adjusting device using such a frequency adjusting method, as shown in FIG.
Has an adjuster 12 including a trimmer capacitor and a coil core. In the adjusting device, the signal of the frequency oscillated from the adjusted oscillator 11 is supplied to the waveform shaping circuit
The waveform is shaped by 3 and measured by the high-precision frequency counter 14, and the microcomputer (hereinafter, referred to as “microcomputer”) 15 compares the measured frequency with the target frequency, and the difference and the target frequency are compared. The height is calculated, and the motor control and drive unit 16 is calculated based on the calculation result.
However, the frequency of the signal oscillated from the adjusted oscillator 11 is adjusted to the target frequency by controlling the rotation direction, the rotation amount, and the speed of the motor 17 that rotationally drives the adjuster 12.

[0003]

However, when the above frequency adjustment method is used for a high precision oscillator such as a crystal oscillator and the target frequency is adjusted in units of 1 Hz, the frequency or cycle of the high precision frequency counter is unchanged. If it is used, it takes more than 1 second to acquire the data, the frequency adjustment takes time, and there is a problem that the automation effect cannot be sufficiently obtained.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a frequency adjusting method capable of performing automatic adjustment to a target frequency in a short time and improving the effect on automation. To do.

[0005]

In order to achieve the above object, according to the present invention, an adjusting means including an adjuster provided in an oscillator is rotationally driven so that an oscillation frequency oscillated from the oscillator is set to a target frequency. In the frequency adjustment method of adjusting to, a signal of the oscillation frequency and a signal of a reference frequency serving as a reference that is set to a frequency apart from the target frequency by a predetermined hertz (the target frequency with an offset frequency added or subtracted) A frequency adjusting method of generating a beat signal by mixing, and controlling the rotation of the motor to rotate the adjuster so that the frequency or the cycle of the beat signal becomes equal to the frequency or the cycle of the set offset frequency is provided. Provided.

According to a third aspect of the present invention, there is provided a frequency adjusting method for rotating an adjuster provided in an oscillator to adjust an oscillation frequency oscillated from the oscillator to a target frequency.
The beat signal is generated by mixing the signal of the oscillation frequency and the signal of the reference frequency serving as a reference, and the motor is rotationally controlled to rotate the adjuster so that the frequency of the beat signal is zeroed.

According to another aspect of the present invention, there is provided a frequency adjusting method for rotating an adjuster provided in an oscillator to adjust an oscillation frequency oscillated from the oscillator to a target frequency. When the frequency is detected and the difference between the oscillation frequency and the target frequency is within the pull-in range of the phase-locked loop (hereinafter referred to as “PLL”), the signal of the oscillation frequency and the target are detected by a PLL method. A high-low signal and a phase difference from the signal of the reference frequency set to the frequency are obtained, and the motor is rotationally controlled according to the phase difference to rotate the adjusting means.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION An adjusting device using a frequency adjusting method according to the present invention will be described with reference to the drawings of FIGS. In addition, in the drawings after FIG. 1, the same components as those in FIG. 8 are denoted by the same reference numerals for convenience of description. FIG.
FIG. 3 is a block diagram showing a first embodiment of the configuration of an adjusting device using the frequency adjusting method by the beat method of the present invention.
In the figure, the adjusting device of the present embodiment oscillates a reference frequency in addition to the adjusted oscillator 11, the adjuster 12, the waveform shaping circuit 13, the microcomputer 15, the motor control and driving unit 16, and the motor 17 shown in FIG. Reference frequency oscillator 21 and P
A frequency / phase detection circuit 22 which is composed of an IC for LL, detects a frequency and a phase difference between an oscillation frequency and a reference frequency, and outputs a signal in which the frequency and the phase are matched, and outputs a beat pulse and a high / low signal from the signal. It comprises a beat pulse / high / low signal generating section 23 and a cycle measuring counter 24 for measuring the cycle of the beat pulse.
When the target frequency is high, the frequencies from the adjusted oscillator 11 and the reference frequency oscillator 21 are also high, and the PL
Since it becomes higher than the response frequency of the IC for L, 1 /
It is necessary to divide the frequency by the N divider. Therefore, in such a case, the 1 / N frequency dividers 25 and 26 are connected between the adjusted oscillator 11 and the reference frequency oscillator 21 and the frequency / phase detection circuit 22. Further, in this case, since one cycle of the beat pulse corresponds to N cycles of the original signal, it is necessary to set the frequency division information of the frequency divider as an initial value in the microcomputer 15 for calculation. is there.

The reference frequency oscillator 21 is the adjusted oscillator 1.
The reference frequency obtained by adding or subtracting the target frequency 1 which is the oscillation target and the offset frequency N is supplied to the frequency / phase detection circuit 22. Note that the reference frequency is a frequency that is several tens of Hz away from the target frequency. In the following description, the target frequency plus the offset N cycles is used as the reference frequency.

As described above, the frequency / phase detection circuit 22 is composed of a general-purpose PLL IC, and as shown in FIG. 2, the R input terminal of the PLL IC has (target frequency +
The output signal of the reference frequency Fr (Hz) set to the N) cycle is input, and the output signal of the oscillation frequency Fv (Hz) is input to the V input terminal. The frequency / phase detection circuit 22 used in the example is shown in FIG.
The composite signal U including the beat component and the high and low components shown in (a)
1 is output to the beat pulse / high / low signal generation unit 23.

The composite signal U1 has a frequency F of both signals.
Due to the height relationship between r and Fv, the signals have the waveforms shown in FIGS. 3 (a) and 4 (a). That is, when Fr> Fv, the composite signal U1 having the waveform shown in FIG. 3 (a) having a steep rise is output, and when Fr <Fv, the steep falling is shown in FIG.
The composite signal U1 having the waveform shown in (a) is output. As shown in FIG. 2, the beat pulse / high / low signal generation unit 23 includes a detection circuit 23a, a differentiation circuit 23b, and a logic circuit 23c. When the composite signal U1 is input, the detection circuit 23a is detected.
To detect the composite signal U1 and output a detection signal U2 (see FIG. 3 (b) and FIG. 4 (c)). Then, the differential circuit 23b generates differential signals U3 and U4 and outputs them to the logic circuit 23c. There is. The logic circuit 23c generates a beat pulse corresponding to the difference between the signals of the reference frequency Fr and the oscillation frequency Fv, and outputs it to the cycle measuring counter 24.

Flip-flop FF of the logic circuit 23c
1 and FF2 are set by the differential signals U3 and U4 and used as information on the rotation direction of the motor. That is, the flip-flop F
F1 is set when Fr <Fv, and the beat pulse corresponding to the differential signal U4 is output from the logic circuit 23c. The flip-flop FF2 is set when Fr> Fv, and the beat pulse corresponding to the differential signal U3 is output from the logic circuit 23c. Also, the flip-flop F
F1 and FF2 are the adjusted oscillator 11 when the device starts up.
Are replaced by a reset signal from the microcomputer 15.

The differential signals U3 and U4 (beat pulse)
Has a cycle t equal to the beat signals of frequencies Fr and Fv (see FIGS. 3 and 4). Counter 24 for cycle measurement
Measures the cycle t of the beat pulse, and the microcomputer 15 determines the beat pulse / high / low signal generator 2
2 depending on the high / low signal input from the logic circuit 23c of 3
After satisfying the height relationship between the two frequencies Fr and Fv, the motor 17 is rotationally controlled so that it becomes equal to the cycle of the offset frequency N (Hz), and the oscillation frequency Fv from the adjusted oscillator 11 is adjusted to the target frequency. Put in. The period measuring counter 24 can measure the period on a time base of 10 (KHz) to 100 (KHz).

For example, if the offset frequency N is 20 (H
z), in this embodiment, the adjuster 12 of the adjusted oscillator 11 may be adjusted so that the cycle of the beat pulse becomes 1 / N set in advance, that is, 50 (ms).
Here, assuming that the adjustment error allowable range is ± 1, 19 (H
The cycle of beat pulse at z) is 52.63 (ms)
In addition, the cycle of the beat pulse at 21 (Hz) is 47.6.
2 (ms), and the resolution for the target value of 50 (ms) is normal timer counter (time base 10 (KH
z) to 100 (KHz) counter 2 for period measurement
It is the accuracy that can be easily realized in 4).

If a counter equipped with a buffer is used, data can be fetched every 50 (ms) and every 100 (ms) even if a counter not equipped with a buffer is used. Compared to the conventional method using the counter, the beat method of the present embodiment can reduce the data acquisition to 1/10 to 1/20. Therefore, in this embodiment, the beat method is used so that the cycle of the beat signal becomes equal to the cycle of the offset frequency.
Since the motor 12 is rotated and the adjuster 12 is rotated, automatic adjustment to the target frequency can be performed in a short time.

FIG. 5 is a block diagram showing a second embodiment of the configuration of the adjusting device using the frequency adjusting method by the PLL method of the present invention. In the figure, in the second embodiment, a signal from the reference signal oscillator 21 set to the target frequency and a signal from the adjusted oscillator 11 are used as a general-purpose I / O for PLL.
It is input to the frequency / phase detector 22 composed of C. The frequency / phase detector 22 outputs an output signal corresponding to the frequency and phase difference from the signals from the reference signal oscillator 21 and the adjusted oscillator 11 to the microcomputer 15, and switches the control signal via the low-pass filter 27. It outputs to the rotation direction determination unit 28.

The microcomputer 15 includes a frequency / phase detector 2
In addition to the output signal from 2, the signal frequency from the adjusted oscillator 11 detected by the frequency counter 29 is input. The microcomputer 15 first outputs a control signal for motor control to the control signal switching and rotation direction determination unit 28 until the signal frequency from the frequency counter 29 falls within the pull-in range of the PLL. Then, when the signal frequency from the frequency counter 29 enters the pull-in range of the PLL, the microcomputer 15 shifts the control to the control signal switching / rotation direction determination unit 28, and thereafter the determination unit 28 and the frequency / phase detector 22. The state is monitored to determine the adjusted T timing. In practice, the motor 17 alternately rotates clockwise and counterclockwise around the phase zero, so that the motor 17 is terminated after a predetermined time has elapsed.

Control signal switching / rotation direction determination unit 28
The motor control and drive unit 16 detects whether the control signal from the microcomputer 15 puts the PLL in the pull-in range or adjusts the frequency of the output signal to the target frequency, and performs corresponding control. Give instructions to.
Further, when the control is the control to match the target frequency, the control signal switching / rotation direction determination unit 28 takes in the output signal from the low-pass filter 27, determines the rotation direction of the motor from the signal, and responds. Is output to the motor control and drive unit 16 to control the rotation of the motor 17 so that the oscillation frequency from the oscillator 11 is adjusted to the target frequency.

Therefore, in the present embodiment, the PLL system is used to adjust the oscillation frequency to the target frequency.
Depending on the method, automatic adjustment to the target frequency is possible.
Further, since the counter of the present embodiment is used until the oscillation frequency falls within the pull-in range of the PLL, it is not necessary to use a high-precision frequency counter as in the conventional example, and the measurement accuracy of the counter can be lowered. The time can be greatly reduced.

FIG. 6 is a block diagram showing a third embodiment of the configuration of the adjusting device using the frequency adjusting method according to the zero beat method of the present invention. In the figure, in the third embodiment, a signal from the reference signal oscillator 21 set to the target frequency and a signal from the adjusted oscillator 11 are added by an adder 31 to obtain a beat signal containing a high frequency component. obtain. Furthermore, this beat signal is detected by the detector and the low-pass filter 32.
7 into a beat signal of the sin wave shown in FIG. 7 in which high frequency components are cut, and this signal is sampled at intervals of 1 (ms) for 100 (ms) and read by the A / D converter 33. The difference d between the value and the minimum value, that is, the amount of change within a certain time is obtained.

As shown in FIG. 6, the higher the beat frequency, the greater the amount of change, and the closer to zero beat, the smaller the amount of change. Using this change, the motor 17 that rotates the adjuster 12 is controlled and stopped at the point where the change amount is closest to "0". In this embodiment, if the sample period T is not more than ¼ cycle of the signal at that time, it may not be possible to determine the high or low, so the sample period T cannot be set too long. However, if the sample period T is short, the sensitivity becomes low when approaching zero beat. For this reason, it is necessary to divide the assumed beat frequency into some groups and set the sample period and the sample period to values suitable for the groups.

In this embodiment, when the beat frequency may be, for example, several hundreds of Hz, the frequency counter 29 is also used to set the oscillation frequency to the target frequency until the oscillation frequency falls within a certain frequency range. Fit together. However, this is not the case when it can rotate endlessly like a trimmer condenser. Therefore, in the present embodiment, since the oscillation frequency is adjusted to the target frequency by using the zero beat method, it is possible to automatically adjust to the target frequency even by the zero beat method.

[0023]

As described above, according to the present invention, in the frequency adjusting method for adjusting the oscillation frequency oscillated from the oscillator by driving the adjusting means provided in the oscillator, the oscillation is performed. A beat signal is generated by mixing a frequency signal with a reference frequency signal.
Since the adjusting means is driven so that the frequency or cycle of the beat signal is set to a predetermined value, automatic adjustment to the target frequency is performed by the beat method in a short time,
It is possible to improve automation.

In the second aspect, the signal of the reference frequency is
Since the difference from the target frequency is set to a frequency (target frequency ± offset frequency) separated by a predetermined hertz, and the adjuster is driven so that the cycle of the beat signal becomes equal to the cycle of the offset frequency, the offset frequency The automatic adjustment to the target frequency can be performed in a short cycle of.

According to a third aspect of the present invention, there is provided a frequency adjusting method for rotating the adjusting means provided in the oscillator to adjust the oscillation frequency oscillated from the oscillator to a target frequency.
A beat signal is generated by mixing a signal of the oscillation frequency with a signal of a reference frequency serving as a reference, and the adjusting unit is driven so that the frequency of the beat signal is zero-adjusted. The automatic adjustment to the target frequency can be performed in a short time, and automation can be improved.

According to the fourth and fifth aspects, in the frequency adjusting method for driving the adjusting means provided in the oscillator to adjust the oscillation frequency oscillated from the oscillator to the target frequency,
When the frequency of the signal of the oscillation frequency is detected, and the difference between the oscillation frequency and the target frequency is within the pull-in range of the phase-locked loop, the signal of the oscillation frequency and the target frequency are detected by a phase-locked loop method. The frequency difference or the phase difference from the signal of the reference frequency set in the above is obtained, the motor is rotationally controlled according to the frequency difference or the phase difference, and the adjusting means is driven to adjust the oscillation frequency to the target frequency. Therefore, even with the phase-locked loop method, automatic adjustment to the target frequency can be performed in a short time, and automation can be improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of the configuration of an adjusting device using a frequency adjusting method by the beat method of the present invention.

FIG. 2 is a configuration diagram showing a configuration of a main part of the adjusting device shown in FIG.

FIG. 3 is a waveform diagram showing waveforms of output signals in each unit shown in FIG.

FIG. 4 is a waveform diagram showing waveforms of output signals from the respective units shown in FIG.

FIG. 5 is a block diagram showing a second embodiment of the configuration of the adjusting device using the frequency adjusting method by the PLL method of the present invention.

FIG. 6 is a block diagram showing a third embodiment of the configuration of the adjusting device using the frequency adjusting method by the zero beat method of the present invention.

7 is a waveform diagram showing a waveform of a beat signal output from the detector and the low-pass filter shown in FIG.

FIG. 8 is a block diagram showing a configuration of an adjusting device using a conventional frequency adjusting method.

[Explanation of symbols]

 11 Adjusted Oscillator 12 Adjuster 13 Waveform Shaping Circuit 15 Microcomputer (Microcomputer) 16 Motor Control and Driving Unit 17 Motor 21 Reference Frequency Oscillator 22 Frequency / Phase Detector 23 Beat Pulse / High / Low Signal Generation Unit 24 Period Measurement Counter 25, 26 1 / N frequency divider

Claims (5)

[Claims] 1. A frequency adjusting method for driving an adjusting means provided in an oscillator to adjust an oscillation frequency oscillated from the oscillator to a target frequency, the signal of the oscillation frequency and a reference frequency serving as a reference. The signal is mixed to generate a beat signal, and the adjusting means is driven so that the frequency or the cycle of the beat signal becomes a predetermined value. 2. The signal of the reference frequency is set to the target frequency and the offset frequency, and the adjustment is performed so that the frequency or cycle of the beat signal becomes equal to the frequency or cycle of the set offset frequency. The frequency adjusting method according to claim 1, wherein the means is driven. 3. A frequency adjusting method for driving an adjusting means provided in an oscillator to adjust an oscillation frequency oscillated from the oscillator to a target frequency, wherein a signal of the oscillation frequency and a reference frequency serving as a reference are provided. A frequency adjusting method, characterized in that the signal is mixed with a signal to generate a beat signal, and the adjusting means is driven so that the frequency of the beat signal is zero-adjusted. 4. A frequency adjusting method for driving an adjusting means provided in an oscillator to adjust an oscillation frequency oscillated from the oscillator to a target frequency, wherein a signal of the oscillation frequency is supplied in a phase locked loop method. , Obtaining the frequency difference signal and the phase difference with the signal of the reference frequency set to the target frequency, according to the phase difference,
A frequency adjusting method characterized in that the motor is rotationally controlled, and the adjusting means is rotated so that the phase difference becomes zero to adjust the oscillation frequency to a target frequency. 5. The frequency of the oscillation frequency signal is detected, and when the difference between the oscillation frequency and the target frequency falls within the pull-in range of the phase-locked loop, the oscillation frequency is adjusted by the phase-locked loop method. The frequency adjusting method according to claim 4, wherein the frequency adjusting method is adapted to a target frequency.