JPH0142185Y2 - - Google Patents

Description

[Detailed explanation of the idea]

The present invention relates to a variable digital output device suitable for use in a so-called digital volume or the like. A conventional variable digital output device, for example a digital volume, has strip electrodes 3 arranged at different predetermined intervals for each row in the sliding direction of a brush 2 on a substrate 1 made of an insulator, as shown in FIG. They are disposed intermittently, and a parallel digital signal corresponding to the position of the brush 2 is output by utilizing the fact that the potential of each bit output terminal 4-1 to 4-n becomes Vc or 0 depending on the position of the brush 2. In this conventional variable digital output device, when the brush 2 is located near the boundary between the electrode 3 and the substrate 1, the contact becomes unstable and there is a risk of chattering. Conventionally, as a circuit for absorbing chattering, there is a chattering noise removal circuit using, for example, an Rc integrating circuit. However, the chattering that can be absorbed by this circuit has an interval of 10 ms.
This kind of conventional chattering noise removal circuit absorbs chattering with irregular intervals and intervals of all lengths, which occur when the brushes 2 are placed at the same position. It is not possible. It is an object of the present invention to eliminate such drawbacks and provide a variable digital output device free from chattering. To achieve this objective, the present invention arranges a first electrode corresponding to a first logical value and a second electrode corresponding to a second logical value in the form of an alternating binary code in the sliding direction of the brush. , each output from the first and second electrodes is supplied to a flip-flop so that the flip-flop is set when the brush contacts the first electrode and reset when the brush contacts the second electrode. , the output of the flip-flop is taken out as each bit output of a digital output. Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 2 shows a first embodiment of the variable digital output device of the present invention, in which on a substrate 1 made of an insulator,
In the sliding direction of the brush 2, there is an electrode 3 shown by hatching.
are placed in the same way as before. Between these electrodes 3, an electrode 11 shown with a dotted pattern is arranged.
The gap between the electrode 3 and the electrode 11 is set to such an extent that the brush 2 does not come into contact with both electrodes 3 and 11 at the same time, but it is preferably made as narrow as possible. An electrode voltage Vc is supplied to each brush 2. The electrodes 3 are grouped in each column and connected to a set terminal S of a NOR type RS flip-flop 12 corresponding to that column, and also grounded via a resistor 13. In the same way, put together the electric wires 11 for each column, and set the Noah type RS corresponding to that column.
It is connected to the reset terminal R of the flip-flop 12 and also grounded via a resistor 13. The output Qnx appearing at the bit output terminal 14 of each NOR type RS flip-flop 12 changes as shown in Table 1 as the brush 2 slides.

[Table] For example, in Fig. 3, when the brush 2 is moved in the direction of arrow A and stopped at the position indicated by the two-dot chain line, if the tip of the brush 2 contacts the electrode 3 even momentarily, the Noah type RS flip-flop Output Qnx
becomes “1”, and then “separate” at that position ←→
Even after repeated "contacts", no chattering occurs at the output 14. Also move brush 2 to arrow A
If the brush 2 is moved in the opposite direction and stopped at the position shown by the solid line, if the tip of the brush 2 touches the electrode 11 even momentarily, the output Qnx will be "0" and then "separate" at that position ←→" No chattering occurs at the output 14 even after repeated contact. FIG. 4 shows a second embodiment. This example is
This embodiment differs from the first embodiment in that the brush 2 is grounded, the power supply voltage Vc is supplied to each electrode 3 and 11 through a resistor 13, and the flip-flop 21 is a NAND-type RS flip-flop. Note that the same parts in the first embodiment are given the same reference numerals. In this embodiment, when the tip of the brush 2 contacts the electrode 3, the potential at the input terminal of the NAND-type RS flip-flop 21 becomes zero, the output Q ₁ x at the output terminal 22-1 becomes "1", and the tip of the brush 2 comes into contact with the electrode 3. When the brush 2 comes into contact with the electrode 11, the potential of the input terminal becomes zero and the output Q ₁ x becomes "0", and when the tip of the brush 2 is not in contact with either the electrode 3 or the electrode 11, the previous output Keep Qn(x-1). This second
Table 2 shows the truth values of the examples.

[Table] A third embodiment is shown in FIGS. 5 and 6. In this embodiment, the voltage Vc is supplied to the electrode 3, the electrode 11 is grounded, the space 31 between each brush 2 is insulated, the voltage change of each brush 2 is detected by a comparator circuit, and the output is used as a NOR type RS. Drives the flip-flop. FIG. 6 shows an example of the circuit configuration for one bit in this embodiment. Here, 32 is an equivalent circuit corresponding to the electrode 3, electrode 11 and brush 2,
When the brush 2 is in contact with the electrode 3, the switch contact 33 in this equivalent circuit is in contact with the Vc side contact 34, and when the brush 2 is in contact with the electrode 11, the switch contact 33 is in contact with the ground side contact 35. come into contact with When the brush 2 is not in contact with either the electrode 3 or the electrode 11, the switch contact 33 is in a neutral state. Resistors 36, 37, and 38 are connected in series, and voltage Vc is supplied to the open end of resistor 36, and resistor 3
Supply voltage -V _E to the open end of 8. A terminal 39 of the switch contact 33 is connected to a connection point 40 between the resistors 36 and 37, and this connection point 40 is coupled to the base of the transistor _Tr1 through a resistor 41. Connection point 42 between resistor 37 and resistor 38 and transistor
It is connected to the base of Tr ₂ through a resistor 43. resistance 44
The voltage Vc is supplied to the transistor Tr ₁ through the resistor 45, and the voltage Vc is supplied to the transistor Tr ₂ through the resistor 45. The collector output of transistor Tr ₁ is NOR type.
It is supplied to the reset terminal R of the RS flip-flop 12. The collector output of the transistor Tr ₂ is supplied to the set terminal S of the NOR type RS flip-flop 12 via the inverter 46. The values of resistors 36, 37 and 38 and voltages Vc and _-VE are determined such that when switch contact 33 is in a neutral state, transistor Tr ₁ is in a conductive state and transistor Tr ₂ is in a cut-off state. In other words, the potential at the connection point 40 becomes higher than the ground potential by a predetermined value, and the transistor
The base current flows through Tr ₁ and this transistor
Also, connect the connection point 42 so that Tr ₁ becomes conductive.
The potential of the transistor Tr 2 becomes close to or more negative than the ground potential, so that no base current flows through the transistor Tr ₂ and the transistor Tr ₂ is cut off. Table 3 shows the truth values of the third embodiment.

[Table] That is, when the brush 2 is in contact with the electrode 3, the switch contact 33 in FIG.
, the potential of the connection point 40 is Vc, and the potential of the connection point 42 is a positive potential that is slightly lower than this. At this time, transistors Tr ₁ and Tr ₂ are both conductive,
The collector outputs of transistors Tr ₁ and Tr ₂ are both at the "0" level, but the collector output of transistor Tr ₂ is inverted by the inverter 46, so
"1" to terminal S of NOR type RS flip-flop 12
is supplied, and its output Qnx becomes "1". When the brush 2 is in contact with the electrode 11, the switch contact 33 is in contact with the contact point 35, the connection point 40 is at ground potential, the connection point 42 is at a negative potential,
Transistors Tr ₁ and Tr ₂ are both cut off. Therefore, "1" is supplied to the reset terminal R of the NOR type RS flip-flop 12, "0" is supplied to the set terminal, and its output Qnx becomes "0". When the brush 2 is not in contact with any of the electrodes 3 and 11, the switch contact 33 is neutral. In this case, as described above, transistor Tr ₁ is conductive, transistor Tr ₂ is in a cut-off state, and the collector output of transistor Tr ₁ is "0".
It is supplied as is to the reset terminal R of the NOR type RS flip-flop 12, and the collector output "1" of the transistor _Tr2 is inverted by the inverter 46, and its output "0" is supplied to the set terminal S. Therefore, the output Qnx of the NOR type RS flip-flop 12 does not change and maintains the previous logical value Qn(x-1). 7A and 7B show an example of the arrangement of the electrodes 3 and 11 when the output of the variable digital output device is 3 bits. In particular, FIG. 7A shows an arrangement of the electrodes 3 and 11 so that the output becomes a normal natural binary code. FIG. 7B shows an example in which the electrodes 3 and 11 are arranged so that the output is an alternating binary code. In the variable digital output device of the present invention, the brush 2 is connected to the electrode 3.
If the power is turned on without contacting any of brush 2 and 11, it is uncertain whether the output Qnx of RS flip-flop 12 or 21 of the bit corresponding to brush 2 will be "1" or "0". It is. In the electrode arrangement according to the normal natural binary code shown in FIG. 7A, in the worst case, the outputs of all three bits may become undefined at the position of the arrow X. On the other hand, in the electrode arrangement corresponding to the alternating binary code shown in FIG. 7B, only one bit output becomes undefined. Note that even if the electrode arrangement is in accordance with the normal natural binary code shown in Fig. 7A, the brush position where the output of one or more bits is unstable is made as close as possible to the gap between the electrodes, so that sliding cannot occur. This is limited to a limited range of possibilities and poses no practical problem. As explained above, according to the variable digital output device of the present invention, even if the brush is stopped near the boundary of the electrodes and chattering continues with uneven spacing between the brush and the electrodes, the output will not suffer from any chattering. Therefore, stable variable digital output can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the main parts of an example of a conventional variable digital output device, FIG. 2 is a block diagram showing the main parts of a first embodiment of the variable digital output device of the present invention, and FIG. 3 is a block diagram showing the main parts of an example of the variable digital output device of the present invention. A partial side view for explaining the operation of the variable digital output device, FIG. 4 is a block diagram showing the main part of the second embodiment of the variable digital output device of the present invention, and FIGS. An example is shown, and FIG. 5 is a configuration diagram showing electrodes, brushes, etc.
Figure 6 is a circuit diagram for 1 bit, Figure 7A is a diagram showing an example in which electrodes are arranged to form a normal natural binary code, and Figure 7B is a diagram showing electrodes arranged to form an alternating binary code. It is a line diagram showing an example of arrangement. 1... Board, 2... Brush, 3... Code "1"
Electrodes corresponding to 4...bit output terminals, 11...
...Electrode corresponding to code "0", 12...Noah type
RS flip-flop, 13...Resistor, 14...
Bit output terminal, 21... NAND type RS flip-flop, 31... Insulating section, 32... Electrode and brush equivalent circuit, 33... Switch contact of equivalent circuit, 34... Vc side contact of equivalent circuit, 35
...Equivalent circuit ground side contact, 36-38...Resistor, 39...Switch contact terminal, 40...
... Connection point, 41 ... Resistance, 42 ... Connection point, 43
~45...Resistor, 46...Inverter, Vc...
Power supply voltage, S...set terminal, R...reset terminal,...set terminal,...reset terminal.

Claims (1)

[Claims for Utility Model Registration] 1. A first electrode corresponding to a first logical value and a second electrode corresponding to a second logical value are arranged in the form of an alternating binary code in the sliding direction of the brush, and Respective outputs from the first and second electrodes are provided to a flip-flop so as to be set when the brush contacts the first electrode and reset when the brush contacts the second electrode; A variable digital output device characterized in that the output of a flip-flop is taken out as each bit output of a digital output. 2 Utility Model Registration The variable digital output device according to claim 1, characterized in that each output from the first and second electrodes is directly supplied to the flip-flop. 3 Utility Model Registration The variable digital output device according to claim 1, characterized in that each output from the first and second electrodes is supplied to the flip-flop via the brush. Output device.