JPH0345186A - Digital phase servo device - Google Patents

Abstract

PURPOSE:To permit phase servo without any problem by a method wherein an object to be controlled is controlled so that a phase comparison output, produced by a second reference information obtained from a first reference information and a comparison information, becomes a predetermined value. CONSTITUTION:A memory means 2 samples a counting output S2 from a counting means 1 with the timing of the arrival of a reference signal S3 to store a first reference information S4 while another memory means 3 samples the counting output S2 with the timing of the arrival of a comparison signal S5 from an object 7 to be controlled to store a comparison information S6. The frequency of the comparison signal S5 is set so as to be integral multiples of the reference signal S3 and, therefore, an operating means 4 operates a reference signal having the same frequency as the comparison information S6 based on the reference information S4 to produce and store a second reference information S7. Another operating means 5 operates a difference between the reference information S7 and the comparison information S6 to output a phase comparison output S8. A control means 6 controls the object to be controlled so that the value of the phase comparison output 8 becomes a predetermined value.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a digital phase servo device that is suitable for phase servo when the frequency of a comparison signal is higher than a reference signal.

Conventional technology Servo devices in magnetic recording and reproducing devices (hereinafter referred to as VTR) have changed from analog servo to digital servo.
Then, digital servos shifted from hardware to software servos. Software servo is a servo device realized by program processing by a microcomputer (for example, there is a digital phase servo circuit disclosed in Japanese Patent Application Laid-Open No. 80-13488), which has a high degree of freedom in design and shortens the development period. It has features such as being measurable.

As is well known, in the conventional servo device described above, the frequencies of the reference signal and comparison signal in phase servo are set to be equal. This is because phase comparison is impossible if the frequencies of the two signals are different; for example, in a home VTR, the frequency for phase comparison is set to 30 Hz, regardless of whether it is recording or reproducing.

Problem to be Solved by the Invention However, in the above configuration, since the frequency of the reference signal is 30Hz, the frequency of the comparison signal is set to 30Hz.
The problem was that it could not be made higher.

The present invention is intended to solve the above-mentioned conventional problems, and can handle cases where the frequency of the comparison signal is higher than the frequency of the reference signal, or when the frequency of the comparison signal is an integral multiple of the frequency of the reference signal. The object of the present invention is to provide a digital phase servo device that can perform phase comparison without any problems even when the ratio is a non-integer multiple.

Means for Solving the Problems To achieve this object, a digital phase servo device according to the invention of claim 1 of the present application includes a counting means for counting clock pulses, and an output of the counting means at the timing when a reference signal arrives. The first information to be detected and stored as the first reference information.
and a second memory that detects the output of the counting means at the timing when a comparison signal from a controlled object having a frequency that is an integral multiple of the reference signal arrives and stores comparison information obtained by the detection. means, a first calculation means for calculating reference information as a reference for the comparison signal from the first reference information, and storing and outputting second reference information obtained by the calculation; a second calculation means that calculates a difference between the reference information and the comparison information and outputs a phase comparison output obtained by the calculation; and control that controls the controlled object so that the phase comparison output becomes a predetermined value. and means.

In addition to this, when the comparison signal has a frequency that is a non-integer multiple of the reference signal, the invention of claim 2 of the present application calculates in synchronization with the reference signal, and calculates the synchronization ratio between the reference signal and the comparison signal. correction value generating means for generating correction information corresponding to the first reference h?; and a correction means for correcting the information using the correction information.

Operation With the above configuration, the present invention calculates and creates second reference information corresponding to comparison information by the first calculation means from the first reference information, and creates the second reference information by the second calculation means. A phase comparison output is created by calculating the difference between the comparison information and the controlled object so that the phase comparison output becomes a predetermined value. Even if the phase servo device is set, a phase servo device can be realized without any problem.

Furthermore, correction information is generated by calculation in synchronization with the reference signal, the first reference information is corrected using this correction information, and the second reference information is calculated and used from the corrected first reference information. Therefore, even if the comparison signal has a frequency that is a non-integer multiple of the reference signal, the phase servo device can be realized without any problem.

EXAMPLES Hereinafter, examples of the present invention will be described with reference to the drawings.

FIG. 1 is a functional block diagram of a digital phase servo device according to a first embodiment of the present invention, and FIG. 2 is a waveform diagram for explaining its operation. Note that in the waveform diagram, digital signals are shown in analog form.

The configuration and operation of FIG. 1 will be described below with reference to the waveform diagram of FIG. 2.

The counting means 1 counts the clock pulses S1, and stores the obtained count output S2 (waveform A in FIG. 2) in the second storage means 2.
, 3. The first storage means 2 samples the count output S2 at the timing when the reference signal S3 (waveform B in FIG. 2) arrives, and the detection output detected by the sampling, that is, the first reference information S4 (waveform B in FIG. 2). D). The second storage means 3 samples the count output S2 at the arrival timing of the comparison signal 85 (waveform C in FIG. 2) from the controlled pair Ji7, and stores the detection output detected by the sampling, that is, the comparison information S6 Store waveform E) in the figure. The frequency of the comparison signal S5 is the reference signal S
Since it is set to an integral multiple of 3 (here, n=3 is exemplified), the first calculation means 4 uses the first reference information S
4, as described later, calculates a reference signal having the same period as the comparison information S6, and by the calculation, momentary reference information, that is, second reference information S7, which becomes the reference of the comparison signal S5.
(Waveform F in FIG. 2) is created and stored.

The second calculation means 5 calculates the second reference information S7 and the comparison information S6.
The difference is calculated by the calculation, and the calculation output obtained by the calculation, that is, the phase comparison output S8 is output.

The control means 6 outputs a control output S according to this phase comparison output S8.
9 and controls the controlled object 7 so that the value of the phase comparison output S8 becomes a predetermined value. Note that a block 8 surrounded by a broken line is a part that can be programmed by a microcomputer.

This embodiment is characterized in that a first calculation means 4 is provided. The characteristic points will be explained below.

As mentioned above, the frequency of the comparison signal S5 is set to an integral multiple n of the reference signal S3, so the first reference information S4 is obtained only once every n times the comparison information S6 is obtained, and the remaining It does not have any information about n-1 times. Therefore, the first reference information S4 cannot be used as the reference information for the comparison information S6 as it is. Therefore, the first calculation means 4 performs the first calculation in order to obtain the missing reference information n-1 times.
The second reference information S7 is created based on the reference information S4. That is, as shown in the example of n=3 in FIG. 2, the values NA, NB,
... from the value NAI of the waveform F (second reference information S7),
NA2. NA3. NBI, NB2, NB3. ...
is being created. Note that NA1=NA, NB1=NB,
..., and the arithmetic expression is given by the following equation (1).

NAm=NA+(m-1)・M.

NBm=NB+ (m-1)6M.

NCm=:NC+ (m-1)-M.

...(1) Here, m is a positive integer from 1 to n, and the value of M is Tr/n, which is 1/n of the period Tr of the reference signal S3, which is calculated by the counting means 1.
or the period T of the comparison signal S5
This is a value obtained by converting c into the count value of the counting means 1, and is given as a constant value. Alternatively, by calculating based on the first reference information S4, for example, % M = (N B N A )
/ n may be used. Note that when performing an addition operation in the first calculation means 4, the sign of M is
+", and "-" when performing subtraction operations.

The second reference information S7 created in this way is used in the calculation of the difference between the comparison information S6 and the comparison information S6 in the second calculation means 5. NA2
and N2. NA3 and N3. NB1 and N4. NB2 and N5.
NB3 and N6. ...and so on.

Note that the second reference information S7 shown in waveform F in FIG. 2 is calculated immediately after the first reference information S4 is obtained to obtain NA1.
NA2. NA3. NB1. NB2゜NB3. ...
This is an example in which reference information is created, stored and used, but it may also be calculated and used every time comparison information S6 is obtained, as shown by waveform G in FIG.

FIG. 3 is a functional block diagram of a digital phase servo device according to a second embodiment of the present invention, and FIG. 4 is a waveform diagram for explaining the same. Note that the waveforms A to G in FIG. 4 correspond to the input and output of each means, as in the case of FIG. 2. The second embodiment will be described below, focusing on the differences from the first embodiment.

This embodiment is suitable for the case where the comparison signal S5 is a non-integer multiple of the reference signal S3. The difference between this embodiment and the first embodiment (FIG. 1) is that correction value generation means 8 and correction means 9 are added, and the correction value generation means 8 makes corrections in synchronization with the reference signal S3. The point is that information S10 is generated and this correction information S10 is given to the correction means 9 as correction data. The correction means 9 includes the first storage means 2 and the first
The first reference information S4 is corrected by the correction information 810, and the corrected reference information S11 is provided to the first calculation means 4 at the next stage. That is,
The feature of this embodiment compared to the first embodiment is that the correction information S10 is generated to correct the first reference information S4.

This is to cope with the fact that the frequency of the comparison signal S5 is a non-integer multiple of the reference signal. This characteristic point will be explained in detail below.

Since the frequencies of the reference signal S3 and the comparison signal S5 are known in advance, the correction information S10 is created based on the value below the decimal point when the period of the reference signal S3 is divided by the period of the comparison signal S5. Now, when the value below the decimal point is α and the period of the comparison signal S5 is Tc, the value Nx of the correction information S10 is 0.
It is a cyclic value that takes a value from to Mc (where, Mc is the value obtained by converting the period Tc of the comparison signal S5 to the count value of the counting means 1), and every time the reference signal S3 arrives, α・Mc
It is created by generating a value by adding (or subtracting) . Note that the starting value when calculating α·Mc by addition (or subtraction) may be any value from O to MG*. Further, Nx may be created by the above-mentioned calculation or by reading from a ROM (recurring memory). When using a ROM, this can be done, for example, by counting the reference signal S3 with a power counter and reading out the content (correction information) previously written in the ROM using the count output as an address.

Note that when the first calculation means 4 performs an addition operation, the sign of Mc is "10", and when it performs a subtraction operation, it is "-". Further, the value Nx of the correction information S10 has a sign of "+" when it is created by addition in the correction value generating means 9, and a sign of "-" when it is created by subtraction.

The correction information S101 obtained as described above is input to the correction means 10 to correct the first reference information S4. Then, the corrected reference information 311 is sent to the first calculation means 4 at the next stage.
is input, and the same calculation as in the first embodiment is performed to create second reference information S7. The second reference information S7 is calculated using the following formula (2
) can be calculated.

NAm=(NA+Nx)+(m-1)・Mc.

N2m=(NB+NX)+(m-1)*Mc.

NCm=(NC×Nx)+(m-1)*Mc.

(2) The second reference information S7 created in this way is used as the comparison information S6 in the second operator stage 5, as in the first embodiment.
Used to calculate the difference between NAI, NLNA2 and N2
．． NA3 and N3. NBI and N4. NB2 and N5. NB3
and N6. ...and so on.

Note that the second reference information S7 shown in waveform F in FIG. 4 is corrected by the correction information S10 immediately after the first reference information S4 is obtained, and the subsequent calculation is performed to obtain NA1. NA2. NA
3. NBI, NB2. In this example, the reference information for NB3, . . . is created, stored, and used. First comparison signal S with respect to reference signal S3
5), the correction may be performed using the correction information 810, and the comparison information S6 may be calculated and used every time the comparison information S6 is obtained.

In the second embodiment, the correction means 10 is provided between the first ρ storage means 2 and the first calculation means 4, but in the third embodiment, the correction means 10 is provided between the first ρ storage means 2 and the first calculation means 4. The object of the present invention can be similarly achieved by providing a configuration between the first calculation means 4 and the second calculation means 5.

Effects of the Invention As described above, in the present invention, when the frequency of the comparison signal is an integral multiple of the reference signal, the comparison signal is detected based on the first reference information detected from the counting means using the reference signal. The configuration is such that momentary second reference information corresponding to the comparison information is created and used, and if the frequency of the comparison signal is a non-integer multiple of the reference signal, the first reference information is used as a correction value. Phase servo is realized by correcting using correction information from the generating means, and creating and using second reference information based on the corrected reference information, and the frequency of the reference signal and comparison signal is Even if the values are different, phase servo can be realized without any problem, and a great effect can be achieved.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a digital phase servo device according to a first embodiment of the present invention, FIG. 2 is an operation waveform diagram of the same embodiment, and FIG. 3 is a digital phase servo device according to a second embodiment of the present invention. FIG. 4 is a block diagram of the same embodiment, and FIG. 4 is an operational waveform diagram of the same embodiment. 1... Counting means, 2... First storage means, 3.
...Second storage means, 4...First calculation means, 5
...Second calculation means, 6.Control means, 7..
・Controlled object, 8...Microcomputer, 9
... Correction value generating means, 10... Correction means.

Claims (2)

[Claims] (1) a counting means for counting clock pulses; a first storage means for detecting the output of the counting means at the timing when a reference signal arrives and storing it as first reference information; A second device that detects the output of the counting means at the timing when a comparison signal from a controlled object having a frequency arrives, and stores comparison information obtained by the detection.
storage means; a first calculation means for calculating reference information serving as a reference for the comparison signal from the first reference information and storing and outputting a second reference signal obtained by the calculation; a second calculation means that calculates a difference between the second reference information and the comparison information and outputs a phase comparison output obtained by the calculation, and controls the controlled object so that the phase comparison output becomes a predetermined value. A digital phase servo device comprising a control means for controlling. (2) a counting means for counting clock pulses; a first storage means for detecting the output of the counting means at the timing when a reference signal arrives and storing it as first reference information; and a non-integer multiple of the reference signal. a second storage means for detecting the output of the counting means at the timing when a comparison signal from a controlled object having a frequency of a correction value generating means for generating correction information corresponding to a synchronization ratio between a reference signal and a comparison signal; a correction means for correcting the first reference information using the correction information; and a correction value generating means for correcting the first reference information using the correction information; a first calculating means that calculates reference information serving as a reference for a comparison signal, and stores and outputs second reference information obtained by the calculation; and calculates a difference between the second reference information and the comparison information. A digital phase servo device comprising: second calculation means for outputting a phase comparison output obtained by the calculation; and control means for controlling the controlled object so that the phase comparison output becomes a predetermined value. .