CN103235178A - Double-button equal-precision frequency meter and calculating method thereof - Google Patents
Double-button equal-precision frequency meter and calculating method thereof Download PDFInfo
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- CN103235178A CN103235178A CN2013101508149A CN201310150814A CN103235178A CN 103235178 A CN103235178 A CN 103235178A CN 2013101508149 A CN2013101508149 A CN 2013101508149A CN 201310150814 A CN201310150814 A CN 201310150814A CN 103235178 A CN103235178 A CN 103235178A
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Abstract
The invention provides a double-button equal-precision frequency meter and a calculating method thereof. The frequency meter comprises a button module and a tested signal processing circuit, wherein the tested signal processing circuit comprises a pulse shaping module, a frequency-dividing module, a single-chip machine module, a driving module and a display module. By a single-chip machine, the problems of relatively excessive functional keys, relatively large size, complex operation, non-ideal measuring precision, low intelligence degree and the like of the ordinary frequency meter are solved.
Description
Technical field
The present invention relates to the electronic metering equipment of signal frequency, is high precision frequency meter implementation methods such as a kind of pair of button specifically.
Background technology
Present common frequency meter, button is more, count example with common F2700L model frequency, except outside the Pass, keep in addition, reset, more than ten mechanical type function buttons such as gate 1s, gate 0.1s, gate 0.01s, cycle, passage A, channel B, decay 1, decay 2, these buttons also are divided into 4 groups of piano type interlock switchs, at one time can only be by next button and self-locking, to connect circuit contact in every group.Too many button makes that the instrument volume is bigger, and button then can be operated inconvenience if arrangement is too tight.In addition, because internal circuit adopts the integrated formation of digital gate, circuit is complicated and intelligent degree is lower.
The single-chip microcomputer frequency measurement is at present modal to be the gate counting method or to survey all methods, counting method refers to that direct ten numbers go out the number of measured signal pulse in specified gate time, survey all methods and refer to that one-period with signal is as time gate, count out the number of clock signal pulse, because always there is the quantization error of intrinsic ± 1 in the number of pulses that counts out, this makes no matter be counting method or all methods of survey, its measuring accuracy numerical value all can rise and fall very big along with the height of measured signal frequency.
Summary of the invention
The present invention is for solving the problems of the technologies described above, high precision frequency meter and computing method thereof such as a kind of pair of button are provided, utilize single-chip microcomputer, problem such as solve that common frequency counter function button is more, volume is big, complex operation, undesirable, the intelligent degree of measuring accuracy are low.
The present invention is that the technical scheme that the deficiency that solves the problems of the technologies described above adopts is: high precision frequency meters such as a kind of pair of button, comprise key-press module and measured signal treatment circuit, the measured signal treatment circuit comprises the shaping pulse module, frequency division module, one-chip computer module, driver module and display module, the Shaping Module input end is connected with passage A, output terminal is connected with single-chip microcomputer, the frequency division module input end is connected with channel B, output terminal is connected with Shaping Module, key-press module is made up of button A and button B, and the electric terminal of button A and button B links to each other with two pins of single-chip microcomputer respectively.
The computing method of a kind of pair of high precision frequency meter such as button:
As Fig. 4, open negative saltus step first when frequency measurement begins earlier and interrupt (a point is constantly), treat f
x(b) triggered first the interruption when first negative edge of pulse arrived, and opened time gate (c) by first interruption subroutine, began measured signal pulse and machine cycle pulse are counted respectively.
Opening tail time negative saltus step in rolling counters forward (d) to the specified gate time interrupts, last negative edge arrival (e) for the treatment of measured pulse triggers the tail interruption, by tail interruption subroutine shut-in time gate (f), stop measured signal pulse and machine cycle pulse are counted respectively.
Maintenance of the present invention is interrupted first occurring to and is played time that time gate opens and tail time interruption and occur to the time that time gate closes and equate, i.e. T
Bc=T
Ef
Described negative saltus step interruption first of the present invention and tail time negative saltus step interruption CPU program pointer before triggering all is directed into a special one-cycle instruction execution area.
In the time-delay process that one-cycle instruction execution area of the present invention is arranged in every number during lighting.
Beneficial effect of the present invention is:
1, the present invention with the maintenance beyond the common frequency meter power switch, reset, a plurality of function buttons such as gate 1s, gate 0.1s, gate 0.01s, cycle, passage A, channel B, decay 1, decay 2, change into 2 and touch button, reduced the instrument volume, given prominence to the panel demonstration, make more convenient operation and be easy to observation, also more elegant in appearance.
2, the present invention uses single-chip microcomputer to be core, replaces complicated numeric door control circuit, and it is simple that circuit is constituted, and effectively realizes miniaturization, high precision int, the intellectuality of frequency measurement instrument.Because the measurement gate time of determining, the measured signal number of pulses of sampling simultaneously once and machine cycle number of pulses, and can eliminate the quantization error of measured signal number of pulses, thereby make measuring error remain the machine cycle of a single-chip microcomputer, realize the measurement of high precision such as each frequency.Can select to arrange automatically metering system during operation, also can select manually to arrange metering system, to adapt to different personalization test needs.
Description of drawings
Fig. 1 is two keying frequency meter synoptic diagram;
Fig. 2 is each modular structure connection layout of circuit;
Fig. 3 is for being the circuit module johning knot composition of example with 80C51;
Fig. 4 is execution process instruction figure;
Among the figure: 1, passage A, 2, channel B, 3, button A, 4, button B, 5, power switch.
Embodiment
Two button designs: as Fig. 1, Fig. 2, self-locking after power switch is pressed continues to connect circuit.Press on ﹠ off switch again, the on ﹠ off switch release is upspring, and circuit is cut off power supply.Key-press module touches button by two to be formed, and the internal electric contact of two buttons links to each other with single-chip microcomputer respectively.The CPU of single-chip microcomputer during operation, detect the electric state of above-mentioned two buttons, according to the current state of living in of system with to the testing result of button contact, demonstrate corresponding measurement code information immediately, glimmer after several seconds, change into the metering system consistent with code and displaying contents thereupon.The instrument start is in the most frequently used acquiescence and measures state, and every setting is selected parameter by the single-chip microcomputer basis automatically to the testing result of signal; But also can enter every by artificial set condition by operation.Above-mentioned two states also can switch at any time by button operation.
The high accuracy frequency measurement design: as Fig. 1, Fig. 2, the measured signal treatment circuit is divided into five circuit modules: Shaping Module, frequency division module, one-chip computer module, driver module and display module.The Shaping Module input end is connected with passage A, and output terminal is connected with single-chip microcomputer.The frequency division module input end is connected with channel B, and output terminal is connected with Shaping Module.The driver module input end is connected with single-chip microcomputer, and output terminal is connected with display module.After measured signal is delivered to pulse shaping circuit after through (perhaps without) frequency dividing circuit and handled, be transformed to f
xSquare-wave signal is connected with single-chip microcomputer, and in the measurement gate time of determining, f once simultaneously samples
xNumber of pulses and single-chip microcomputer machine cycle T
mNumber of pulses is located at inside counting gate time value and is respectively N
xWith N
m, N is then arranged
x/ f
x=N
m/ f
m, can get f
x=N
x/ (N
m* T
m) or f
m* N
x/ N
mBecause the start-stop of counting gate time all is controlled by former and later two negative edges of measured signal, can eliminate N
xThe quantization error of value, and to T
mCounting be passive stopping, N
mAlso just there is ± 1 quantization error in value.Because T
mBeing worth generally lessly, and is a constant, has so also just realized the error amount that each frequency equates.
For making the purpose, technical solutions and advantages of the present invention more clear, further specify below, those skilled in the art can understand and enforceable degree to reach, and concrete example and data related in the explanation all are not used in limitation of the invention.
5.0.0 be and touch button as Fig. 3,4, two buttons, " button 1 " is connected through the 10k Ohmage P3.0 pin of single-chip microcomputer 80C51 when being pressed with+5V power supply, " button 1 " when upspringing, the P3.0 pin is unsettled; " button 2 " is connected through the 10k Ohmage P3.1 pin of single-chip microcomputer when being pressed with+5V power supply, " button 2 " when upspringing, the P3.1 pin is unsettled.The CPU of single-chip microcomputer detects the level state of P3.0 pin and P3.1 pin during operation.The button time of being pressed is less than 0.5s and is judged as a little and touches, more than or equal to be judged as in 0.5 second long by.After button is put tactile or long pressing, single-chip microcomputer is according to the current state of living in of system with to the testing result of button contact (P3.0 and P3.1), demonstrate corresponding code signal immediately, glimmer after 3 seconds, namely change into the metering system consistent with code and displaying contents thereupon.
5.0.1 code with F * * * C * A * or with P000C * A * formal representation, wherein F is frequency measurement, * * * be to select gate time, C * be channel selecting, A * be that decay is selected, P000 is measuring period." button 1 " mainly is in charge of preceding 4 of code, and " button 2 " mainly is in charge of C * A * content.
5.0.2 measured signal inserts passage A or channel B before measurement, but also can insert or the change passage in measuring process.Direct input mode in the passage A corresponding circuits is used for measuring low frequency signals; The corresponding frequency division input mode of channel B is used for measuring than the high frequency signal of the specified frequency measurement scope of passage A.Usually measured signal should be inserted the passage of its frequency correspondence, if the unknown of measured signal frequency approximate range, can be earlier with its exploratory access B passage, then according to showing the result, whether determine reconfiguration passage A.Passage A is the direct measurement without frequency division, so preferential selector channel A.But the direct measured frequency upper limit of passage A fixes on really among 5.2.4 and the 5.2.6 and specifies.
5.0.3 instrument start acquiescence is in the state of the acquiescence survey frequency of being the most frequently used gate 1s, all the other every by inner single-chip microcomputer according to the testing result of signal is selected parameters automatically; But also can enter parameters by the artificial state of setting by operation, and can switch two states at any time by button operation.
Below to operating concrete introduction:
5.1.0 after turning on the power switch, display screen fast blink formula (with the 0.5 second quickflashing in interval) shows that F001CxAx(is that F is frequency measurement, 001 is that selection gate 1s, Cx and Ax are that single-chip microcomputer is according to passage and attenuation parameter that the testing result of input signal is recommended), continue after 3 seconds, if other operations of nothing just enter the kinetic measurement and dynamic show state of gate 1s, passage x, decay x automatically.
5.1.1 during lasting 3 seconds of 5.1.0, point touches (less than 0.5 second time, as follows) " button 1 ", flash type shows F001C1A1, continues after 3 seconds if other operations of nothing just enter the kinetic measurement and dynamic show state of gate 1s, passage 1, decay 1 automatically.
5.1.2 during lasting 3 seconds of 5.1.1, put and touch " button 1 ", flash type shows F00.1C1A1, continues just to enter automatically as if other operations of nothing after 3 seconds kinetic measurement and the dynamic show state of gate 0.1s, passage 1, decay 1.
5.1.3 during lasting 3 seconds of 5.1.2, put and touch " button 1 ", flash type shows F0.01C1A1, continues just to enter automatically as if other operations of nothing after 3 seconds kinetic measurement and the dynamic show state of gate 0.01s, passage 1, decay 1.
5.1.4 continuing during 3 seconds of 5.1.3, point touches " button 1 ", flash type shows P000 C1A1, continues after 3 seconds if do not have that other operations just do not enter measuring period automatically, a kinetic measurement of passage 1, decay 1 and dynamic show state.
5.1.5 during lasting 3 seconds of 5.1.4, point touches " button 1 ", flash type shows F001C1A1, namely enters the 5.1.1 process again.
5.1.6 continuing between 3 seconds of 5.1.1, put and touch " button 2 ", flash type shows F001C1A2, continues after 3 seconds, if other operations of nothing just enter the kinetic measurement and dynamic show state of gate 1s, passage 1, decay 2 automatically.
As if continuing to touch " button 2 " between 3 seconds again last one, flash type shows F001C2A1, if other operations of nothing just enter the kinetic measurement and dynamic show state of gate 1s, passage 2, decay 1 automatically.
As if continuing to touch " button 2 " between 3 seconds again last one, flash type shows F001C2A2, if other operations of nothing just enter the kinetic measurement and dynamic show state of gate 1s, passage 2, decay 2 automatically.
As if continuing to touch " button 2 " between 3 seconds again last one, flash type shows F001C1A1, if other operations of nothing just enter the kinetic measurement and dynamic show state of gate 1s, passage 1, decay 1 automatically.
If continue to touch " button 2 " between 3 seconds again last one, flash type shows F001C1A2, namely enters the 5.1.6 process again.
5.1.7 during lasting 3 seconds of 5.1.2, put and touch " button 2 ", flash type shows F00.1C1A2, continues after 3 seconds, just enters kinetic measurement and the dynamic show state of gate 0.1s, passage 1, decay 2 automatically as if other operations of nothing.
As if continuing to touch " button 2 " between 3 seconds again last one, flash type shows F00.1C2A1, if other operations of nothing just enter the kinetic measurement and dynamic show state of gate 0.1s, passage 2, decay 1 automatically.
As if continuing to touch " button 2 " between 3 seconds again last one, flash type shows F00.1C2A2, if other operations of nothing just enter the kinetic measurement and dynamic show state of gate 0.1s, passage 2, decay 2 automatically.
As if continuing to touch " button 2 " between 3 seconds again last one, flash type shows F00.1C1A1, if other operations of nothing just enter the kinetic measurement and dynamic show state of gate 0.1s, passage 1, decay 1 automatically.
If continue to touch " button 2 " between 3 seconds again last one, flash type shows F00.1C1A2, namely enters the 5.1.7 process again.
5.1.8 during lasting 3 seconds of 5.1.3, put and touch " button 2 ", flash type shows F0.01C1A2, continues after 3 seconds, just enters kinetic measurement and the dynamic show state of gate 0.01s, passage 1, decay 2 automatically as if other operations of nothing.
As if continuing to touch " button 2 " between 3 seconds again last one, flash type shows F0.01C2A1, if other operations of nothing just enter the kinetic measurement and dynamic show state of gate 0.01s, passage 2, decay 1 automatically.
As if continuing to touch " button 2 " between 3 seconds again last one, flash type shows F0.01C2A2, if other operations of nothing just enter the kinetic measurement and dynamic show state of gate 0.01s, passage 2, decay 2 automatically.
As if continuing to touch " button 2 " between 3 seconds again last one, flash type shows F0.01C1A1, if other operations of nothing just enter the kinetic measurement and dynamic show state of gate 0.01s, passage 1, decay 1 automatically.
If continue to touch " button 2 " between 3 seconds again last one, flash type shows F0.01C1A2, namely enters the 5.1.8 process again.
5.1.9 continuing during 3 seconds of 5.1.4, point touches " button 2 ", flash type shows P000C1A2, continues after 3 seconds, if do not have that other operations just enter measuring period automatically, a kinetic measurement of passage 1, decay 2 and dynamic show state.
If continue to touch " button 2 " between 3 seconds again last one, flash type shows P000C2A1, if do not have that other operations just enter measuring period automatically, kinetic measurement and a dynamic show state of passage 2, decay 1.
If last one continue touch " button 2 " between 3 seconds again, flash type shows P000C2A2, if do not have that other operations just enter measuring period automatically, kinetic measurement and a dynamic show state of passage 2, decay 2.
If last one continue touch " button 2 " between 3 seconds again, flash type shows P000C1A1, if do not have that other operations just enter measuring period automatically, kinetic measurement and a dynamic show state of passage 1, decay 1.
If touch between last one lasting 3 seconds " button 2 ", flash type shows P000C1A2, namely enters the 5.1.9 process again again.
5.1.10 in the kinetic measurement 5.1-5.9 and the dynamic show state, point touches " button 1 ", quickflashing shows the current measuring state code, namely enters one of state of 5.1-5.5.
5.1.11 in the kinetic measurement 5.1-5.9 and the dynamic show state, point touches " button 2 ", enters the locking display mode under precondition.Touch " button 2 ", the display mode that unlocks is recovered the dynamic display types under precondition again.
5.1.12 in the kinetic measurement 5.1-5.9 and the dynamic show state, longly surpass 0.5 second by " button 2 ", system resets, after enter 5.1 states automatically.
5.1.13 in the kinetic measurement 5.1-5.9 and the dynamic show state, long press " button 1 " was above 0.5 second.Can change the measurement state being set automatically and manually arranging between the measurement state.
Below instruction process during to precision frequency measurements such as single-chip microcomputer carry out further specify, to reach the degree that those skilled in the art can understand and can specifically implement.
5.2.1 as Fig. 3,4, after measured signal is delivered to pulse shaping circuit after through (perhaps without) frequency dividing circuit and handled, be transformed to f
xSquare-wave signal and single-chip microcomputer
,
, T1 connects, T1 is used for the counter mode.T0 does not connect external circuit, only is used for the timer mode, to machine cycle T
mPulse (is that frequency is f
m) counting.
5.2.2 open earlier when frequency measurement begins
(a point constantly) interrupted in negative saltus step, treats f
x(b) triggered first and interrupts when first negative edge of pulse arrived
, open time gate (c) and close this interruption by this interruption subroutine.The machine cycle counted number of pulses of T0 is N
m, the measured signal counted number of pulses of T1 is N
x(d) opens before T0 counts up to specified gate time
Negative saltus step is interrupted, and treats f
xNegative edge arrive (e) trigger tail and interrupt
, by this interruption subroutine shut-in time gate (f) and close this interruption.Then, calculate tested frequency f
x=f
mN
x/ N
mSend BCD transcoding program, deliver to driving circuit again, deliver to display circuit at last.
5.2.2 have only maintenance T
Bc=T
EfCould guarantee T
m/ T
CfTheoretical precision, for this reason, can control twice down trigger before CPU all be in the one-cycle instruction executing state so that twice interrupt response is definite 3T
mCan before twice down trigger of head and the tail, all earlier program pointer be directed to a special one-cycle instruction execution area (hereinafter to be referred as districts such as lists) circular wait and interrupt taking place.This zone should shield interruption if there are 2 cycles per instructions when then carrying out.
5.2.3 for improving program efficiency, in the time-delay process during district such as single can being arranged in every number and lighting.
5.2.4 control T1 moves as early as possible, the high precision frequency measurement upper limits such as ability broadening, and because being triggered to from interruption in the time of T1 action, measured pulse should not be counted again, otherwise can bring than mistake.Instructions such as SETB TR1 and CLR TR1 should be placed directly in 003H and 0013H interruption entrance (two porch have 8 address locations to use respectively) with the ORG pseudoinstruction, to guarantee that from interrupting being triggered to the T1 action be to be 4 T the shortest time
m, the frequency measurement upper limit of this numerical value respective channel A, and then carry out all the other non-critical items with the LJMP instruction program of turning.
5.2.5 if tail interrupts
Be nested in T0 and overflow for the last time in the interruption, should put
Interrupt preferential.When T0 overflows for the last time, also should carry out and once shift out T1 low level count value and clear command, in order to avoid T1 overflows and with tail contention interrupt to take place or produce hardware length disturbance interrupted response cycles such as 2 cycles per instructions such as to call by chance.
5.2.6 whole assembly instructions of above process are all passed through the PROTEUS software verification, validate result is correct.At present a lot of single-chip microcomputer frequency of operation have surpassed 30MHz, and selecting frequency of operation with single-chip microcomputer is that 30MHz is example, if regularly 1s frequency measurement, it will be no more than (Df/f) in the counting frequency measurement error that directly can survey scope 0-7.5MHz
Max=± 3.3 * 10
-8Enable frequency dividing circuit, can measure wideer scope, the multiple of frequency division is made needs according to reality and is decided.
Claims (7)
1. high precision frequency meters such as two buttons, it is characterized in that: comprise key-press module and measured signal treatment circuit, the measured signal treatment circuit comprises shaping pulse module, frequency division module, one-chip computer module, driver module and display module, the Shaping Module input end is connected with passage A, output terminal is connected with single-chip microcomputer, the frequency division module input end is connected with channel B, and output terminal is connected with Shaping Module, and key-press module is made up of button A and button B.
2. high precision frequency meter such as a kind of pair of button as claimed in claim 1, it is characterized in that: the electric terminal of described button A and button B links to each other with two pins of single-chip microcomputer respectively.
3. according to the computing method of high precision frequency meters such as right 1 described a kind of pair of button, it is characterized in that:
Open negative saltus step first when frequency measurement begins earlier and interrupt (a point constantly), treat f
x(b) triggered first the interruption when first negative edge of pulse arrived, and opened time gate (c) by first interruption subroutine, began measured signal pulse and machine cycle pulse are counted respectively.
4. opening tail time negative saltus step in rolling counters forward (d) to the specified gate time interrupts, last negative edge arrival (e) for the treatment of measured pulse triggers the tail interruption, by tail interruption subroutine shut-in time gate (f), stop measured signal pulse and machine cycle pulse are counted respectively.
5. according to the computing method of high precision frequency meters such as right 3 described a kind of pair of buttons, it is characterized in that: described maintenance is interrupted first occurring to and is played time that time gate opens and tail time interruption and occur to the time that time gate closes and equate, i.e. T
Bc=T
Ef
6. according to the computing method of high precision frequency meters such as right 3 described a kind of pair of buttons, it is characterized in that: described negative saltus step interruption first and tail time negative saltus step interruption CPU program pointer before triggering all is directed into a special one-cycle instruction execution area.
7. according to the computing method of high precision frequency meters such as right 3 described a kind of pair of buttons, it is characterized in that: in the time-delay process that described one-cycle instruction execution area is arranged in every number during lighting.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN103954835A (en) * | 2014-03-25 | 2014-07-30 | 苏州经贸职业技术学院 | Frequency display apparatus and work method thereof |
| CN107064631A (en) * | 2017-03-21 | 2017-08-18 | 昆明理工大学 | A kind of SCM Based high-precision frequency meter realizes circuit and method |
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| CN103954835A (en) * | 2014-03-25 | 2014-07-30 | 苏州经贸职业技术学院 | Frequency display apparatus and work method thereof |
| CN107064631A (en) * | 2017-03-21 | 2017-08-18 | 昆明理工大学 | A kind of SCM Based high-precision frequency meter realizes circuit and method |
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Application publication date: 20130807 |