JPS5833797B2 - Digital pitch control method for rotating machines - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a digital pitch control system, and is used, for example, in a servo system for controlling the rotation speed of a rotating machine in audio products.

In the conventional digital pitch control system, as shown in FIG. 1, the output frequency f of a crystal oscillator 1 is controlled.

The frequency is divided (-2-) by the frequency divider 5 and the output frequency signal is outputted to the phase detector 6.

Phase 1 The output of the phase detector 6 is applied to a voltage controlled oscillator 7, and the output of the voltage controlled oscillator 7 is divided by a frequency divider 9 to become an output frequency f and supplied to a motor 10.

If the frequency division ratio of frequency divider 9 is m2, its input frequency is m
It is 2f.

This frequency m2f is divided by a desired frequency division ratio m in a divider 8 provided in the feedback circuit, and the output frequency knee f is applied as a second power to the phase detector 6.

Since the two inputs to the phase detector 6 are controlled to be equal, the relationship f □ = m 2 · f is established, and f = fo / m1 m2! Well.

1. However, in the circuit of FIG. 1, if the divider 5 is used with, for example, 10 stages, the divider 9 with, for example, 14 stages, and the frequency divider 8 with, for example, 11 stages, the total number of dividers is 3.
There are problems in that a five-stage branching unit is required, as well as a phase detector 6 and a highly stable voltage controlled oscillator 7.

Therefore, as an alternative to the device shown in Fig. 1, the output frequency fo of the crystal oscillator is given to the input of the program counter, the frequency is divided by 1/n by the program counter, and the output frequency f
A possible method is to supply =fo/n to the electric motor 10.

However, in this case, the n value given to the program counter is specified as n=1.2.3 as in a normal program counter. ..., then the output frequency is f = fo.

fO/2. fO/3. ...and is not directly proportional to the change in the n value.

This is not appropriate when the rotational speed of a rotating machine is controlled by a percentage value of the rotational speed change rate, such as digital pitch control of a rotating machine.

Therefore, it has been difficult to apply a program counter to digital pitch control of conventional rotating machines.

SUMMARY OF THE INVENTION In view of the above-mentioned problems with the conventional type, an object of the present invention is to develop a digital pitch control system based on the idea that a calculation circuit outputs a set division ratio determined by a percentage value that represents a desired rate of change of the output frequency with respect to a reference output frequency. - We have created a highly practical digital pitch control system by making the system relatively simple, reducing the number of original drawings required for manufacturing, and realizing an output frequency change that corresponds directly to the key force applied by the operator. be.

In the present invention, in a digital pitch control method in which the output of an oscillator is frequency-divided by a counter serving as a divider to obtain a desired output frequency, the frequency division ratio for obtaining a reference output frequency is set to n.

A nuclear counter is controlled by a calculation circuit that outputs a set division ratio n when α is a percentage value representing the desired rate of change of the output frequency with respect to the reference frequency. A digital pitch control method is provided that is characterized by controlling rotation.

FIG. 2 shows a circuit used in a digital pitch control system for a rotating machine as an embodiment of the present invention.

Output frequency f of crystal oscillator 1. is divided by the frequency divider 4 to obtain the desired output frequency f.

A counter is used as the branching unit 4.

In general, the counter is operated as an N-ary counter so that the frequency f of the input signal can be adjusted.

Since it is possible to obtain an output signal with a frequency corresponding to 1/N of , it can be used as a branching device.

The branching unit 4 uses the set branching ratio n as a control input to branch the receiving station.

The set frequency division ratio of the divider 4 is determined as follows.

That is, the division ratio for obtaining the reference output frequency f8 is n.

Assuming that the desired rate of change of the output frequency with respect to the reference output frequency is α, it is determined by the following relational expression.

In order to obtain a set division ratio n that satisfies this relational expression, a calculation circuit 3 is provided, and the calculation circuit 3 is operated by the key device 2.

When the set division ratio n satisfies the relationship of equation (1), the set division ratio changes in response to a change in the value of α given as the output of the key device 2, and the output corresponds to a change in the set division ratio. The frequency f changes.

The value of α is 0.1, 2. In response to the change, f
”, 1.01o, 1.02u, ... n□.

In this way, the change in f is directly proportional to α, which is convenient when operating digital pitch control.

FIG. 3 shows one example of a specific configuration of the calculation circuit 3.

The key buffer register 31 receives the output of the key device 2.

By operating keys on the key device 2, the output frequency of the counter can be set to the reference value f, the output frequency can be changed in percentage steps on the positive side with respect to the reference value f, or it can be changed on the negative side in percentage steps. It is possible to vary the output frequency.

Note that the key may be such that by continuously pressing it, the output frequency changes in percent increments, and by pressing it in steps, the output frequency changes in steps in percent increments. It is possible.

The desired rate of change of output frequency with respect to the reference output frequency is α
It is called φ, but the minimum increment is called pitch P,
Obtain the α-KP relationship.

K is an integer.

A digital signal corresponding to K is output from the key buffer register 31 to the arithmetic unit 33.

The digital signals are added or subtracted in the arithmetic unit 33.

Further, the arithmetic unit 33 outputs an address signal corresponding to the contents of the key buffer register 31.

The memory 34 called up by this address signal outputs data for creating the division ratio n for obtaining the output frequency f from the division ratio n for obtaining the reference output frequency f 2 , and this data is input to the arithmetic unit 35 .

The arithmetic unit 35 calculates a desired set division ratio n based on input data and a reference frequency division ratio n.

Arithmetic unit 33 and arithmetic unit 35 are controlled by the output signal of control circuit 32.

The output signal of the calculator 35 sets the set division ratio n of the divider 4.

As a result, the splitter 4 outputs the frequency f.

The output frequency 1 obtained by dividing the frequency by 1/n is supplied to the electric motor 10.

The calculation circuit 3 of FIG. 3 may be in the form of a microcomputer.

Thereby, the circuit shown in FIG. 2 can be realized using a microcomputer.

Figure 4 shows circuit 3 as another example of the specific configuration of the calculation circuit.
′ is shown.

The key buffer register 31' receives the output of the key device 2.

An addressing signal corresponding to the percentage change in the output frequency is output from the key buffer register 31'.

The address of the memory 34' is designated by this output, and from the address, pre-stored data corresponding to the percentage value, ie, the set division ratio n, is read out, and this is supplied to the division unit 4.

FIG. 4 shows a so-called frequency division ratio storage format. The calculation circuit 3' in FIG. 4 can also be in the form of a microcomputer.

Thereby, the circuit shown in FIG. 2 can be realized using a microcomputer.

According to the present invention, the system for digital pitch control of a rotating machine has a relatively simple configuration, reduces the number of manufacturing originals, and realizes an output frequency change that corresponds directly to the key force by the operator, and is highly practical. High digital pitch control method % type %

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a conventional digital pitch control system, FIG. 2 is a diagram of a circuit used in a digital pitch control system for a rotating machine as an embodiment of the present invention, and FIGS. Each figure is a diagram showing a specific configuration of the calculation circuit in FIG. 2. Explanation of symbols, 1...Crystal oscillator, 2...
・Key device, 3, 3'... Calculation circuit, 4...
... Counter as a frequency divider, 5... Frequency divider, 6... Phase detector, 7... Voltage controlled oscillator, 8... Frequency divider, 9... Frequency divider, 10... Rotating machine, 3L31'... Key buffer register, 32... Control circuit, 33
......Arithmetic unit, 34.34'...Memory, 35...Arithmetic unit.

Claims (1)

[Claims] 1. In a digital pitch control method in which the output of an oscillator is frequency-divided by a counter serving as a frequency divider to obtain a desired output frequency, the frequency division ratio for obtaining a reference output frequency is n. The counter is controlled by a calculation circuit that outputs a set frequency division ratio n when α is a percentage value representing the desired rate of change of the output frequency with respect to the reference output frequency, and the counter is rotated by the output of the counter. A digital pitch control method for rotating machines that is characterized by controlling the rotation of the machine.