JPH03219463A - Noise elimination device - Google Patents

Abstract

PURPOSE:To eliminate noise without malfunction by providing a pulse width measurement means, a comparison means, a storage means and a control signal output means. CONSTITUTION:The pulse width of inputted pulses for controlling P1 and P2 is measured by the pulse width measurement means 13 and 14. When 1/2 of the width of the pulse for controlling is regarded as a reference, for example, and the pulse having the narrower width than the reference is inputted, the comparison means 15 makes the storage means 17 store the width value of the pulse as a noise width value. The control signal output means 16 compares the pulse width value of the pulse for controlling with the noise width value, judges whether the inputted pulse is the noise or not and outputs a control signal. Since the noise width value is updated every time that the pulse for controlling is inputted, the noise is eliminated corresponding to the change of a peripheral environment.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a noise removal device, and particularly to a noise removal device suitable for a video tape recorder, etc. that employs a jog switch or an on/off switch. .

(Prior Art) Conventionally, when electronic equipment is controlled by a computer, control pulses to be input to the computer may be generated by operating a jog switch, an on/off switch, or the like. For example, a stationary video tape recorder (
Some VTRs (hereinafter referred to as VTRs) are equipped with a jog switch for instructing frame forwarding and the like. This jog switch has mechanical contacts, and by rotating it left and right, the contacts open and close. Furthermore, by providing two contacts at different positions in the rotational direction, the rotational direction of the jog switch can be determined based on which contact is turned on first.

FIG. 5 is an explanatory diagram for explaining a jog switch. FIG. 5(a) shows the outer shape of the jog switch, and FIG. 5(b) shows an equivalent circuit of the jog switch. Further, FIG. 6 is a timing chart for explaining the operation of the jog switch.

In FIG. 5(b), power supply terminal 3 is connected to output terminal 1 via resistor R1, and switch SW1, which is a mechanical contact, is connected between output terminal 1 and the reference potential point. There is. Further, the power supply terminal 4 is connected to the output terminal 2 via a resistor R2, and a switch SW2, which is a mechanical contact, is connected between the output terminal 2 and the reference potential point. These two contacts are provided at different positions in the rotational direction. For example, when the jog switch 5 is rotated clockwise, the switches SW1, SW1, and SW2 are turned on in this order.

Now, when the jog switch 5 is rotated clockwise, the switch SW1 is first turned on, and as shown in FIG. 6(a),
Pulse P1 appearing at output terminal 1 is low level (hereinafter referred to as L
11). Then, the switch SW2 is also turned on, and the pulse P2 appearing at the output terminal 2 also becomes 11 L II, as shown in FIG. 6(b). Conversely, when the jig switch 5 is rotated to the left, the switch SW2 is first turned on and the pulse P2 becomes low, as shown in FIG. 6(d), and then the pulse P2 becomes low as shown in FIG. 6(c). As shown, the switch SW1 is turned on and the pulse P1 becomes L''.

In this way, the rotational direction of the jog switch 5 can be determined based on which of the pulses PI and P2 is generated first, and the angular velocity of the jog switch 5 can be determined based on the generation timing of the pulses P1 and P2. You can also do it.

Therefore, when controlling the playback speed of a VTR based on the pulses P1 and P2, for example, the playback speed can be freely controlled in forward and reverse directions by appropriately setting the rotational direction and angular speed of the jog switch 5. Configurable.

By the way, noise such as sliding noise accompanying the rotational operation of the jog switch 5 is normally generated and applied to the computer 6 in addition to the control pulses generated by the jog switch and the on/off switches.

Therefore, a noise removal device is employed to prevent the computer 6 from malfunctioning.

FIG. 7 is a circuit diagram showing such a conventional noise removal device, and FIG. 8 is a timing chart for explaining the operation of FIG. 7.

The output terminal 1 of the jog switch 5 is connected to a reference potential point via a resistor R3 and a capacitor C1, and a connection point between the resistor R3 and the capacitor C1 is connected to a control input terminal of the computer 6. Further, the output terminal 2 of the jog switch 5 is connected to a reference potential point via a resistor R4 and a capacitor C2, and a connection point between the resistor R4 and the capacitor C2 is connected to a control input terminal of the computer 6. These resistor R3, capacitor C1, resistor R4, and capacitor C2 constitute an integrating circuit, respectively. The computer 6 controls the controlled system 7 based on the signal input to the control input terminal.

Now, assume that jog switch 5 is rotated clockwise. When the switch SW1 is turned on, the pulse P1 at the output terminal 1 becomes L'', and then the switch SW2 turns on.
is turned on, and the pulse P2 at the output terminal 2 becomes L''.

Now, as shown in FIGS. 8(a) and (b), the pulse P1
It is assumed that the noise 8 appears at the output terminal 2 before the timing of . If the pulse at the output terminal 2 is used as is, the computer 6 will erroneously determine that the jog switch 5 has rotated to the left since the noise 8 occurs before the timing of the pulse P1.

However, the pulse at the output terminal 1 is integrated by the resistor R3 and the capacitor C1, and the control input terminal of the computer 6 is given the signal shown in FIG. 8(C). Also,
The pulses at the output terminal 2 are integrated by the resistor R4 and the capacitor C2, and the signal shown in FIG. 8(d) is applied to the control input terminal of the computer 6. The computer 6 determines that the control signal is manually input and removes noise only when the signal input to the control input terminal exceeds the threshold level (downward in FIG. 8(d)). .

That is, if the width of the noise 8 shown in FIG. 8(b) is less than the predetermined width, the peak value of the integrated noise 8 will not exceed the threshold level, and the computer 6 will switch the switches SW1 and SW2. Only pulses P1°R2 caused by on and off are determined as control signals.

Incidentally, in order to remove noise, it is necessary that the noise width be equal to or less than a predetermined width based on the time constants of the resistors R3 and R4 and the capacitors CI and C2. In other words, the noise width that can be removed is the resistance R3°R4 and the capacitor CI
, C2 and the threshold level of the computer 6.

However, the width of the noise changes depending on the environment, such as temperature, humidity, power supply status, and contact failure due to rust on the switch contacts, and may become relatively large. Also,
The time constant of the integrating circuit may become small due to variations in the resistors and capacitors that make up the integrating circuit. For this reason, the computer sometimes judges noise applied to the control input terminal as a control signal, resulting in malfunction.

(Problems to be Solved by the Invention) As described above, the conventional noise removal device described above has the problem that malfunctions may occur due to changes in the noise width and changes in the time constant of the integrating circuit due to the surrounding environment. was there.

The present invention has been made in view of such problems, and includes:
It is an object of the present invention to provide a noise removal device that can prevent malfunctions by learning the state of noise generation.

[Configuration 1 of the Invention (Means for Solving the Problems) A noise removal device according to the present invention includes a pulse width measuring means that measures the pulse width of an input control pulse and outputs a pulse width value, and a Compare the pulse width value of the control pulse input with reference to a predetermined ratio of the pulse width value of the control pulse input immediately before or after the control pulse,
Comparing means for outputting the pulse width value of this pulse as a noise width value when a pulse having a width smaller than the reference is input; storage means for storing the noise width value; and the input control pulse. If the pulse width value of the control pulse is smaller than the noise width value, the control signal output means outputs a control signal for determining that the control pulse is noise.

(Function) In the present invention, the pulse width of the control pulse inputted by the pulse width measuring means is measured. For example, when a pulse having a width smaller than the reference is inputted using 1/2 of the pulse width of the control pulse as a reference, the comparison means stores the pulse width value of this pulse in the storage means as a noise width value.

The control signal output means determines whether the input pulse is noise by comparing the pulse width value of the control pulse with the noise width value, and outputs a control signal. The noise width value is updated every time a control pulse is input, and noise removal is performed in response to changes in the surrounding environment.

(Example) Hereinafter, an example of the present invention will be described in detail based on the drawings. FIG. 1 is a block diagram showing an embodiment of a noise removal device according to the present invention.

For example, pulses p1 and R2 from the output terminals of a jog switch (not shown) are applied to the input terminals 11 and 12, respectively. These pulses Pi and R2 are pulse width measuring means 1
3.14 respectively, and pulse width measuring means 13.14.
measures the pulse widths of pulses P1 and R2, respectively, and outputs the pulse width values to comparison means 15 and control signal output means 16. Comparison means 15 compares the pulse width value of pulse P1 with 1/2 of the pulse width value of pulse P2, and if the pulse width value of pulse P1 is smaller, stores the pulse width value of pulse P1. It is stored in the means 17. Also, comparison means 15
compares 1/2 of the pulse width value of the pulse P1 and the pulse width value of the pulse P2, and if the pulse width value of the pulse P2 is smaller, the pulse width value of the pulse P2 is stored in the storage means 1.
7 to be memorized. The storage means 17 stores the input pulse width value as a noise width value for determining whether or not the pulses P1 and R2 are noise, and provides this noise width value to the control signal output means 160. The control signal output means 16 outputs pulses P1°P2
, and the noise width value from the storage means 17, and if the pulse width values of the pulses Pi and P2 are smaller than the noise width value, the input pulses P1. ．． A control signal for determining pulse P2 as noise and ignoring pulses P1 and P2 is output to a control combi coater (not shown).

Note that these pulse width measuring means 13, 14, comparing means 15, control signal output means 16, and storage means 17 can be configured by software.

Next, the operation of the noise removal device configured as described above will be explained with reference to the flowchart of FIG. 2. Second
The figure shows a case where it is configured by software.

First, in step S1, an initial value of the noise width value is set. As a result, the predetermined noise width value is stored in the storage means 17.
is memorized. In step S2, main routine processing is performed, and in step S3, a pulse P is applied to input terminals 11 and 12.
1, it is determined whether P2 is input or not. When pulses Pi and P2 are input, the process moves to steps 84 and 85. Step 84.8
5, the pulse P is measured by the pulse width measuring means 13.14.
1, the pulse width of P2 is measured. The pulse width value, which is the measurement result, is output to the comparison means 15, and then the next step S6
, the pulse width value of pulse P1 and 1/2 of the pulse width value of pulse P2 are compared. If the pulse width value of the pulse P1 is smaller, the pulse width value of the pulse P1 is output to the storage means 17 and stored in the next step S7.

Next, similar processing is performed in steps 88 and 89, and if the pulse width value of pulse P2 is smaller than 1/2 of the pulse width value of pulse P1, the pulse width value of pulse P2 is stored in the storage means 17. Make me remember.

In the next step SIO, the storage means 17 outputs the stored data as a noise width value to the control signal output means 16. The control signal output means 16 is connected to the pulse width measurement means 1.
From 3.14, the pulse width values of pulses P1 and P2 are also input, and these pulse width values and noise width values are compared. If the pulse width value of the pulses P1 and P2 is smaller than the noise width value, the control signal output means 16 determines that the pulses P1 and P2 are noise, and performs control to ignore these pulses in the next step 811. A signal is sent to the control computer.

In this way, in this embodiment, a pulse width smaller than 50% of the pulse width of pulses P1 and P2 is used as the noise width value, which is the criterion for determining whether an input pulse is noise. By updating this noise width value every time P1°P2 is input, it is made to correspond to changes in the surrounding environment.

In addition, since the jog switch is operated by the user's hand, the pulses P1, P
Although the pulse width of a pulse smaller than 50% of the pulse width of No. 2 is used as a reference for noise discrimination, it is not limited to 50% and may be set to an appropriate value depending on the system. Furthermore, although negative polarity noise has been described in this embodiment, positive polarity noise can also be dealt with in the same manner.

FIG. 3 is a block diagram showing another embodiment.

This embodiment is an example applied to a jog switch or the like having one contact point.

This embodiment differs from the embodiment shown in FIG. 1 in that the pulse width measuring means 14 is omitted and a comparing means 18 is used in place of the comparing means 15. The comparison means 18 compares the pulse width values of the pulses inputted one after the other. That is, the input terminal 11
When the pulse P1 inputted to is smaller than 1/2 of the pulse width value of the previously inputted pulse, the pulse width value of this pulse P1 is stored in the storage means 17 as a noise width value. .

Next, the operation of the noise removal device configured as described above will be explained with reference to the flowchart of FIG. 4.

The processing up to step S4 is similar to the embodiment shown in FIG. In the next step 812, the control signal output means 16
compares the pulse width value of the pulse P1 with the noise width value from the storage means 17, and if the pulse width value of the pulse P1 is smaller, the pulse P1 is judged to be noise and the pulse P1 is Outputs a control signal to the computer to ignore it.

Further, in step 813, the comparison means 18 compares 1/2 of the pulse width value of the previous pulse with the newly input pulse P.
1 and the newly input pulse P.
If 1 is smaller, this pulse width value is converted into a noise width value and stored in the storage means 17 in step 314.

In this embodiment as well, the noise width value is updated every time a pulse is input, and the same effect as in the embodiment shown in FIG. 1 is obtained.

[Effects of the Invention] As explained above, according to the present invention, since the noise width value is updated every time a control pulse is input, it is possible to remove noise in response to changes in the surrounding environment, etc. has.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing one embodiment of the noise removal device according to the present invention, Fig. 2 is a flowchart for explaining the operation of the fifth embodiment of Fig. 1, and Fig. 3 shows another embodiment. A block diagram, FIG. 4 is a flowchart for explaining the embodiment of FIG. 3, FIG. 5 is an explanatory diagram for explaining the jog switch, and FIG. 6 is a timing chart for explaining the operation of the jog switch. FIG. 7 is a circuit diagram showing a conventional noise removing device, and FIG. 8 is a timing chart for explaining the operation of FIG. 7. 13, 14... Pulse width measuring means, 15... Comparing means, 16... Storage means, 17... Control signal output means.

Claims (1)

[Scope of Claims] Pulse width measuring means for measuring the pulse width of an input control pulse and outputting a pulse width value; Or compare the pulse width value of the control pulse that is input immediately after using it as a reference, and if a pulse with a width smaller than the reference is input, the pulse width value of this pulse is output as the noise width value. a comparison means for storing the noise width value; and a control for determining the input control pulse as noise when the pulse width value of the input control pulse is smaller than the noise width value. 1. A noise removal device comprising: control signal output means for outputting a signal.