JPH0441631Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a multipurpose adjustment circuit that adjusts a plurality of circuits.

[Prior Art] Measuring instruments such as oscilloscopes have been increasingly equipped with functions as a result of recent technological advances, and one instrument has come to have a wide variety of measurement functions. For that reason,
The number of push buttons and rotary knobs used to adjust each function is increased, increasing the area of operation pulses, but at the same time, there is also a strong demand for smaller measuring instruments. One way to simultaneously solve these conflicting demands is to reduce the number of adjustment knobs by allowing one adjustment knob to control multiple functions.

FIG. 2 is an example of a conventional circuit in which two circuits are controlled by one adjustment knob. The variable resistor 20 controlled by the adjustment knob can continuously output an adjustment voltage from -V to +V to the output terminal (movable contact terminal). The output terminal of the variable resistor 20 is connected to the switch 2
2 and the first input terminal of the comparator 23. The second input terminal of the comparator 23 has a reference voltage.
Vref is input. The output terminal of the comparator 23 is
The signal is input to a control circuit 24, and the output terminal of the control circuit 24 is connected to the control terminal of the switch 22. The first and second output terminals of the switch 22 are connected to regulated circuits 26a and 26b, respectively. Variable resistor 2
When the output voltage of 0 is lower than the reference voltage Vref, the output of the comparator 23 is in a low potential state, and when the output voltage of the variable resistor 20 exceeds Vref, the output of the comparator 23 changes to a high potential state. A control circuit 24 monitors the state of the output of the comparator 23, and alternately switches the connection state of the switch 22 every time the output of the comparator 23 becomes a high potential state. Further, in this case, the value of Vref is selected to be an appropriate value that is slightly lower than the value of +V. Therefore, the operator can alternately adjust the circuit to be adjusted 26a or 26b each time the operator rotates the adjustment knob to one end (+V) of the adjustment range of the adjustment knob.

[Problem to be solved by the invention] However, in this conventional adjustment circuit, the value of Vref must be set to a value slightly lower than the value of +V, so the entire variable range of the variable resistor 20 (+V
to -V) could not be used as an adjustment range. Furthermore, since the switch 22 is switched at a value slightly lower than +V, there is a risk that the switch 22 may be switched against the operator's intention and the selection of the circuit to be adjusted may be changed. Furthermore, since the relationship between the values of +V and Vref must be constant, the voltage in the variable range of the variable resistor 20 (+
V and -V) must be stable and constant voltages, and there are limitations in the circuit configuration, such as the resistance value of the variable resistor 20 itself not being available.

Therefore, the purpose of the present invention is to avoid using a comparator,
It is an object of the present invention to provide a multipurpose adjustment circuit which has a simple circuit configuration and eliminates the above-mentioned conventional drawbacks.

Another object of the present invention is to provide an improved multi-purpose adjustment circuit that allows a single adjustment knob to selectively adjust a plurality of circuits to be adjusted.

[Means and effects for solving the problem] In the present invention, a variable resistor that operates in conjunction with a switch element is used. A switch is provided between the output terminal of the variable resistor and the plurality of circuits to be adjusted, and the output terminal of the variable resistor is connected to any one of the plurality of circuits to be adjusted. A control circuit monitors the open/close state of a switch element that is interlocked with a variable resistor, and controls the connection state of a switch depending on the state.

When the movable contact of the variable resistor associated with the switch element is adjusted to a predetermined end of the movable range, the switch element opens; otherwise, the switch element closes. The control circuit switches the connection state of the switch each time the switch element is opened. Since a different circuit to be adjusted is selected each time the switch element is opened or closed, a plurality of circuits to be adjusted can be adjusted with one adjustment knob.

[Embodiment] FIG. 1 is a block diagram showing an embodiment of the present invention suitable for measurement equipment such as an oscilloscope.
The variable resistor 10 with a switch is a variable resistor 10a.
is interlocked with the switch element 10b, which are integrally constructed and controlled by one adjustment knob. The variable resistor 10a is connected, for example, between a reference potential source (ground) and a potential source (+V), and can use the entire range from 0 to +V as an adjustment range. The output terminal (movable contact terminal) of the variable resistor 10a is connected to the ground and the output is 0.
, that is, when the movable contact is adjusted to one predetermined end of its movable range, the interlocking switch element 10b opens. The output terminal of the variable resistor 10a is connected to a switch 12, which is an electronic switch such as a multiplexer, for example.
and the output terminal of the switch 12 is connected to the circuit to be adjusted 1.
Connected to 6. The circuit to be adjusted 16 includes, for example, a sweep circuit 16a of an oscilloscope and a holdoff circuit 16b, so that the sweep speed and holdoff time can be varied. The control circuit 14 detects the open/close state of the switch element 10b, and when the output terminal of the variable resistor 10a is connected to the ground and the output voltage becomes 0, the switch vehicle speed 10b becomes the open state in conjunction with this, and the control circuit 1
4 changes the connection state of the switch 12 every time a change in the switch element 10b to the open state is detected. In order to realize this operation, in the control circuit 14, for example, one end of the switch element 10b is grounded,
The other end is connected to the T terminal of the flip-flop, and the Q output terminal of the flip-flop is connected to the connection control terminal of the switch 12. Further, the T terminal of the flip-flop is connected to a positive power supply via a resistor. Therefore, the T terminal of the flip-flop receives a pulse whose level changes each time the switch element 10b is opened or closed, thereby changing the connection state of the switch 12. When the movable contact of the variable resistor 10a is adjusted to a predetermined end (ground) of the movable range, the switch element 10b becomes open, and since the output voltage of the variable resistor 10a is 0, it is input to the controlled circuit 16. The regulated voltage also becomes 0, and the controlled circuit 16 is in the calibration mode. When the operator moves the movable contact of the variable resistor 10a from a predetermined end (ground) in order to enter the adjustment mode in which the controlled circuit 16 is arbitrarily adjusted using the adjustment knob, the switch element 10b closes and the variable resistor 16 is closed. 10
The output voltage of a is adjusted to a desired value between 0 and +V in response to operator adjustment. When the switch element 10b closes and enters the adjustment mode, the control circuit 14
The T terminal of the flip-flop inside is grounded, but since this flip-flop inverts the state of the Q output only in response to the rising edge of the input pulse, even if the switch element 10b is closed, the connection state of the switch 12 remains unchanged. It does not change. Therefore, the operator can adjust the selected circuit to be adjusted at the time of switching to the previous calibration mode. That is, the operator can alternately adjust the two controlled circuits each time one adjustment knob is switched from adjustment mode to calibration mode. The entire variable range (from 0 to +V) of the variable resistor 10a is the adjustment range of this adjustment circuit. Furthermore, since the operator can reliably recognize the switching of the switch element 10b by the switching sound and the sensation of the hand, it is possible to prevent the circuit to be adjusted from being selected unintentionally. Furthermore, since no comparator is used, the voltage that determines the adjustment range of the variable resistor does not need to be a constant reference voltage.
There is no longer any restriction on circuit configuration as in the past.

FIG. 3 is a block diagram showing another embodiment of the present invention. The variable resistor with switch 30 is similar to the circuit shown in FIG. A plurality of adjusted circuits 36a,
Any one adjustment input terminal in the group of circuits to be adjusted 36 including 36b, . . . 36n and the variable resistor 30
The output terminal of a is selectively connected by a switch 32. The control circuit 34 changes the connection state of the switch 32 every time it detects a change in the switch element 30b to the open state. In the control circuit 34, for example, a counter is used, and the clock terminal of this counter is configured to receive pulses whose level changes by opening and closing of the switch element 30b, as in the case of the control circuit 14, and the count value of this counter is used to control the switching device 32.
The configuration may be such that the connection state of the terminals is changed sequentially and periodically. Alternatively, a microprocessor may be used as the control circuit to switch the switch 32 according to a predetermined program. The selection signal output from the control circuit 34 is also input to the display circuit 38. Since the display circuit 38 displays information representing the currently selected circuit to be adjusted, the operator can easily confirm the circuit to be adjusted. Furthermore, it is of course possible to provide a means for independently selecting the circuit to be adjusted, but according to the present invention, a plurality of circuits to be adjusted can be adjusted simply by using an adjustment knob having one interlocking switch without such a selection means. You can select and adjust the adjustment circuit.

Although the present invention has been described above based on examples, the present invention is not limited to the examples described herein, and various modifications and changes can be made without departing from the gist of the present invention. is clear to those skilled in the art. For example, one of the movable contact terminal and fixed contact terminal of a variable resistor can be used as a pair of control terminals, or both can be interconnected and used as one control terminal, and these control terminals can be used as a switch. Therefore, it can be easily applied to the case where the variable resistor is connected to one of the circuits to be adjusted and changes in the resistance value itself of the variable resistor are utilized.

[Effects of the invention] According to the invention, a switch element that operates in conjunction with a variable resistor is used, and the switch element is switched by adjusting the movable contact of the variable resistor to a predetermined end of the variable range using an adjustment knob. It is possible to select different circuits to be adjusted at a time and adjust a plurality of circuits to be adjusted with one adjustment knob. Therefore, although it has an extremely simple circuit configuration that does not use a comparator or a fixed reference voltage source, the entire variable range of the variable resistor can be used effectively, and the possibility of incorrect adjustment contrary to the operator's intention is prevented. It is possible to realize a multi-purpose adjustment circuit with increased versatility in terms of circuit configuration, such as by utilizing changes in the resistance value itself of the variable resistor.

[Brief explanation of drawings]

FIG. 1 is a block diagram of one embodiment of the present invention, FIG. 2 is a block diagram showing a conventional adjustment circuit that adjusts two circuits with one adjustment knob, and FIG.
The figure is a block diagram of another embodiment according to the present invention. 10, 30...Variable resistor with interlocking switch (1
0a, 30a...variable resistor, 10b, 30b...
...switch element), 12, 32... switch, 14,
34...Control circuit.

Claims (1)

[Claims for Utility Model Registration] A variable resistor interlocked with a switch element, a switch that selectively connects one of a plurality of circuits to be adjusted to an output terminal of the variable resistor, A multi-purpose adjustment circuit comprising: a control circuit that controls the switching device according to opening/closing.