CN108388303A - A kind of variable frequency square-wave generator - Google Patents
A kind of variable frequency square-wave generator Download PDFInfo
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- CN108388303A CN108388303A CN201810172864.XA CN201810172864A CN108388303A CN 108388303 A CN108388303 A CN 108388303A CN 201810172864 A CN201810172864 A CN 201810172864A CN 108388303 A CN108388303 A CN 108388303A
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- square wave
- resistance
- microcontroller
- power supplys
- connection
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F1/00—Details not covered by groups G06F3/00 - G06F13/00 and G06F21/00
- G06F1/02—Digital function generators
- G06F1/022—Waveform generators, i.e. devices for generating periodical functions of time, e.g. direct digital synthesizers
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- Engineering & Computer Science (AREA)
- Theoretical Computer Science (AREA)
- Physics & Mathematics (AREA)
- General Engineering & Computer Science (AREA)
- General Physics & Mathematics (AREA)
- Control Of Voltage And Current In General (AREA)
Abstract
The present invention discloses a kind of variable frequency square-wave generator, belongs to instrument field.Including microcontroller, digital regulation resistance, square wave generation circuit, display circuit and keyboard circuit；It is characterized in that：Square wave generation circuit generates square wave, and the frequency of square wave is adjusted by the resistance value that digital regulation resistance exports, and the resistance value of digital regulation resistance output is controlled by microcontroller；And the output of square wave generation circuit is connect with microcontroller, forms closed loop feedback control, microcontroller is controlled the output valve of digital regulation resistance by feedback signal, makes the frequency stabilization of square wave；Display circuit and keyboard circuit therein connect to show square wave frequency value and setting square wave frequency value with microcontroller.The present invention is replaced adjusting potentiometer for changing the common manual of square wave frequency with digital regulation resistance, so as to control the resistance value of digital regulation resistance by microcontroller, to realize the automatic function of changing square wave frequency.
Description
Technical field
A kind of variable frequency square-wave generator, belongs to instrument field, in various instrument and meters and control unit.
Background technology
Current instrument and meter or some control units mostly use microcontroller core in order to control, are produced with microcontroller itself
Raw variable frequency square-wave is possible, but is easy to bring unnecessary work load to microcontroller itself, this is to use one at present
A microcontroller core and needs to generate the problems of variable frequency square-wave in order to control；Electric type student electronics skill in university
Art Experiment Training equipment and single chip computer experiment training equipment are mutual indepedent, and Experiment Training resource is not combined together organically,
Experimental resources utilization rate is low, is a kind of wasting of resources, the knowledge of student's study is also without effectively, continuously, synthetically obtaining
Consolidate and applies.
Invention content
The present invention proposes a kind of square-wave generator for using digital regulation resistance as the adjusting potentiometer for changing square wave frequency, uses
Microcontroller controls the resistance value of digital regulation resistance, can change and stablize the frequency of square wave automatically in real time, mitigates with a monolithic
Machine is the work load of the instrument and meter of core or the microcontroller of control unit.
This invention takes following technical solutions：A kind of variable frequency square-wave generator, including microcontroller, digital current potential
Device, square wave generation circuit, display circuit and keyboard circuit, wherein square wave generation circuit generates square wave, and the frequency of square wave is by number
The resistance value of potentiometer output is adjusted, and the resistance value of digital regulation resistance output is controlled by microcontroller；And the output of square wave generation circuit with
Microcontroller connects, and forms closed loop feedback control, and microcontroller is controlled the output valve of digital regulation resistance by feedback signal, makes square wave
Frequency stabilization；Display circuit and keyboard circuit connect to show square wave frequency value and setting square wave frequency value with microcontroller.
The microcontroller uses the chip of model 89C52, and the digital regulation resistance is using model MAX5401's
Chip, side's wave generation circuit are made of operational amplifier, and operational amplifier uses the chip of model LM324, described
In closed loop feedback, diode D1, D2 and microcontroller that the output of square wave generation circuit is connected by dual serial are connected；Respectively
The connection of device is：6,7,8 feet of 89C52 are separately connected 5,4,3 feet of MAX5401, and 20 feet of 89C52 connect
Connect the ground of+5V power supplys, the 40 foot connection+5V power supplys of 89C52, the moon of the 5 feet connection diode D1 of 89C52
The anode of pole, diode D1 is connect with the cathode of diode D2,7,8 feet of MAX5401 link together and with two poles
The anode of pipe D2 connects, the 6 foot connection+5V power supplys of MAX5401, the 2 foot connection+5V power supplys of MAX5401
Ground, one end of the 1 foot connection resistance R1 of MAX5401, one end of the other end connection capacitance C of resistance R1 and
2 feet of LM324, the ground of the other end connection+5V power supplys of capacitance C, the 4 foot connection+12V power supplys of LM324,
The 11 foot connection -12V power supplys of LM324, the 3 feet connection resistance R2 of LM324, one end of resistance R3, resistance R2
Other end connection+5V power supplys ground, the other end connection resistance R4 of resistance R3, the one of bi-directional voltage stabilizing diode VZ
End, while also being connect with the anode of diode D2, the other end of the 1 foot connection resistance R4 of LM324, bi-directional voltage stabilizing two
The ground of the other end connection+5V power supplys of pole pipe VZ, the ground of+5V power supplys is also the ground of ± 12V power supplys.
Effect of the invention is that：Microcontroller controls to adjust the resistance value of digital regulation resistance, and electricity occurs to adjust square wave
The frequency for the square wave that road generates, so as to realize the automatic function of changing square wave frequency by programming.And it is reliable adjustment square wave
Frequency, a port that the output of square wave generation circuit is connected to microcontroller form closed-loop control, realize square wave frequency oneself
Dynamic stability.
Description of the drawings
The block diagram of Fig. 1 variable frequency square-wave generators.
One embodiment circuit diagram of Fig. 2 variable frequency square-wave generators.
Specific implementation mode
Below in conjunction with the accompanying drawings 1, the present invention is described in detail by Fig. 2, the circuit block diagram of variable frequency square-wave generator
As shown in Fig. 1, the circuit diagram of one embodiment of circuit occurs for variable frequency square-wave as shown in Fig. 2.It is single in Fig. 1
Piece machine connects digital regulation resistance, and microcontroller is with serial communication mode to digital regulation resistance transmission data, and digital regulation resistance is according to must
To transmission data the potentiometer of its inside is adjusted；Digital regulation resistance connection side's wave generation circuit refers to digital current potential
Three external connection ends of the potentiometer of its internal adjustable are connected in circuit and square-wave by device；Square wave generation circuit is according to digital electricity
The resistance value that position device provides generates the square wave of corresponding frequencies；Microcontroller passes through the connection with square wave generation circuit square wave output end
Come obtain square wave occur circuit output square wave frequency, the purpose is to for monitor square wave frequency whether reach control require, side
Whether wave generation circuit has square wave output, forms closed-loop control.
In Fig. 2, microcontroller uses chip model for MCS-89C52, digital regulation resistance use chip model for
MAX5401, the operational amplifier in square wave generation circuit use chip model for LM324；LM324 is used as hysteresis loop comparator,
1,7,8 feet of MAX5401 constitute the negative-feedback circuit of LM324 with resistance R1, capacitance C, and resistance R2, R3 are constituted
The positive-feedback circuit of LM324, resistance R4 are current-limiting resistances, and bi-directional voltage stabilizing diode VZ makes the amplitude of output voltage be limited
System is that the voltage of output+6V is dropped to+4.6V in ± 6V, diode D1, D2, so that monolithic function reciever wave exports
The voltage value of circuit output.Specifically connection is as follows for circuit：6,7,8 feet of 89C52 are separately connected 5,4, the 3 of MAX5401
Foot, the ground of the 20 foot connection+5V power supplys of 89C52, the 40 foot connection+5V power supplys of 89C52,5 feet of 89C52
The cathode of diode D1 is connected, the anode of diode D1 is connect with the cathode of diode D2,7,8 feet of MAX5401
It links together and is connect with the anode of diode D2, the 6 foot connection+5V power supplys of MAX5401, the 2 of MAX5401
The ground of foot connection+5V power supplys, one end of the 1 foot connection resistance R1 of MAX5401, the other end connection electricity of resistance R1
Hold 2 feet of one end and LM324 of C, 4 feet on the ground of the other end connection+5V power supplys of capacitance C, LM324 connect
+ 12V power supplys, the 11 foot connection -12V power supplys of LM324 are connect, 3 feet of LM324 connect one end of R2, R3, R2's
The ground of other end connection+5V power supplys, the other end connection resistance R4 of resistance R3, one end of bi-directional voltage stabilizing diode VZ,
It is also connect simultaneously with the anode of diode D2, the other end of the 1 foot connection resistance R4 of LM324, bi-directional voltage stabilizing diode
The ground of the other end connection+5V power supplys of VZ, the ground of+5V power supplys is also the ground of ± 12V power supplys.
Specific working mode is as follows：As shown in Fig. 2,3 feet of MAX5401 are chip selection signal end (low effective),
For 89C52 to before MAX5401 serially-transmitted datas, 89C52 exports low level by its 8 foot makes the 3 of MAX5401
Foot is low level, and 4 feet of MAX5401 are serial data inputs, and 5 feet of MAX5401 are clock (CLOCK) inputs
End.89C52 is stored with the program woven.Desired square wave frequency can be keyed in by keyboard, display portion can show key entry
Frequency, 89C52 is according to the frequency of key entry, and calculating the series that MAX5401 should be in, (MAX5401 is to its 100K Ω
Resistance is divided into 256 grades), then 4 foot serial transmissions of the 89C52 by its 7 foot to MAX5401 count accordingly
According to (concrete operations mode can refer to the operation instructions of MAX5401), MAX5401 adjusts its electricity according to obtained data
The sliding end of position device, square wave generation circuit generate the square wave of corresponding frequencies according to the resistance value of MAX5401.Pass through 89C52
5 feet and diode D1, D2, the square-wave feedback of circuit output is occurred into for square wave to 89C52,89C52 is according to the frequency of detection
Rate can be finely adjusted to calculating the series that MAX5401 should be in.Square wave generation circuit in the present invention is typical circuit,
Its working principle is that routine techniques.
Claims (2)
1. a kind of variable frequency square-wave generator, including microcontroller, digital regulation resistance, square wave generation circuit, display circuit and key
Disk circuit；It is characterized in that：Square wave generation circuit generates square wave, the resistance value tune that the frequency of square wave is exported by digital regulation resistance
The resistance value of section, digital regulation resistance output is controlled by microcontroller；And the output of square wave generation circuit is connect with microcontroller, formation is closed
Ring feedback control, microcontroller are controlled the output valve of digital regulation resistance by feedback signal, make the frequency stabilization of square wave；It is therein
Display circuit and keyboard circuit connect to show square wave frequency value and setting square wave frequency value with microcontroller.
2. according to a kind of variable frequency square-wave generator described in claim 1, it is characterised in that：The microcontroller uses
The chip of model 89C52, the digital regulation resistance use the chip of model MAX5401, side's wave generation circuit
It is made of operational amplifier, operational amplifier uses the chip of model LM324, and in the closed loop feedback, electricity occurs for square wave
Diode D1, D2 and microcontroller that the output on road is connected by dual serial are connected；The connection of each device is：89C52's
6,7,8 feet are separately connected 5,4,3 feet of MAX5401, the ground of the 20 foot connection+5V power supplys of 89C52,89C52's
40 foot connection+5V power supplys, the cathode of the 5 feet connection diode D1 of 89C52, the anode and diode of diode D1
The cathode of D2 connects, and 7,8 feet of MAX5401 link together and connect with the anode of diode D2, MAX5401's
6 foot connection+5V power supplys, the ground of the 2 foot connection+5V power supplys of MAX5401, the 1 foot connection resistance R1 of MAX5401
One end, 2 feet of one end and LM324 of the other end connection capacitance C of resistance R1, the other end connection of capacitance C
The ground of+5V power supplys, the 4 foot connection+12V power supplys of LM324, the 11 foot connection -12V power supplys of LM324, LM324
3 feet connection resistance R2, resistance R3 one end, the ground of the other end connection+5V power supplys of resistance R2, resistance R3
Other end connection resistance R4, bi-directional voltage stabilizing diode VZ one end, while also being connect with the anode of diode D2,
The other end of the 1 foot connection resistance R4 of LM324, the other end connection+5V power supplys of bi-directional voltage stabilizing diode VZ
Ground, the ground of+5V power supplys are also the ground of ± 12V power supplys.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810172864.XA CN108388303A (en) | 2018-03-01 | 2018-03-01 | A kind of variable frequency square-wave generator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810172864.XA CN108388303A (en) | 2018-03-01 | 2018-03-01 | A kind of variable frequency square-wave generator |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN108388303A true CN108388303A (en) | 2018-08-10 |
Family
ID=63070173
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201810172864.XA Withdrawn CN108388303A (en) | 2018-03-01 | 2018-03-01 | A kind of variable frequency square-wave generator |
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| Country | Link |
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| CN (1) | CN108388303A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116707495A (en) * | 2023-07-12 | 2023-09-05 | 湖南师范大学 | Frequency and amplitude adjustable triangular wave generating circuit based on memristor |
-
2018
- 2018-03-01 CN CN201810172864.XA patent/CN108388303A/en not_active Withdrawn
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116707495A (en) * | 2023-07-12 | 2023-09-05 | 湖南师范大学 | Frequency and amplitude adjustable triangular wave generating circuit based on memristor |
| CN116707495B (en) * | 2023-07-12 | 2024-03-26 | 湖南师范大学 | Frequency and amplitude adjustable triangular wave generating circuit based on memristor |
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Legal Events
| Date | Code | Title | Description |
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| PB01 | Publication | ||
| PB01 | Publication | ||
| WW01 | Invention patent application withdrawn after publication |
Application publication date: 20180810 |
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| WW01 | Invention patent application withdrawn after publication |